Transformer for A40 Power Amp Build

[Robbie010]

Just looking for a little advice on the required transformer for A40 build.

The parts list says 44V 6A centre tapped, which doesn’t seem to be common but I can get 22V or 24V dual output toroidal transformers. However, what would be the ideal VA rating for the transformers?

Thanks.

 

[llwhtt]

When I built my A40 a few years ago I used the Signal 88-8 that was listed in the article. Signal was still making them on special order.

Craig

 

[gary s]

Nelson specified the Signal 88-8 EI core transformer in the original design which had 2 off 44VAC centre tapped (22V+22V) secondary windings, one for each channel at a current of 8 amps for each winding - so the overall VA rating is 44 x 2 x8 = 700VA.

He also specified a different transformer later on for those building the amp with 2 separate transformers (one for each channel) being 22V + 22V secondary at 6 amps, so the VA rating will be 22 x 2 x 6 =264VA (a 300VA toroidal transformer will be the nearest size). Two of these will be required obviously for a stereo power amplifier.

Hope that helps, I will be using the second option.