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the tung-sol reissue 12au7? any thoughts???
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Asking opinions about a 12au7 is like serving a prison sentence and getting recommendations for the best canteen meals.
Better not to be in prison in the first place!
12FQ7 and prefer it to the 12AU7 and I have many different 12AU7's in NOS.
The Elaborate DAC=Johnny's Balloon Meshplate 27 Balanced Preamp=Balanced Six Pacs=Newform Research 645
iRiver H140/MB Balanced dac/amp/Ultrasone Ed. 9/JH13 Pro IEM's
see images at: www.pbase.com/jamato8
Hey John! How's it going? (Besides over 100°F).
Have you run into a circuit where the idle bias current draw of the 12AU7 is an issue? In terms of substitutions.
Much thanks!
want to plug in. If it with within the curve then I might try it but otherwise it wouldn't make sense.
Triple digits here all the time now. Hot and hotter. Need to head back to northern Calif.
The Elaborate DAC=Johnny's Balloon Meshplate 27 Balanced Preamp=Balanced Six Pacs=Newform Research 645
iRiver H140/MB Balanced dac/amp/Ultrasone Ed. 9/JH13 Pro IEM's
see images at: www.pbase.com/jamato8
course the 105deg...was better than 115deg of Phoenix,...
and the camping on Cool Mt Lemon was a perfect desert....
anyway...Big Peace in Tucson...and keep on rolling to the music
-3db
and of course 12au7's got to go...and 12ay7 will almost always do wonders...
Mendicino sounds so good, now. I know several ppl on other boards that live in Santa Rosa. You ever been to the Wells Fargo Concert Center, in SR? Great place to hear good music.
to have never gone. What a place and I was right there! What was I thinking.
The Elaborate DAC=Johnny's Balloon Meshplate 27 Balanced Preamp=Balanced Six Pacs=Newform Research 645
iRiver H140/MB Balanced dac/amp/Ultrasone Ed. 9/JH13 Pro IEM's
see images at: www.pbase.com/jamato8
Swap a few wires. Unless, of course, the filament transformer hasn't the reserve to cope.
Rolling 12AU7s is a waste of money and time.
Note that a post in response is preferred.
Warmest
Timothy Bailey
The Skyptical Mensurer and Audio Scrounger
And gladly would he learn and gladly teach - Chaucer. ;-)!
'Still not saluting.'
Timbo,
Are you saying the tube can not impact on the sonics due to its archetecture, or that they all sound bad, so what's the point?? I have seen many amps that employ them, why are they used so often?
I have rolled many 12AU7s and found definite changes in the sound of my amp. I ended up using 7136s in place of the 12AU7s in my Jadis DA-60 integrated. I am no EE and not tech savvy, so I don't know what they do in the circuit. The DA-60 requires 3 X 12AU7 and 2 X 12AX7 in the "preamp" section.
Steve
12AU7s - good ones - make great zero-gain buffers, e.g. cathode-follower with maximum NFB and a gain of .95. That is what I use mine for. I would never use any of the 12AU7 varieties in a critical role like splitter/driver.You'll also notice that I'm not alone in my considered view of the 12AU7.
I'm into good sounding audio to listen to simply recorded acoustic music, IE mostly classical, and choral music. I'm an ex cathedral chorister, and still sing in my current parish.
I listen to such music at least once a week, live. And once I had a system that did a very good job at that, and letting me hear how different each recording is. Well, my need to worry fell. Issues like the room, better amplifiers, wider FR range took primacy. Playing around with small tonal changes strikes me as a waste of time, and money.
The rebuilt classic valve PP NFB power amps I've used since the mid 1990s contain role-appropriate valves. They have very large storage in their PSUs and have very good bass, they are quiet, sweet, and crisp, valvey, yet neutral.
For me audio is about knowing where I am going, learning, and sticking to it. Likely return on investment in improving believability and involvement is my main criterion.
