kev313 Posted February 23, 2005 Share Posted February 23, 2005 Anyone have a nice spare pair of mullard GZ37's for sale? Thanks, kev Quote Link to comment Share on other sites More sharing options...
DRBILL Posted February 23, 2005 Share Posted February 23, 2005 Michael Marks has them at $75 each www.vacuumtubes.com. But come on. We are talking rectifiers. There are some excellent nos tubes of other brands at half that price. I would challenge anybody to tell the difference by ear or test equipment. This is just asking for a blast from a flame thrower. Sorry. Just trying to help. Could we abandon voodoo for the scientific method? DR BILL Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted February 23, 2005 Share Posted February 23, 2005 I don't know, voodoo is kind of fun sometimes.... Sure, there are a bunch of good 5 volt rectifiers out there, but Kevin is not alone in having an interest in them. I used them for years in my Moondogs, and they worked well. To me, they are also among the nicest looking vacuum tube rectifiers, too! Erik ...we don't need to go into the purpose of rectifiers, I know very well that they are used to increase the damping factor of the input transformer direct coupling benefactor that's housed in the electrostatic shield next to the electrolytic resistor supply cathodes. All of those are of course contained within the output transformer primary secondary. Quote Link to comment Share on other sites More sharing options...
kev313 Posted February 23, 2005 Author Share Posted February 23, 2005 yeah...what Erik said. Look - I'll be honest with you. It's all voodoo to me. I'll read Erik's, Dean's, Craig's, Tom B's and Mark's posts all day not because I have any idea what in the hell they are talking about. I don't. I REALLY don't. I like the enthusiasm and love for the hobby that is conveyed by their posts. I don't care to delve into the technical side of amp building, circuit nuances, etc. Frankly, I have a time consuming day job that leaves enough left over for me to enjoy the "basics" of audio - swap gear, listen to changes, and enjoy the music. To that end a little tube rolling is feairly cheap and harmless. YMMV Quote Link to comment Share on other sites More sharing options...
ben. Posted February 23, 2005 Share Posted February 23, 2005 IME, rectifier rolling would yield the most subtle differences as compared to line- phono- or power stage tubes. Have at it, though. They do make some difference. Quote Link to comment Share on other sites More sharing options...
kev313 Posted February 23, 2005 Author Share Posted February 23, 2005 I hear you, Ben. I had fun swapping tubes in my pre and phono for a while (it's really easy when you have 4-6sn7's 2-12au7's and 2-12ax7's in the same unit!). My power tubes are TJ 45's and I really don't feel like moving them out yet. Quote Link to comment Share on other sites More sharing options...
jazman Posted February 24, 2005 Share Posted February 24, 2005 ---------------- On 2/23/2005 8:27:07 PM DRBILL wrote: Michael Marks has them at $75 each www.vacuumtubes.com. But come on. We are talking rectifiers. There are some excellent nos tubes of other brands at half that price. I would challenge anybody to tell the difference by ear or test equipment. This is just asking for a blast from a flame thrower. Sorry. Just trying to help. Could we abandon voodoo for the scientific method? DR BILL ---------------- Dr Bill, No flame is intended but................Some equipment will allow you to hear the difference in rectifiers. This should not be news, and I can provide examples. I also assume from your statement you have not heard metal base GZ34's in a system capable of allowing the difference to be heard. Klipsch out. Quote Link to comment Share on other sites More sharing options...
maxg Posted February 24, 2005 Share Posted February 24, 2005 "I know very well that they are used to increase the damping factor of the input transformer direct coupling benefactor that's housed in the electrostatic shield next to the electrolytic resistor supply cathodes. All of those are of course contained within the output transformer primary secondary." Gee I wish I could have said that. I wonder what it means? Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted February 24, 2005 Share Posted February 24, 2005 Max: It was absolute gibberish! One way rectifiers can possibly provide different sonic characteristics has to do with the fact that they can differ in terms of power output. The 5Y3, which provides fairly moderate B+ supplies, might work well in one circuit and not so well, depending on circuit requirements, in another. They also differ in terms of power handling ability, and the 5Y3 is also not as robust in that respect as a 5AR4 or GZ37. I tried a Chinese 5Y3 on my Moth amp, and it immediately shorted -- there is an explanation for that, but no time now to describe it. But, I have been using an RCA 5Y3 with the Moth, because in lowering the plate supplies just a bit, it also has brought along the benefit of lower noise; and for headphone listening that has been a welcome change. In other words, essential rectification of AC is taking place, but at a level that improves the overall signal to noise ratio of the amplifier. There is a problem in using the 5Y3 with the Moth, though. The power transformer it uses exceeds the power handling of the 5y3 by a fairly important margin, and I'm going to burn it up much more quickly than would a good 5AR4. Also: Mullards are built like tanks, and should provide many years of good use. I can attest to that myself. The GZ37s provided years and years of trouble-free operation in the Moondogs, and looked really nice at the same time. The 5AR4 is also a good replacement for the GZ37. ...time to get to school to load the kiln for another firing. Erik Quote Link to comment Share on other sites More sharing options...
maxg Posted February 24, 2005 Share Posted February 24, 2005 Thank God for that! I had a feeling you were joshing but wasnt sure enough to continue to joke. The "primary secondary" looked rather suspicious to my non-tech mind. Quote Link to comment Share on other sites More sharing options...
dbflash Posted February 24, 2005 Share Posted February 24, 2005 Kev, Send me an email. I tried sending you one but it can back. I really would like read your thoughts on your Cain & Cain Abbys. I'm thinking about getting either a pair of Abbys or Single Horn Ben. Just thinking at this point. I'm suppose to drive to Atlanta next week to hear them. Thanks, Danny Quote Link to comment Share on other sites More sharing options...
jazman Posted February 24, 2005 Share Posted February 24, 2005 Kev, I was visiting the Tube World cite today and I noticed; 2) GZ37 Mullard used/test good "D" getter 1950's $40(that's each) D getters and 1950 vintage are good things, usually. GZ37's usually aren't cheap. You might also try ebay where it usually cost about $100 for a pair that test new, maybe a bit less if it's a European seller, but then there is the $12-$15 shipping cost. Just thought I'd mention the sighting. Klipsch out. Quote Link to comment Share on other sites More sharing options...
DRBILL Posted February 24, 2005 Share Posted February 24, 2005 How silly of me. The METAL BASE! Why didn't I remember that. That makes all the difference in the world. Does it go to ground? Yes? That explains everything. I can sleep easy tonight. DR BILL Quote Link to comment Share on other sites More sharing options...
kev313 Posted February 24, 2005 Author Share Posted February 24, 2005 Thanks for the replies. Danny, The Abby's are VERY different than the Cornwalls they bumped out. Less bass? Sure. I also run them with DRD 45's, so you can guess I'm pretty much taking the "heavy" music off of the play list. The Abby's sound much more natural. Moving to a single Fostex took a bit of getting used to. It took a few sessions to acclimate my ear to the sound. Of course, the speakers could have been breaking in during this period, if you subscribe to that school. Now, however, the sound seems much more coherent. The midrange on the Abby's is out of this world. Much nicer than the 45's on Cornwalls (which was also superb), so I attribute the improvement to the Abby's. Strings sound full. It's a very "rich" tone that wasn't there before. I cannot yet figure out why this is different, but at this point it seems like the speakers do a much better job presenting the leading edge or the attack of the notes. It's just more three dimensional. They sound like they are giving me "more" music to listen to. Same comments apply to vocal and winds reproduction. The obvious weakness, again, is the bass. It's going to take a lot more listening, but so far the difference is most clearly expressed by pop or rock recordings. Since tis represents about 5% - 10% of what I listen to, I not too worried. For example, the new Tom Waits album sounds much better on the Cornwalls or even on my Promedia's. On THAT recording, taking away the bass makes everything else sound congested. The soundtrack to Garden State, on the other hand, sounds absolutely stunning. Since most of my listening involves classical or jazz, these speakers suit me quite nicely. The cornwalls will not be comng back until I can find a new space for them. I can wait. It is likely that large scale classical recordings will fall a bit short at places with this combo. I haven't found that point yet, but I am realistic. Just to cut you off Minn Male, I know my speakers will not accurately reproduce the cannon blasts on the 1812. That is correct. The Abby's do poorly with cannons. Quote Link to comment Share on other sites More sharing options...
jt1stcav Posted February 24, 2005 Share Posted February 24, 2005 I dunno if the GZ37 is any better than my NOS '51 Sylvania 5U4G blackplate, but it sure is HOT! Quote Link to comment Share on other sites More sharing options...
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