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Dynaco PAS Rebuild

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warpedcorp

Member
Joined 2006
I'm in the midst of rebuilding a dynaco PAS and have the following question:

The original circuit (Dynaco PAS Preamp) has a 250K volume control and a 750K balance control.

I'm thinking of replacing the original 250K volume control with the 250K alps I and then replacing the original 750K balance control with two individual 100K Alps pots to allow me to individually 'trim' each channel instead of a single balance control. Will this work or is the 750K value for balance a critical spec?

Thanks
 

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SY

SY

Ex-Moderator
Joined 2002
SYclotron.com
One of the many crippling weak points of the Dynaco PAS topology is the poor load capability. Keeping the load high will keep the distortion down. Going down to 100k won't be night and day worse, but will be worse. And you'll have to pay a great deal of attention to what you have the preamp drive.

Just out of curiosity, what's the attraction of the Dynaco design for you?

edit: to maintain response in the bass, you'll also have to go up on the coupling caps, from 0u1 to 0u47.
 
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