Tweet
I have a mid 60's Lafayette PA amp that I recently bought for $30 for my next project intending to just take the trannies and scrap the rest. After getting it and doing a little more research (and seeing how well it is made) I'm thinking I want to keep it as is (see link) but want to hear it first.
The situation is I cannot find a schematic anywhere. The amp has a power section which is a GZ34 and 2 EL34's putting out (so they say) 75 watts with well over 500v on the plates. The PI is a 12AX7. There is a separate 5y3gt rectifier for the preamp which consists a 12AX7 and a 6AV6. There are 2 multisection can caps. One 80/10/10 for the b+, output and PI sections and another which I cannot read for the preamp. I've tested them and they are dried up. I want to replace them, put in a couple inputs and outputs and see how it sounds. I'm looking for advice on cap values for replacements as I know I will never find an 80/10/10 can. Also, something had to be wired in series as the caps were rated at only 450v and I can't imagine that 80uf was connected to a GZ34. Hopefully this is enough info for someone to recommend adequate filtering. The attached link is a lower power version but if it sounds anything like this I'll keep it as is.
YouTube - Lafayette Model PA622 Class A push pull all tube PA head used as guitar amp
The situation is I cannot find a schematic anywhere. The amp has a power section which is a GZ34 and 2 EL34's putting out (so they say) 75 watts with well over 500v on the plates. The PI is a 12AX7. There is a separate 5y3gt rectifier for the preamp which consists a 12AX7 and a 6AV6. There are 2 multisection can caps. One 80/10/10 for the b+, output and PI sections and another which I cannot read for the preamp. I've tested them and they are dried up. I want to replace them, put in a couple inputs and outputs and see how it sounds. I'm looking for advice on cap values for replacements as I know I will never find an 80/10/10 can. Also, something had to be wired in series as the caps were rated at only 450v and I can't imagine that 80uf was connected to a GZ34. Hopefully this is enough info for someone to recommend adequate filtering. The attached link is a lower power version but if it sounds anything like this I'll keep it as is.
YouTube - Lafayette Model PA622 Class A push pull all tube PA head used as guitar amp