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In Reply to: According to some experts, your generalizations are wrong. posted by Dave VH on May 28, 2001 at 14:41:43:
>>>Tubes are only part of the equation.<<<
True, but they are a big part, and to discount their effect is foolish.
Yes, different 300B amps sound different, but they still have a "300Bness" to thier sound-even PP amps.>>>Gordon Rankin of Wavelength Audio, one of the foremost SET designers in the world,<<<
He also sells an all WE version of the Cardinals-same cicuit, different tubes. Not to mention, 3 versions of the Mercury.There is a reason why so many people lust after 45s. Do you think all those DIYers thast use them have the same circuits?
Some people are willing to spend hundreds of dollars on used cunninghams(each) for thier amps. I'm going to go out on a limb, and guess its not for the looks. Why don't they just save money and use EL-34s?
The last time I talk to george Wright, he stated that he LOVED 45s, and if there was a cheap reliable source of them, he would build amps for them.
If OPTs, resistors, Caps, wires and other parts can have an effect on the sound, tubes (including driver and rectifier) can have more.
Jack
Follow Ups:
***Some people are willing to spend hundreds of dollars on used cunninghams(each) for thier amps.***I have a pair that test fine, but they SUCK in my Fis (they make the Fis sound like Audio Research). Haven't tried them in the Moth.
Did George designed a distinct 45 amp, or did just tweak the current and voltages and otherwise use the 2A3 amp?Mark (S-D) wanted to use one amp design for any of several different output tubes, and that's a different story. Your reported experiences show a clear distinction between many of the same types of tubes in several respected amps, but each amp was specifically designed for that one type of tube. Otherwise, you'd still be using the Cardinals with mods and sticking in different types of tubes.
A Cardinal modified to run 10's?? Or perhaps Steve Sammet could modify it to run KT88's or EL34's!!
Jack, you're making me think like a crazy man!!
;-)
Dave
-- Mark (S-D) wanted to use one amp design for any of several different output tubes, and that's a different story. --Dave, that is not what i want to do.
-Mark
Hi Mark, reading this thread has put my head in a spin.So what you are asking, not what necessarily people have responded with, is which of the 71a, 45 and 300b has which qualities, and once you know the answer to that question you will go ahead and work with the output tube of choice operating it to the best of your ability?
I haven't heard the 71a, but Jonathan Noble likes it even better than the globe 45, and I like his opinion always. But then you are seriously restricting available power.
The 45 I find more natural transition from it's lovely mids to a better high frequency realism as compared to 300b which too has lovely yet not believable midrange and compressed less believeable high frequency, once one has the benefit of hearing tubes that do that so much better such as the PX4 the 45 and the Svetlana SV811-10. One soon tires of the 300b. Not saying it can't be worked with or doesn't have it's place, but other tubes give you the realism of presentation with little external support. I did like the Western Electric 300b though and wouldn't bother with any other from my limited experience but all I've heard are VV, JJ, and Golden Dragon to compare against it.
However if you are in need of the power I would have to say you should consider the Western Electric 300b.
Now I seem to remember from other posts that you are against high voltages so you are limiting your choice to these tubes that are readily available. Don't forget the PX4 and PX25 with the proviso that you'll have to pay good money and future problems securing replacements are guaranteed. The advantages of these types are that like the 45 over the 300b they continue that lovely midrange into the higher registers.
Some say they are better at base too. As I don't have good base reproduction from my Lowthers I can't comment, all the above tubes can support the pathetic base of my Lowthers (50hz).
Hello,-- Hi Mark, reading this thread has put my head in a spin.
So what you are asking, not what necessarily people have responded with, is which of the 71a, 45 and 300b has which qualities, and once you know the answer to that question you will go ahead and work with the output tube of choice operating it to the best of your ability? --Yes, that is exactly what i will aim to do, and what i was trying to find out.
-- I haven't heard the 71a, but Jonathan Noble likes it even better than the globe 45, and I like his opinion always. But then you are seriously restricting available power. --A 45 would probably do better in my system, yet maybe a 71A would work just fine. My speakers are not super efficient. They are only 94db compared to speakers in the 99-103db range i usually see 71A'a used with. However, i have never listend past 94db at home. Usually, i listen at moderate levels.
-- The 45 I find more natural transition from it's lovely mids to a better high frequency realism as compared to 300b which too has lovely yet not believable midrange and compressed less believeable high frequency, once one has the benefit of hearing tubes that do that so much better such as the PX4 the 45 and the Svetlana SV811-10. One soon tires of the 300b. Not saying it can't be worked with or doesn't have it's place, but other tubes give you the realism of presentation with little external support. --
Since you have heard these and put the 45 in the same league as the PX4 in the midrange/treble quality the 45 is what i will use. The added power over the 71A may become useful sooner or later.
-- I did like the Western Electric 300b though and wouldn't bother with any other from my limited experience but all I've heard are VV, JJ, and Golden Dragon to compare against it. --
If i could afford WE 300B's, i'd get the PX4's :-)
-- However if you are in need of the power I would have to say you should consider the Western Electric 300b. --
I'm not too worried about power.
-- Now I seem to remember from other posts that you are against high voltages so you are limiting your choice to these tubes that are readily available. Don't forget the PX4 and PX25 with the proviso that you'll have to pay good money and future problems securing replacements are guaranteed. The advantages of these types are that like the 45 over the 300b they continue that lovely midrange into the higher registers. Some say they are better at base too. As I don't have good base reproduction from my Lowthers I can't comment, all the above tubes can support the pathetic base of my Lowthers (50hz). --
Maybe one day i can get a chance to hear those PX4 and PX25 tubes. Too much for me at the time.
Your response has solved a lot of questions regarding tube choices. Thanks for all the descriptions of those tubes.
-Mark
The 300B is still the King of direct heated tubes IMHO.Do you have experience with any of these triodes?I do,with the exception of the px4 and px25.I like all these tubes but in the long run I prefer the tone of the 300B.I don't think the 300B has a tubby sound at all,to me it's one of the most refined and mature tubes ever built.There is good reason for it's wide spread use.Do not take this post as negativly,because I mean it to have postive note.
