Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: punkykatt on January 06, 2017, 07:52:01 pm
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http://el34world.com/charts/Schematics/files/rivera/rivera_r_series.pdf (http://el34world.com/charts/Schematics/files/rivera/rivera_r_series.pdf)
Hey Guys, got is amp in for snap, crackle, pop complaint. Did a clean & service, pots, jacks, switches, tube sockets, grounds, retention tube pin grippers, reheated and added solder to PCB tube socket pins, installed all known good preamp and power tubes. Amp still making noise for a few minuets and then works flawlessly. Shut it down, let it cool, turn it on and snap crackle pop is back. I put my listening tool on the amp and traced the noise source to V1 47k 2w (R103) plate load resistor. I replaced R103 and inspected all other solder joints while I had the PCB out. All solder joints look healthy. Go to fire up the amp and it still snap crackle pop for a few minutes then quiets down nicely. I checked (C101) 10uf/450v with my ESR meter and is reading where it should be. Then I clipped in a new 10uf/450v cap across C101 and it did not help. V1 tube socket looks like new. Did I miss anything? Bad PCB maybe? Any input is much appreciated. Punky