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So since getting my humble 2A3 amplifier going on the weekend (see my other post), I have been bitten by the SET bug. One item which seems to pop up as a low hanging fruit, in terms of improvements, are the 2A3 tubes themselves. Unlike other modifications which require some actual effort on my behalf, new tubes are a no brainer... plug and play, all I need to do is make sure the bias looks good. Plus, If I am using this amplifier regularly it would be foolish to not have a spare set on hand... it boarders on a small tragedy when a tube goes south and the replacement is days or weeks away!I have a pair of Valve Art bi-plate style Chinese 2A3's. These are the cheap ones which were sold through the 90s, for around $15 a tube, and apparently exist no longer as new production (at least I can't find any)
Now, keep in mind that I haven't looked into buying triodes for almost ten years... the landscape has changed a lot. Gone are the affordable used RCA tubes, and the bargain basement Chinese ones.
In their place is an almost bewildering selection of moderately to extremely expensive options which are sold with all the fanfare of Swiss automatic watches or high dollar olive oil, or cigars, rather than mere electronic parts. Shopping for tubes I feel sorry for anyone restoring a 1930s radio, however unlike ten years ago I can certainly spring for a luxury product now and again!
Okay down to the actual point... which new production 2A3 would you buy with your money, for your amplifier? How about with my money, for my amplifier? The Treasure series looks great, but something inside me says don't waste a lot of money on anything from China! (I once bought a set of Chinese 807s and they died dramatically one by one in my RCA mono theatre amps)
Edits: 11/24/14Follow Ups:
First, fhese are some visually impressive tubes! Open the box and there is an individual test sheet with a serial number on it. Under a piece of foam is the tube itself, sparkling clean and not a mark on it. I pulled it out of the box, and was surprised and impressed by the size and weight of the tube! If dwarfs a normal 2A3.Sound is fantastic. A hard thing to quantify but it definitely sounds better than the old valve art tubes and I would say it could possibly be more powerful too.
Edits: 12/04/14
Max,
If you only buy one pair of 2a3 tubes, make it the EH 2a3 Gold Grid. Then you can go as crazy as you want.
They are better than any bi-plate ever made, and 95% of everything else.
$120
Trust me on this one.
Jamie
Big speakers and little amps blew my mind!
I use these Sovtek/EH (premium Sovtek) types for "dinking around". Cheap-tube initial fire-up of a new piece before it's tested.If all voltages and currents are spot-on, these go out, and JJ 2A3-40 go in.
I have tried to listen to these-- EH2A3's-- they give you a listenable slice of the midrange-- they are Sovteks that have been gold-gridded and improved in other areas-- premium Sovteks.
Alas! As soon as the JJ or the EML gets in the door, these go into the Closet-- they gather dust there until a new amp needs initial fire-up.
Typically, I buy 5 in order to get a usable pair-- if I'm lucky--- TWO pair? Typically, one of the 5 is no good at all.
I have used over 75 JJ's now, and have not found ONE bad one! I do, however, never send out ones that have loosely-stretched filaments in them. I don't like the higher distortion sound, although it's never bad.
I have used about 55 EML's. Again, not a single bad one! (but I do get some loose ones which I keep around here and abuse at will-- these will NOT go out to customers-- only the best ones-- the tight ones that "ring" identically (as close as I can get them) are for that.
We get what we pay for.
---Dennis---
Edits: 11/25/14
"they are Sovteks that have been gold-gridded and improved in other areas-- premium Sovteks"
What are the "improved in other areas?" Did you speak with someone at New Sensor?
I recommended these because AFAIK they are drop in replacements for a stock 2a3. Maybe not exact but very close. The 2a3-40 seem to be a different beast which would have different load lines. Maxhifi may have to get the pencils and paper out. I know a 2a3-40 will work in a 2a3 circuit, but is it optimized?
Jamie
Big speakers and little amps blew my mind!
"The 2a3-40 seem to be a different beast which would have different load lines."
I don't understand why the myth that the JJ 2A3-40 is not a 2A3 continues to be perpetuted. It's not as if the plate curves are a secret; see the link below. Yes, it has a 300B plate but if you actually use the tube in circuit you will find that it conforms to the 2A3 plate curves. Want to operate the tube at 250V with a cathode current of 60mA? Fix the bias at -45V and you are good to go.
I continue to be amused by people that proclaim any one tube variant to be "the best." How can anyone make that claim without hearing every variant at multiple operating points?
I looked at the curves before I hit "buy"
Is your nickname on here a wireless world reference? If so that's pretty cool.
Cathode Ray Tube,
"Yes, it has a 300B plate but if you actually use the tube in circuit you will find that it conforms to the 2A3 plate curves. "
I'll be happy to take the hit, and say I didn't know that. Thank you for pointing out that very important fact.
"I continue to be amused by people that proclaim any one tube variant to be "the best." How can anyone make that claim without hearing every variant at multiple operating points?"
True, but how many people have done that. Then how many of those have written it down, then published it? Thorsten Loesch might do something like that, but then no one would believe him.
Jamie
Big speakers and little amps blew my mind!
On sale at antique electronic supply, went for a matched pair... can't wait for them to show up!
I've tried
Old Stock Sylvania 2A3
Sovtek 2A3
Shuguang 2A3C
JJ 2A3-40
Sophia 2A3 Mesh Plate (perf plate in reality)If it were me and my money, or me and your money, I'd buy either the JJ or Sophia (probably the JJ), although the Shuguang is very close.
The difference between Sylvaina or Sovtek and JJ is significant in my system.
The pic shows Sylvania, Sovtek, Shuguang, JJ
Edits: 11/24/14
I am not set up to test tubes, but my friend Dennis Fraker has been a big 2A3 tube buyer, over the years. It seems he bought 40 pieces of AVVT mesh plates one time, long ago !!!
Dennis regularly RAVES about how good the JJ 2A3-40 is in his latest amps.
He says he is tremendously happy with them, and considers them to to be the deal ( or steal ) of our times in tubes. Now this is a person who has uber experience with 2A3s, from the Harp vintage RCAs on up. According to Dennis, now a days, its a no-brainer ...just order the JJs !!
A week ago, unsolicted, he was RAVING to me on the phone about how much performance he gets with the JJs. He owns EML mesh, AVVT mesh, etc, but he USES the JJs and is simply excited about "that much tube" for $115.
There is a ten percent sale an Antique Electronic for a few more days, I think till month end. They stock JJs, and are nice people to do business with.
I hope this helps the original poster. If you run them conservatively as we do, 250 VDC P-K at 42 to 43 mA., these will last till your Grand Kids inherit your amp !! JJ 2A3-40s are going into my most current build .