I can't remember if it was you, but someone suggested I listen to the WE 300b, which I duly did and I was truly impressed. It seems reading below that Mark has need of three tubes in all, so I'm sure as there isn't really a competitor to the 300b that's 10 or 12 watts amongst the ones under discussion I'm sure it'll fit into his plans somewhere, I suppose he'd be tempted to go for the midrange driver and many would recommend that, but I'd say the 45 for the money does that better than the sub WE standard 300b's and he stated already he can't afford the WE, or would rather buy the PX4/25 at that money. I'm not too sure about that, perfect condition PX series don't come up very often, one major UK valve dealer gets about 3 a year and has a waiting list a mile long, at least the WE is a new tube and he can be more confident in longevity and replaceability. But maybe the sub WE 300b's for the base section?Mark has a very unusual request to most people here I'd say, certainly to me with one speaker per side, DHT SET isn't usually about tri amping, but good luck to him, maybe someone else out there has done this?
Regards
Paul Barker
-- The 300B is still the King of direct heated tubes IMHO.Do you have experience with any of these triodes? --I have heard the 300B, but in a valve-state type circuit. The sound was not too good untill i made it a all tube circuit. The tone was very warm and "pillow" sounding which i did like. The valve-state setup made the sound more "solid state dynamic", losing the "tone". (these were Tesla 300B's btw, not the classic WE)
-- I do,with the exception of the px4 and px25.I like all these tubes but in the long run I prefer the tone of the 300B.I don't think the 300B has a tubby sound at all,to me it's one of the most refined and mature tubes ever built. There is good reason for it's wide spread use.Do not take this post as negativly,because I mean it to have postive note. --
What don't you like about the 45 compared to the 300B?
Is the 45 "toneless"? What would you describe each tubes strong and weak points? I am actually tri-amping so i could use tube A on the bass, tube B on the mids and tube C on the treble. Using similar design ideas with each amp.thanks,
-Mark
Are you really heartset on triamping?I personally think this mucks up the sound but to each his own.Now 45 vs 300B.I've goofed with both these tubes for a while and they both are excellent.I think that the 45 is more detail orientated and the 300B is better all around.I've had some fun with adjusting the operating points on both tubes,with the 45 not changing much in signature but the 300B changing very nicely.I've run the 300B at 330v(270vgk)and running 20ma,10K load and I thought it sounded excellent at these points.I currentlty run my 300B's at 340v(280vgk) and with 40ma on the plate.They sound great and should last a long time at these points(Valve Art nickel plates,no WECO's as they are too exspensive for me).As for the others I thought the 71A sounds a little 2a3ish and I don't mean that in a positive way.The 811A I don't have a lot of experience with but from what little I have heard it came off as being a little sterile sounding.
-- Are you really heartset on triamping? --Yes. My drivers require 4th order filters and attenuation.
Passive does not sound as good to me with my drivers, mostly the midrange.-- I personally think this mucks up the sound but to each his own. --
Your talking about the different sonic signatures of each amp creating a tone imbalance correct?
I could always use the same or very similar amps. What system have you experimented with using multiple amps?
Did you compare the multi-amped speaker with the same amps vs different amps? Where were these speakers crossed at?-- Now 45 vs 300B.I've goofed with both these tubes for a while and they both are excellent.I think that the 45 is more detail orientated and the 300B is better all around.
I've had some fun with adjusting the operating points on both tubes,with the 45 not changing much in signature but the 300B changing very nicely. --Does the 45 tube have mids like the 300B or does it give up warmth for detail? I have heard the 45 tube described as "gutless" by a lot of people, so i assume its not too good below the lower midrange. Is this what you mean by the 300B being better overall?
Do you think the 300B's strong points are the lower mids and bass?
-- I've run the 300B at 330v(270vgk)and running 20ma,10K load and I thought it sounded excellent at these points.I currentlty run my 300B's at 340v(280vgk) and with 40ma on the plate. They sound great and should last a long time at these points(Valve Art nickel plates,no WECO's as they are too exspensive for me). --
Thanks for sharing. I'd like to run my 300B's that way also to preserve tube life. Previously i was running them at 450V i think it was.
-- As for the others I thought the 71A sounds a little 2a3ish and I don't mean that in a positive way.The 811A I don't have a lot of experience with but from what little I have heard it came off as being a little sterile sounding.--
Thanks! 45 and 300B seem to be what i'd like to use then based on everyones comments.
thanks,
-Mark
Warning Mark, the 300b operated like that is great, I used to do that also, but it's then way under power so don't use those operating points if you're looking for 8 to 10 watts for your base driver.Paul Barker
Bi,Tri amping.I never tried it at home(I use a single full range driver per channel),but I have heard it at other places.The sound just isn't coherent to my ears but take that with a grain of salt and salsa dip.If you like a "clear" sound with tone look at the 845.I run em low,real low but they sound awesome and are easy to drive.This is the one tube I have that I probaly like more than the 300B.The 801 is also an awesome tube.
Do you really believe that??? With high Gp (grid-plate) capacitance, it is any wonder the amps are "magical" in the midrange. From the schematics I have seen, the bass is trimmed and the highs are rolled off. No wonder it appears the midrange is "magical". It is predominate. That isn't high fidelity is it? I thought the response was suppose to be flat.
2nd reason may be propaganda. I have seen misinformation posted at AA from your greats about the plate resistance of KT88s being too high, for instance, when is almost identical (within 30 ohms) of a 300b. More and more magazines, lately, are beginning to understand the truth about KT88s and EL34s,and are printing it.
In my opinion, the reason many don't use the EL34 is because they don't know how to use them. Tinkering doesn't make an expert. And of course there is always that HUMM problem, especially when it fills the whole room.
Steve from SDS audio labs writes:
> > In my opinion, the reason many don't use the EL34 is because they don't know how to use them. < <
and then in reference to DHT tubes :
> > And of course there is always that HUMM problem, especially when it fills the whole room. < <Maybe you just don't know how to use a DHT.
Tom §.
