Adcom GFP 750 transformer specs

[rickcl]

Hello. I have a GTP 750 that probably has a blown power transformer. It blows a fuse with secondary disconnected. Looks like it has dual windings one powering a 12 volt and 5 volt output. The other much higher around 60 volts.
It looks like the original might be a custom unit.

Thank you all!

 

[rayma]

Probably custom, but you could stack two standard transformers in that same space.

 

[rickcl]

Yes I did that with a B&K preamp. If I could find out the ratings.

 

[rayma]

Looks like 62VDC and 12VDC supplies (it's hard to read the 62VDC).

So 12VDC/1.4 needs 8.5VAC, or maybe 10VAC.
And 62VDC/1.4 needs 44VAC, or maybe 48VAC.

Just buy two transformers, each the same physical size as the original,
one for each voltage. That will give VA to spare.

 

[rickcl]

Thanks that gives me a starting point. Probably 500ma should do it. Looks like it might have gotten warm

 

[rayma]

I would go by the core size, and use the same brand if possible.

 

[rickcl]

To me it looks like they have the primary fused at 500ma?

 

[rayma]

Power consumption is 30VA, so 30W/120V = 250mA current draw. The 500mA fuse sounds ok.

 

[rickcl]

Thanks again Rayma for the insight. I have a nice Triad toroidal coming for the higher voltage. It is going to be a tight fit. I might even consider moving the transformers outside the case. I have built them before.