Jeff Medwin
.
"In the beginner's mind there are many possibilities, in the expert's mind there are few." Shunryo Suzuki
after all the fuss about their pentodes' reliability.
Observe, before you think. Think before you open your yap. Act on the basis of experience.
... that concerns about reliability are justified. Mine have pins that are too large diameter and are a bit rough; the bases seem loose. The tube matching specs are not as detailed as EML, but I guess that is fine for the price. You would probably be OK if you got them from someone who checks and tests thoroughly.I just received my EML 2A3 solid plates... I don't know how long they take to burn in or even if they need to... or whether I will enjoy them in the longer term. But, they make me want to get all funky without the enhanced yet mildly soft bass and highlighted sibilance of the JJs. I have also been able to adjust hum lower than with other tubes (~2mV and ~1mV noise with AC fils - not bad), but the pot positions are quite different to the EML 2A3Ms (I would not entrust hum mitigation to CT transformers alone - tubes vary too much!). These EML 2A3-S tubes could become my daily drives - in my amp they should last for a very long time!
Cheers.
"In the beginner's mind there are many possibilities, in the expert's mind there are few." Shunryo Suzuki
Edits: 11/26/14 11/26/14 11/26/14 11/26/14
My understanding is that they are JJ 300Bs with the 300B 5v filament folded for the 2.5v and bang, you're a 2A3. So running them at 2A3 points they will last a long time.
But I have also heard that most current production 2A3s are really 300Bs, so IDK...
And it may be true for SOME Russian tubes, or some Chinese tubes but I don't think it applies to ALL 2A3 tubes because I have as pair of 2.5V 300B's which were sold as 300B's and the same firm made 2A3's and claimed that the tubes were completely different regards operating points.That said I HAVE run Russian 2A3's in my 300B amps (which I build with both 5V DC filaments as well as an optional 2.5V AC filament supply) and they did not sound bad. J.C.Morrison of New Sensor said they would not last long as the cathodes were not made to be run at 300B operating points.
Edits: 11/26/14
Hi Jeff,
I must have read your mind - AES has been my preferred vendor
For over 20 years now, the Sale just solidified their place. My output transformers (sowter sa02) are good for 45mA and I have 280V of B+ to work with, so basically spot on exactly how you use them.
-Max
You really can't go very wrong with the standard Shugang or the Sovtek 2A3, unless you want to spend a lot of money. If so, my listening preference would be for the EML hard plate, given that the AVVT meshplate is no longer available.
Observe, before you think. Think before you open your yap. Act on the basis of experience.
New production. I have run Shuggie 2A3C (which at one stage were well regarded), JJ2A3-40, EML 2A3M; I am awaiting delivery of EML 2A3-S. Each of the types I have tried have noticeably different sonics and I have a firm favourite in the context of my amp.Caveats re EML tubes
In a directly-coupled amp, the EMLs require their filaments be lit up before full B+ applied; easily achived with a slow start-up of the B+.
A consensus is evolving that the EML 2A3-M is best run at non-classical operating points... but I suspect this is so for most 2A3s (and 300Bs).
Cheers.
"In the beginner's mind there are many possibilities, in the expert's mind there are few." Shunryo Suzuki
Edits: 11/24/14
do you mind sharing your listening experience about EML 2a3 vs vintage black plate 2A3?
I am too using a DC 2a3 and itch to get a pair EML but man $ 700 for a pair, it can almost get me a pair of mono plate RCA.
Thanks
Sorry mate, have not tried any NOS. I hope to some day, but not yet.
I can say that the EML 2A3Ms are my favourites in my current amp, which runs them at ~51mA plate current (interestingly, the EMLs draw more current than the JJ 2A3).
The JJs are the dynamic expanders. They seem to simplify then expand the sonic presentation. Even dynamically-compressed music gives the impression of, well, dynamics. However, quiet music never seems quiet enough. The bass also seems a little enhanced, which klikely contributes to a sense of dynamics at low volume.
The EML meshies are more transparent, more nuanced and generally more musically expressive than other 2A3s I have tried; musical. Initially I wished for more dynamics, but that is rarely the case any more... mostly when I listen to pop music at low volumes; thankfully,dynamics seem to scale well with volume, so not really an issue.
I am curious to hear the EML 2A3-S, which should arrive any day now.
Not what you asked for, but hopefully this helps.
Cheers.
"In the beginner's mind there are many possibilities, in the expert's mind there are few." Shunryo Suzuki
thanks pal for the information.
I also have DC 2a3, but driver tube is parallel 6sl7, may I ask how you keep your EML 2a3 "happy"? What is the bias voltage and plate dissipation?
thanks again.
I am not running directly-coupled yet. My operating points are ~250V (plate to cathode) and 51mA. I run a directly-heated rectifier that does not inherently ramp up the B+ slowly and do use a separate filament transformer. So, to bring up the B+ slowly (~25 seconds from switch on) I place a CL-80 thermistor in series with the B+ transformer primary.
In my next, directly-coupled amp, I will drop the plate current back further and bypass he thermistor with a small cap to supposedly reduce noise, though I have not noticed any noise issues with it unbypassed.
This is untested, but I think the EML 2A3 might like a ~1:6 plate mA:V ratio, mildly conservative dissipation and 4k - 5k load. I don't think the EMLs need the extra sense of oomph that comes from a relatively higher mA and they probably benefit from the extra touch of "elegance" that the higher ratio and load brings. Just some random thoughts.
Cheers.
"In the beginner's mind there are many possibilities, in the expert's mind there are few." Shunryo Suzuki
My 2 cents worth for whatever it's worth.
The most authoritative and dynamic op point for most 2A3 tubes seems to be 250 VDC across the tube, drawing 42.5 ma.
This won't square with the calculation-rich people, but it works extremely well into the standard 2.5K load.
One might load-adjust-- experiment and try something like 3K with the EML, but don't expect any new revelations.. Triodes aren't super critical as to loading, but as you come closer to normal op points, loading gets more critical.
The Thermistor definitely requires bypassing-- that will become more obvious as your amp leans towards better transparency. With sensitive speakers, it will become obvious to you.
The JJ-2A3-40 is easily the most powerful and sensitive. It's a great tube, once you dial-in your amplifier to it's different sound characteristics as compared to other 2A3's. Nothing else sounds the same as it does, so just plunking one into an amp won't reveal what it is capable of sonically, plus it's very powerful with that 42.3 ma.
You won't get more "oomph" from any 2A3 by running more than 45 ma. It doesn't work that way. When the tube is not run as hard (as the standard 60 ma.), it can stand far more input swing without distorting. This will translate into superior perceived power and dynamics. Sometimes, an output transformer that is a cheapie may require quite a bit of current thru the tube, (I'm not discussing transformer saturation level here, I'm talking about the transfer efficiency of the transformer instead), so you must use an efficient transformer to take advantage of the lesser plate current in the tube.
