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6SN7 sound performance

202.190.8.1

Posted on March 31, 1999 at 02:03:30
Greetings,

Something to share with all
TA lurkers.

Took this thread off
RAT(rec.audio.tubes) newsgroup about 6SN7 sound performances.

Enjoy.

Regards.

::-)

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(beginning of original message)

Subject: Re: 6SN7 sound performance
From: chimera1@idt.net
Date: 1999/03/26
Newsgroups: rec.audio.tubes
Glad everyone enjoyed the first sound performance opinions. The key work
is opinions. This is an update on the sound performance of the vintage
6SN7 types.

I have added all the customer feedback on how the various tubes sounded
in their system. Let me stress that the optimum tube for your system
will depend on your equipment and how your ears judge the tube's ability
to reproduce live music.

The general consensus is that the vintage 6SN7 types, especially the
VT-231s, sounded better than 5692s. I must add that the 5692 is a
very quiet tube, if you have equipment where 6SN7 tubes are microphonic,
a 5692 may be the best choice.

Only one customer who had problems with microphonics(CSL-6SN7-WGT long
plate with metal band).

The Sylvania long plate 6SN7WGTs & 6SN7WGTAs have received very
favorable reviews. Work great as a driver or cathode follower. They also
seem to "wake up" tube gear that sounds a little soft or slow. A few
customers preferred these tubes to the VT-231s in this case.

I want to caution everyone that various 6SN7 types have different
voltage and plate dissipation ratings. The voltage rating refers to
voltage across the tube's plate and cathode. To ensure good tube
reliability you should probably run a tube at 70% or less of its maximum
plate dissipation.

5692 - 275 Volts maximum & maximum 1.75 Watts per section
6SN7GT/WGT -- 300 Volts maximum & maximum 3.5 Watts per section
6SN7GTA/GTB - 450 Volts maximum & maximum 5.0 Watts per section

Using the tube service recommendations of 250 plate volts, a bias of 8
volts results in 9ma of current and a plate dissipation of 2.25 Watts.

5692 - runs 43 % over maximum rating
6SN7GTB/WGTB - runs 64% of maximum
6SN7GTA/GTB - runs 45% of maximum

I know the 5692 is considered a "10,000" hour tube, but years of audio
fans trying them in circuits designed to run 6SN7GTs in a low distortion
linear mode may be why they are so rare and expensive. The 5692 service
recommendation recommends 250 Volts, -9.0 volt bias and 6.5 ma
current for a plate dissipation of 1.625 Watts or 93% of maximum. That's
still seems pretty "hot" for long tube life.

Here are the rankings. If you have anything to add, email me and I will
add it to the list. Yes I still have some stock of these tubes left. No
I have changed my prices based on the new performance evaluations. Email
me and I will send you the current list.

VT-231 Tungsol, round black plates - Clean, fast, the best in everything
VT-231 Raytheon, black flat plates - like the Tungsol a little sweeter
VT-231 RCA, black plates, rich harmonics like a 5692, wide soundstage
VT-231 Ken-Rad, flat black plates - Great Bass, drive, sweet midrange
VT-231 National Union - good drive and great midrange, softer bass
VT-231 Sylvania, black plates, wide bandwidth, delicate & laid back
6SN7WGT, Sylvania Metal rim, big tube, big sound, super soundstage
6SN7WGT, Sylvania, Long Plate, same big tube minus the metal rim
6SN7WGT, Syl Standard Black Plate, transparant, images very well
6SN7WGT, Syl Green Label, like the Standard but front row center
6SN7GTA, General Electric Black Plate, the great driver tube?
6SN7WGTA, Syl black base green label, another great driver tube
6SN7GT, CBS Black Plate, very good tube, quiet, and musical
6SN7GT, Sylvania or RCA Black Plate, very good and easy to find
5692, CBS-Hytron, fast, good dynamics, lot of air and great timbre
5692, RCA Red Base, very warm sweet sound, great on voices and jazz
6SN7GTB, RCA, sounds like a 5692 with slight veiling
6SN7GTB, Syl, like the Syl militaries but not as focused or quiet
6SN7GTB, G.E, Gray plates, work horse, lacks refinement, a good tube