I could design one with no hum, but am past that. I use "in my opinion" because a lawyer friend of mine told me always use "in my opinion" in any statement you make.
The hum problem I was referring to was from Stereophile magazine. The reviewer had to call a famous person down the street who had to redesign the DHT amp by redesigning the grounds which the manufacturer said he would incorporate in the future. Then the hum was only loud enough to hear when sitting. Hope this helps.
Steve,First the interaction with Bob's system and the Gemini required only that the chassis be connected to the ground of the RCA instead of earth ground. Big deal, it only happened because of Bob's system and the routing of power and cabling in this setup.
As some of you may know and others not the KT88 and 6550 where co-designed by TungSol and GEC. The fact as we know that any two plants that make the same tube sound differt is the only reason for their difference. The Rp for the KT88/6550 in triode mode is very similar but when used in this manner is not nearly as linear as the 300B or have the power capabilites because of the limited biasing area in A1.
When I was in college we were taught that using Pentode/Tetrodes in triode mode was a waste of time. We were shown the results of amplifiers in spectral, distortion and output power. It was a pretty shocking study that concluded to me at least that tubes work better as intended instead of other ways.
If we use the KT88/6550 in Pentode/Tetrode configuration the Rp is 12-27K depending on the operating point. Very much higher than the 300B.
Of course one of the best things about audio is the fact that none of us listen the same way. Some may prefer this sound over 300B's in the same arrangement, that what makes it interesting.
Steve, no one is right or wrong except the customer.
Gordon
J. Gordon Rankin, WA
Dear Gordon,
I don't understand where you are coming from.
Your explanation sounds logical enough, but why didn't you fix it over the phone and why did the reviewer have to call another expert to come over and change the internals if it was so elementry?Secondly, I still don't understand why you stated the plate resistance of a KT88 was too high when it was the lower than most all the other DHTs out there? Was it a slip up? You have never explained yourself or even just apologized for the misinformation. This is clear, stated in the spec sheet and even if it wasn't, is easily calculated.
Third, under what condition were the KT88s tested in college? Do you just blindly accept what the professors say? What was the Rp, bias, plate current etc? Did the professors know what they were doing? I had a couple of professors (who taught tubes in the 60s) who were hired to design a lower freq transmitter for a Transmitting company some 21 years ago. The company who hired them sold some and they nearly all failed. I got to discuss the failures with the professors and found out they didn't know the first thing about using the tubes or reading the spec sheets, even though they had taught tubes for years.
Did your instructors know what they were doing? I don't know, except that the KT88 can put out 11 watts rms with approx. 1.9% distortion as actually measured.
I know what is being built using 2A3s, using 2.5K trannies that are being advertized and sold, and advertised as 3.5 watts output matches the spec sheet, so I can only assume the distortion is 5% like the spec sheet states, and not counting previous stages. This would only be different if the new 2A3s are being designed for lower distortion or distortion cancelling circuits are being used.
Anyway, I hope you apologize for your mistaken misinformation about the KT88 triode Rp being too high.Sincerely,
Steve Sammet
SAS Audio Labs
nt
See my last postings on the subject below Jeff. It explains some things. Hope this helps.
Dear Major,
With all due respect I haven't seen any circuit or description here yet that uses the KT88 properly. It is hard to judge a car when the engine isn't tuned up. Hope this helps in your understanding where I am coming from.
Steve,The reason Bob had Neil come in was because he said he was local and wanted to meet him and get him in to check his overall system. Neil used a aligator clip removed the noise and called, I agree to the fixes simple fix and let it go.
About the Rp, I don't remember what I said. But I am sure it was meant in pentode/tetrode mode, which as you know is much higher.
Steve, I use to sell a KT88/6550 SET amp using a 3K transformer at 40W disapation. I checked it out in Triode and Pentode/Tetrode (15W's) and I could not get more than 7W's in Triode mode without using some feedback to get the distortion down lower than 5%.
My Gemini uses higher primary than 2.5K, since the grid is choke loaded it has a very low dcr and is easly driven higher than 3.5W's. Also the power supply is choke loaded so that also gives the output more kick.
Steve, at ONU where I graduated I was taught by a Bell Labs professor who had more patents on analog amplifiers, more than any in the buisness. We tested the amplifier sections as outputs only. We had both PP and SET output transformers, peerless as I remember. We tested the output section using a HV regulated supply, with Ultralinear, Pentode/Tetrode and Triode mode. We tested distortion, spectrum, determined damping, discussed A1, A2 (for triode), AB and B setups.
To tell you how much of a pro Professor Gunzler was he had made all the instruments himself out of heathkit chassis. Actually he took the stock kits, redesigned them and then sent details to Heathkit on the upgrades. Those where other classes by the way.
I remember by Friday's classes all 4 boards covered with concepts, designs math etc... When he came in on Monday and all the boards where clean he would recall all the stuff as if it had never left the board in the first place. He could usually out do problems to 8 significant digits faster than we could on our HP calculators.
We had only 18 pepole in my graduating class, we each had our own labs. open to us 24 hours a day, CPU to the VAX11/780 all the test equipment you could ask for. Dating myself with that VAX11/780 aren't I?
Do I trust his judgement, YEA... Ron Gunzler knew more about this stuff than anyone I have ever talked to... including WE engineers. He died in early 80's saving his two girls from a fire in his house. I am always in thought of things I was taught by this man.
in sober thought...
Gordon
J. Gordon Rankin, WA
Thank you Gordon. I appreciate your candor very much. Dr. Gunzler sounded like quite a guy. Sorry to hear what happened to him. I feel for his daughters too. They have gone through an awful lot. I too havea good friend who past away this last fall. His name was Roland Johnson and he silkscreened. Every fall he would work from scratch on a brand new Christmas card for 2 or 3 months, print them and send them out for free. He was the most kindly gentleman I ever met. A true man.
Thanks for clarifying the posting. I appreciate that also and very right. I harbor no hard feelings towards you or anyone else. Just want to get the facts straight.
Yes with higher Rl the distortion will go down. Must keep the wattage up though, which I am sure you have done.
