Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: mresistor on July 02, 2018, 03:34:22 pm

Title: Question about 1 ohm resistor in older Fender amp
Post by: mresistor on July 02, 2018, 03:34:22 pm

Good afternoon all, hope you're all handling the heat well and staying cool.


I have a 60s Fender amp and am considering adding the 1 ohm resistors to the cathodes. It's a bassman. Wondering how you all implement adding them physically.
Would you unsolder the braided ground strap and then replace with the 1 ohm, soldered back in where the braid was,   or
would you connected the grounded end somewhere else? 
Or would you not even bother with adding the 1 ohm resistors  and use a bias tool to bias the amp?
Thanks..

Title: Re: Question about 1 ohm resistor in older Fender amp
Post by: uki on July 02, 2018, 05:03:22 pm

I did it with my 1st build the Fender 6G8, the 1Ohm resistors from pin 8 to ground, this amp have 6L6 tubes and a mod resistor of 1.5k between pin 1 and 5, pin one isn't connected to 8, the ground goes to the PT bolt, I hope this help!

Title: Re: Question about 1 ohm resistor in older Fender amp
Post by: EL34 on July 02, 2018, 05:21:26 pm

I have seen people unsolder the braided wire from pin 8, then add in the one ohms from the braid to pin 8
Easy and quick way to do it

Title: Re: Question about 1 ohm resistor in older Fender amp
Post by: 2deaf on July 02, 2018, 05:43:50 pm

Quote from: mresistor on July 02, 2018, 03:34:22 pm

Would you unsolder the braided ground strap and then replace with the 1 ohm, soldered back in where the braid was,   or
would you connected the grounded end somewhere else? 

The amp worked fine with the cathode connected to the nearby chassis and it will continue to work fine with a 1r resistor connected to that same little puddle of solder on the chassis.  But if you solder the end of the resistor to the chassis instead of to the free end of the braid, you better heat-sink that resistor well because it takes a substantial iron and some time to properly solder to the chassis.

Title: Re: Question about 1 ohm resistor in older Fender amp
Post by: mresistor on July 02, 2018, 06:00:19 pm

thanks guys


2 deaf  you bring up a very good point. If I was going to solder the ground end of the resistor to the solder puddle, I'd surely heat sink that side of the resistors lead..
I'm thinking of just wraping the ground side lead of the 1 ohm resistor around the braid nearest the puddle and crimping and soldering it there..

Title: Re: Question about 1 ohm resistor in older Fender amp
Post by: Colas LeGrippa on July 02, 2018, 08:36:54 pm

yep that's the right way to do it