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PostPosted: October 17th, 2019, 8:32 am 
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Joined: February 28th, 2013, 1:19 pm
Posts: 331
For Sale

A Pair of 2A3 SET amplifiers. 4W output (or more depending on tube selection).
Fine working condition.
Screen regulated Pentode driver (6688), cap coupled to grid of 2A3.
Shunt screen regulator uses gas regulator tube.
AC Heater with 10 turn hum pot.
Tube rectifier
Magnequest FS-030 output transformers!
Angela Instruments Power transformer with 320V and 380V B+ windings, and 2.5V and 5V filament windings for either 2A3 or 300B. Very cool running.
Motor run caps in power supply (under chassis).

Perfect for very efficient speakers, such as a midrange horn in a multi-amp setup.

Shown with JJ 2A3 output tubes, which have similar power output as 300B.
The Mullard GZ34 rectifier tubes shown are not for sale, a Sovtek or Chinese rectifier GZ34 will be substituted.

They are a bit dusty from storage, but worked perfectly the last I used them and are VERY quiet due to the fine adjustment capability of the multi-turn hum nulling pot.

$900 for the pair. Local pickup only.


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PostPosted: October 17th, 2019, 10:35 am 
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Joined: April 4th, 2016, 4:07 pm
Posts: 22
Hi Dave,

I hope you don't mind my inquiry - I'm not really a likely candidate to purchase, but more likely to copy/be inspired. What's the other octal tube next to the 6688? And do you have an under-the-hood photo to see how you mounted the motor-run caps?

Thanks, and good luck with the sale - they look great!

Pete


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PostPosted: October 17th, 2019, 11:01 am 
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Joined: February 28th, 2013, 1:19 pm
Posts: 331
The octal tube is the gas regulator tube. Don't remember which one I used, but will check and update, including an under the hood view.

When using a pentode for a gain stage (or driver), you can really nail down performance using a screen regulator. It fixes the characteristics of the tube, which can move around with a screen supply off of B+ through a voltage divider to ground.

David


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PostPosted: October 17th, 2019, 11:03 am 
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Joined: April 4th, 2016, 4:07 pm
Posts: 22
That's a helpful tip - thanks!


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