3K is not the best load for a 6550/KT88 so your conclusions are correct for your design. It is expected that the power output will be low and distortion figures to be high with that load. This is not meant to be criticism, but to confirm that your conclusions are correct with the circumstances present.
Thanks for the chat, Gordon. Some day I hope to meet you over a beer and tell some good jokes. Take care.Sincerely,
Steve Sammet
SAS Audio Labs
I know this conversation has been about power tubes, but do you think the same conclusions apply to small signal pentodes used as triode?
I am thinking about the 7788, 6688, and the old EF86... etc.
Opinions?
Regards, David
I know I haven't anything in that particular area Dave. Sorry.
Wish I could help. Take care.
In the interests of learning it's good to hear what Steve has to say, and should we try it we may find he's right?I have no axe to grind, I make no commercial product as yet, but i keep an open mind, and Steve offers another way which works for him. I don't think spouting his way is going to sell his product in this forum, so I don't see his comments as advertising but as informative, It is up to us to test it for ourselves.
What Steve says about hum is a very valid point. I won't embarass the person conserned but after a friend of mine with associate had been to listen to a certain famous person's 300b amp they came away saying to each other "didn't it hum?" are we sometimes deaf to the inadequacies of our own baby? I have to say that I tolerate a little hum in dht's, but I'm honest about it, it's there!
Regards
Paul Barker
Thanks Paul. I don't want to sell to anyone here. I am not trying to convert anyone, only to correct misinformation and maybe downright lies posted here.
The hum problem I was talking about was so bad the reviewer heard it when he entered the room and had to call someone down the block to rewire the grounds in the amp as the designer couldn't fix it. Then the reviewer only heard the hum when he sat in his listening position, I believe 8 or 9 feet away. It was amazing how the postings in AA didn't even mention this and how those same postings were deleted when going into the archives. At least I couldn't find them.
Secondly, I concluded very early on not planning on selling anything to the audience at AA. It is definitely a DHT forum and I am not trying to convert. After first being acquainted to AA some 1-1/2 years ago, I saw misinformation, maybe outright lies, on IDTs and you get a feel. So I am just trying to correct some misinformation. When someone has 24 years experience and either missed the information or outright lies about the plate resistance of a KT88 being too high when it is actually 30 ohms less than a 300b, well what do you think?? This is just one example or many.
Thirdly, when mentioning the bass and treble and schematics, I can see right away what sonically is happening. It is as clear as glass. I have no problems with individual or group tastes. But when a group constantly needles and attacks my designs and tubes with misinformation before I even knew AA, that is pretty low. It is obvious some never wanted a good relationship with any IDT as it would hurt business. But blackball me from getting a certain brand output tranny is pretty sad. But then I don't wish to give my designs away so it is ok.
Thanks Paul for your open mind and being willing to listen to what is happening in the backround as well as in postings. I have never knowingly gave any false information in any posting and will never knowingly do so in the future. I have never tried to get a customer to drop a purchase of DHT equipment, but I have one account and probably more out there of those who have cutthroated my company.Steve
OK Steve,the more people that are just interested in exploring single ended audio issues whther directly or indirectly heated in a respectful manner the better the forum will become, let's work towards that end rather than allow it to degrade into a mud hole for industry toadies.
Regards
Paul Barker
The hum problem I was talking about was so bad the reviewer heard it when he entered the room and had to call someone down the block to rewire the grounds in the amp as the designer couldn't fix it. Then the reviewer only heard the hum when he sat in his listening position, I believe 8 or 9 feet away. It was amazing how the postings in AA didn't even mention this and how those same postings were deleted when going into the archives. At least I couldn't find them.
Lordy, Steve... Not quite sure what you are talking about here as it took me aproximately 15 seconds to find that amp and posts in question. Indeed, I was involved in the exchange and I dont remember anything deleted. In fact, if you look, Gordon even posts the name and location of the Neil Muncy paper concerning the grounding scheme. Gordon goes farther to admit it made for good reading and included some good ideas etc. He also discusses the perils of a piece of equipment going to Stereophile and how sometimes things dont turn out there as they were in your designers system. On the whole, that amp you are referring to received a GLOWING review. Ironically enough, Stereophile has not yet even printed Gordon's Manufacturer Comments which should go in the issue the review is in... Wasnt in this month's edition either. Perhaps, it will finally make it in next month. I believe Gordon responded for the original issue.I dont think the SET crowd is as closed as you think, at least not ALL are, although, like any "club," it has its staunch members...Members who are more into the club/exlusive aspect than the product, or even the music, unfortunately.
Still, you are coming down a bit hard on the ole SET. These are sensitive sorts that dont like loud sounds, sounds which might startle them... please.... respect their peace...
But, seriously, keep the opinions coming. As Paul said, info is good. But your tone does need some serious work, as does the chip on your shoulder, which has become more like a solid block. I sometimes get accused of my humor being misunderstood or taken the wrong way; however, your tone is not too hard to ascertain and it's not a matter of tongue in cheek satire going awry.
Dave touches on some good points below, although I am not too sure I agree with his analysis of engineers logic being the downfall. Indeed, I find that the engineers use their EGOS in the arguement, far more often than the average loon walking these parts. The manufacturers that tread lightly and are humble do well, while the fiends that come back speaking of lawsuits with accusations flying left and right...well...they seem saddening. One thing is for sure, the written word, especially via an email or forum is not the best way to judge humanoids. Most are terrible at it. And most read what they want from it as well. It's a double edge sword and I have been on both edges in the past. One other thing, this forum is not known for its keen sense of humor...
Perhaps a different approach will bring results and responses that you will find more pleasing all the way around.
kh
I'm new here but I hadn't detected a chip on Steve's shoulder. I'm dedicated to DHT's so I'm not in his camp and have no axe to grind.Reading between the lines it seemed to me that Steve's posts seem to elicit a response from people who are perhaps clamping down on his opinions without giving him a fair go at free speech, as though the chip was not on Steve's shoulder, but the respondents'.
