6SN7 recommendations for my monoblocks?

BossaNova31 · « **on:** 2 Mar 2008, 02:42 pm »

Hi everyone,

I just wanted some opinions on which NOS 6SN7 variant would be best for my Manley 300b SET monoblocks. I currently have a set of 1940s RCA 6SN7 GTBs in the driver stage, and they were a big improvement over the OEM Sovteks. Makes me wonder if I can do even better

I have read that the VT-231s are the best but just wanted some opinions.

Has anyone tried any of these?
1940s Tung Sol VT-231
1940s Slyvania VT-231
1940s Ken Rad VT-231
NOS RCA red base 6SN7
Others?

Dealers are starting to ask insane prices for some of these (I saw one guy asking $500 for a matched pair of Tung Sol VT-231s!), and I am really only willing to pay $200 or so for a matched pair. In terms of what I am looking to gain versus my RCA GTBs it would be tighter deeper bass, bigger soundstage, smoother mids, etc.

Thanks

schw06 · « **Reply #1 on:** 2 Mar 2008, 03:04 pm »

I own the Sylvanias and they are fantastic from "the belt up". Bass is not their forte and I would look explore other options for better bass.
Dave

BossaNova31 · « **Reply #2 on:** 2 Mar 2008, 03:52 pm »

Thanks. I had read that about the Sylvanias but its good to get that from an actual owner.

The Ken Rads supposedly are strong in the bass department but maybe not as good elsewhere as the Tung Sols from what I have read. IMO my 300b SETs do better than some others in the bass area, but I am still looking to solidify things just a bit more. If I can get that and perhaps a smoother midrange and airier highs I would be really pleased

Les Lammers · « **Reply #3 on:** 2 Mar 2008, 05:28 pm »

Price and sonics do not always go hand in hand with NOS tubes. The Tung Sol 6SN7GTB tall bottle is a good tube and is much cheaper than
the round plate. The circuit the tube is in plays a big part in the sound too. I have tried so many 6SN7's and can hardly make a recommendation unless I know how it sounds in a particular piece of gear.

Les Lammers · « **Reply #4 on:** 2 Mar 2008, 05:30 pm »

Quote from: schw06 on 2 Mar 2008, 03:04 pm

I own the Sylvanias and they are fantastic from "the belt up". Bass is not their forte and I would look explore other options for better bass.
Dave

The short bottle back base Sylvania Chrome Domes have bass too.

JoshK · « **Reply #5 on:** 2 Mar 2008, 05:35 pm »

I wouldn't rule out new production tubes. The Tungsol new prod 6SN7 is suppose to be really damn good. It also costs like <$40/pr. Worth trying. EH 6SN7's are suppose to be ok too.

JoshK · « **Reply #6 on:** 2 Mar 2008, 05:37 pm »

It would be my strategy to try out a whole bunch of cheaper 6SN7's before splurging on expensive ones. This way you get a mix of different types and sounds, see what you like and maybe you'll get lucky and find a home-run with something non-expensive.

goldlizsts · « **Reply #7 on:** 2 Mar 2008, 05:47 pm »

Quote from: BossaNova31 on 2 Mar 2008, 02:42 pm

Hi everyone,

I just wanted some opinions on which NOS 6SN7 variant would be best for my Manley 300b SET monoblocks. I currently have a set of 1940s RCA 6SN7 GTBs in the driver stage, and they were a big improvement over the OEM Electros. Makes me wonder if I can do even better

I have read that the VT-231s are the best but just wanted some opinions.

Has anyone tried any of these?
1940s Tung Sol VT-231
1940s Slyvania VT-231
1940s Ken Rad VT-231
NOS RCA red base 6SN7
Others?

Dealers are starting to ask insane prices for some of these (I saw one guy asking $500 for a matched pair of Tung Sol VT-231s!), and I am really only willing to pay $200 or so for a matched pair. In terms of what I am looking to gain versus my RCA GTBs it would be tighter deeper bass, bigger soundstage, smoother mids, etc.

Thanks

When I first built my 6SN7-based preamp, I was lucky, I came in contact with a gentleman in TX, and he gave me a list of pretty much most if not all the 6SN7 brands out there, and their rankings according to his experience. I have since collected pretty much a set of most of them. What I found was that the TungSol VT231 is tops. Next comes the KenRad VT231s. RCA VT231s are dynamic, but less warm. These are the top 3 in my books for American issues. HOWEVER, I was very pleasantly surprised to find that the Shuguang 6SN7 turned out to be a favorite of mine as well. It has a certain warmth, lack of a better word, tho I know it's not entirely the warmth, that certain quality, made it my favorite. I pretty much use the Shuguant most of the time in my system. The Tungsol, KenRad, and RCA types are in my prized collection, since they've gotten that expensive. I use them sparingly, when I'm in the mood for a different sound. You may note that Cary uses the 6SN7 from Shuguang in their original equipment. So, there must be a reason. Either they thought it's so cheap and yet gives a good performance (and the bottom line) that the cost-benefit advantage made them do it, or it simply is among the better ones.