The EML falls between the older predecessor of it-- the AVVT Mesh Plate, and the JJ-2A3-40. It won't handle the idle current of the JJ, but it will handle more than the older AVVT.
The JJ, however, performs GREAT at the 42.5 ma., something one wouldn't expect. This is a really good amplifier tube-- really excellent in every way.
If you just plug-in the JJ, the EML and then the old AVVT Mesh, into an existing amp setup for standard 2A3 operation, you'll hear greatest transparency with the AVVT, less with the EML, and then less yet with the JJ almost to the point of boredom.
All you have to do is re-voice the amp for what tube you're using. When you do that, the JJ-2A3-40 will amaze you. It will deliver EVERYTHING!
That sense of great power will reel you in, once you have it doing all the details and bandwidth right.
And, yes, it can be very elegant. It just needs a different voicing arrangement than any other 2A3.
---Dennis---
TW,
Okay, I've started stalking the JJ 2a3-40, and other prey. I found a pair of used KR 2a3 with 200hrs for $400. I remember you said they had complicated filament arrangements and are prone to failure. These have 200 hrs on them, so maybe they are safe? I'll pick up the JJs for sure.
Since the troll patrol has showed up on the 32ohm thread, why don't you make a comment. It's a very old school question. Not saying you're old school or anything, but well, you're old school. :)
Take all of this with a grain of salt.
Jamie
Big speakers and little amps blew my mind!
"the troll patrol"
Hey, I was only trying to help.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Tre'
This wasn't aimed at you, or meant to be plural. Just poetic. This refers to the other thread.
FSU vs UF. Gotta run.
Later,
Jamie
Big speakers and little amps blew my mind!
" When the tube is not run as hard (as the standard 60 ma.), it can stand far more input swing without distorting."
Dennis please understand I'm not making a judgement on what you claim to hear but the above just isn't true.
If you lower the plate current, without increasing the plate to cathode voltage and increasing the load impedance to rotate the load line more towards the horizontal, the tube will run into distortion faster. Just the opposite of what you say.
This is not my opinion. This is just the matter of fact.
Just plot load lines each way and see for yourself.
When you lower the plate voltage, leaving the slope angle of the load line the same (in other words, leaving the load impedance the same), the load line to the right of the idle point runs into the non-linear area sooner. The non-linear area is where the grid lines are bunched closer and closer together causing harmonic distortion.
The plate voltage rate of change is less going to the right from the idle point vs. the rate of change going to the left.
This lack of symmetric behavior is the cause of harmonic distortion.
To achieve low HD we want to pick an operating condition (idle current, idle Vpk and load impedance) where the plate voltage rate of change is the same, left vs. right along the load line.
Paul Joppa's formula gives good results. For your operating point you should be using a 3.9k output transformer.
OPT Z = (VPk/current)-(2.38*plate resistance)
If you're really not interested in power (and you have indicated that) you could use an ever higher load impedance. But a lower load impedance will give you more total power but more HD at all power levels.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Partially correct. 100% correct calculation-wise.
That is if the tube is pushed to near full output, something that my designs will not allow-- ever.
When substantially less than full output, using lower plate current (not too low) the tube is stressed less, so it performs better.
This is a deliberate design decision, not a miscalculation. The overall design is a balance of many factors like this.
Another deliberate choice is the 2.5K output. It is common knowledge that higher impedance load on the plate equals lower measured distortion numbers.
It is also in my head that higher impedance transformers have a higher turns-ratio--, and if the lamination stack and the output windings are identical, then the input loop will be wound with more turns of finer wire. Of course, the transformer builder could choose to re-balance these two windings, and change BOTH windings to get a new "match". That is-- if he decides to do it that way. He has lots of options.
Although I talk to transformer builders a lot on the phone, and have even designed some of them, it's really nice when something that makes sense is already available, works extremely well, and sports a nice, lower turns-ratio..
This is simply another case where circuit calculations don't tell the whole story. Transformer construction also weighs in.
Don't get too excited, just continue on as you are. It's just another deliberate decision on my part: how much "distortion" am I willing to tolerate VS how much do I want to give away to higher turns-ratio.
TRE, you're free to rigidly follow all the proven formulas you like!
---Dennis---
"Partially correct. 100% correct calculation-wise.
That is if the tube is pushed to near full output, something that my designs will not allow-- ever."
You're wrong again Dennis. The HD is lower even at lower power levels with a higher load impedance vs. a lower impedance load.
"....something that my designs will not allow-- ever."
How's that? You use a high gain driver tube. The output of a CD player will over drive your output tubes if not attenuated.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
HUH? I'm not wrong, and neither are you!
OF course a High-Impedance load has lower HD. I agree-- my previous (and yours) agrees with that.
"Lowest" HD is NOT the ONLY consideration here.
---Dennis---
Sorry Dennis, we both got off track talking about impedance loads.
You're original statement claims that if you lower the idle current of a 2a3 loaded, with a 2500 ohm load, with 250 VDC across the tube, from 60ma. to 43.5ma the distortion will go down.
The fact is the distortion will go up, not down.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
HD depends on your drive level into the tube.
---Dennis---
Yes and no.Certainly the % of distortion goes up as the grid drive level and the output power goes up, and the % of distortion goes down as the grid drive level and the output power goes down.
But if the operating condition (idle current, plate to cathode voltage and load impedance) is not properly chosen the distortion will be higher at all grid drive levels and all power levels.
In your response please stick to the point and remember this discussion is only about the HD produced by the output tube and the effects of lowering only the idle current leaving the other parts of the operating condition unchanged.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 11/25/14 11/25/14
Maybe adding extra % of distortion products makes for a more realistic listening experience in DF's system?
One listener describes the DF audio system as sounding "organic" and not overly detailed, whatever that means.
If lowest THD is the design goal, we should be listening to PP tubes or solid state amps that measure better.
"Maybe adding extra % of distortion products makes for a more realistic listening experience in DF's system?"A more realistic listening experience in some people's opinion? Probably.
"One listener describes the DF audio system as sounding "organic" and not overly detailed, whatever that means."
I think the key phrase there is "whatever that means"."If lowest THD is the design goal, we should be listening to PP tubes or solid state amps that measure better."
Not my goal!
That's been the problem since the Williamson circuit of the late 40's, global negative feedback and the power wars.
THD tells us just about nothing of how an amplifier will sound.
