dodger Posted August 30, 2004 Share Posted August 30, 2004 Hello: Not knowing your amplifiers, I will only speak for mine. One has the GEC U52, beautiful looking, very smooth. The other is a later IEC Mullard, IEC put the 5U4GB on it. It is difficult at times to tell the difference. The Sylvanias are great as are the RCA 5U4G. Dodger Quote Link to comment Share on other sites More sharing options...
jt1stcav Posted August 30, 2004 Author Share Posted August 30, 2004 Allen, you sure got a helluva deal on those rectifiers back in the day, before their value jumped sky-high due to their rarity in today's market. And even my '51 Sylvania 5U4G blackplate was $25 a couple months back! Nevertheless, I'm pleased with it! Erik, if it gets to where I'd have to exchange resistor values just to use a certain rectifier, then to me I'd doubt if it'd be worth it...I can't do even the simplest mod, and I'm not gonna take the chance of ruining the amp's circuitry for what little benefit there is. I'll leave any modifications to people like you and my dad who know what they're doing. Quote Link to comment Share on other sites More sharing options...
jt1stcav Posted August 30, 2004 Author Share Posted August 30, 2004 Mike, the Sylvania rectifier pops on within a second or so, and then the power and driver tubes do their thing. The 5U4G does ping a little at warmup, but it's not distracting and seems to operate just fine! Yeah, I don't have that kind of money either, and the Sylvania does a smack-bottom job of rectifying (uh, yeah...)! Yeah, Dodger, I'm afraid I'm into the aesthetics. The British rectifiers are classy looking bottles IMO. Love my preamp's GZ30, and I thought a sweet lookin' slender Mullard ST-shaped rectifier would dress up my amp. But the Sylvania does that as well, so I can't complain any. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted August 31, 2004 Share Posted August 31, 2004 Jim: Experimenting with different appropriate rectifiers would just result in fairly moderate/slight increase or decrease in B+ voltages. I don't think, at least it hasn't in my experience, that the overall sonic character of your amp would change. The only reason I was using a 5Y3 instead of the GZ34 or GZ37 in the Moondogs is that I wanted a lower plate voltage on a pair of vintage RCA 2A3s I was using. Quote Link to comment Share on other sites More sharing options...
sunnysal Posted August 31, 2004 Share Posted August 31, 2004 whether or not the rectifier will have a noticable effect on the amps sound has to do with a variety of factors; circuit design, operating voltages, rectifiers tried, etc. In my latest amp (JFL 2A3) rectifier changes were quite apparent, expecially in the bass. while in my dynaco (mkIV) I could not be sure I heard any differecne when swapping rectifiers. the only way is to find out what is safe to try and try them out yourself. regards, tony Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted August 31, 2004 Share Posted August 31, 2004 I've had some rectifiers that were quieter than others, and I also have -- well sort of -- a JFL Horus. Mine is quite a bit different from the original in a number of ways, however. Increasing B+ might have some effect on bass, but it's primary job is to supply the working voltages for the amplifier. With the rectifiers mentioned above, the increase or decrease is not that large. I would rather spend more money on different driver and output tubes than rectifiers, but I would say we should enjoy listening to and tweaking equipment the way that's suits us best. ...and reading the title of Jim's original post, it seems I've gotten off track, anyway. Sorry, Jim! I'm backing out now. Erik edit: but after a correcetion. I believe Tony's amp is Lessard's PP 2A3 amp. Quote Link to comment Share on other sites More sharing options...
jt1stcav Posted August 31, 2004 Author Share Posted August 31, 2004 No problem, Erik. Everyone's experiences make for great reading, and in my limited knowledge, I also believe that changing driver and power tubes would probably make more sonic sense then the rectifier (not that it wouldn't also make a difference). But I still have a problem figuring out which GZ-series (if any) would be a best matchup for my amp, and I'm too chicken$hit to try for fear of frying the amp's innards! I did write to Edmund about my little dilemma, but as of yet I haven't received any response...Guess e-mail to Hong Kong is just as slow as the slow boat he uses to ship his gear over to these shores)! Quote Link to comment Share on other sites More sharing options...
NOSValves Posted August 31, 2004 Share Posted August 31, 2004 My personal experience would say changing rectifier types should have a pretty noticeable effect on the sound. Every tube has its sweet spot of operation changing its voltage will change its character. If it didn't matter I sure wasted a ton of time adjusting the PS dropping resistors to fine tune the front end of the VRD. Craig Quote Link to comment Share on other sites More sharing options...
jt1stcav Posted August 31, 2004 Author Share Posted August 31, 2004 I hear ya, Craig. From what I've read so far, you definately didn't waste your time perfecting your circuit for your gorgeous VRDs (and I'm still waiting for my free pair...I'll throw in my 300B to sweeten the deal)! Quote Link to comment Share on other sites More sharing options...
