N Cook wrote:

Cut out in use then came back.
Next time failed to give output but owner noticed clip light in pre-amp
functioned as normal
Now I have it, I cannot induce it to fail.

Of course not. ;-)

Anyone know of generic/specific Eden problems?
Likely suspects the discrete wire IDC connectors for power and signal
interconnects, unsupported wire-wounds on end, mains thermal switch.
Anyone know the identity of the valve/tube ?

12AX7.

If it's got an effects loop (or pre-in pwr-out jacks)
check for dirty normalling contacts.

Lord Valve
Expert