In Reply to: RE: Rebuild of MC30s posted by Lee of Omaha on April 29, 2016 at 20:50:26:
...the Mac unity coupled design does indeed utilize a lot of corrective feedback although it's a combination of local and global. Anecdotally I've heard something on the order of 30-40dB overall but haven't taken the time to verify it.
The output stage is actially very low gain ~2 considered from a-k. As such, one of the practical considerations in overall amp design was getting sufficient voltage swing to g1 of the finals. Also, the finals are operated in true pentode mode where the voltage betw g2 & k is held constant at all times (regardless of signal level), contrary to what a cursory examination of the schematic seems to indicate.If you're so inclined, a simple search will turn up numerous detailed explanations of the operation of the unity coupled circuit on the net.
Overall, I agree: it's best not to mess with something one doesn't understand.
Edits: 04/30/16
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Follow Ups
- RE: Rebuild of MC30s... - Steve O 09:59:22 04/30/16 (11)
- RE: Rebuild of MC30s... - Michael Samra 10:50:07 04/30/16 (10)
- Name dropping vs. circuit analysis - PakProtector 07:11:39 05/02/16 (0)
- RE: Rebuild of MC30s... - Steve O 14:10:03 04/30/16 (8)
- RE: Rebuild of MC30s... - Michael Samra 22:51:41 04/30/16 (7)
- RE: Rebuild of MC30s... - Steve O 05:50:18 05/01/16 (6)
- RE: Rebuild of MC30s... - Michael Samra 11:47:52 05/01/16 (5)
- RE: Rebuild of MC30s... - Steve O 13:26:54 05/01/16 (4)
- RE: Rebuild of MC30s... - Michael Samra 17:31:09 05/01/16 (3)
- RE: Rebuild of MC30s... - PakProtector 03:50:29 05/02/16 (2)
- RE: Rebuild of MC30s... - Michael Samra 13:01:42 05/02/16 (1)
- RE: Rebuild of MC30s... - PakProtector 03:05:31 05/03/16 (0)