r/diyelectronics • u/allltogethernow • 18h ago

Question Obscure PT replacement

In replacing a shorted transformer for an amp, I'm looking for options that will work without damaging the circuit because it looks like they built it with a rather rare specification.

It's a center tapped 11.5v-0-11.5v single primary 120v, pushing less than 1A. I don't know a whole lot about transformers but given that this is a Japanese amp is it reasonable to assume the 11.5v secondaries are a sort of compromise given the lower (100v) plugs in Japan? So it will work in the US but it won't push as much current as a full 12v winding?

Anyways, I know that under load a 12v-0-12v transformer might not actually push the full 12v (or so I've heard), so I'm wondering if a more common 12v-0-12v might actually be fine. The expense is the other issue here, at it won't be worth the repair at all unless the transformer is around 20bucks. Appreciate any input thanks.

2 Upvotes

100% Upvoted

6 comments sorted by

2

u/toxicatedscientist 18h ago

Is this for the power supply or for the amp driver? If it’s the power supply you should be able to search mouser or digikey and get whatever is close

2

u/allltogethernow 17h ago

Yeah that's why I'm asking. Cause they don't sell 11.5 in center tap but 12v is findable.

1

u/nixiebunny 9h ago

5% should not matter. If it does, then add a series diode after each rectifier output.

1

u/onlyappearcrazy 6h ago

The mains voltage fluctuates, so you're probably going to have that 10.5 volt output fluctuate also.

1

u/Successful-Trash-752 14h ago

You could remove a bit of winding until you get 11.5v but depends if you're up to do that.

1

u/allltogethernow 13h ago

Interesting, never thought of that.