Vox AC50/2 Layout

[Jalmeida]

Hey folks,

I spent some time going over my AC50/2 amp chassis and decided to put together a layout. This is a V1 diagram and I have gone over it, but another set of eyes are appreciated if any of you see anything missing or a mistake. This is stock layout quirks and all. The wire colors don't seem to follow a standard like the older ones. And looking over other similar period amps show some different colors. So left many colors default. Hopefully this of help..

[Jalmeida]

And schematic

[pdf64]

Well done, that’s great work!
You’ve even got the old British red black green mains cable 

One discrepancy is that the schematic shows switch then fuse, whereas they’re swapped over on the layout.

When I refurbed my friend’s MkII, the 56k DCCF cathode resistors put me in a quandary. The stock 1W resistors overdissipate and drift up in value, I think they both were up around 75k.
Plus the valves were well over their Vh-k limit.
The solution I came up with was to increase the HT droppers to those stages to 22k, which brought the cathode voltage down to around 200V. I think I also used 2W 56k resistors, so they weren’t idling up at their limit.

[Jalmeida]

Well done, that’s great work!
You’ve even got the old British red black green mains cable 

One discrepancy is that the schematic shows switch then fuse, whereas they’re swapped over on the layout.

When I refurbed my friend’s MkII, the 56k DCCF cathode resistors put me in a quandary. The stock 1W resistors overdissipate and drift up in value, I think they both were up around 75k.
Plus the valves were well over their Vh-k limit.
The solution I came up with was to increase the HT droppers to those stages to 22k, which brought the cathode voltage down to around 200V. I think I also used 2W 56k resistors, so they weren’t idling up at their limit.

I just double checked mine, and it is the way I drew it. However, mine has had the Voltage selector removed as well as the Power transformer replaced. I agree that it doesn’t match the schematic. I will look a bit into other pictures of original amp before I change it to be sure. Not sure if it is worth drawing in the voltage selector into this layout.