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

Image

Image
Attachments
Amplifier.zip
Schematics
(74.25 KiB) Downloaded 481 times
-Ice cream is irresistible.

-Spaghetti and salt is irinductable.

-Artichokes are ircapacitable.
User avatar
kt88pppamp
KT88
 
Posts: 530
Joined: Tue Sep 26, 2006 12:11 am
Location: Rochester, NY

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.
User avatar
kt88pppamp
KT88
 
Posts: 530
Joined: Tue Sep 26, 2006 12:11 am
Location: Rochester, NY

Re: Zero Semiconductor MKIII Upgrade

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

What about the bias diode
Mark
Image
User avatar
battradio
KT88
 
Posts: 927
Joined: Tue Mar 10, 2009 12:58 am
Location: near ST.Louis MO.

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.
-Ice cream is irresistible.

-Spaghetti and salt is irinductable.

-Artichokes are ircapacitable.
User avatar
kt88pppamp
KT88
 
Posts: 530
Joined: Tue Sep 26, 2006 12:11 am
Location: Rochester, NY


Return to poseidon

Who is online

Users browsing this forum: No registered users and 13 guests