Tube pre amp needed

disneyjoe7

Hello all,

My Conrad Johnson PV-5 pre amp died the Transformer is bad, looking for a new / used pre amp to replace.


Steve

disneyjoe7

May have jumped the gun, so standby may have figured out what's wrong... The bridge rectifier may had a bad connection on the pcb and caused the transformer to be very hot. I'm trying to fix it now... But I think it may live.

disneyjoe7

Well think it may live giving these facts....

1.) after replacing the fuse it did play but with hum.

2.) It started smelling and transformer got very warm giving time on.

Found bridge rectifier needing some TLC resolder and clean up of PCB, but now found the bridge rectifier is defective having a short in a leg. This part well is 31 years old being date code 8336 (meaning 36 week of 1983) and a bit hard to find info on but believe its 400v 4amp does anyone know for sure? I think its the tube filament power supply circuit. The part is large having a screw holding a heat sink MDA970A1 M 8336

disneyjoe7

Now see MDA970A1 maybe 50v 4amp but is 4amp strong enough to power 8 tubes?

Strong Bad

I've been trying to get time to post a For Sale, but i'm looking to get rid of my Dodd ELP. If you still need one and are interested, hit me up privately.

disneyjoe7

That pre amp you're selling is Sweet and I know it.... Trying to fix mine only because I mod it to be a HT bypass amp also. When off it switches 2 relays to bypass the HT input.

disneyjoe7

Got mine to work again, bad bridge rectifier caused to transformer a half a sine short. This caused the transformer to get hot, and hummed.... Caught it in time to safe the transformer. Playing it again my MUSIC LIVES

george daniel

Attaboy Steve

disneyjoe7

Thanks George, it's surely missed when it doesn't work being a center of everything with a HT bypass mod.