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Hallo ! I am working on two old Quad 2 amps . One has an old GZ32 rec.tube and
I measure 333 VDC on the anodes of the russian 6N3C-E , new powertubes .
The other amp had a worn out rec.tube , 5V4G . In that amp I tried a new,
Ruby GZ34 and got 370 VDC on the new pair of russian 6N3C-E tubes. Guess
here only about 10-15 VDC in voltagedrop . I feels that GZ34 might be a bit
too efficient for this old QUAD !??? Therefore I tried some new NOS , russian , 5U4C , which should be similar to GZ30...? With these rec.tubes in both amps , I got 346 VDC , which feels good ! BUT , do You think this
tube can handle about 120 mA of current ? Perhaps more when playing music
at high volume ? I have a 1N4007 in front of each anode of the rec. tube to reduce backvoltage at the rec.... Regards Stewen
Follow Ups:
I agree with Roland. And here's a good source for the gz32. I've gotten two pairs myself, and they're terrific.
http://www.ebay.com/itm/SEL-Lorenz-GZ32-5V4G-CV593-German-NOS-high-quality-rectifier-MILspec-tubes-/201072593867?pt=Vintage_Electronics_R2&hash=item2ed0dc4bcb
Hi Stewen
Why not get another GZ32 and get rid of the 1N4007
and restore it to the state it was from the beginning.
It a wonderful little amp that deserves that.
Hard finding GZ32, just drop me a mail?
Cheers
Roland!
If I were you, I would use a GZ34 and put a 30 ohm resistor in series right off the pin 8 of the rectifier. This will give you plenty of headroom and the equivalent voltage drop. 5V4G is rated for 175 mA. The original design pulled 147 mA out of the rectifier. Don't plug in anything rated below 175mA.
gz34 is fine in quad-II
But as powertubes KT-66 is recommended ( and sounds best ), in addition make shure the common cathode resistor is 180 ohm and 5W .
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