Paul Barker
Thank you for your comments. It is appreciated that there are some good guys out there. What makes me a little miffed is that I lost a customer of two components because of an email he received from another manufacturer, who posted, only what I can call a flat out lie. He was very cunning. I hadn't even heard of him or his company. Then I was referred to AA and found, every so often some misinformation, like the plate resistance posting. I feel this is a real disservice to audio and only feeds self.
If I missed the AA postings, my mistake, although I looked twice.
What interested me was that the review, I believe, remarks that the speaker is what the manufacturer used. So has he had that kind of hum all these years? And yet the gloating and arrogance is upseting. I just hate to see postings that are clearly erroneous being posted as fact and misleading the public. I just hate it. Opinions are fine. I am trying to impress that using KT88s is completely different than 300bs.
On the other hand, your postings within the Forum seem to have a life of their own and don't do much to set a good example as to the kind of business you run or the product that you represent. If I were you, I would take the high road, instead of lounging in ditch, practicing much of what you dislike. A simple idea, but a worthy one in this instance. I cant imagine what you would be saying here if some other manufacturer was bringing up a review of your KT-88 amps in a major publication, and continuing to shed it in a negative light, especially given the manufacturer and the forum members that discussed this very amplifier, did indeed, bring up some of the bad points of that review.
Concerning the products of Wavelength Audio, I have talked to quite a few. Ironically enough, many say that Gordon's amps actually hum less than a number of the other commercial makes. One manufacturer told me that Gordon's amps are the most quiet he has heard! That is why I found that review rather ironic as well. Gordon was just as incredulous that his amps produced a hum of this magnitude in the reviewer's system. Do you think he would have been so foolish to send a pair of humming amps to a Stereophile review, a review capable of doing serious damage to the sale of this new model (and also the first super low watt SET reviewed within that magazine's pages)? Yes, Gordon and the reviewer did uncover a better approach to the grounding, and Gordon was very humble at this and even said he would implement the new approach, even though he had not been having hum problems of this nature personally.
Frankly, I don't see the gloating you speak of. Most were surprised (including myself), that a SET amp employing a 45 tube made it within the rather conservative Stereophile review stable. And to my surprise, this wasn't even a Sam Tellig review! If you read the review, the amps actually do get a VERY good review. See this quote:
"What the Gemini offers...is transparency, detail, harmonic 'rightness,' and an ability to maximize musical values with a minimum of electronic artifacts. For those of you that value these characteristics more than sheer loudness, the Gemini may in fact be the ideal amplifier."
I find this a rather positive conclusion to this review. Yes, there were negative comments made, the hum being the most troubling, but one cannot discount the system at hand as well as the fact that Gordon has personally looked into the matter, and even posted as much within this very forum. Where is the gloating? I personally went back and re-read ever post in that exchange and I never saw any "gloating" at all.Finally, I do understand you wanting respect for your product. And if people are blindly attacking it without experience or much more than conjecture, than that is circumspect as well. On the other hand, you are heaping tons of criticism on SET amps in general and a manufacturer in particular that I dont feel is justified. You are guilty of the very thing you detest. And you are doing your product and the KT-88 no justice by firing these acusations. If anything, your are damaging your credibility. Just by my own experience, I have found properly designed SET amplifiers employing DHT to be very extended in the bass, with EXCELLENT highs! Indeed, that is one of the most magical things about these amps besides their magic midrange; the bass and treble regions, with proper speakers, are so damn natural and well defined, without being HI-FI!
As Tom said, I think that great sound can be wrought from the KT-88 and perhaps your amps. I love my EICO HF-81 as much as any amp I own for its supreme musicality, and it employs the 6BQ5.
Why not start anew from now on...wipe the slate clean... Remove the horrifying chip from your shoulder and let it go. Hell, you might be able to hear the music (or the hum) better...
kh
I wish what all you said was true. And it sounds very nice on the surface. However, I have lots of downloads of sly comments like "true" triodes are better, IDTs produce higher distortions and so much more. Very cunning and sly remarks have certain phychological effectgs and give certain impressions and I am suppose to keep my mouth completely shut? Go back and look at the unsolicated hate postings that I did challenge. I finally put in a page on my website that listed a distortion chart of IDTs and DHTs, and did you see all the hate in the postings. There was some 80 horrible postings attacking the validity. Yet they were claimings IDTs were terrible distortion producers and I lied about my distortion measurements. Attacks that I was lying, cheating etc. And I didn't see more than one posting supporting the measurements and the truth. Just pure hate to try to discredit me. I then saw that none of the business sites listed their distortion specs. The overall scheme appears pretty clear between the backbiting in the backround, the attacks and sly comments on AA (I have downloaded maybe two dozen or more), and the fact that nearly no one condemns will condemn the backbiting (except you). The last time I posted the backbiting in the backround, I got not one posting condemning such backbiting activities. Not one. That told me alot about the group. Sometimes what you don't say speaks very loud.
So if you guys want to continue with your sly little comments and misinformation that is up to you. It is on your conscious.
Gordon's comments about triode wiring in a M3 or ST70
Another triode wiring post.
Concerning DIY Vs. Manufactured that got ugly.I find it funny that in the data you posted on 300B's etc. are from old manufacturer data sheets and are not current measured data (i.e. old data based on taking a dozen or so measurements and doing a calculation method to interpolate curves). Even then, that THD data uses a static resistance at a single frequency. There's so much more to it than that. The deltas play more of a part in the sound than just squirting out THD measurements at 1khz. Then again, you should know this since you have sooo much experience with tubes. Seems to me you just have a personal grudge against Jeff Mai, Rankin, and an unnamed person in an e-mail. Why attempt to damn AA as a whole if your beef is with 3-4 people?
Tom §.
I don't think so Tom. The reason, if I may explain, has been several postings stating that 300bs had lower distortion than KT88s. I had taken measurement several years ago and knew according to the specs of the 300b that this wasn't so in my opinion and measurements. Since they didn't present proof, I thought the consumers should not be mislead, even if by mistake.
If one measures the distortion of a tube and another measures with a very low distortion driver etc., I would assess the second as showing the tube has better performance than the first person. If a third could show the distortion even lower, with a very low distortion driver, then I would assess that the tube would do even better.
