I completed my SSE several years ago...everything is good, no problems. Still using the 6CA7 fat boy Electro-Harmonix outputs. I have been experimenting with the 12AT7 and it's variants to determine which type suits my setup best, as in delivering the best sound. I know this is subjective, and highly dependent on all aspects of the amp and it's associated equipment. I have a couple of favorites, but I'm interested to know what other SSE owners have found to be "best". Also, if any found types not compatible with the standard 220-ohm cathode resistor.
A few notes for reference, about my amp setup: operation is triode mode, no cathode feedback, 5AR4 rectifier, EH 6CA7 outputs with 680-ohm cathode resistors. Edcor output trannys are GXSE15-8-5K, plate voltage running about 420v. Usual operation is direct via a CD player, current speakers are Klipsch KG4 and or JBL-L50.
I have some of the 6201 GEs, they are one of the best-sounding 12AT7 types in my amp. Also nice are the CV4024 British tubes...a bit mellower perhaps. I ran some 12AV7 for a while, but I'm not sure they liked the default cathode resistor setup. And somewhere in all that experimentation, I fried the mosfets. Also ruined at least one 6211 tube, before I realized it couldn't handle 10ma current. So I'm now checking what I install in the amp by monitoring the cathode current (measured across R10 and R20) and calculating the ma from the voltage drop. With most 12AT7 types I'm getting about 8.5ma, with anywhere from 200 to 250v at their plates. I did increase the size-area of the heat sinks for the regulators, and my board is built all on the top side so they cool pretty well.
Next I plan to revisit the 5965. I recall it sounding very clear in the top end.
I am late for the party.
I may be misunderstanding your question. This is my response to to my read on your posit.
My SSE started with a Jan 12AT7WC. Using EL34IIs and KT88s the amp sounds very good.
I picked up original release British made Mullard 12AT7, German Telefunken 12AT7 and US RCA12AT7 blackplate.
Using the Mullard with the EL34IIs the amp sounds incredible for symphonic, strings and the female voice. The RCAhas more bass, but the strings and female voice isn’t quite as good.
Using the KT 88s the return isn’t quite there. I need to install a switch for caps when switching between the ELs and KTs.
Just using different brand/ models of the 12AT7 give surprisIng different responses. Finding the one/s you like best can be fun
I may be misunderstanding your question. This is my response to to my read on your posit.
My SSE started with a Jan 12AT7WC. Using EL34IIs and KT88s the amp sounds very good.
I picked up original release British made Mullard 12AT7, German Telefunken 12AT7 and US RCA12AT7 blackplate.
Using the Mullard with the EL34IIs the amp sounds incredible for symphonic, strings and the female voice. The RCAhas more bass, but the strings and female voice isn’t quite as good.
Using the KT 88s the return isn’t quite there. I need to install a switch for caps when switching between the ELs and KTs.
Just using different brand/ models of the 12AT7 give surprisIng different responses. Finding the one/s you like best can be fun
Yes, my question was about what other users have found in trying out different NOS 12AT7 or equivalent tubes in the SSE. I've only tried a few other output tubes, after settling on the EH 6CA7 some time ago, but I've been noticing the different 12AT7 brands, and variants such as 6201, mil-spec 12AT7WA,B,C etc. CV4024 British valves (especially the Brimar) all have different "presentations" so to speak. Mullard and Brimar seem to make vocals, especially females, sound really nice. Sylvania tubes have quite prominent bass, the GE 6201 triple-mica are really nice for treble detail without sounding harsh or shrill, etc. The GE 5965A is really a 12AV7 designed for computer use, but it has a huge soundstage. One tube that seems especially well balanced in it's presentation is the 6679 Tung-Sol, although the only one I have is microphonic. I'm going to look for more, but they're not common. Adding two o-rings around it seems to tame it enough to be useful.
What have others found with current production tubes? All my experience so far has been with NOS or used tubes from mostly 1960-70 production, a few from the 80s.
Anyone like New Sensor reproductions?
What have others found with current production tubes? All my experience so far has been with NOS or used tubes from mostly 1960-70 production, a few from the 80s.
Anyone like New Sensor reproductions?
How do you do the auditions? Any favourite pieces for the music olympics?
Is there a simple way to take a more scientific approach, say using a sound card to compare spectra?
Is there a simple way to take a more scientific approach, say using a sound card to compare spectra?
I haven't tried to capture anything digitally for comparison, not really set up for trying that approach. I do like to change only one thing, like substituting a different 12AT without adjusting anything else in the system, then replaying. So it's all done by ear for me...how it changes the presentation is what I'm noticing. Highly subjective, I know! And my experience with a certain different tube would not necessarily be the same for anyone else, our individual systems and setups being different.
Thanks to George for creating such a dynamic and responsive amp design!
Good morning, I'm taking advantage of this not recent thread for a question...
I have an amp with 6CA7 with 12AT7 (SRPP) as driver tubes, I was trying to "swap" the latter to see which ones sound better. I have a beautiful Philips branded Mullard, but unfortunately it's only one, then a Telefunken and a couple of National (Chinese).