What I want is low upper ordered HD. It's the upper HD that, in my opinion and I believe it has been shown to be the case scientifically, damages the sound.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 11/25/14 11/25/14
Dennis made a straight up statement that lowering the idle current allows for more grid swing before distortion sets in.
That is a false statement. Period
I showed, probably not using the right words as I'm self taught and not an EE, that he is dead wrong. It's the other way around.
What say you?
What does Dennis say in rebuttal to my technical point?
Dennis, I don't what your opinion about how it sounds or any of your gibberish, etc. I want a technical answer and if you can't give one I want a retraction of your false statement.
Jim, there's my expectations.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
This luckily is not a problem of philosophy but rather a technical one. if the lower portion of the wave is driving the tube into cutoff, you will also get more distortion and less output. The bias point has to be chosen for symmetrical distortion, meaning the top and bottom of the waveform get clipped at approximately the same magnitude... If you raise it too much the top will distort first, lower it too much and the bottom will.
There is an excellent section in the RCA Tube manual which discusses biasing and how to draw load lines. Reading this section will go a long way toward understandibg the how and why behind operating points. I like to print or photocopy the tube curves and use a pencil and a ruler to figure out how to best run a tube, then use a signal generator and scope to check for symmetrical clipping. In my experience though, the tube curves really don't lie, and if I designed it properly on paper it will indeed work properly in reality, and all testing does is confirm I didn't make a mistake.
I'm not Dennis, but I know a lot of what he considers and thinks after about thirty years of friendship.This load line thing is looking at ONE thing, which is very short sighted. It pertains to maximum swing and distortion at maximum outputs!!
Most of the time, with efficient speakers, we use 50 to 500 milliWatts of power, seldom over three quarters of a Watt. WTF, why look at maximum power and swing.
There are OTHER considerations to running a JJ, etc, at reduced currents, conservatively !!
What a technical person does is look at load lines, as though THAT is the only consideration. I will give you technical types TWO considerations YOU FORGOT, or never even thought of !!!!
(1) How much happier is the SE output transformer coping with an unbalanced current of 42 mA. versus 60 mA. ?? Certainly, the lower mA. is a PLUS for the SE output. Duhh, why not consider that ?
(2) What is the thermal temperature of the 2A3 triode operating at close to a Golden Ratio plate dissipation, versus the "often used" 100 percent of plate dissipation ( 60 mA. times 250 VDC equal 15.0 Watts, a 2A3's rated maximum ).
What do you think the lower dissipation does for life of the tube ? It probably triples useful life, while sounding better doing it on a LONG TERM use basis !!!
Is reliability and performance consistency worthwhile to have?
Have you RDH-4 memorizing, pencil pushing, HIVE boys ever listened to a WELL WIRED amp, and a triode run at maximum plate dissipation, versus the same tube run at a Golden Ratio dissipation?? Which ones SOUNDS better ? I will tell you. In a well made amp, the lower mA. draw will always sound more free, easy, relaxed, whereas the higher draw will have a STRESSED AS ALL GET OUT unpleasant sound. Where is THAT on the tube characteristic curve chart ????? Missing in action !!!
Screw it, I want the free, easy, relaxed music presentation, without the thermally STRESSED sound for MY listening.
There is a LOT more to building a satisfactory amp, than the HIVE engineering formulas. You gotta consider EVERYTHING in a SE amp, and get it ALL right, ALL at the same time !!! It takes superior experience and mentality to get things really right sounding, not everyone has such a gift.
We need to encourage and support the few who have the skill set and experience to produce audio gear that PERFORMS. Some of you out there do GET this, I am sure !!
Myopia.
It doesn't work so well in the real world of listening and obtaining absolute maximum performance. No need to say any more.
Jeff Medwin
Edits: 11/25/14
Jeff,
I used the term "hive" in another post in a larger Meta-sense than just amp designers who adhere to long proven design equations.
I would hate to think I coined a term that will be used pejoratively against forum members for God knows how long.
I ask you nicely to refrain from using the term, hive.
Thanks,
Jamie
Big speakers and little amps blew my mind!
OK, its a good term, and I will not use it any further. I'll certainly respect your wishes, no problem. Thanks for posting it.
Jeff Medwin
As if I understood this well enough to comment.
OK, at one time I did but that was eons ago. :-(
.
Have Fun and Enjoy the Music
"Still Working the Problem"
Let's not send ANOTHER thread off into the weeds.
.
Have Fun and Enjoy the Music
"Still Working the Problem"
Why try to bait Dennis into another long and unproductive thread?
False? HMMM---MMM!
Whatever.....! Hey! If it pleases you, who am I to argue.
Why not regard the whole build as a set of different requirements-- which all affect each other, since that is what it actually is.
Then, decide what you have to do to allow available components to provide max. overall performance musically and also provide trouble-free, long life operation.
And then, try to convince the experienced among us that you won't have to violate some of your mathematics, and bend quite a few rules..., because you WILL HAVE TO.
The real world still exists last time I looked. Those who adjust to it best can have the better performance.
I'll try to get to RMAF 2015. You really can benefit to hear what is possible-- no kidding, and then decide what you need to change, and where you need to bend the rules to get at what are the audio performance standards today-- realities that are being met and exceeded right now.
---Dennis---
Please stop
No GEO,Dennis gave a decent response, I understand what he is trying to say. YOU are not a moderator here, and we are discussing audio design, the reason for this Forum. There CERTAINLY were no false statements what so ever.
Please read my post, I am more specific. Maybe you, or others deserving, will LEARN something new !!
Jeff Medwin
Edits: 11/25/14
He should move it to the DIY Asylum where most of the people are not paying customers. Marketing disguised as advice. If he cares so much about the community, why not cut his price in half so more people can see for themselves.
Edits: 11/26/14
"He should move it to the DIY Asylum where most of the people are not paying customers. Marketing disguised as advice."
+1
OTOH, if someone wants to discuss how running a lower current on a tube effects sound quality, then I don't see anything wrong with that.
I think some common sense, and a little fraternity would solve a lot of these problems. How many SET guys are there out there? Not enough to be committing fratricide.
Jamie
Big speakers and little amps blew my mind!
Free to post the question on the DIY section. Dennis and DLM are a lot like Bobby at Merlin and his worshippers. Bobby finally got off the speaker board. Never has one man gotten so much mileage out of tweaking the same design for almost 20 years. Its remarkable. They've value of Bobbys' tweaks, now cost more the the the original speakers. Dennis could easily set up his own forum. Ralph at Atmosphere would never so blatantly promote his product on the tube forum.
Should Maxhifi have started his thread on 2a3 operating points on the DIY forum?
These are hard calls.
Jamie
Big speakers and little amps blew my mind!
I am talking about Dennis marketing and Dr low mu shilling on the set board.. Don't they have M designations?
