Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: plumcrazyfx on February 24, 2022, 08:53:39 am

Title: SF Princeton (NR) Trem Mod Question
Post by: plumcrazyfx on February 24, 2022, 08:53:39 am

Sorry for not having pictures, I'm bad at uploading stuff.


I have a mid-to-late 70s SF Princeton (No Reverb).  I'm going through it getting it ready for a sale and noticed a mod that I'm wondering if someone can help me figure out what someone did and why.  In the trem circuit there are a couple resistors (a 220K and a 1M) that tie directly to the oscillator caps (.022, .01, .01).  Someone completely bypassed the 1M resistor with a wire  - so they directly connected the 220K/.022 to the .1 going to the intensity pot and the .022 going to ground.  Why? 

Title: Re: SF Princeton (NR) Trem Mod Question
Post by: sluckey on February 24, 2022, 09:46:15 am

stronger tremolo

Title: Re: SF Princeton (NR) Trem Mod Question
Post by: plumcrazyfx on February 24, 2022, 11:54:23 am

Makes sense.  I was thinking of cloning it.  Guess I'll include the mod.  I like trem.


Thanks.

Title: Re: SF Princeton (NR) Trem Mod Question
Post by: sluckey on February 24, 2022, 12:17:40 pm

I would plan the layout to include that 1M and .02 cap but use a 100K and .01 cap instead.

Title: Re: SF Princeton (NR) Trem Mod Question
Post by: plumcrazyfx on February 24, 2022, 03:42:43 pm

Just replacing those with your values does effectively the same thing as the wire bypass?