Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: JPK on December 10, 2022, 12:27:35 pm
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So I was reading a thread on another forum and this issue came up that stumped me (not hard to do). He wants to use a 290AX with the Champ 600 RI that I'll post a schematic of below. What confused me is the 290AX has center taps on the HV and 6.3V filament supplies. The trans in the schematic does not. So how exactly to connect the 290AX HV and filaments to the schematic is my question. I thought Red/Wht to J14 and Red/Yel center tap to J13 and should be grounded? Not sure if this plays well with the diode rectifier. Also the filament center tap wouldn't be needed since the schematic has 100/100 ohm resistors to ground. Or better to remove the resistors and just use the center tap? If anyone wants a link to the thread I can, just not sure if forum admin is ok with that.
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The 290AX is meant to be used with a conventional full wave rectifier. But the Champ 600 RI requires a PT built to be used with a ***FULL WAVE BRIDGE*** rectifier. He needs to use a proper PT.
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Thanks Slucky. Just before I came to see your post I found the linked thread below. Man oh man do I have much to learn. :w2:
https://el34world.com/Forum/index.php?topic=25003.0
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It'll work as you drew it EXCEPT DON'T GROUND THE HV SECONDARY with a FWB. It WILL run warm, and B+ will possibly be lower than expected.
Source the correct replacement.
--Pete
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Ok thanks. He initially hooked it up with the wires flipped from what I show and it took out the fuse. People are suggesting that he find the right trans so he knows what to do now. And now I know a little more than when I woke up this morning. :think1: