G7 and OEP A262A3E

Guys I have a problem!

I assembled  my secound G7 with OEP trannie A262A3E 1:6,45 ratio!

I wired it serial S1 is +OUT,F2 is -OUT on primary, 2,2uf to S1 and F2 with screen together to ground on secoundary!

But when i load G7 i have very low output on my G7,and my measure on trannie show that i have 1,5Kohm instead of 25Kohm, how is written in

specification of this OEP A262A3E trannie!

Than i send a question direct to OEP factory and they told me this:

"I think you are measuring the DC resistance (1143 ohms +/- 15%) not the AC impedance.

When 600 ohms is connected across the primaries (series connected), you will measure 25k ohms impedance (AC not DC) across the secondaries (series connected)."


So im confused!

What i need to do!?

You are measuring DC resistance - which is not the same as impedance.

1.5KOhm DC resistance is decent enough for a 25K impedance winding.

I'm not sure the OEP's are a good choice for G7 - they seem to be a bit grainy at low levels (cheap core material?)

Make sure to use the transformer reversed - as 6.45:1 (or even 12.9:1) - the "primary" windings goes to output of mic.

Jakob E.

Thanks Jakob!

I wired it reverse output goes to primaries!

http://www.groupdiy.com/index.php?topic=1839.msg29066#msg29066
I've done it this way. Worked fine for me.

I wouldn't recommend the A262A3E. I tried one in my G7 and wasn't a fan. I replaced it with one of the AA BV8 style transformers from here http://www.aamicrophones.com/parts.htm and I'm much more pleased with it now.

Kris