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Hoffman Amps Forum image Author Topic: Question about 1 ohm resistor in older Fender amp  (Read 2440 times)

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Offline mresistor

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Question about 1 ohm resistor in older Fender amp
« 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..

Offline uki

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Re: Question about 1 ohm resistor in older Fender amp
« Reply #1 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!

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Offline EL34

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Re: Question about 1 ohm resistor in older Fender amp
« Reply #2 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

Offline 2deaf

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Re: Question about 1 ohm resistor in older Fender amp
« Reply #3 on: July 02, 2018, 05:43:50 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.

Offline mresistor

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Re: Question about 1 ohm resistor in older Fender amp
« Reply #4 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..









Offline Colas LeGrippa

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Re: Question about 1 ohm resistor in older Fender amp
« Reply #5 on: July 02, 2018, 08:36:54 pm »
yep that's the right way to do it
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