Capacitor

[Demsy]

Hi, would changing the 0.1uF coupling cap on the output stage grid with the Russian teflon bring any improvement? I still have several of them, if it is better than the stock caps, why not use them.

Thanks for any input.

 

[Grainger49]

In the 300B version of the Paramount there is an interstage coupling cap of 0.1uF.  If you change it with a KK Teflon it will definitely change the sound.  You should break the capacitors in first for a minimum of 100 hours (4 days). 

Break In Post

 

[Demsy]

Thanks for your input, Grainger. Yes it is the 300B version I'm busy with. I also have read your writing regarding the burning in device for the capacitors, very helpful!

 

[Grainger49]

I just wanted to be sure.  IIRC the Parafeed cap is something like 3.3uF. 

 

[STURMJ]

He is talking about a cap that is on the grid resistor. That one is 0.1uf. I had upgraded mine, I did it in the initial build so I can't say if it made a difference.  I know that the 3.3uf is a worthy upgrade, I too would be interested to know if the 0.1 would make a difference.

 

[Grainger49]

Yup, got it.  According to the schematic the driver plate is connected to the output grid with a 0.1uF cap with a 249k load resistor to ground.  The grid stopper resistor, 220 ohms or there about, is the actual connection to the grid but in electrical terms, for audio frequencies it isn't there.  It stops RF oscillation.

 

[glynnw]

Replacing the stock .01 cap with a Vcap Teflon was a VERY noticeable improvement, and not of the kind "I think this wire is better".  It was immediately apparent that the amp sounded better.  Several months prior to that I  put in a Mundorf gold 3.3 uf (or some such - memory getting bad) which created a much smaller improvement