I would never use a multi-miked, phased Eq'd, Aphexed, mix-down pop recording as a guide.
While simpler recordings have a good deal of variation* in the sound-field they create, I am reasonably across that and can understand what I hear. EG ORTF, 2 spaced omnis, or 3!, Decca's mix. Crossed pairs, sound-field mikes, Kimber Iso-Mike. etc.
In the late 1970s I was lucky to find a speaker design that beat the QUAD 57s, almost new black mesh ones that I nearly bought, and did a bettr job on the inevitable baby boomer pop/rock collection as well. They are 2-way 8 inch spheres and since the 90s bi-amped: actively in the bass since there IS no low-pass, and passively in the treble.
The side of the audio hobby with changing cables, valves, or regular changes in equipment seems a pretty pointless tail chase to me. I feel it is driven by trying to get a hi-fi system to sound good on recordings for which the term high-fidelity to an ensemble in a space in real time just does not apply.
E.g. One visitor (who because he has a dipl.eng in EE thinks he's 'a scientist') turned up with a carry bag of nothing but pop CDs and put on a Linda Ronstadt album - famously discussed in Rolling Stone for its use of the Aphex Aural Exciter, and which I have on LP and still enjoy.
He proceeded to tell me that there was a lot of MR distortion. Well, hell yes!
Dig it.
Note that a post in response is preferred.
Warmest
Timothy Bailey
The Skyptical Mensurer and Audio Scrounger
And gladly would he learn and gladly teach - Chaucer. ;-)!
'Still not saluting.'
Edits: 06/15/12 06/15/12
Tim, I know what you are saying!
But the supply of 12FQ7 is very limited and will be gone in the not too distant future. I recommend that the tubes be set up to use the 6CG7 since the EH is available and a nice sounding tube. Or the 12BH7 EH.
I don't remember 12fq7s being available in big numbers even in peak tube years.Do they really sound that much better with a 12v filament?
When problems become increasingly difficult,we can always rely on our collective knowledge and seek relief.
Mike, I think Jim is saying that the 12FQ7 sounds better than the 12AU7 and can be used without mods where the 12AU7 is being heated with 12.6V, of course assuming the filament supply can provide the extra current the FQ draws. There should be little sonic difference between the 12FQ7 and 6CG7/6FQ7. True, Jim?
True - but a BIG difference in availability. That was my point. 12FQ7s are old stock only, and that supply never was all that large.
I didn't think the supply was all that large.
When problems become increasingly difficult,we can always rely on our collective knowledge and seek relief.
Has been my experience that lower voltage on filament translates to lower potential for hum.
All things considered.
The Mind has No Firewall~ U.S. Army War College.
Thats been my experience also.
When problems become increasingly difficult,we can always rely on our collective knowledge and seek relief.
a quieter tube.
The Elaborate DAC=Johnny's Balloon Meshplate 27 Balanced Preamp=Balanced Six Pacs=Newform Research 645
iRiver H140/MB Balanced dac/amp/Ultrasone Ed. 9/JH13 Pro IEM's
see images at: www.pbase.com/jamato8
John
Do you mean with an above ground DC source tied to the filaments? That is the best way I have seen to reduce troublesome hum.
When problems become increasingly difficult,we can always rely on our collective knowledge and seek relief.
you are good to go.
The Elaborate DAC=Johnny's Balloon Meshplate 27 Balanced Preamp=Balanced Six Pacs=Newform Research 645
iRiver H140/MB Balanced dac/amp/Ultrasone Ed. 9/JH13 Pro IEM's
see images at: www.pbase.com/jamato8
On some phono stages I have gone up to 90vdc tied thru a pair of 100k resistors.
When problems become increasingly difficult,we can always rely on our collective knowledge and seek relief.
the problem. On my dac I built, I set the tubes to around 60 volts above ground. Worked very well and the analog stage is very quiet. You gotta love tubes.