For my personal taste, the Sylvania, etc. are not in the same league as those quoted above. That's my personal taste, to note.

Jon L · « **Reply #8 on:** 2 Mar 2008, 06:21 pm »

Quote from: BossaNova31 on 2 Mar 2008, 02:42 pm

Hi everyone
Has anyone tried any of these?
1940s Tung Sol VT-231
1940s Slyvania VT-231
1940s Ken Rad VT-231
NOS RCA red base 6SN7
Others?

Personally, I wouldn't waste my money on "RCA red base 6SN7" (You actually mean 5692). Mediocre sound, and if you must try 5692's, much cheaper CBS 5692 sounds better balanced IMO.

TS roundplates are good, but once again, I wouldn't pay the price they go for. The SQ is not worth that kind of money. JMHO of course. Some people really think this tube is *IT," and it may be for their system/tastes.

Sylv VT231 and KenRad VT231 are still not quite as overpriced and worth trying to see which you prefer. RCA grey glass VT231 is a good one, too. Just keep in mind that all these tubes have pretty obvious personalities and none are "perfect." It'll depend on your tastes and system synergy. In general, if you prefer a sparklier, airier sound, Sylv VT231; earthier smooth powerful sound, Kenrad; dense sculpted tone, RCA greyglass.

Don't forget the National Unions. Grab them if you see them, esp greyglass. Actually, if you see the greyglass, let me know

jimbop · « **Reply #9 on:** 2 Mar 2008, 07:47 pm »

The problem with many of the reviews and opinions of the 6SN7 tubes is that they are typically based on using them as preamp tubes. The OP is looking for recommendations for using them as a driver tube in an amplifier. Do the came comments and characteristics apply to this application?

BossaNova31 · « **Reply #10 on:** 2 Mar 2008, 08:33 pm »

Thanks everyone,

It sounds like both the Tung-Sol and the Ken Rad VT-231s would fit the bill, but at half the price for the Ken Rads I will probably go that route first

Tube rolling with SETs and Omegas should be fun next weekend

PaulFolbrecht · « **Reply #11 on:** 2 Mar 2008, 11:31 pm »

When I had a Supratek pre, I asked Kevin Deal @Upscale what the best pair of 6SN7s for midrange liquidity was and he sold me a pair of Popes ($300). These tubes were utterly amazing. The EH tubes are indeed passable and the RCA and Sylvania NOS a step up, but these Popes were just in another league and with no weaknesses.

Dmason · « **Reply #12 on:** 2 Mar 2008, 11:46 pm »

I have it on very good authority, from a high end guitar amp builder, that the new production TungSols are in his opinion, "at least as good as most old stock Tungsols." Personally, I would try some new TS, first.

This fellow also feels that a triode strapped New TungSol 6550 is something a 300B tries to be.

I should add two things: for whatever reason, the dual triode tubes are NOTORIOUS for taking 4-Ever to burn in. Second, as regards NOS TungSols, I have a pair of NOS TungSol 6DN7 in my hotrod SEX amp and after awhile, hole e. schit they are little monsters, with a smooth as glass sound, and it was like the power of the amp doubled. No kidding. Alot of people think the little SEX amp is a toy. Wrong.

Take Robert Simpson's word though, and try the new Tungsols, and let em cook for a goodly while.

PaulFolbrecht · « **Reply #13 on:** 2 Mar 2008, 11:49 pm »

Quote from: Dmason on 2 Mar 2008, 11:46 pm

I have it on very good authority, from a high end guitar amp builder, that the new production TungSols are in his opinion, "at least as good as most old stock Tungsols." Personally, I would try some new TS, first.

I wouldn't doubt it given the quality of the new-prod Mullard 12AT7s. Perhaps we're finally starting to catch up to the 1930s.

BossaNova31 · « **Reply #14 on:** 3 Mar 2008, 02:07 pm »

I just scored a strong testing matched pair of 1940s Ken Rad VT-231 on Ebay for what I think is a pretty reasonable price ($125). The seller has over 500 feedback with a 99.5% positive rating (and only sells tubes) so I'm banking that the tubes are as advertised. I'm seriously considering a set of RCA VT-231 too if the price is right. Thanks everyone for your responses!

JoshK · « **Reply #15 on:** 3 Mar 2008, 04:03 pm »

I for one would be really interested to hear your impressions of your KenRad VT231's vs. a pair of new prod TS 6sn7's. Here is one place to get them: here. $34/pr.

