2022 Wangs 1987HW

This is a handwired copy of the famous Marshall circuit of the same name. The amp had it’s original B+ and Screen filter capacitors failed open when received - as well as worn power tubes and V1 preamp tube due to stress from failed components. I’ve actually never seen an amp this new with failed filter caps. I suspect it was a bad batch of parts. This was the cause of all symptoms.

Both of the failed filter caps were replaced with higher quality MOD brand electrolytics (80uf 500V 105deg C), and all associated wiring was re-soldered and put back in place. The V1 preamp tube was replaced with a medium plate JJ 12AX7MG and the power tubes replaced with a selected JJ E34L Matched Pair. The fixed bias was set to 64% Class AB Plate Dissipation with a B+ of 453VDC. All tubes were selected for best tone and reliability. Amp now functions normally.