Home OTL Asylum

OTL, Output Transformerless Amplifier User Group.

MP Engineering OTL

I just scored a pair or very rare OTL amps that were build by MP Engineering in about 1960. I am no expert by any means so I am looking any help this group can offer.
I am in the process of bringing them back to life as they have not been fired up in decades (maybe 5).
So far I have warmed up the amps and checked voltages. All test points are surprisingly close to spec. I have the bias dial in to -20v.
The amps have a built-in offset meter with a balance pot. I need to get these dialed in and am looking for advice/ tips.
One side will pin the needle and reads 3.4VDC at the speaker terminal. The other side reads .01VDC and the needle is about 1/2 way between 0 and pinned. Turning the balance on either channel seems to have little to no effect on the readings. I have not done any testing of the tubes.

This post is made possible by the generous support of people like you and our sponsors:
  Amplified Parts  

Topic - MP Engineering OTL - Kasanay 14:16:47 06/02/16 (19)


Post a Message!

Forgot Password?
Moniker (Username):
Password (Optional):
  Remember my Moniker & Password  (What's this?)    Eat Me
E-Mail (Optional):
Message:   (Posts are subject to Content Rules)
Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:  Automagically notify you when someone responds.