Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: frank57 on September 29, 2010, 01:40:24 pm

Title: Good idea to change these resistors to a higher value on Hiwatt?
Post by: frank57 on September 29, 2010, 01:40:24 pm

Suggestion was made to up  r33 and r34 to 100k.
Good idea?

Title: Re: Good idea to change these resistors to a higher value on Hiwatt?
Post by: FYL on September 29, 2010, 02:05:45 pm

47K is on the low side, but should be OK with EL84s. You may try 100K.

Title: Re: Good idea to change these resistors to a higher value on Hiwatt?
Post by: frank57 on September 29, 2010, 03:18:36 pm

What exactly is their function?
To protect the power tubes?
I don't notice much change in the bias  or anything like that.

Title: Re: Good idea to change these resistors to a higher value on Hiwatt?
Post by: FYL on September 29, 2010, 03:44:02 pm

Bias mixers and grid leak Rs. There's very little current across them, so their impact is small when it comes to bias voltage.