Without doing research, what do YOU think my "M" designation is about ?Be curious to know, what you are thinking. Thanks !
I will respond, nicely too.
Jeff Medwin
Edits: 11/26/14
All "members of the trade" (manufacturers, dealers, distributors, manufacturer's reps, importers, magazine and e-zine writers and others) shall identify themselves as such in the login profile that posters can access by the "profile info" link (M, D or R). That way any reader who wants to know if the poster has any special expertise - or vested interest - in the subject of the post can find that information.If your "M" means something other than the above, then its just par for the course. Happy Thanksgiving. We all know by now that rules don't apply to you and Dennis. I like the part about "vested interest". Set up a forum for you and Dennis and those interested in your modern design and your special expertise. Let the rest of us suffer in peace. You and Dennis can spread the gospel in a separate forum. Call it low DCR road or something. For god's sake, leave us in peace.
Edits: 11/27/14 11/27/14 11/28/14
Hi Jeff,
I know you didn't ask me, but here's my answer.
It identifies you as a manufacturer. That should serve two purposes. First, it alerts the reader that what you say may be biased for financial reasons. Two, it should alert you that if you overtly promote your products it will be seen as advertising. Who really wants a sales rep shilling at our little audio get-togethers. That's not what we're here for. Also, if that's what you are doing, then you picked a really bad spot to do it. You should target a different demographic.
OTOH, I swear both of you are just so immersed in the Absolute Sound culture that all this conflict is from a culture clash. You gave a one page infomercial on a DAC on the Great Amps thread. It read like it was straight out of AS. Maybe that's just the terms you think in.
I really think you and Dennis have so much to contribute, but it's all very fitful, and sometimes painful. I loved your little half watt amp. I had just joined, and I didn't comment on it, because I didn't want to get in the middle of anything my first day here. I left that for the second day.
Honestly I write all of this because I like you. Just chill the F out on the advertising copy, and talk about tube amps. Feel free to freak everybody out with tales of operating points that don't go by the book. I say more power to you.
Can you dig all of this?
Jamie
Big speakers and little amps blew my mind!
Nice post, thanks !! First of all, I don't think GEO and you KNOW what I do, for ME to list myself as a "M".
Lets just WAIT and see what GEO has to say, without doing any research. Others up here know. I wanna see what GEO says - without any coaching.
I owned La Scalas once BTW, mid 1980s, for just a little while.
PS : This evening I am scraping the GE Silicone 2 off of my old powder coated 12 gauge steel chassis, with seemingly NO negative effects on the midnight blue / pearl wrinkled powder coat. Hoorah !! So happy ! 'Getting ready to have a blank canvas, to lay -in my new stereo 2A3 SE DC amp. Lotsa room in this chassis. Thirty pounds of steel - this chassis and bottom plate ALONE pre magnetics attachment. Ought to have good bass response. That comes from heavy chassis and how little I bypass my Rks, opposite pedantic RDH4 formulas. I determine uF amount by ear. LMAO !!
Ordering two Woo Audio UX4 sockets and one 20 A. Hubbell IEC combo from Percy on Friday AM. 15 A. IEC is kiddie league, ask Percy.
Regards and best wishes.
Jeff Medwin
nt
Big speakers and little amps blew my mind!
I still dig it.
Do you want them to shill at the DIY AA forum? Boy, I bet the guys over there are not liking the turn of this conversation.
Big speakers and little amps blew my mind!
The fact that everything I have asked about has nearly immediately generated an extremely helpful and useful response, has sort of told me I am in the right place. To be honest I am enjoying having access to the level of experience and knowledge here, I every time I log in I am learning something, which is certainly not the case on all internet forums.
Yes I'm glad you are posting here too.
I think SETs are such a sub-niche that they are inextricably tied to DIY, so might as well post here as anywhere.
Jamie
Big speakers and little amps blew my mind!
Push-Pulls belong on the DIY forum, or somewhere. :)
That's a SET joke.
Big speakers and little amps blew my mind!
I have to say I have always been a committed push pull guy - testing the amplifier last night and seeing it clip asymmetrially, as the grid started drawing current and drag down the driver was really weird! It took me a little while to figure out that is what I should expect! I am used to push pull amplifiers which overload in a very predictable way - this single ended thing is new territory !
I keep forgetting to look at people's systems to see where they're coming from. I should finish mine. You still running the Tannoy Saturn S6? You mentioned mid horn in another post. No wonder you run PP, you have to. Do I remember you mentioning bi-amping? Am I gonna have to keep dragging out big ugly Chinese SET amps for you guys? I don't like it anymore than you do. But even a BUF Sino SET amp is better than any PP.On the other thread tubes were mentioned, but I'll reply here, since this one is about tubes. I've had very good luck with NOS 45s. Hunt deals for them on ebay, and feel good about it when you score. TJ Fullmusic is the only Chinese brand I would own. The quality is very acceptable. Solid plates are better at full range or bass, and mesh/perf sound signifcantly better in the mids and highs. Mono plates sound better than dual plates. Gold grids are a desirable feature. I understand Emission Labs just went to GG.
I have a feeling you will want more power, or different speakers. These threads have gotten me thinking of a Tannoy red in a MLTL enclosure, but I already know the end result. It would sound great at normal listening levels, but if you turned it up it would distort. My speakers are very low distortion, and when I crank my system up - it only gets louder.
Oh, and if you don't follow your SET investigations all the way through, then if I die before you do - I'll come back and haunt you.
Jamie
Big speakers and little amps blew my mind!
Edits: 11/26/14
I saw an alarming statistic recently about what percentage of North Americans believe in ghosts, it was mind blowing how high it was! That said if ghosts did exist I doubt you would be the only one :)
Yes I still have the Tannoy Saturns, Rome wasn't built in a day, My original point in coming here was to discuss the western electric 91a, however the discussion side tracked me into reviving an unfinished project from last decade, namely my 2A3 amplifiers. Now prior to getting them going I was absolutely ignorant of how much I would actually like the SET sound.
In the past I owned Goodmans Triaxiom speakers, and also Realistic Mach Ones - that's my only real high efficiency experience. I can't say either are aomething I want to own again. A klipsch or a vintage altec is possuble, and if I was to go in that direction I would consider bi amplification, however I am also considering the full range route. You are correct that different speakers are on the horizon though!
If you build that 2A3 amp right, then there is no 300B in the world that can touch it.
A lot of discussion has taken place in these pages lately, about the Model 91, and possible variants of the circuit that one could pursue.
I didn't comment on those posts earlier because it's opening a can of worms on this forum, but the Model 91 has so many designed-in mistakes in it that I would caution you to VERY carefully examine any schematics for Model 91's, and for any ordinary 300B amp in general.
