Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: chocopower on December 30, 2010, 03:59:05 pm

Title: Another "old" volumen control tip?
Post by: chocopower on December 30, 2010, 03:59:05 pm

Hi!
have any try this?

http://www.google.com/patents?id=pSI3AAAAEBAJ&printsec=abstract&zoom=4#v=onepage&q&f=false (http://www.google.com/patents?id=pSI3AAAAEBAJ&printsec=abstract&zoom=4#v=onepage&q&f=false)

Mixing fixed and cathode bias for the output tubes is nothing new, but here they are using a reostat in the "cathode bias" section as power control...

Weird?
Dangerous?
Posible?

Title: Re: Another "old" volumen control tip?
Post by: PRR on December 30, 2010, 05:25:19 pm

It's not "dangerous".

I don't think it will give any large reduction of power with the values cited, except maybe that the phase-inverter (not covered or detailed) will overload.

Title: Re: Another "old" volumen control tip?
Post by: Tiny_Daddy on December 30, 2010, 05:37:00 pm

There's plenty of amps out there that have a switch across the cathode resistor. Really that's all you need.

Title: Re: Another "old" volumen control tip?
Post by: jojokeo on December 31, 2010, 01:32:54 pm

 :laugh: :laugh: This caught my eye in glancing and immediately gave me a memory out of the past from the movie 2001: A Space Odyssey. "I am a HAL 9000 computer. I just picked up a fault in the AE35 unit. It can only be attributable to human error..."