RE: Need Futterman H3aa schematic and biasing instructions

Posted by rhinohifi714 (A) on September 10, 2013 at 16:39:51

In Reply to: RE: Need Futterman H3aa schematic and biasing instructions posted by topround on September 2, 2013 at 18:58:18:

I think you would be better off to rewire the amp to the otl-3 schematics, that will allow you to do a proper alignment, if you look at the zener's on the H3aa schematic you will notice it doesn't tell you what the proper value is. Julius used to do the alignment with a box full of zeners testing them one by one until he was happy with the alignment. If you use the otl-3 schematic you will be able to dial them in even if your zeners are slightly off. Also Julius recommended that if you retubed the unit to send it to him so he could make sure the voltages were correct, some of the 6lf6's are very hot and would end up self destructing if dropping too much current, that was a thing of the past when the otl-3 was produced, reguardless of how strong the tube were you could still get them aligned properly.
Good Luck to your rebuild.

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Follow Ups Full Thread

Topic - Need Futterman H3aa schematic and biasing instructions - topround 02:02:56 09/01/13 (10)

RE: Need Futterman H3aa schematic and biasing instructions - Banat 05:00:53 09/01/13 (9)

RE: Need Futterman H3aa schematic and biasing instructions - topround 18:58:18 09/02/13 (8)

RE: Need Futterman H3aa schematic and biasing instructions - rhinohifi714 16:39:51 09/10/13 (7)

RE: Need Futterman H3aa schematic and biasing instructions - airheadair 19:35:21 09/11/13 (6)

RE: Need Futterman H3aa schematic and biasing instructions - rhinohifi714 06:42:08 09/12/13 (5)

RE: Need Futterman H3aa schematic and biasing instructions - airheadair 19:01:45 09/12/13 (4)

RE: Need Futterman H3aa schematic and biasing instructions - adam2a3 00:46:20 09/15/13 (3)

RE: Need Futterman H3aa schematic and biasing instructions - rhinohifi714 08:18:49 09/15/13 (2)

RE: Need Futterman H3aa schematic and biasing instructions - adam2a3 16:35:31 09/15/13 (1)

RE: Need Futterman H3aa schematic and biasing instructions - rhinohifi714 18:55:47 09/15/13 (0)

Follow Ups

RE: Need Futterman H3aa schematic and biasing instructions - rhinohifi714 16:39:51 09/10/13 (7)

RE: Need Futterman H3aa schematic and biasing instructions - airheadair 19:35:21 09/11/13 (6)

RE: Need Futterman H3aa schematic and biasing instructions - rhinohifi714 06:42:08 09/12/13 (5)

RE: Need Futterman H3aa schematic and biasing instructions - airheadair 19:01:45 09/12/13 (4)

RE: Need Futterman H3aa schematic and biasing instructions - adam2a3 00:46:20 09/15/13 (3)

RE: Need Futterman H3aa schematic and biasing instructions - rhinohifi714 08:18:49 09/15/13 (2)

RE: Need Futterman H3aa schematic and biasing instructions - adam2a3 16:35:31 09/15/13 (1)

RE: Need Futterman H3aa schematic and biasing instructions - rhinohifi714 18:55:47 09/15/13 (0)

RE: Need Futterman H3aa schematic and biasing instructions

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