sunnysal Posted May 31, 2003 Share Posted May 31, 2003 I just spent two days tube rolling and came out with surprising results. as y´all know I just bought a 2A3 PP stereo amp from Jean-Francios Lessard. I initially equipped it with all new production Sovtek tubes; 4 X 2A3 (which have been positively reviewed) 2 X EH 6SN7 (which are pretty close copies, in construction of RCA 5692s) and 1 X 5U4G (ST shaped glass, pretty!)... of course I anticipated the tube rolling NOS upgrading (I experienced good results going high quality NOS on my Dynaco amp) and ordered in parallel some NOS tubes. I first asked around on AA and elsewhere about what to get in 6SN7s, 5UR rectifier variants and 2A3s... I ended up ordering the following: for rectifiers the consensus was to buy 40s-60s RCA or sylvanias 5U4Gs or go "holy grail" and find a 50´s or 60´s Mullard GZ37 or a GEC U52 from the same period, both had almost unanimous support and correspondingly high prices...I could not resist giving the amp the best I could so...bought one of each. Second the hunt for 6SN7s was more difficult, seems there is more disagreement but I settled once again on two of tubes mentioned as two of the most desirable around the forums; the first, Tung Sol 40´s black roundplates and the second, a 1950´s Sylvania black triangluar plate GTB (they are those wierd plates set at angles to each other)...again I bought a pair of both. I decided to put on hold the 2A3 hunt since the choices there are fewer and I wanted to evaluate these tubes beofre settling on a new 2A3 choice... Well, here are my thoughts after two days of swapping tubes in and out. I am back to all new sovteks. why? well with the 6SN7s I found the Sylvanias to be light weight in the bass and seemed to thin out the lower mids as well, it also had more hum then the others, its strength was in nicely detailed highs, but it had lower gain than the Sovteks or Tung Sols and the highs sounded somewhat splashy during complicated passages (though nice with simple music, a cymbal in a jazz combo for example, sounded really nice with the Sylvania). the Tung Sols were very meaty and solid in the bass but had a slightly recessed sound on top, not veiled or muddy but slightly farther down in the mix, so the mids sounded too forward...the lowly EH 6SN7 remain king of the hill on the amp for now...I am not sure where to look for better now that I have eliminated two "holy grail" tubes. the order came out (best to worst in my system) new Electro Harmonix, 1940s Tung Sol, 1950s Sylvania. The rectifiers were a similar story, the vaunted Mullard GZ37 was light in the bass and lower mids and seemed to lack some of the dynamic punch of the Sovteks, I especially noticed this on Snare drum hits which lacked body compared to when the amp was fed by the Sovteks. The GEC U52 had nice lower mids and full bass but again seemed to lack the impact (that snare again) of the Sovteks. I had two other rectifiers sitting there during testing to try out; a Sovtek 5AR4 and a Electro Harmonix 5U4GB both from my guitar amps. I popped them in to try them and found that the 5AR4 was very similar in sound to the Mullard GZ37 and the 5U4GB came close to the 5U4G (somewhere between the U52 and the 5U4G really). but both those tubes semmed to bring forward mids more than I like. the order came out (best to worst in my system) new Sovtek 5U4G, new Electro Harmonix 5U4GB, NOS 1950s GEC U52, NOS 1950s Mullard GZ37, new Sovtek 5AR4. I suppose some of the lack of "magic" from the NOS tubes could be due to lack of break in (assuming they are really NOS, which they do look and they were bought from reputable tube dealers). However the New Sovtek and EH tubes have not had significant break-in yet either so I suppose it was even ground for a comparison. I may put the NOS tubes back in the amp to run on days when I am not home to help burn them in for a future comparo (after all I spent big bucks for those "golden oldies"!!!). BUT.... In the mean time I am enjoying great music from my new amps with new production Russian tubes! If there is any moral to be found at all for my friends it is perhaps not to underestimate these new tubes...the good news is that, unlike with NOS tubes, one does not have to spend an arm and a leg to try them out in ones system. you could buy a full compliment of Russian tubes for the price of one highly regarded NOS tube and see if the turn out to be "giant killers" in your amp as well. Best regards, Tony Quote Link to comment Share on other sites More sharing options...
