When I was swapping out some speakers in my Maz Jr last night, I decided to try the new JJ GZ34 rectifier I recently got in place of the stock Sovtek 5AR4. Fired the amp up, flipped the stand by on and....nothing . I looked at everything in back, power and preamp tubes glowin' away, but the GZ34 was black as night. I checked all my connections and tried again, still no output. Popped the old 5AR4 back in and we're back in business, glowing hot and loud 'n proud.
Any ideas? I'm not a tube expert, but I thought if the rectifier isn't heating up and passing current, then the AC isn't being coverted to DC and the rest of the amp just isn't going to get any power. But, with the GZ34 dead, the power and preamp tubes were still glowin' and ready to go . It's likely that I just got a bad rectifier tube, but I would appreciate it if someone could explain how this works to me. Thanks.
Last Edit: Mar 31, 2006 23:32:35 GMT -7 by Greg G.
Maz 18 Jr. Reverb Head JDesign Vintage 112 Cab (Hellatone 30) Parker NiteFly SA Gibson Les Paul Standard
You ought to be able to return the tube to the vendor for replacement.
If you are of a mind to do so, check the end of the pins at the base of the tube under magnification. I have seen a few where the solder was not applied properly and the tiny wires inside the hollow pin were not making contact. This generally will result in intermittent operation, but could also give you a dead tube. If you find this, reheating with a soldering iron and wicking a bit of solder into the pin will usually correct it.
The power transformer in your amp has 3 separate winding sections on the secondary side [ the primary side being connected to your power plug ] - the highest voltage winding section feeds the plates of the rectifier tube. Another section of the winding supplies 5v. AC to the rectifier tube filament. The final winding section provides 6.3v. AC to the remainder of the tube filaments.
As long as the fuses haven't blown and your power transformer is healthy, you can still get other voltages throughout the amp, pilot light, tube filaments glowing, etc. even if your rectifier is dead and isn't providing the DC needed to drive the signal through the amp.
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