Conrad Johnson PV-8: how to convert 110v to 220v

[TBL]

I am having a Conrad Johnson PV-8 preamp on which I wanna know how to convert it from 110v to 220v input.

It has a big power transformer of Northlake Engineering with marks C-128-126. I tried rewiring but the fuse kept blowing. I hope I haven't destroyed it yet......

Someone can advice?

Terence

 

[mullardel34]

Most conrad-johnson products for which I have schematics (I don't have schematics for the PV-8) are shipped with a re-configurable power transformer. Usually, there are two primaries on the power transformer; these primaries are wired in parallel for 110VAC operations --- the primaries are simply wired in series for 220VAC operations. 😎

 

[Palustris]

I have to wonder why you wouldn't contact conrad-johnson first:

service@conradjohnson.com

 

[Triodethom]

Bill at this location was involved in the design from the get go he should be able to helpTube Amplifier Repair | Audio Equipment Repair | Amplifier Repair

 

[HollowState]

I tried rewiring but the fuse kept blowing. I hope I haven't destroyed it yet......

I doubt you have damaged anything since the fuse did it's job and protected it. Assuming it worked set up for 110V, you may have one of the primaries out of phase. So try reversing one of them. Also, connect a standard 100 or 60 watt incandescent lamp in series with the mains power input. This will protect everything. If the lamp glows brightly, something is wrong. When wired correctly the lamp will not glow, or maybe just a very tiny amount at most.

 

[TBL]

My PV-10 has a TRIAD tranny on which the instructions read clearly for the colour-coded wires to go. On that, now the black goes to red, put aside, and the other two orange, and white goes to the inputs.