Zero Semiconductor MKIII Upgrade

for Dynaco Mark II/III/IV and DIY PP monoblocks

Zero Semiconductor MKIII Upgrade

Postby kt88pppamp » Tue Jun 04, 2013 10:19 pm

What are your all's feelings on this upgrade I make to the MKIII's circuit? I am getting similar number's to Shannon's Poseidon circuit with 15dB of feedback. At present I am using KT90 tubes but KT88s will yield the same numbers as well when optimized.

The mod uses all point-to-point wiring and a sheet of stainless to replace the driver board. Cermet pots are used for the phase compensation and bias pots. Photos and the schematic are below.

Image

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Attachments
Amplifier.zip
Schematics
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Re: Zero Semiconductor MKIII Upgrade

Postby kt88pppamp » Sun Jun 09, 2013 7:18 am

What do you all think?
-Ice cream is irresistible.

-Spaghetti and salt is irinductable.

-Artichokes are ircapacitable.
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Re: Zero Semiconductor MKIII Upgrade

Postby battradio » Tue Jun 25, 2013 3:01 pm

What about the bias diode
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Re: Zero Semiconductor MKIII Upgrade

Postby kt88pppamp » Wed Jun 26, 2013 12:40 am

As far as I am concerned, that does not count because the original circuit called for a selenium rectifier. With fixed bias, I would not feel comfortable using a 6X5 as it would need to warm up not delivering immediate bias voltage.
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