JC-120 in need of a lot of love

Amps, Cabs, Speakers, etc
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bigtone23
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Re: JC-120 in need of a lot of love

Post by bigtone23 » Mon Mar 10, 2025 7:42 pm

laurie wrote:
Sun Feb 23, 2025 1:11 am
In another post I was looking for a darker speaker for this amp.

I couldn't find anything reasonably priced so i decided to adjust the preamp instead - to roll off the highs being sent to the speakers.

After a bit of trial and error I landed on a 6n8 high frequency roll-off capacitor after the signal mixer and before the voltage amplifier.

The highs are tamed and the amp sounds much better.

Just waiting for the corners now and it will be completely done.
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JC-120 finished2b.jpg
Nice! Much cheaper than speakers!

I used to have a 85 Marshall 2203 that I sent to Bruce Egnater for a gain mod (adding an extra 12AX7) around 1994. I also asked him to tame the brightness of the amp, as I am a single coil guy and therefore my usual setting was bass on 10, treble/mid/presence set at fully off to 1-2. Not sure exactly what he did (the amp is long gone now), but I think it was something along the line of this same tweak, as well as perhaps removing the bright cap from the gain pot.

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Pepe
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Re: JC-120 in need of a lot of love

Post by Pepe » Mon Mar 10, 2025 8:16 pm

Very nice job! 8-)
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