The Elaborate DAC=Johnny's Balloon Meshplate 27 Balanced Preamp=Balanced Six Pacs=Newform Research 645
iRiver H140/MB Balanced dac/amp/Ultrasone Ed. 9/JH13 Pro IEM's
see images at: www.pbase.com/jamato8
Rolling them is damned close to a waste of time. there are a few which ar good enough but all NoS and already demanded to rare and $$$$. The Brimar 13D5 is the one I've used and NoS 6189s aren't bad. Yes there are others.
I hesitate to say this ;-) but I agree with Mike Samra. There are other noval tubes which are a good swap. The 12AY7 (no rewiring needed and less heater current, and more gain - possibly), the 6DJ8 family, the 5687, ECC99, ....
Note that a post in response is preferred.
Warmest
Timothy Bailey
The Skyptical Mensurer and Audio Scrounger
And gladly would he learn and gladly teach - Chaucer. ;-)!
'Still not saluting.'
I have built a couple of amps with that tube in the schematic and say to myself "Well, good schemo but 12AU7 will have to go, substituted by 6SN7"
The Mind has No Firewall~ U.S. Army War College.
Agreed 100%,and I don't eve hesitate to say that!! Argh arch!
When problems become increasingly difficult,we can always rely on our collective knowledge and seek relief.
so why do big name(well known designers) use them?
Freelance reviewer for StereoMoJo
12AU7 is available in new manufacture and that is attractive to a new manufacture amp to keep costs down. I also say the big name designers are cutting corners unless perhaps used as a cathode follower or cathodyne phase splitter. Even at follower or phase splitter service there are better new manufacture tubes such as the 6SN7.
Most DIYers are wise not to use 12AU7. Why shoot yourself in the foot when a fortune was spent everywhere else in the DIY design to have a 12AU7 muck it up?
Earnie
What I found about 12au7s is,I like them in a preamp mu follower stage but in most amps,I would rather move the fil wires and use 6CG7s.If I am staying with the 12au7s in an amp,6189s are not a bad choice.I would prefer an ECC802 tho.
When problems become increasingly difficult,we can always rely on our collective knowledge and seek relief.
Hi Mike,
Based on the number of posts on the subject over the years, you've been a pretty big advocate of the VTA boards for Dynaco equipment. Have you converted that circuit to use the 6CG7?
The 12AT7 VTA circuit offers too much gain, and the 12AU7, well, what Timbo said!
I'm trying to sort out what I'm going to do with these Dynaco MkIII's I just awoke from a twenty something year slumber.
I have converted that circuit to 12au7s and from there I have scraped and moved the filament wires.The dyna mk3s are not too bad with the 12at7s.You need to remove that bypass 47uf on the cathode of the input stage...I would use one 12at7 and one 6cg7 to experiment tho.
When problems become increasingly difficult,we can always rely on our collective knowledge and seek relief.
Too often IME 12AT7s are quite steely in tone.
NB it doesn't HAVE to be a 6072 hand-selected for super quiet, and rolled on a virgin's thighs, maate. It's not a microphone amplifier now is it?!
Basic 12AY7, should have enough gain and you can probably use less NFB, which can't hurt.
Note that a post in response is preferred.
Warmest
Timothy Bailey
The Skyptical Mensurer and Audio Scrounger
And gladly would he learn and gladly teach - Chaucer. ;-)!
'Still not saluting.'
I have and am not impressed with them. Seem lean to me. I prefer the JJ Tesla short plate (warmer) or Shuguang (more resolving and balanced, if somewhat forward overall).
Likewise I prefer the JJ Tesla (short plate), Shuguang and Mullard re-issue 12AX7 over the Tung-Sol re-issue of same.
Haven't tried them. But, if they are anything like the T.S. 12AX7, they are probably pretty nice. The T.S. 12AX7 is a very good tube, IME.
Vinyl + Tubes= Bliss
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