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Hoffman Amps Forum image Author Topic: Pull down resistor question  (Read 1879 times)

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g-man

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Pull down resistor question
« on: March 14, 2024, 10:38:26 am »
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« Last Edit: August 06, 2024, 03:25:25 pm by g-man »

Offline sluckey

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Re: Pull down resistor question
« Reply #1 on: March 14, 2024, 10:42:11 am »
no
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline stratomaster

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Re: Pull down resistor question
« Reply #2 on: March 19, 2024, 03:54:55 pm »
Jack function is unaffected.  However the Traynor version is a slight voltage divider in the high channel, whereas Fender's isn't.  It's only~3% attenuation, so you'd probably never notice it. 

Also, strictly speaking, the Traynor first triode doesn't have a grid stopper and the Fender does. 

Offline PRR

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Re: Pull down resistor question
« Reply #3 on: March 19, 2024, 04:14:29 pm »
Also, strictly speaking, the Traynor first triode doesn't have a grid stopper and the Fender does. 

Sure it does. The 68k work the same on Traynor as on Fender?
https://el34world.com/Forum/index.php?action=dlattach;topic=31465.0;attach=112483

Offline stratomaster

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Re: Pull down resistor question
« Reply #4 on: March 19, 2024, 11:18:15 pm »
I was referring to the order. The grid leak on the Traynor sits downstream of the 68ks, making them the upper leg of a voltage divider in the High input.  Traditionally the grid leak is upstream of the grid stopper precisely to avoid this.  I doubt it makes much of a difference in this instance though.

If the grid leak were smaller I imagine there might be an effect.  Say a 220k instead of the 1M.  Then essentially the grid leak is bypassed by the Miller capacitance when it's directly at the grid rather than upstream of the grid stopper. Haven't done any calcs, so I'm thinking out loud and asking more than asserting. 

 

 


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