That is why when I saw postings that supposively showed the KT88 as not even having, just say, 5 or 6 watts output, I knew it wasn't an accurate measurement as I have gotten 11 watts out of the tube by measurement and much lower distortion than their findings.
My own measurements showed me what the tube would do and I assessed that my measurements were more accurate than calculations etc. This is my last posting on this subject.
Hope this helps, Tom. Take care and have a great week.
The Asylum forums are open forums.Anyone can lie, brag, whine, bitch, cajole, and react however they want, as long as they do not libel or harm others in a legal sense. I long ago learned to ignore the posts of those who believe in unsubstantiated tweaks and unproven modifications. I also believe that if a tweak or "improvement" produces pleasures that are placebo-effect related, it is o.k.It is not the facts that have gotten you into this deep quagmire, but the way you handle people. Only you can control the way you interact with others, and I see no evidence that you are capable of diplomacy and tact. You seem to believe only in attacks and counterattacks, and as long as that happens, you will be engaged in perpetual pissing contests.
You may be correct with many of your engineering facts, but please be aware that the SET crowd, in general, does not believe that vanishingly low distortion measurements is the key to musical pleasure, the goal of their listening. You will not be able to beat down this crowd with mountains of facts.
Me thinks that you should consider changing your strategy.
Dave van Harn
It's not what you say, but how you say it.Engineers, in general, do not have a great reputation for personal and effective communication. The non-technical world runs more on emotions and opinions than facts. This frustrates many logical people like scientists and engineers, and is why so few of them make good salesmen. I know this because I worked as a lab technician in high-tech and biomedical industries and as a "Sales Engineer" in aerospace and computers for many years. In sales I had to sound logical and use emotional sales methods subtly. I quickly learned that simple logic did not close many sales, and that many of the best sales engineers were the least technical.
Like Audiophilander, you seem to have a nack for making people angry toward you. You may be correct about many things, but your negative attitude seems to draw even more negative reactions. It will be interesting to discuss these personality conflicts with other tube fanatics (and many SET fanatics) at the VSAC tube audio conference in September.
I don't believe Asylum regular Jeff Day is lying he says that his 45 Wavelength amp has hum that is nearly inaudible through his 100dB+ sensitive Avantgarde horns. I wonder why his experience is so much different that that of the Stereophile crew. It could be partly because Jeff did carefully assemble a synergistic system over time, and Stereophile tried to plug the amp into and existing system and room, which no serious SET fanatic would do.
I sense anger and frustration in many of your posts, and you've got a long ways to go before people stop snapping back at you. I enjoy your logical/technical posts, but when your emotional reactions to the popularity of SET's, especially from Gordon (similar SET designs in various price ranges are also made by Ron Welborne, George Wright and others).
BTW, I have a Chinese Kailin EL84 PP amp that is dead quiet, a KT88 SE amp that is very quiet, and an Italian (Tektron) 2A3 amp that has significant hum that I haven't had time to work on. I still am fascinated by SET's for some unknown, illogical reason, and feel no compulsion to desert them. This is highly illogical, but I'm not into music and audio for logical reasons.
It's your attitude, snide remarks and your inability to initiate civil discourse about your dislike of DH pure-triode SET amps in general, and Gordon Rankin that upsets me.
Also, you should be aware that Asylum moderators do not delete any post when archiving, and ANY of the rare deletions are done only after careful and deliberate consideration when the rules are violated (except for "for sale", "WTB" and flagrant personal attacks). If you have questions as to why any particular post was deleted, ask privately (via the "Comment" link below) or publically in a post. There is no hidden agenda here. You have always had the opportunity to build and maintain your on-line reputation. What people think of you, and how they react to you is almost always due to the character of your on-line persona. And only you can control that.
I think that you probably have excellent amps, although they are more utilitarian and homely than even George Wright's. Yet George thrives as a favorite, inspite of complaints about poor response to requests. Of course, he doesn't come here and offer himself up for flogging, but that's probably because he is not an internet type, and doesn't have time.
Points well taken Dave. Thanks. What bothers me has always been the misinformation like the plate resistance of the triode KT88. If he didn't know exactly what the plate resistance is, although it is listed in specs, then it is good not to mention it.
Some postings seem so flagrant that the only assumption is that it is purposely done. And what aggravates the situation is the back biting, like one email I got, I believe before I ever knew of AA, condeming the tubes I was using and switching him over to a DHT. It cost me two sales. I can't even purchase transformers from one company, not that I want to now, because a DHT man blackballed my company, before I knew of AA or DHT company competitors. See where I am coming from? I was strictly trying to get a business going and find out there is backbiting coming from DHT companies and found AA. Then I read some of the postings that reinforced these views. I hope this helps you see where I am coming from. Thanks Dave for your posting.
Yes and points well taken as well. Basically, AA has always been primarily a hobbists venue. I sure don't try to verify any technical data and all our moderators together probably read less than 5-10% of total posts. We get about 10 Million page views a month and hundreds if not thousands of new posts a day.I'm sorry to hear about the back biting. I get it too in a different way and have just come to accept that everyone won't like my product and my way of doing things. Oh well, you please those that you can.
This board in particular does get the SET religion going. I admit to being enamoured with them, how low can you go? But I've heard great EL34 amps and OTLs and lots of other stuff, even sand amps. If there's overt misinformation, let us know. Post a response.
We've never selectively deleted information to skew a point of view. And we don't delete and archive to skew a position though I admit you might find a contenious topic or two trimed and archived. If you find a suspicious one, let me know. I've got logs and can find out what was deleted.
Anyway, when you've got the blind leading the blind, you'll find them stuck in the corner now and then. We surely welcome expert opinions and knowledge.
BTW: I think the name Steve was registered to another inmate so that the (i) link goes to another person. Registering on your part would resolve that confusion.
I also noticed your exchange with Gordon and am pleased that you've resolved those questions. It brings the question of AC versus DC heaters to mind. I've heard that the AC heater level on the 300B and other SETs can be a source of hum. JA implied in the Stereophile article that using DC would solve that problem. Yet, I suspect that this is yet another trade off. Any thoughts on that from anyone?