bkrop Posted May 31, 2003 Share Posted May 31, 2003 Maybe it shows that the theory that an amp sounds best with what brand it was engineered for using, in it. Craigs theory, I think. Quote Link to comment Share on other sites More sharing options...
sunnysal Posted May 31, 2003 Author Share Posted May 31, 2003 I do think that Jeff used Sovtek 2A3s when building the amp but I am not sure about the 6SN7s...I will ask and report back. regards, tony Quote Link to comment Share on other sites More sharing options...
sunnysal Posted June 2, 2003 Author Share Posted June 2, 2003 jeff confirms he used new sovteks for the 2A3s and RCA 5692s for the 6SN7s...BTW my sovtek 5U4G just blew up! so much from russian reliability! (but it sure sounded good!) regards, tony Quote Link to comment Share on other sites More sharing options...
bkrop Posted June 2, 2003 Share Posted June 2, 2003 Hey it's Craigs theory, I think. Quote Link to comment Share on other sites More sharing options...
Dflip Posted June 2, 2003 Share Posted June 2, 2003 When you think you have a good sound, then sit back and listen to it for a while. Part of the deal is letting your ears get used to the sound and when you are familar with it (two weeks or a month), then change to preference two. It took me a while to get used to a pair of Telefunken 6U8's, but I now like the sound coming from them. Remember, you can always switch tubes when you are in mood to listen to different types of music for a whole evening. Sit back, grad a cold beverage of your choice and listen. Quote Link to comment Share on other sites More sharing options...
AnalOg Posted June 3, 2003 Share Posted June 3, 2003 Sunnysal, I don't think you gave it a fair evalution. First by changing out the tubes so quickly, some tubes sound good out the box, others need to burn in. Not having a batch of 2A3's to throw into the mix may have also prohibited you from experiencing the full potential of what said tubes had to offer. One more thing, how many hours on the amp itself can also contribute to the outcome of the musicality you are getting out them there tubes. Before you discount those NOS tubes pick up some RCA 2A3's, hell, for the heck of it get the ValveArt 2A3's, to my ears they were more musical than the Sovteks. The Sovteks were to lean and lacked that natural bottom end. The ValveArts had a balanced sound from top to bottom. The NOS RCA 2A3 were the best all around performer to me. This of course is just my personal observation in my equipment & my limited hearing abitlity so take all this with a grain of salt. Tom Quote Link to comment Share on other sites More sharing options...
sunnysal Posted June 3, 2003 Author Share Posted June 3, 2003 Tom I do plan to experiment with 2A3s in the future, my intent this time was to focus on specific tubes, the 6SN7 and rectifier. In listening tests only one type of tube was changed until I found the sound I liked, then I moved on to the mext type. If I were to change multiple types of tubes at the same time I will introduce too many variables in the mix too make informed, focused decisions about a specific tubes contribution. I cannot think of any other way to do the testing. flopping in different input, rectifier and output tubes at the same time would have, IMO, created too much chaos and made it virtually impossible to tell what tube was doing what to the sound. this way I could hear clearly the difference each brand of tube made in the mix. I admit, in the original note above, that perhaps each NOS tube needs to break in some more to give its best and I do plant to age them (when I am not trying to enjoy the music with the better sounding un-broken in tubes) and try agian later to see if break in affects things. But for now the best "out of the box" 6SN7 and rectifier remain the sovteks in my system. thanks for the comments. tony Quote Link to comment Share on other sites More sharing options...
