I'm collecting parts ready to build ODS 183, I'm looking at the transformers I need to get.
I have used Hammond transformers in my previous builds so I'd like to keep with them.
power = 290HX
output = 1750U
choke = 194F
are these suitable for this build? I've been offered a special price for all 3 together from a company here in the UK, but thought I'd better check they were the right ones before I pull the trigger!
Thanks guys for all the information I have gleaned from this board, I'd never feel confident enough to embark on this without you
Looks good to me, but note the PT is an upright mount, and will use a FWB rectifier. Voltage will be a bit higher (~10%) than with the Fender PT. The 100V bias winding will require a minor change to the bias circuit. If you want to go with the original Fender type, use 290FEX or 291FEX.
Thanks for the input Martin, I will be making my own chassis so lay down/stand up isn't too important, but the other points you raised are!
I think I got thrown by the output/choke being Marshall types, and assumed (badly) that the PT would be also - thanks for putting me right on that one.
The 291FEX is available from my supplier so I will go with that one, I'd like to keep it as faithful to the original as I can.
One other point, just so you are aware, is that the filament winding on 290FEX/291FEX is rated 5.5A @6.5V, which is typical for Fender Twin PT's. With 4x EL34 and 3x 12AX7 you have 6.9A total, which is 25% over the spec. I don't think the Hammond PT will have trouble supplying that current, as they are known to be conservatively rated.