We have a pro bono attorney available who watches over things and helped us set up the rules. However, we tolerate a wide range of "opinions" that can be tough on some industry and publishing people. As long as real libel and fraud are not being perpetrated here, and other rules are not being broken, we let posts stand.I suggest that you e-mail Asylum site owner Rod M. (webmaster@audioasylum.com) and open a dialog off-line to see how you can work to change things and become one of the good guys in people's eyes. Gordon Rankin and Ron Welborne were at each others throats a couple of years ago, and have since learned to co-exist here, although Ron has his own Asylum "sponsor" forum and pretty much stays there. You'll find that most of the inmates are pretty forgiving, and grudges can be overcome.
I think that when tube/SET designers join the discussions here, while not promoting their own products per the rules, we all come out ahead. But it can be a delicate path for you industry types. Just work with Rod to make things better.
Dave van Harn
I really agree with you Dave. I must have at least two dozen postings that are either sly or downright misleading or factually wrong and everyone of those postings is against IDTs. This was before I ever knew of AA so the attacks were before I ever knew you guys. I wanted only peace but soon found I or "my" tubes were continually attacked. Sorry but I don't have to be a sitting target. And I don't care if none of you purchase from me. That isn't my goal. But misleading, ignorance, or lying in a posting misleads, is close to fraud and just isn't right. All these horrible postings are phychological warefare. Remember when I mentioned the low distortion KT88s produced, the chart on my website and the 80 some odd hate postings against me? Well, that chart probably wouldn't have been put up if I hadn't gotten so many sly and hate postings against IDT tubes. And what happened when I just started posting, nothing but hate and put downs. Actually it started way before I even knew about AA. I have also seen one or two IDT guys quit posting here because of the harrassment and hate. Let's face it, in my opinion, the purpose of AA is to phychologically prime the public and newcomers to the propostion that there are no alternatives to DHTs or at least that IDTs are always second to DHTs. That, to me, clearly, clearly appears to be the goal. There are a couple of exceptions, like Dave who are good guys. But they are the exception.
Thanks Dave for being open minded and you are at risk. At the risk of you and a few others from being harrassed I ask the others not to firebomb them.
> > But misleading, ignorance, or lying in a posting misleads, is close to fraud and just isn't right. All these horrible postings are phychological warefare. Remember when I mentioned the low distortion KT88s produced, the chart on my website and the 80 some odd hate postings against me? < <I hope you aren't referring to our friendly exchanges, Steve. My specific dispute is with your claim that a triode connected KT88 has lower distortion than a 300B. I've repeatedly asked for proof of this and I'm still waiting. There is no lying, misleading or hate here; just a desire for the facts to be known.
I actually measured it in a low distortion circuit. That is proof. IF you don't like it, that is too bad. If someone measures distortion of a particular tube and another measures lower, much lower with a very low distortion driver etc., then the second is more correct as to what the tube can accomplish. It is that simple.
It also seems to me that the so called "friendly" postings were not friendly but attacking my products.
Another interesting point, BFS listed only my SE7.0W from 1999 in the review of the Edgarhorn slimline and not yours.
I looked at the spec sheets and I actually measured the distortion with an honest to goodness distortion analyzer. You didn't if I recall.
But remember, Jeff, it was you guys, look at the postings Jeff, it was some of you who stating that the KT88s were higher in distortion. Look it up Jeff. Tell the truth. I never stated my findings with actual measurements until you guys mentioned it.
SEE DAVE what I have been saying. Go back and look at how many postings where they said the KT88s had higher distortions than the 300b and 2A3s etc. There were several. I never posted first, just them. Yet it turns out my measurements from an actual distortion analyzer showed the KT88 to be lower.
SEE DAVE what I mean. There is obviously bias and an adgenda here. You got to be blind not to see it.
Steve,Disagreeing with you is an act of hate????? Asking for legitimate proof is an act of hate?????
I do not hate you or your products. I do not disagree with other claims you've made. IHTs do produce less hum than DHTs, other things being equal. Triode connected pentodes often do have more gain than triodes. Triode connected pentodes can make excellent amplifier output tubes and fine sounding amps. The Rp of a KT88 is very similar to the Rp of a 300B. Triode connected KT88 amps *may* have lower distortion than a 300B amp, but whether this is true or not depends on the design of the amps and has nothing to do with the tube itself.
What I do disagree with is your claim that a KT88 has lower distortion than a 300B. That's all; plain and simple. You offer the data on your web site as proof of your claim. By your own admission, this web site lists distortion figures for the WE300B that come from Western Electric's data sheets. This data was either measured or calculated for the 300B output tube in isolation. The data you provide for the KT88 is at the output of a complete amplifier. Because of this, comparison of these two pieces of data are not meaningful, i.e. you're comparing apples to oranges. For pointing this out, you accuse me of hatred and lies?????
Western electric used measurements, not calculations for their specs. That is what I did. Using a low distortion driver and very conservative output tranny means very low distortion which does not affect the outcome of the tests. Thus apples to apples.
If the design of the DHT amps could have low distortion, then they should have done it instead of continually hiding the specs.
The printed curves are very general and not nearly good enough to determine specs. Just a couple of mils off because of interpolation means the calculations are way off.
By the way, how did Western Electric drive the 300b to get the specs. with a low distortion driver circuit. That is what I did.
This is my last reply on the subject. Take care.
BTW, here is the "missing post" - was there all the time, with all responses. But Steve, you ststed twice it was deleted, as though it was FACT. You do tend to make other statement of opinions as fact as well.http://www.audioasylum.com/forums/set/messages/9188.html
Another point - You appear to think no one of competence has designed SE amps with EL34s before. John Atwood designed and published in VTV the Randall Amplifier many years ago. He in fact, had HUM problems, which he solved in a novel way, as described in the VTV text.
here it is -http://www.one-electron.com/Randall/Randall_Info.html
Last, you have made a point of telling the forum the designs you see are rolled of, lack bass, etc. but you never give specifics. Same for the KT-88 plate Rp. Show the posts or designs.