Best Regards, Dennis

Dennis Boyle, email chimera1@mail.idt.net
Chimera Laboratories - www.ChimeraLabs.com/~CL/
1414 South Akard Street
Dallas, TX 75215
TEL: 214-428-3901
FAX: 214-426-6605


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    ...
Interesting, posted on March 31, 1999 at 05:23:58
Jack G


 
Good list, tho my experience tends to differ a bit in some areas. For one thing, with high efficency speakers, almost all 6SN7s are microphonic in my preamp, so I use 5692s(CBS). The list doesn't seem to go into vintages, which is unfortunate, since that appears to change the sound of the tube as much as changing brands. As for VT-231s, they are AWFULLY hard to find, but I'm willing to try them if I can get my hands on some.I'll have to e-mail him since I cannot download his list.\
enjoy,
Jack

 

Re: 6SN7 sound performance, posted on March 31, 1999 at 05:58:41
Tazsmonn


 
Thanks for post, working on it!

 

Re: Interesting, posted on March 31, 1999 at 06:37:11
Chrisp


 
Jack,

What of other varieties of 6SN7's do you have experience with. I recently purchased some Sylvania 6SN7GTA's from the 1940's for my BAT VK60 monos. I only put in a couple of tubes in each amp because certain tubes are more important to the sound, and these tubes were not cheap.

It only took 10 seconds of hearing them that all the Sovteks had to leave. It is a crime that they can't (hoping they will) make better tubes today.

Anyway, what are your suggestions on types and sources. I used Vintage tubes, he stands behind his tubes, but he is expensive.

I might have a problem with 5692's related to voltage capacity.

Thanks,
Chris



 

Heres a partial list, posted on March 31, 1999 at 07:08:57
Jack G


 
Bear in mind, your milage may vary...
Sylvania 6SN7s vary greatly with vintage-the aerlier the warmer(actually true with many brands). I've tried the 6SN7GTs, 6SN7ws , GTB,WGTAs. The Ws are interesting, but unacceptable as preamp tubes due to *hideous*microphonics. As drivers they are OK-extended but a touch edgey, with HUGE soundstage and good images. The GTBs (later vinteages)tend to be cooler with good control and killer bass-good soundstageing. The WGTAs(70s-80s) are rather veiled.The GTs aren't bad-but a tad microphonic and noisey in my system.
GEs later ones are coin base, earlier onse are standard base-all have grey plates(that I've seen) as a rule, they tend to be somewhat cool and lean sound-VERY quiet and non-microphonic. very good extension tho.
Brimar-6SN7GTY(CV1988s)-chocolatey, smooth dark and dull-not a fan of these.
Mullard CV1988s-warm smooth midrangey, but noisey and microphonic and forward.
Philco-6SN7GTBs nothing special-probably made by sylvania-sound like later ones
RCA-black base,50s-60s. Not bad, I'm using a pair as drivers for my 2A3s. smooth and extended. detailed but not edgey. very good overall. I like these, and may stock up on more.
Phillips 6SN7WGTA-made in 1980s. better then sovtek, but thats about it-very rugged tho.

5692s-Note despite the voltage difference, everyone still uses them as a substitute for 6SN7s

RCA Red base-VERY warm rather soft, rolled off and laid back-bass is mediocre at best @ $60 each, I think they are over rated and over priced. also note-the earlier the warmer and smoother-these were made from the 50s to 70s, and dont all sound the same. however, they are NOT microphonic but can be noisey.
CBS brown base-I like these as preamp tubes-smooth warm detailed and lush-better focused than RCAs, and much better bass-there's alittle more lower mids too. rather quiet tubes, and non-microphonic. I much prefer these as preamp tubes than drivers.
Thats about it off the top of my head. I'll call chimera tonight, and see about the tungsol VT-231s-I just hate to fall in love with a tube that I cannot get more of later.
enjoy,
Jack

 

