Hello,
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.
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Topic - MP Engineering OTL - Kasanay 14:16:47 06/02/16 (19)
- RE: MP Engineering OTL - Kasanay 10:04:56 06/06/16 (0)
- RE: MP Engineering OTL - Kasanay 08:11:38 06/06/16 (10)
- RE: MP Engineering OTL - Banat 13:43:51 06/06/16 (2)
- RE: MP Engineering OTL - Kasanay 14:16:09 06/06/16 (1)
- RE: MP Engineering OTL - Banat 15:19:15 06/06/16 (0)
- RE: MP Engineering OTL - Lew 12:40:55 06/06/16 (5)
- RE: MP Engineering OTL - Kasanay 14:01:03 06/06/16 (4)
- RE: MP Engineering OTL - Lew 14:38:45 06/06/16 (3)
- RE: MP Engineering OTL - Kasanay 14:57:18 06/06/16 (2)
- You might have to move some tubes around to get the DC balance - Ralph 11:43:59 06/07/16 (1)
- RE: You might have to move some tubes around to get the DC balance - Kasanay 12:16:53 06/07/16 (0)
- RE: MP Engineering OTL - Kasanay 08:14:02 06/06/16 (0)
- RE: MP Engineering OTL - Lew 07:58:42 06/03/16 (6)
- RE: MP Engineering OTL - Kasanay 21:45:08 06/05/16 (0)
- RE: MP Engineering OTL - airheadair 17:06:52 06/03/16 (4)