In stock form, even with its feedback removed and even with the first stage removed, the Model 91's sound is narrow-band , lazy (slow musically) and lacking dynamic drive severely. To it's credit, it is more musically involving than Push/Pull amps, as are all S.E.'s.
My (above) point of view here regarding using the 2A3 (only single-plate versions) is about total musical accuracy.
If, instead, you prefer lazy, smooth, relaxed sound, and aren't concerned about capturing music's leading edges (kick-drum, etc.), then the Model 91-- seriously re-engineered can serve as a basis for your study and consideration.
All I am saying is don't expect this circuit-- or the antique amp itself-- to compete with today's best do-it-all amps.
Music sources are getting better and much more dynamic as High Resolution takes over the recording studios, and it is very thrilling to listen to.
Very few tube amps can even begin to do it justice, nearly all of them flatten the dynamics and limit capture of music's leading edge attacks.. The few Solid-State amps that can do Hi-Res. music correctly (as it has been recorded) are truly excellent in every musical way, but they cost upwards of $60,000 or so.
That cost makes your interest in S.E. tube amps worthwhile, but I think you should pursue the 45 (only EML) or 2A3 tube (EML and JJ-2A3-40) to the max. if you want to reproduce today's best recordings. The LEAST euphonic of the two tube types is the 2A3.
Construction-wise, the JJ-2A3-40 IS a 300B (the plate and glass bottle are the same), but the 2.5 Volt filament and the 2A3-tuned grid structure make the JJ 2A3 far superior to any 300B.
I know this may offend 300B mavens, but I have taken the 300B tube design to its limits with many 300B designs, including the original Model 91 amp, and have found the 300B to be wanting as an accurate playback device.
The above does not mean that one can't listen to a 300B amp and like it. I did, also-- to a limited extent, but after a while one will tire of ANY component that changes music to its own formula.
---Dennis---
"I saw an alarming statistic recently about what percentage of North Americans believe in ghosts, it was mind blowing how high it was! That said if ghosts did exist I doubt you would be the only one :)"
Do you really want to take the chance that I could haunt you for the rest of your life?
A reproduction of the WECO 91a? The best I can describe that is; Quixotic.
When you get ready to change speakers you can always check back in. I say before you buy, that you have the entire system laid out on paper. Buy a pair of speakers, and you've locked yourself into a topology. There is almost no escaping it.
Jamie
Big speakers and little amps blew my mind!
And herein lies the hard part.
Locally there's some Altec 755c's in JE labs style baffles for sale, there's some klipsch la scales for more money, and some Cornwalls. I haven't read the entire Fostex catalogue yet, but that's another route. I am aware of quite a few of the options regarding speakers, but Making up my mind is another story. Then there are altecs, but that is really committing myself both financially and real estate wise!
If you think my desire to build the 91a is Quixotic, it is not the half of it, last year I decided to build a pair of "sweet sixteen" speakers per early 60s popular electronics, I just always wanted to know what are they really like, if some magic occurs which makes it more than the sum of their parts (hint: there is no magic). In the end it was fun, gave me a fun wood working project, and didn't cost a whole lot... Some people spend way more than that on a weekend skiing. My interest in copying the 91a is similar, however as a nod to practicality I do want to buy good output transformers, which can be reused in as many projects as possible going forward, in the remote chance the 91a design fails to meet my expectations :)
Max,
Building sweet sixteen speakers is a hell of a lot less Quixotic than the 91a. SSS were designed for home audio. The 91a was designed to be used with an Edison Film Projector.
You should check out Minh at Tube Audio Lab. He sells kits of an updated Sound Practices 91a, and offers remote assistance by phone, not like you would need that.
I have a feeling you will be designing an amp around your new tubes. It's so easy for the cart to get in front of the horse. A SP91a running your tubes at 2.5v would be very cool.
If you want to talk high efficiency speakers, then it would probably be better to do it on that forum. Start a thread if you like, and give your listening area particulars.
Oh, you can get a pair of 45s on ebay for $60, so that's what you're out if you convert your little amp to a 45.
Jamie
Big speakers and little amps blew my mind!
Yeah, I am thinking JE Labs baffle with some as yet unknown driver... it will get me started with a minimal investment. Don't want to lock in to some high dollar horn system just yet. Already posted on the High Eff form.
I think you're totally right about using the JJs in my "big" amplifier. It's almost trivial to design in an adjustable filament voltage and change the bias, so probably at first it will use these before I actually buy any 300B's. To be honest I am just way too cheap to buy expensive tubes like that and not use them... it must be genetic or something.
If I do build a 91a, it won't be *exactly* as per original design. The main element from the original I want is negative feedback. I want to at least have it possible to add some, just to experiment with speaker damping and see what it does to the sound. Obviously the power supply won't be identical, and I certainly will need to improve the frequency response. The first stage can always be removed later on if I decide I don't like it, making it easily convertible to an SP91A anyway.
To be honest I probably have a couple of 45s in my "shop", if I only go through all the other tubes I will find them. I just at this point don't see the value in making my amplifier LESS powerful :)
How much are the Cornwalls you know about?
" The first stage can always be removed later on if I decide I don't like it, making it easily convertible to an SP91A anyway."
You go boy. Just keep in mind that it's a rabbithole.
" I just at this point don't see the value in making my amplifier LESS powerful :)"
True. Do you want to run SET on the Tannoy's?
Jamie
Big speakers and little amps blew my mind!
"How much are the Cornwalls you know about?"
$2700 CDN, and the seller makes note of them being Cornwall III. If it was a cheap pair of first gen I would call it a no brainer, but this is way too much. I also recently listened to some Heresy 3's, and to be honest I found them very coloured sounding. I prefer my Tannoy speakers. I am not completely sure classic klipsch is for me.
"You go boy. Just keep in mind that it's a rabbithole."
A 6J7 is a $10 tube (with other uses), and there's a small handful of passive components. It will take me what, a couple extra hours to install and remove? I may even make it so it can be switched in and out. I have to find out for myself that NFB won't make an SET sound better...
"True. Do you want to run SET on the Tannoy's?"
No, they will find application in my other system, I am just using them now, well, because they exist. I don't have more efficient speakers on hand, and the Tannoys sound very good... the 2A3 just runs out of oomph.
As a note, the room is 30x14x8, speakers on the narrow end. Acoustic tile ceiling, carpet floor, wood panelling on the walls. A 1960s style basement rec room, but with newer carpet and furniture. It's more or less my favourite room of the house, and I have no problems using whatever speakers my heart desires in that room - price and personal preference being the main factors.