DIY'ers are notoriously cheap, but we have that luxury given the performance of some off-the-beaten-path choices available to us. But I've heard a number of DIY'ers suggest that some of the better new production tubes, like these TSs and just as good or better than their best old stock treasures. $34/pr is much cheaper than $125/pr, even if the $125/pr is a bargain.

I am sure it would hard to be completely unbiased about your new purchase but it might be beneficial to all to see where they stand. I am in total agreeance with others that said it will be complete circuit/system dependent, but it'd still be interesting to see if in a typical circuit such as your amps, where they stand.

If I had a pair, I'd send them to you to try out, but I don't.

Tangent: In amps, I think the performance of tubes are even more circuit dependent and here is why I think that. Take for example a typical 2 stage SE 300b amp (not saying his mono's are, I don't know his circuit). A lot has been written about finding the appropriate driver for a 300B, which is a pretty hard load, but not the worst, but the story holds over to other amps too. A case study was done in AudioXpress a while back about which tube performed best as a driver for a 300B.

The interesting thing was that the best tubes where not the ones with the most gain, lowest distortion, lowest output impedance (function of rp). The best tube was the 6AQ8 (or is it the 6AN8 I forget off hand) which performed best because its distortion cancelled, at least partially, with the distortion of the 300B. So in this case it is offsetting distortion compliments that overalled lowered the distortion of the amp, having lower overall distortion that placing the lowest distortion driver in the first stage.

I think it is equally plausible that within a certain type of tube, in this case the 6SN7, that the tube that works best in your amp will be the one that compliments the overall design with its harmonic distortion structure producing something that is more than the sum of the parts. This is also why I think that the best in one amp won't necessarily be the best in another amp. The best we can hope for is that the best in one SE 300B amp will likely be the same best in another similar SE 300B amp.

Josh

Dmason · « **Reply #16 on:** 3 Mar 2008, 04:15 pm »

For the above mentioned reasons, I think the 6DN7 would be the best driver of all, for a 300B. Big gain capabilities, linear as hell TV Class A triode vertical oscillation tube, a real taskmaster to the 300B. Cheap, and out their in their millions. Dr. CC Poon agrees with me. I thought this circuit needed to be explored, and Monarchy Audio has one. I really wanna get my Uber Beamer built and compare, CC wants to compare the DN7/300B to it. Been sick with mono. Audio is something I read about, until sometime into the future.

I will reiterate what Robert Simpson has been saying: "New production TungSol dual triodes, and beam tetrodes, and big pentodes, are better now, than then." A very hard opinion to ignore. According to my brother, who is quite close to Robert, he is building a trioded Beam Machine for Alex Lifeson, for home stereo. Using new TungSol 6SN7.. if it is good enuff for Rush, it is good enuff for you...

JoshK · « **Reply #17 on:** 3 Mar 2008, 04:19 pm »

Shhhh.... We don't want the price of the TV tubes going through the roof.

They have been the secret of DIY'ers for years.

BossaNova31 · « **Reply #18 on:** 3 Mar 2008, 04:32 pm »

Hi Josh,

For $34 you convinced me to order up a new production pair of Tung Sols too

I still havent upgraded the output tubes from the OEM supplied Electroharmonics. From what I have read and a magazine review (where the reviewer was testing using my monoblocks), the Manley's really respond to better 300bs as well. I am leaning toward the KR Audio 300b balloons, but I need 4 so roughly $1100 retail for a quad which is why I havent made that investment yet

The KRs are supposedly very neutral sounding, not coloring the sound, so hopefully whatever improvements I get from 6SN7 rolling will just be accentuated by the KRs.

JoshK · « **Reply #19 on:** 3 Mar 2008, 04:47 pm »

Well, when it comes to 300B's, I only know what I've read, which is quite a bit because I am building the Karna amps, which is a penultimate PP 300B amp using incredibly expensive iron, both in quantity and quality. So I bought some decent 300B tubes based on what I've read because I didn't want to cheap out on the tubes. I haven't bought KR tubes yet because of the cost reasons, but I've read they are excellent (even better than the WE 300Bs from those who've heard both).

However, like all things this is incremental and the price goes up by a huge amount for smaller and smaller returns in performance. That damn diminishing returns curve! For this reason, I've read from some that JJ 300Bs are quite good for still reasonable money and went that route, at least for now. The EH 300B's are suppose to be good too, which is why Manley probably chose them for their amps. I've read that JJ 300Bs are a bit better than the EH 300Bs, but I guess like all things it is up to who you ask and what amps they've tried them in.

Your amp is unique in that you can choose both PP and SE, right? Which do you typically operate in?

When it comes to the 2A3, the JJ is suppose to be about the best thing out there for sane money, with only the KR 2A3 topping it by not much for a whole lot more. I've read some of the same about the 300B, but not quite as definitively.