Ampeg V4.com

forum

You are not logged in.

#1 2012-08-17 14:38:00

Liquids
Member
From: CT
Registered: 2010-08-01
Posts: 491

Cathode Bias...

So I am considering tweaking one of my V4s to work via cathode bias.

I still want them biased to around the same 50-60& plate dissipation though, rather than max plate dissipation - the thought of this is basically just to compare/try out any differences from the reduced voltage by grounding the input grids (rather than negative grid bias) and voltage on the cathode, bypassed with a capacitor.

How do a calculate the 'moving target' cathode bias so as to know a range of resistors?

What wattage resistor do I need - 25W or 30W for each individual tube?

I can use all the help here I can get.
Thanks


Matthew

Offline

 

#2 2012-08-24 16:01:23

rob
Member
Registered: 2008-10-28
Posts: 171

Re: Cathode Bias...

800 ohm 25 watt is good. Bypass with 100v 47 to 100 uf cap.

Offline

 

#3 2012-08-26 01:48:45

Liquids
Member
From: CT
Registered: 2010-08-01
Posts: 491

Re: Cathode Bias...

What voltage, more or less, does that arrangement tend to put on the cathode of the tube?    Is that one tube, or for a pair?

Last edited by Liquids (2012-08-26 01:49:01)


Matthew

Offline

 

#4 2012-08-30 14:36:15

Liquids
Member
From: CT
Registered: 2010-08-01
Posts: 491

Re: Cathode Bias...

Just trying to find out more or less what the idle bias point range that configuration would yield.


Matthew

Offline

 

Board footer

Powered by PunBB
© Copyright 2002–2005 Rickard Andersson