Why not show the URL with schematic, show us your calculations, and why you think it is a poor design. Instead of reapeating the same statement about some ? SET design you keep referring to. It is this fuzzy condemnation without specifics that is most troubling to me. The curves on the Wavelength amp in Stereophile are there for all to see, -3dB@ 18Hz w/ 2A3, @24 Hz w/ 45 tube, and -3dB @ over 50kHz for both.
There are ways to get practically zero hum (way down in the microvolt range) from DHT tubes. This "room filling" remark is just as unfair and misleading as anything Steve is trying to combat to get market penetration for his amps. I have a standard hum balance pot on my 300B amps and I get around 2 mV noise output. It requires a quick check once every 2-3 days as the position does change a little due to thermal expansion/contraction etc. There are ways that can reduce that amount anywhere from 6-12dB. I can't hear hum from my setup unless I have my ear 6 inches from the speaker and I certainly can't hear a damn thing in my listening chair. My refrigerator in another room makes more noise. Hell, I even have a DHT for a preamp tube. Using a DHT for a preamp tube is even more critical to get hum and noise down because everything gets amplified in the system about 50 times afterwards. Guess what? Quiet as a cemetary. DHT's can be made stone quiet folks. What a f***ing suprise, eh?Now, did I ever say a SE EL34 or KT88 cannot sound good? No. I'm sure they can be made to sound lovely in some systems. I just find Steve's logic as a contradiction since all these folks who formed a preference towards DHT after trying SE EL34/KT88/6L6/EL84 just "didn't know how to use them." As for your "famous" person/amp story, why didn't you tell the person that the humming was noticeable? Why do you automatically attribute the cause of the hum to the 300B amp? Perhaps it was a ground loop. You just never know until you bring it up and investigate.
Tom §.
I was relating the experience of a third party, whay he didn't tell the person I would presume was in respect. We shouldn't do that should we?I play my amps to a friend that is not into any of this, if he sits quietlty and says nothing I know I'm kiding myself, it's really not good at all, yet I'm so prowd of it. My friend won't tell me but his not saying anything says enough, I have to take another look.
If I get it right, and it seldome clicks into place, even my wife notices how like the real piano etc the thing sounds, when you don't have to explain it to a totally ante person and they bring it up, you know you're there. Very subtle though, and somehow the builder gets so engrossed it's subtely taken away by one change he may have made that somehow slips his notice.
Hum, I use Sukuma San's system, works for me, more hum, than an iht, but tollerable, if I eliminate it, I get less lifelike reproduction, it's a compromise I'm prepared to live with, until I've solved it. Sometimes I think I have solved it, but then after a while I realise the life has gone, I duped myself again.
Paul Barker
I am not even trying to penetrate this market, that is for sure. When I saw the misinformation or maybe outright lies on AA about IDTs, that is when I decided to give factural information.
The hum filling the room can be found on the stereophile review.
The circuitry had to be redesigned to lower the hum which the manufacturer stated he would incorporate. I noticed the postings pertaining to this review were deleted when it went into the archives.
And you mentioned nothing of this hum problem.
The only way you are going to use a DHT in a preamp is if you use DC for the filament and how many parts did you include in this circuit path?? What about microphonics? Were you able to rid of them?
After looking a the schematics, it is very clear how they sound. They were designed to sound that way, "weaken" the bass and highs and the midrange is bound to be prominate with more detail. That is as old as the hills.
But remember Tom, the design of a KT88 is completely different than that for a 300b. So you cannot use a 300b circuit and expect the KT88 to be optimal. Again, frankly, I don't want your business, never did.
Hope this helps.
> > The hum filling the room can be found on the stereophile review. < <Well DUH! Why do you keep harping on that?
> > The only way you are going to use a DHT in a preamp is if you use DC for the filament and how many parts did you include in this circuit path?? What about microphonics? < <
Well, there are the shottkey rectifiers, 2 adjustable regulators set up to regulate voltage and a 3rd adjustable regulator to regulate current along with caps to ground between each stage for filtering. If you're trying to use the "less is more" axiom here then you better slow down a bit. All AC signal current in the circuit I built is referenced between the plate, grid, and cathode. The input and output grounds are the cathode of the tube. Think that's as simple AC signal path as possible?
> > After looking a the schematics, it is very clear how they sound. They were designed to sound that way, "weaken" the bass and highs and the midrange is bound to be prominate with more detail. That is as old as the hills. < <
Well, that's a nice ambiguous narrative meant to over-generalize DHT amps.
> > But remember Tom, the design of a KT88 is completely different than that for a 300b. So you cannot use a 300b circuit and expect the KT88 to be optimal. < <
When did I ever say or even imply this? You're doing a bang up job of attempting to interface with things that just aren't there.
You know Steve, one day we may meet in person and probably have a beer and laugh about all this sillyness. Until then, I'd suggest calming down a bit and defocusing on your intent to polarize things.
Tom §.
And I also want to highlight that Jack is correct that ALL the components have a certain sonic signature that will appeal or not to different people, regardless of circuit.How you get the most from your choice output tube is a big thing, too. But as good cooks know, you have to start with the best ingredients, and there's no way Nutra-sweet will make it better than old fashioned sugar for good taste. :-)
Kurt
I can agree with you on that Kurt. The best resistors, caps etc.
Unfortuneately, their are some other problems with some of the older tubes. The Gp (grid to plate) capacitance is twice or more that of IDTs. IDTs offer lower distortion, less drive, fewer stages needed or more effectively utilizing that stage if used, fewer parts in the overall design, fewer solder connections. I could go on but the overall superiority appears clear. And if each part does distort like we both agree, the fewer stages and accompanied parts means less non measurable distortions. For instance how do you measure "sheen" in music. I think one of the very best designs is DC coupled where you can get rid of a coupling cap. and bypass cathode resistor cap. Even the best are deficient. Good conversation.
Well, I like IDHT SETs, too, for different reasons. I also have a homebrew triode-connected KT88 SET that I like a lot. But it is not built to the same degree as my globe 45 SET and is not in its league. It might make it there, but my experience tells me it's real hard to beat a good globe 45 for my tastes.Kurt
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