2N3055 Posted August 31, 2004 Share Posted August 31, 2004 ---------------- On 8/31/2004 10:05:09 PM jt1stcav wrote: No problem, Erik. Everyone's experiences make for great reading, and in my limited knowledge, I also believe that changing driver and power tubes would probably make more sonic sense then the rectifier (not that it wouldn't also make a difference). But I still have a problem figuring out which GZ-series (if any) would be a best matchup for my amp, and I'm too chicken$hit to try for fear of frying the amp's innards! I did write to Edmund about my little dilemma, but as of yet I haven't received any response...Guess e-mail to Hong Kong is just as slow as the slow boat he uses to ship his gear over to these shores)! ---------------- jt, You can use any tube with the 5T or 5L pinout with the exception of the 5AU4. With your amplifier, the only real thing to watch out for is the filament current rating of the power transformer (which, in this case, is 3A 5V). The 5AR4, 5U4, 5V4, 5Y3 and GZ equals can all be used without causing any damage. While switching between different types, there will be some voltage output variations, but nothing significant. For instance, compare the 5AR4 to the 5U4. Both will supply rated current without a problem, but the 5U4 drops slightly more voltage. The drop of the 5U4 is approx 50V, while the drop on the 5AR4 is approx 30V. A 20V difference in a tube rectified supply feeding tube stages is peanuts. You are not likely going to hear a difference. The 20V difference is truly insignificant. Even two 5U4's made by the same manufacturer will not have identical voltage drops, there is a tolerance of 30% between identical types. Trying other types that have the same pinout and suitable current handling ratings is just fine. Rectifier tubes have such a wide tolerance that calibrating an amplifier to use a single type with a specified voltage output is impractical. If the tube used in calibration were replaced with another brand, or even the same brand, the voltage output value would have a variation up to 30% from the design center value. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted September 1, 2004 Share Posted September 1, 2004 Hi, 2N Thanks for a much more comprehensive explanation! Jt: This, in my opinion, is exactly correct. Again the only reason I was using a couple of different rectifiers in my Moondogs had to do with some (probably kind of nutty) concern I had with keeping the plate-to-cathode voltages on the 2A3s at or slightly below the max. listed specs for the tube. I think 2Ns statement about 20-30 volt differences in B+ as having minimal impact in the overall sound of the amp is right on the money. If others have experienced extraordinary improvements by way of rectifier rolling, I am envious! I have found some rectifiers more quiet than others, but that is more likely simply related to individual tube variations. Quote Link to comment Share on other sites More sharing options...
dubai2000 Posted September 1, 2004 Share Posted September 1, 2004 I admit that I belong to those people whose amps sound different with different rectifier brands. And I am not only talking about currently owned amps, but also the Cayin integrated or the Wright 3.5 monos. So I could try let's say 5Y3GBs or even a 274 replica (only four pins this one!) in my MC30s without any harm? Wolfram Quote Link to comment Share on other sites More sharing options...
NOSValves Posted September 1, 2004 Share Posted September 1, 2004 The difference in the 5AR4 and 5U4 has been closer to 50V on any amp I have ever tried both in. I myslef would ask the designer of the amp like I stated earlier. Quote Link to comment Share on other sites More sharing options...
jt1stcav Posted September 1, 2004 Author Share Posted September 1, 2004 I'm still waiting for Edmund's response before I do anything. Quote Link to comment Share on other sites More sharing options...
radiob Posted September 1, 2004 Share Posted September 1, 2004 Man I learn alot from you guys. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted September 1, 2004 Share Posted September 1, 2004 Nothing beats the 5J7654321-65ab! Quote Link to comment Share on other sites More sharing options...
NOSValves Posted September 1, 2004 Share Posted September 1, 2004 LMAO !! Quote Link to comment Share on other sites More sharing options...
rtaylor Posted September 1, 2004 Share Posted September 1, 2004 ---------------- On 8/30/2004 12:27:50 AM Allan Songer wrote: I would have a hard time paying these prices! My 274B tubes came in a big lot of mostly worthless TV tubes for $50 at the Rose Bowl swap meet about 15 years ago. There were about 100 tubes and the only things worth a damn were the three 274B and some RCA 12BH7. I bought the U52 out of Australia back in the early 1990's when they were "only" $50 each. The Brimars I got on the VERY early days of ebay (1998 or 1999)---I bought 6 of them for about $80 from a guy in Manitoba. But you know what? Those 1940's black plate coke-bottle Sylvanias are right up there with ANY of this exotic stuff and you can still get them for about $10 ea.!!!!!! ---------------- Hi Allen, you mentioned getting black plate Sylvania rectifiers for 10 bucks a pop. Would you mind telling me where??? Have 2 macs that need a pair each and would love to find some. Thanks, Randy Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted September 1, 2004 Share Posted September 1, 2004 Jim: You've got an email and pm. Quote Link to comment Share on other sites More sharing options...
Dflip Posted September 1, 2004 Share Posted September 1, 2004 Randy: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=5717436468&ssPageName=STRK:MEWA:IT They will probably go in the $30-40 range, but still very good value. You may find the odd pair for $12 each, i bought a pair off of ebay from the organdoctor, but shipping was excellent but expensive, extra wrapping plus insurance, so it brought them up to $20 each. But those coke bottles looks so much nicer on the front of your Mc. Don Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.