WEM Custom 15

[Bushbaby]

I would like to take this opportunity to thank Trevor (Murphy V310) for all his help, guidance and advice in reviewing the 'hum' issues. Under his mentoring, today we reviewed with a scope (Tektronix T935a with x10 probe) the smoothing cap, phase splitter valve (ECC83) and finally across the speaker itself. Its apparent that its a ground loop issue and its due to the circuit design so it does seem that I've reached the end of the road on this one. On a positive note, the amplifier is working well and to be honest the 'hum' is only exacerbated when the volume is control is quite high with nothing connected.

Perhaps I can understand now why old WEM amps were not as popular as other UK brands such as Marshall etc but I am also aware that they had some issues too.

Best Regards

Rob