Vintage tubes services?, posted on March 31, 1999 at 09:03:36
Jack G


 
I've used him a couple times. He sold me the sylvania 6SN7Ws-despite being tested for microphonics, and rated, they RING like a bell in my system, and one of them blew up (I lost the recept:-(). OTOH, he rivals Kevin Deal as the most expensive tube supplier in this part of the galaxy. IMO, unless he has something you cannot get elsewhere, get it elsewhere.
enjoy,
Jack
PS sources:
tubeworld www.tubeworld,com
SND tubes www.vacuumtubes.com
Angela instuments www.angela.com
Prices vary dramatically between vendors. supplies vary and change rapidly, so one must check back periodically.
PPS. It is not uncommon for tubes tested for noise and microphonics to be noisy and microphonic in my system-makes me real popular with some tube dealers.;-(

 

he doesn't take plastic-bummer! :-) (nt), posted on March 31, 1999 at 10:15:37
Jack G


 
Ò¿Ò

 

Re: Vintage tubes services?, posted on March 31, 1999 at 10:20:13
Chrisp


 
As I was reading the thread, I just bought 12 Sylvania 6SN7GT/VT-231's (both designations were on each tube)from someone who pulled them from some unused military equipment (tested as new). They were priced at only $8.75 each.
I should receive them in a couple of days. My problem is I need so many of them 16 for both amps.

PS: Thanks for your list.

Chris


 

Re: Vintage tubes services?, posted on March 31, 1999 at 10:41:08
Jack G


 
Need 16? Ouch! that aint easy:-( you have to wait for folks to get a buttload in-tube world has 50+ GE 6SN7s, not sure if thats what you want tho. BTW forgot to mention the 1957 versions of 5692 are far superior to the 1961 versions. FWIW, my tastes and whats is "commonly" known as "better" tubes tend to differ.
enjoy,
Jack

 

Re: Vintage tubes services?, posted on April 1, 1999 at 04:35:48
Jack G sorry to hear that you had any problems with tubes you bought form me at himera Labs. The good news is that you can send back tubes for a full refund whenver you have a problem, if they are microphonic or if they fail.
You don't need a receipt I have domputer records of all the purchaaes.

Sorry if you feel my tube prices are expensive. Most of my tubes are priced 50 to 75% below Antique Electronic prices. Also sell tested pull tubes at 50% below NOS prices. If you have a tube tested sell just pulls for below a buck.

Certainly with rare tubes like the JAN 6SN7W(not 6SNWGT), tubes that predate even the VT-231As and were made in the 1930s, I think prices of $15 to $17 each is quite acceptable for the sound performance.

Send me an email and let's get your microphonic/blown tubes straightened out.

Thanks, Dennis Boyle


 

Miscommunication?, posted on April 1, 1999 at 05:00:20
Jack G


 
This thread also is about Vintage Tube Services(I thought) as related by this comment:
>>> I used Vintage tubes, he stands behind his tubes, but he is expensive.<<<
My comment was about Vintage Tube services-which tests all their tubes and grades them. FWIW, since my speakers are 100db efficient,many tubes tested for noise and microphonics dont cut it in my system.
I have bought nothing from you yet, and did not mean to imply that I had. I apoligize if that is the impression you have.
As for your prices, They are Ok-comparing them to AES is no great shakes, since their prices tend to be rather high anyway.
Again I apologize for any miscommunications.
Jack
PS. Let me know when you start taking plasic:-)

 

Correction, posted on April 1, 1999 at 05:48:00
Jack G


 
I went and checked last night-got my Sylvania GTBs and GTs mixed up. The GTBs I tried were 50s, and Ok but a tad noisy and microphonic. The GTs I tried(vintage unknown, but suspect later) are built well, but seem to have a slightly taller bottle-flashing looks perfect-ruler straight and goes 1/4 way down. These guys are dead quiet, no microphonics, very well extended, but lack mids, and sound a bit cool. Killer sound stage and imaging tho.
The RCAs I have are black plates, NOT the grey plate versions that angela instruments has.I still like them-did some quick comparisons-just as detailed as any of the Sylvanias that I have on hand,but fuller, with better bass and a bit smoother overall. I will be checking out the Sylvania brown bases after a while.
enjoy,
Jack

 

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