AnalOg Posted June 3, 2003 Share Posted June 3, 2003 Tony, I agree with you whole heartedly. You can't change out more than one tube compliment at a time, wont't know which tube creates which sonic difference. Maybe I should have been more specific. In the way you did your rolling is fine, but I think you should have implimented different power tubes once you made your decision in driver and rectifier with the Sovteks in place. Then start the process all over with the next set of power tubes to see if you come out with the same results. I bet not. Of course this process would probably take alot longer than a couple of days & you probably would need to take notes to keep track, but I think its half the fun and a good education of how tubes interact with each other. Now I may be wrong but the power tube is going to give you the most sonic change, then the driver, last the rectifier, so thats why I proposed putting that into the mix. Just my opinion, it seems like the fairest way to asses what tube compliment goes best with each other. Tom Quote Link to comment Share on other sites More sharing options...
sunnysal Posted June 3, 2003 Author Share Posted June 3, 2003 thanks tom, I discussed a little with jeff and he seems to think the input tube has the biggest role followed by the output and then the rectifier. he also mentioned that this design is extraordinairely sensitive to tube changes due to the lack of caps in the signal path, all those trannies ya'know! I can tell you that I was floored by the amount of difference made by the rectifiers, obviously those little differences in voltage drop, etc. make a big difference in sound! so I can see what you are saying about the inter-tube interaction, I think the rectifier sets the base on which the output tubes stand and the input flavor everything as it comes in. I wll have fun with further tube rolling on this amp in the future. BTW newsensor has a phenominal deal on sovtek 2A3s right now, they offered me $18 each for sovtek 2A3s with gold grids...I bought a quad today! tony Quote Link to comment Share on other sites More sharing options...
AnalOg Posted June 3, 2003 Share Posted June 3, 2003 All that sensitivity will defenitley make tube rollin a blast!! My conclusion of the power tube making more of a sonic difference was attributed to the changes I've experienced in my 2A3 system. I'm sure Jeff knows what works well in his builds, take his word as gospel, he is the maker!! Tom Quote Link to comment Share on other sites More sharing options...
Gregorius Posted June 3, 2003 Share Posted June 3, 2003 Tony, I have noticed the same thing with the Sovtek/EH tubes, they are very good and for the price the are a no brainer! In my Fisher 800C, which came with TFK 12ax7's and Westinghouse 7591A's, the Electro-Harmonix 12AX7's and 7591A's do a very good job,and lack nothing. I paid $8 and $16 each respectively, I saved quite a few bucks by buying them. I have no regrets. Regards, Greg Quote Link to comment Share on other sites More sharing options...
NOSValves Posted June 3, 2003 Share Posted June 3, 2003 Greg, Paul at Bizzie Bee Audio which I converse with often loves the EH tubes. I use EH 7591's in a Scott 208 stereo power amp and they sound great ! I haven't used EH 12AX7's before but have used Sovteks and they do a nice job. Paul told me he likes the 5751's in the his Fisher rebuilds he is sending me a quad to try out. We all need to rethink this NOS preference the new production tubes are the only hope for tube audio NOS supplies will run out sooner or later that is a sure thing ! Craig Quote Link to comment Share on other sites More sharing options...
Gregorius Posted June 4, 2003 Share Posted June 4, 2003 Craig, I know what you mean! There is some difference between TFK and the EH 12ax7's, but they are not crap, and I am too cheap to pay $50 per NOS TFK, when I can get EH for $8 each. I have not tried them in the Scott 299B, Ryan said "Scott places all four 12AX7 heaters in series, for a total current draw of 150 mA. I have found that the new EH 12AX7's draw more than 150 mA of heater current, so I avoid them" so the Scott still has the TFK ribbed plates that came with it. I may still send the Scott to you sometime for a checkup. Regards, Greg Quote Link to comment Share on other sites More sharing options...
sunnysal Posted June 4, 2003 Author Share Posted June 4, 2003 yeah the EH tubes are getting pretty good comments everywhere. the guys at newsensor have told me they are about to come out with a EH 2A3 with gold grid...THAT should be cool! tony Quote Link to comment Share on other sites More sharing options...
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