Eico ST-40 PT specifications?

[soma_hero]

Hello to all, new here. I've greatly enjoyed reading through posts here, and need some help.

I have an Eico ST-40 power transformer I'm considering using for a tube amp project. Does anyone know the current specifications? None of the heater windings have lower gauge wire, so i'm guessing they're not super high current. I've measured my HT voltage as 357-0-357, which is close to schematics I've seen.

Thanks for any help!
Michael

 

[Tom Bavis]

I'd guess 160-200 mA. Measure the winding resistance and that will give a good idea...

 

[Squidward]

Best way to guess it's capability would be to find a schematic and see what it used to drive.

 

[soma_hero]

Four 7591's, Four 12DW7, Two 12AX7. So if i look at plate (and screen?) current consumption in the datasheets and then estimate ~10% +/-, I should have an accurate guess?

 

[Squidward]

I would think that guess would be fine. What sort of amp are you planning on building with it?

 

[soma_hero]

The amp will be a Trainwreck Rocket style amp using KT-66 output tubes. Very similar to a 59 Fender Bassman. Three 12AX7 preamps and two push pull KT66 tubes with a GZ34/5U4GB or 5AR4 rectifier. So I'm guessing this transformer has plenty of juice on the HT, but I know the rectifier's have maximum current ratings so I wanted to be safe.

 

[GordonW]

A power transformer made to run four 7591s (which idle at around 40ma each, or 160ma for all four combined) will run a single pair of KT66s (made to idle at around 50-60ma each, or 100-120ma for a pair) just fine.

Same goes for the 5AR4 rectifier. Should work very well with a pair of KT66s.

Regards,
Gordon.

 

[soma_hero]

Excellent info, thank you!