Re: Mullard 5-10 amplifier
Looking closely at the photo of the layout I personally think that the grounding needs rerouting. It seems that all the 0V connections on the transformer are connected together at the transformer, they then go by a thick piece of tinned copper to a valve centre pin and then to the tag board, along the tag board and then via another piece of TCW to the octal socket, presumably for the pre-amp. Other grounds are connected to the tagboard such as the switch. It is not clear where the capacitor 0V connections go, probably to chassis locally.
As has been suggested by others on this thread the charging current loops for the power supply should be separate and only connected to the chassis / 0V at a single point, likewise the centre point of the heaters should only be connected to ground at this point.
On the plus side I see the heaters wires are twisted and run clear of other wires which is good.
Peter
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