Now I would have the chance to grab either a pair of Tung-Sol 6201 or General Electric 6201 "close disc getter", each pair for around €25. Which do you think would be worth more? Thanks in advance
I have an amp with 6CA7 with 12AT7 (SRPP) as driver tubes, I was trying to "swap" the latter to see which ones sound better. I have a beautiful Philips branded Mullard, but unfortunately it's only one, then a Telefunken and a couple of National (Chinese).
Now I would have the chance to grab either a pair of Tung-Sol 6201 or General Electric 6201 "close disc getter", each pair for around €25. Which do you think would be worth more? Thanks in advance
What with manufacturing tolerances, and unknown provenance, I don't think it is possible to say. If they are NOS then neither price is too outrageous, so you ought to be able to find an alternate home if they do not perform in the way you want.
What does the carton look like?
I do not recall seeing a U.S. made JAN 12AT7WC marked like that. I have probably at least a hundred JAN or FAA out at my warehouse; and found a half dozen NOS JAN 12AT7WC here at the office the latter of which are marked as you would expect any JAN tube to be marked.
I don't recall ever seeing a specific mil spec code on a vacuum tube. Google suggests the code on that tube is a long obsolete code for force air cooled power triodes. Like a 3-500 or something.
Win W5JAG
I do not recall seeing a U.S. made JAN 12AT7WC marked like that. I have probably at least a hundred JAN or FAA out at my warehouse; and found a half dozen NOS JAN 12AT7WC here at the office the latter of which are marked as you would expect any JAN tube to be marked.
I don't recall ever seeing a specific mil spec code on a vacuum tube. Google suggests the code on that tube is a long obsolete code for force air cooled power triodes. Like a 3-500 or something.
Win W5JAG
I don't either. I have lots of 12AT7's in various flavors from old to relatively new. I looked in every JAN 12AT7WC box that I have and found a possible match. I looked carefully at your picture, and I think I see the "GE etched dot codes" on the back side of the tube. Please confirm. If They are there, your tube is likely a GE tube from the late 70's through early 80's. It has been repainted. Mine is from June of 1983. It is also etched "6201" but some of them are not screened. I also found a tube from 1975 that looks the same.
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Of the half dozen JAN 12AT7WC I have here at the office, the GE tubes have double support rods, like the GE's in your picture.
The Sylvania/Phillips ECG tubes do not have side rods, but my Grey plate tubes are smooth and distinctly different from the tube under discussion.
If it's a GE, I think it's probably an ordinary 12AT7.
Win W5JAG
The Sylvania/Phillips ECG tubes do not have side rods, but my Grey plate tubes are smooth and distinctly different from the tube under discussion.
If it's a GE, I think it's probably an ordinary 12AT7.
Win W5JAG
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Well, what can I say... I'm perplexed, I even tried to ask a friend here but he couldn't tell me about it, the same as you.
This seller (collector) has a myriad of valves but given the distance I was unable to meet him to clarify. The only thing he told me is that it is part of a super-selection of valves for military use: I took it as a good idea. For the pair I paid 30 euros shipped (I don't know if it's a bargain or a cheat).
However I will send some more detailed photos, if useful. It appears in the 2nd that the pins (to plates?) are gold-plated.
In the 1st, on the opposite side of the 12AT7WC sigla is reported 6201 USAΔ (Delta?).
This seller (collector) has a myriad of valves but given the distance I was unable to meet him to clarify. The only thing he told me is that it is part of a super-selection of valves for military use: I took it as a good idea. For the pair I paid 30 euros shipped (I don't know if it's a bargain or a cheat).
However I will send some more detailed photos, if useful. It appears in the 2nd that the pins (to plates?) are gold-plated.
In the 1st, on the opposite side of the 12AT7WC sigla is reported 6201 USAΔ (Delta?).
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Ah ok thank you, so the GE brand would be dotted at the bottom of USA writing?
So I learn it for the future...
So I learn it for the future...
Has anyone ever seen these National branded tubes marked as 12AT7's? I think they are 6414's erroneously marked 12at7.
I am not possitive but anyway has anyone tried a 6414 in a SSE? It is supposed to have less gain but will work in a 12at7 circuit. Once i can confirm it is a 6414 i might try it.
I am not possitive but anyway has anyone tried a 6414 in a SSE? It is supposed to have less gain but will work in a 12at7 circuit. Once i can confirm it is a 6414 i might try it.
Probably.
https://vacuumtubesinc.com/index.php/hallofshame
Richardson is fairly well known for this sort of thing.
However, anytime you see a National box labelled 6V6GT or 6AX5 or the like, be sure to look at the tube inside. Often, they have a Bendix clone like a 5992 or 6106 inside as Richardson was at some point (Cetron era?) apparently a second source for those tubes.
https://vacuumtubesinc.com/index.php/hallofshame
Richardson is fairly well known for this sort of thing.
However, anytime you see a National box labelled 6V6GT or 6AX5 or the like, be sure to look at the tube inside. Often, they have a Bendix clone like a 5992 or 6106 inside as Richardson was at some point (Cetron era?) apparently a second source for those tubes.