-Max
"the 2A3 just runs out of oomph". It isn't the tube! Nor is it the speaker.
what's left?
---Dennis---
Dennis, the Tannoy Saturn S6 are rated at only 90db.
Are you saying that 3.5 watts is enough power for a 90db speaker?
That goes against common wisdom but you're good at that. :-)
Why won't you answer my other question about what happens when you change only the idle current WRT HD?
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Thanks, TRE. I stand corrected.Tannoy with a 90 db speaker. That's like Ferrari with a $15,000 3-cylinder automobile. What FOR?
That's not what Tannoy is famous for, and is not what I've seen and heard from Tannoy at audio shows. Reasonably Hi-Eff., large speakers is what Tannoy MEANS to audiophiles.
It won't be the only speaker Co. to broaden-out their range and Kow-Tow to the low-eff. speaker crowd. After all, sales count also, and there are plenty of big-power, low-cost (and low quality) amps out there to choose from.
But the SET Asylum for INEFFICIENT speakers?That is an Oxymoron! When you go below about 93/94 db/watt, you normally go Solid-State. SET Tube amps start sleazing out of accurate audio reproduction range after about 3-4 watts unless they are very carefully engineered, and that costs real money. (yes, I'm building one. No, it can't be cheap).
If you don't believe it, just take any speaker that needs and is using about 10-12 watts from a SET (I don't care how big the SET is, some SETS are 200 watts!), and swap-in a really good Solid-State amp like Boulder, MBL, Spectral.
If the difference in overall speed, rhythm, pace and timing isn't obvious, then one doesn't require accurate reproduction of music anyway.
---Dennis---
Edits: 11/29/14 11/29/14
Shilling your own product.
Are you scared to death about hearing from people in the field who actually have experience with more than one design philosophy and audio setups?
You have your own philosophy, I'm sure, and I don't fault you for that.
But what about people who have used all of these systems-- and know how to approach a set of audio needs, and get it right the first time, saving wasted time and a lot of wasted effort and money?
Looks like you want to shut them up! What are YOU selling?
If someone builds something that one could buy? So what! There are many contributors on this forum that regularly sell things to forum members. What I referred to is a FACT-- if you haven't used a great Solid-State amp-- (which I DO NOT sell!), and you think a medium or high-powered tube amp is going to beat it musically, then you are sorely mistaken... it DOES NOT OCCUR, period.
Did you see my post selecting DecWare (Steve) as great value/dollar? I DO NOT sell it! I was honest with the guy who could benefit from it.
Again, so what? If the guy gets something right that's useful to you, then go after it. If it doesn't apply to your situation, then DON'T go after it. What could be easier than that?
If you want widely experienced people to quit posting so you can have this forum all to a narrow band of identical thinkers who do nothing much better than swap schematics and mathematics, but do little to understand what really performs in the home, then you have created a closed society.
Closed societies are always terminal in the end.... Why? They're relevant only unto themselves-- and that, in itself, becomes irrelevant.
Are you insisting that the forum become irrelevant? A place where only the cheap to buy or build and the most commonly understood-- become the only items up for discussion?
If you like that, then you're getting more of it every day, and less and less of what really matters. The question is-- do others on this forum really want that?
---Dennis---
.
When you have an M in your profile, you are held to a different standard. Decware is nice, if you can't do any better. That's the kind of statements you routinely make. Soft peddling product. You are like Bobby Palkovic of Merlin. Selling couched in advice. Why not set up your own forum? Seems like a direct way to get your message out. Closed society? That is a good description of you and Dennis and your groupies. A cult is a closed society and you and your ilk are far more cultish than most contributors here.
Edits: 11/30/14 11/30/14 11/30/14
GEO,
How about this?
I start a thread on the SET forum about the DCR PS concept. I have heard Paul Joppa call it a "double-stacked" PS. I think that's what he called it. I would let DF decide the nomenclature.
Then when someone starts a thread and says, "Hi, I want to design a Pi filter." Then DF or JM can post a little note to check out the LDCR thread and give a link, and leave it at that. It may work.
The shilling is another matter entirely. That last one barely blipped up on the radar, but you are right, it was there.
I have to go do yard work. Maybe by the time I get back there will have been some discussion about this idea.
Just trying to help,
Jamie
Big speakers and little amps blew my mind!
I enjoy reading what people have to say but those guys are only interested in one perspective and Dennis is always soft selling. Nobody has said their amps don't sound good. Most people have not heard them. No other manufacturer shills like that. Palkovic at Merlin was notorious in speaker asylum. That company has groupies too. Bobby should get a room just like Dennis. Trying to act like he is being philanthropic. Cut his price in half for the good of the hobbyist if he is so benevolent.Larry Moore uses a double stacked supply. I had his 2A3 . It was nice. These guys are no Larry Moore. And I am not saying their amps don't sound good. An equalizer can make an amp "sound good" also, if you are into that.
Edits: 11/30/14 11/30/14
On the "old, tired, broken record": Dr. low mu is correct-- only in the case of a 2-stage D.C. amp.
For cap-coupled amps, if one applies a separate power source to each stage, there will be substantial benefits.
In the case of a 2-stage S.E. D.C. amp, the object is to get the two direct-coupled tubes to act as one tube-- in theory-- in sync with each other..
In actual practice, the result is pretty awesome if separate filtering is applied to the first stage power. Effectively, one is providing a separate power source for the driver, which is de-coupled from the main supply, BUT-- and this is very important-- the main supply is still in sync with the driver supply that comes from it.
I'm rambling here to be sure, so accept my apology. This is, however, proven technology-- it works like gangbusters when used correctly.
---Dennis---
Share your thoughts via private email with Don as he will not be on this board shilling his Direct Coupled 2A3. You continue to slight his amplifiers with backhanded compliments.
Anyone can, and should post on the forum if he thinks that he can benefit forum members, maybe help them save some cash by getting/building what they need first, rather than later.I don't wish to offend anyone who builds and sells equipment-- rather I appreciate them for what they do. I know how tough it can be, and I think their efforts, like my own, are to be applauded.
That doesn't mean that one shouldn't keep advancing the state of the art, but if that advancement comes at too high a price for someone who could still benefit substantially from a lower-priced, good piece of equipment from someone else, that it can't or shouldn't be discussed objectively.
Perhaps I am not the one who should discuss that, and for that reason I apologize-- right here, right now, if anyone feels offended-- that was not my intent.
Normally, forum members don't buy from any of us-- they want some ideas before they build something for themselves. The chance that a forum member is going to call up one of us and buy anything-- is extremely remote, to say the least, so WHY are we then contributing here?. Most members are looking to build for themselves.. or buy at a lower price.
