Hi Jan,
beautiful example, congratulations.
often the problem with these amps is the eq inductors failing. While there are workarounds, , your combo is so pristine, better to leave it as it is,, if you are happy with the sound, 'till you can find an original replacement inductor.
oh, and Hi Frank,
408, not often you see those, now ! Love mine .
370's , brilliant, my main gigging amp, at the mo'
best Wishes
mike.