Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dbishopbliss on October 01, 2013, 02:46:11 pm

Title: Resistor type for phase inverter
Post by: dbishopbliss on October 01, 2013, 02:46:11 pm

I think I remember reading that it is better to use metal film resistors for the phase inverter, but I can't find where I read it.  Problem is, I'm not really sure that is what I read.  I might have the resistor type wrong, or I might have the section of the amp circuit wrong.  

Did I read something like this?

Title: Re: Resistor type for phase inverter
Post by: Willabe on October 01, 2013, 02:56:56 pm

MF R's are way quitter than CC R's and way less prone to drift from heat. That includes the value drifting/changing while playing the amp for an hour or so then going back when they cool off.

So yes you probable read something on them (MF) being preferred by some maybe most.


                  Brad      :icon_biggrin:
 

Title: Re: Resistor type for phase inverter
Post by: EL34 on October 03, 2013, 08:25:45 am

Any type will work

Metal films usually have a closer tolerance like 1% so that's a plus

Title: Re: Resistor type for phase inverter
Post by: tubeswell on October 03, 2013, 10:22:23 am

Metal films have a quieter noise floor where the resistances are relatively large and where they are used in any application that affects the signal path, like plate resistors and/or grid leak resistors.