Dr low mu has been so kind as to try and give out as much info as he can to those who ask "what can I build or buy that is better than the average that I can afford"? The price to buy probably leaves my stuff out!! I put into in what I know it takes-- would I buy it? YES! Should you? Not if it's too expensive for you, and I understand that.
I don't think anyone who contributes on this DIY forum is trying to "Schill"-- where did that term come from-- I think he's probably giving of his time for free-- offering the gift of experience to those who care about it.
Perhaps some of you other manufacturers out there in the closet would like to join the forum and offer help to the DIY builders who can't afford to buy your equipment, but would appreciate hearing from you on your design expertise......
People have asked me for a "KIT". That's not something I could set up to do, but it is an opportunity for some of my competitors for sure.
Do you hear opportunity knocking?
None of us will be here forever-- are we going to leave anything for others?
---Dennis---
Edits: 12/01/14 12/01/14
Many here are paying customers. As far as your gear being too expensive. I would be surprised if you made as much as I do in a year, but anything is possible, I suppose. However, I will stick with my cheap budget equipment because it sounds good to my ears.
Edits: 12/01/14
According to Wikipedia, the term "shilling could have originated in carnivals. They also says this:
"Marketing
See also: Astroturfing
In marketing, shills are often employed to assume the air of satisfied customers and give testimonials to the merits of a given product. This type of shilling is illegal in some jurisdictions but almost impossible to detect. It may be considered a form of unjust enrichment or unfair competition, as in California's Business & Professions Code § 17200, which prohibits any "unfair or fraudulent business act or practice and unfair, deceptive, untrue or misleading advertising."http://en.wikipedia.org/wiki/Shill
Hardly a reason to get a real cowboy all riled up, unless of course you were trying to pawn your friends horse off as a Kentucky Derby winner when in fact it should be on the way to the glue factory.
Edits: 12/01/14
Definition of SHILL
1a : one who acts as a decoy (as for a pitchman or gambler)
b : one who makes a sales pitch or serves as a promoter
Fitting...
Thanks for the link. Yes, it just goes on and on. I can see the fallacies.
I think I'll give up on power supplies for a while, and leave them to somebody who understands them. Sorry if I annoyed anybody.
Jamie
Big speakers and little amps blew my mind!
There are plenty people. All Jeff and Dennis need to do is say they don't care if their supply is poorly designed, they like they way it sounds and move on and so does Dennis' paying customers. Dennis comes on this board and softly denigrates the Fi amps.Jeff and Dennis are relentless
Edits: 11/30/14
"I have to find out for myself that NFB won't make an SET sound better... "
Go for it. Better than listening to someone elses opinion about it. That's a deep subject in itself.
Sorry I can't contribute anything about wide range drivers.
Jamie
Big speakers and little amps blew my mind!
Sounds like you could use a good transformer on the cheap. I saw a pair of Magnequest FSO-30's on E-Bay. Price was reasonable.Used, normally-- (if not abused) should not hurt an output trans.
The FSO-30 could be used with a wide variety of small/medium-sized output triodes-- 2A3, 300B, etc. You could run the KT-88, triode connected into this if you really wanted to.
Input Impedance is 3K, there are options for impedance-matching at the output..
---Dennis---
Edits: 11/27/14
nt
Big speakers and little amps blew my mind!
Okay,
Buy more expensive tubes that don't sound as good. That makes plenty of sense.
And I listen to a super low distortion fully horn loaded system, that you would have to hear to believe, so go ahead and listen to your higher distortion direct radiators. You did notice I said, "listen" didn't you?
"Maybe adding extra % of distortion products makes for a more realistic listening experience in DF's system?
One listener describes the DF audio system as sounding "organic" and not overly detailed, whatever that means.
If lowest THD is the design goal, we should be listening to PP tubes or solid state amps that measure better."
I've been meaning to post on this type of subject. Long weekend coming up. Maybe I'll get the chance.
Jamie
Big speakers and little amps blew my mind!
Will the JJ tube work just as well at the specified operating point when used with a 3.5K OPT? How about at a 5K load?
.
Original US made H plate 2A3s, are available all day everyday on ebay.
Doesn't matter if they're new, as long as they test good. This type holds up well in direct coupled circuits too, with a 500V supply. Without a pair of these around as a reference, you won't know how much better or worse any one of the many New production types compare.
The RCA's bring more $ for whatever reason, while the off-brand ones like a Philco (made by Sylvania) or a Silvertone (made by RCA) will be less usually.
Hmmm digging deeper it looks like the going rate for a pair of used USA 2A3's is around $100, and about double that for a pair of NOS. This is pretty darn competitive with most of the new offerings.. although the new ones promise "mono plate", "gold pins", "deluxe presentation box", etc. I should quit being a sucker for advertising and just order up some "real" tubes.
Just get a pair for reference as suggested, they might end up staying in the sockets. BTW, I've witnessed several cases where a new production replacement for an older type tube, has HIGHER MU than what it replaces, thus giving the sensation of being "more robust" or whatever, if plugged into the same hole. The Russian 6B4G's are like this, most Chinese or Russian 6L6's are too, and numerous 6550 types. It's a trick, or an accident, but don't be confused by this. I'd guess the JJ's have this "quality" as well, but I never tried them.
The Sovtek 2A3 gets you 95% of the way to anywhere you want to go. The returns diminish greatly after them. IMO.
What do you think sounds better?:
A. $100 Output transformers with $600 tubes
B. $600 Output transformers with $100 tubes
The great thing is that the OPTs sound better over time and do not wear out. You would be amazed at the number of people running with "A".
...or
C. $450 OPT with $250 tubes.
D. $600 OPT with $600 tubes.
I say C... or D if the funds were available ;^)
A and B are extreme examples and perhaps not relevant.
For $700, I'd opt for JJ2A3-40s and some solidly-performing transformers (which can be very good). This is what I did, but have moved on to EML tubes (though in a different amp, I might choose differently).
Cheers.
"In the beginner's mind there are many possibilities, in the expert's mind there are few." Shunryo Suzuki
Just trying to say that plugging million dollar tubes into an amp that has cheap OPTs is not going to gain you anything. People always try to gain performance with fru-fru chinese marketing tubes, but true gains are often much more economical with circuit and parts changes. Sometimes, what you have is what you have.
"People always try to gain performance with fru-fru chinese marketing tubes"
Not all people. :)
--------------------------
Buy Chinese. Bury freedom.
.
"In the beginner's mind there are many possibilities, in the expert's mind there are few." Shunryo Suzuki
My output transformers apparently cost £285.12 per pair now... Ouch! I am sure I didn't pay quite so much when I ordered them in 2003.
I have had very good luck with Sovtek tubes in the past (guitar and other push pull applications.
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