Marshall c5 RAT

semaphoresteve

Hey wonder if anybody can help. 

I have a heavily modified Marshall C5 (by Andy at RAT amps now retired). Suddenly faded and died during rehearsal. Everything looks ok visually. Absolutely no sound and all tubes seem dim. All fuses are ok. an external speaker doesn't work nor headphones. I think it may be the output transformer. I'm trying to find a drop-in replacement or one that I can match. Any ideas? My trusted amp tech has also retired but I'm trying to get hold of him.

thanks

steve

ecc83

Hi Steve, I have found a schematic for the basic C5 and there is nothing there that any decent 'old time' radio tech would find challenging. You suspect the OPtraff? Well they do have a bit of a hard time in SE stages ICBM will know if failure is likely. An EL84 to 8Ohm (?) 5W traff should not be hard to find but won't be peanuts. A few voltage checks will soon tell you if it has failed.

Dave.

RiftAmps

DWJ is in Liverpool, he'll be able to sort it

ecc83

RiftAmps said:

DWJ is in Liverpool, he'll be able to sort it

Ha! I always seem to forget you as an amp guru! Sorry neighbour!

Dave.

semaphoresteve

Thanks for the responses. Dan would be my next move if I can't sort it.

jasonbone75

I have used these: https://primarywindings.com/product/amp-maker-5w-single-ended-output-transformer/

andy_k

I'd check preamp tubes before sourcing an output transformer, and don't do anything else unless you know what you are doing.
I have a couple of RAT C5s, and it is more likely to be a bad solder joint on a circuit board, than a tranny.

longi

Email him anyway, he might well take a look at it. Tbh, anyone competant that knows what they are looking at would be able to work it out without a schematic. ecc83 and ICBM are the best bets for advice. Thye've forgotten more than I ever knew. Proper heros them two. Depending where you are, there's also Pete Agate in Bognor that I used, who knew his stuff. He just likes fixing stuff. Another hero. He's dirt cheap as well.