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Is anyone having issues with the quality of the Impedance switch? Mine just melted down.

I have a working Tramp, all voltages in range, correct impedance match to speaker & correct bias switch selection. I wired the switch as a 6 way as described in the Tramp docs.

After the 4th or 5th power up on the amp, the switch started smoking/melting. I was using a 6V6 at the time, again with the bias switch set for 6V6.

I pulled the switch and checked the wiring which was correct per the doc & nothing had shorted out externally. One terminal was "evaporated" (burnt away) and the switch body was beginning to melt. I compared it to a Marshall switch I had and there was a big difference in the terminal thickness.

A recent subject ("KT88 Confusion") shows a good alternate switching setup with a 2nd switch that selects 2.5K or 5K (for EL34/KT88 & 6L6/6V6 selection) and which would allow use of a different 3 way Impedance selector switch (i.e. Marshall). This eliminates the need for a 6 way switch for Impedance for both 2.5K & 5K at 4,8, and 16 ohms.

Any other meltdowns? Tom

The switch is up to spec to do it's job. Should be fine, but there is always odd ball cases.

Were you changing the impedance control while the amp was turned on?

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Followup on Switch Meltdown

I must have had a bad switch that isn't representative of the switch quality. I converted the impedance selector to a Marshall 3 way switch and added a separate SPDT switch to select 2.5K or 5K for the OT. There are now 3 switches:
Bias, Impedance, & OT (2.5K or 5K). There is much less crowding of the wiring versus the original impedance switch.

Just FYI - Tom