follow-up comments

Posted by JJ Triode (A) on April 5, 2014 at 22:06:38

In Reply to: RE: Magnavox Rebuilds and Fultons (longish) posted by Fitero on April 5, 2014 at 19:50:03:

Your oil cap power supply will do fine just as it is. The original console amp had much less capacitance, and just cheap electrolytics.

The Z565 output transformers should be a nice improvement and will permit you to experiment with UL operation of the output tubes, as well as reduced feedback (since those Dynaco reproduction OPTs will have better bandwidth than the Magnavox originals, they should need less or even no NFB.)

As far as I know there is no exact formula for the cathode bypass capacitance, other than that it should be large enough not to roll off the bass unacceptably. You can experiment and listen.

I don't know much about how to optimize the paraphase gain-splitter circuit. The original Magnavox parts values and operating points may reflect an effort to tailor the amplifier to the original console speaker drivers and enclosure. As long as you do not exceed the tube safety margins, I think you should just follow your ears.

Good luck,
JJ

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Follow Ups Full Thread

Topic - Magnavox 9302 Rebuild - Fitero 22:18:10 04/04/14 (24)

RE: Magnavox 9302 Rebuild - johnmil 05:41:28 04/08/14 (1)

RE: Magnavox 9302 Rebuild - Fitero 06:09:24 04/08/14 (0)

Magnavox Rebuilds and Fultons (longish) - JJ Triode 14:48:08 04/05/14 (16)

Fulton Speakers and FMI , website One Day In the Future - drlowmu 11:53:59 04/08/14 (3)

RE: Fulton Speakers and FMI , website One Day In the Future - Fitero 17:11:49 04/08/14 (2)

RE: Fulton Speakers and FMI , website One Day In the Future - drlowmu 08:36:16 04/09/14 (1)

RE: Fulton Speakers and FMI , website One Day In the Future - Fitero 20:31:51 04/09/14 (0)

RE: Magnavox Rebuilds and Fultons (longish) - Michael Samra 15:40:55 04/06/14 (4)

RE: Magnavox Rebuilds and Fultons (longish) - JJ Triode 16:55:16 04/07/14 (0)

RE: Magnavox Rebuilds and Fultons (longish) - Fitero 16:44:44 04/06/14 (2)

Williamson schematic (longish) - JJ Triode 17:22:30 04/07/14 (1)

RE: Williamson schematic (longish) - Fitero 20:37:27 04/07/14 (0)

RE: Magnavox Rebuilds and Fultons (longish) - drlowmu 21:16:22 04/05/14 (2)

RE: Magnavox Rebuilds and Fultons (longish) - Fitero 16:28:58 04/06/14 (1)

RE: Magnavox Rebuilds and Fultons (longish) - drlowmu 19:09:40 04/06/14 (0)

RE: Magnavox Rebuilds and Fultons (longish) - Fitero 19:50:03 04/05/14 (1)

follow-up comments - JJ Triode 22:06:38 04/05/14 (0)

RE: Magnavox Rebuilds and Fultons (longish) - Eli Duttman 16:04:39 04/05/14 (1)

shared cathode resistors - JJ Triode 17:42:17 04/05/14 (0)

RE: Magnavox 9302 Rebuild - drlowmu 01:18:44 04/05/14 (4)

RE: Magnavox 9302 Rebuild - Fitero 06:35:39 04/05/14 (3)

RE: Magnavox 9302 Rebuild - drlowmu 15:25:26 04/05/14 (0)

Good Job Pete - Michael Samra 14:18:51 04/05/14 (1)

RE: +1 - deathtube 667 14:48:31 04/05/14 (0)

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follow-up comments - JJ Triode 22:06:38 04/05/14 (0)

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