AR amplifier, problems after recap

[Multiverse25]

Hello all. I must admit I feel like a bit of an idiot. I finished recapping my AR AU amplifier. It’s the first amplifier that I’ve recapped, and I made a big mistake towards the end, and I’m hoping someone can help me out or point me in the direction of a good tech in my area. You see everything appeared to be going smoothly. I took my time and tried to make sure everything was done correctly. Took lots of pictures along the way. One thing I did was open up the large can capacitors and gutted them and put the new large capacitors inside the old cans and sealed them back up. Drilled two small holes in the lid for the can so that I could run two wires out coming from the + and - of the new capacitor out to the original + and - terminals on the old can. I thought doing it this way would make things easier and far as mounting everything back where it originally went. Unfortunately I unknowingly wired one of the bias capacitors opposite from the way the other one was wired before sealing the can back up and wiring everything back place. I got anxious and didn’t bother to test the amp in any way before hooking it up to my speakers and turning it on. Turned it on and turned the volume up a little and the heard a loud pop come from the amp. Then I saw a small bit of smoke come from the amp. I turned it off and looked inside. Two diodes the were connected to the one bias capacitor had burst apart. Something made me think that maybe I wired one of the capacitors the wrong way. So I replaced the two diodes and removed the large can and opened it up. Sure enough I wired it opposite from the way I wired the other matching capacitor. So I switched the wires around and sealed up the can and put it back in place. Hooked everything back up and turned on the amp. Now everything seemed to be fine. Except the left channel has no sound. The right channel works fine and actually sounds pretty great. One thing I should mention is that the left channel was already having issues when I purchased the amp. It worked but only by fiddling with the interconnects. I would actually have to stand there and squeeze them together slightly to get the left channel to stay on. Another thing that’s weird is that it appears that the channels are backwards. If I hook up my left side speaker to the left terminal and the right side speaker up to the right terminal and try out the hifi news test lp the voice that’s supposed to come from the right side comes from the left side instead. Switch the speaker cables around (right side speaker to left terminal and vice versa) and now the voice that’s recorded on the right hand channel comes from the right hand speaker. Not sure what that is about. Anyhow, is this something that someone with little to no experience servicing amplifiers could possibly trouble shoot with help from you guys or should I take this to a proper tech to get sorted out? Does anyone know of a good tech in the Philadelphia/Pottstown PA region? Thanks!

 

[reddish75]

Imo what you have done with the caps is a terrible idea and its asking for trouble, you can with little effort find capacitor clamps, brackets to retro fit new caps.

Take it to a tech but expect the price to be high as its essentially been messed with.

 

[Doug G.]

What you did is normally fine. Many restorers who wish to retain original appearance do it that way. You just need to be extra careful with large value capacitors. Triple/quadruple check your work.

Doug

 

[Multiverse25]

Yeah like I said it’s the first one I’ve done and the idea to use the old cans was suggested to me by someone with extensive knowledge of amplifier restoration. I figured that I will likely have to take it to a tech but I need to know if someone knows a good one in my area. I am pretty good with audio restorations but I usually stick to turntables and speakers. I was just hoping this is something I could troubleshoot myself with help from AK.