DR-412 Mic Pre build - need help with XFMRs

[Toobme]

Update: Finished the psu, now just wiring pots.

Hey all - I’m nearly done this one, but having trouble wiring up both the psu transformer and the output transformer.
I do not have schematics or a layout (save for the board), so am getting list and don’t want to fry anything doing the trial and error type testing I’m capable of!

It’s an API style build with EA2503 output transformer (need help with wiring to this board).
The PSU toroid is dual 115v, with two whites and two blacks, and dual 25v secondaries with two reds and two blues. No part number, but it looks Slovenian.
I want to wire for 120v (North American), so would i just use one black and one white, and then just one blue and one red?
On the psu board, it just labels the pins as 1, 2, 3, 4, 5, 6, G, G.

Wish I had the schematics, but if you have a clue, I’d appreciate it!

Has anyone put this mic pre together and know these two answers?

Here is a shot of the transformer and board - no label on the pins of the transformer header.

Thanks for any nudging/advice!



And here’s my attempt (minus the grounds yet) for the psu.
Totally confused, but I’m hoping/assuming that brown lead is pin 1.
Again, without the layout and schematic, I’m flying blind (for my ability, I’m sure many of you out there can do this asleep!).

 

[Toobme]

And here is the psu pics . . .

 

[soulsonic]

No schematics? Was there a bill of materials? How did you know what components to buy? Where did this all come from? Was it a kit?

 

[Toobme]

Not a kit, but the boards came with the transformer.

Last night I finished the psu and dialled in the +/- 16V and the 48V phantom.
Now to wire the gain switches and volume pots.

The boards and case are from DIY-RACKED.COM, Tat Perushka.
There was a BOM, bad sadly he can’t find the schematic.

Now I’m just trying to figure out the gain setup.
6 pins on the output header, presumably going to 4 pins on the volume pot (Hairball Audio’s), and 2 to ground.
But it’s a bit of a guessing game without a schematic, as to the hooking up or wiring.

Nice boards, though, I built a pair of La2a’s from his cases. Nice.

When I finally get this together, I’ll make a PDF of the finished wiring and post here.

Thanks for looking/helping!

 

[Toobme]

I decided to try going with a hopefully logical assumption and wired the output transformers in the order the wires exist in. Brown=1, etc.

Where I’m stumped now is the output level header. It has six pins. The Gain header has 2, which I assume go to the 2 pins on the gain switch board.
But the output level header must go to the volume pot board, which has 4 pins. I’m guessing the other two need to go to ground, but that might be only on one end.
Scratching and hmmm-ing here.