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Author Topic: RG100ES GAIN mod?  (Read 4159 times)

BMWFREQ

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RG100ES GAIN mod?
« on: April 07, 2011, 02:19:46 PM »
Does anyone know how to modify the GAIN stages for the RED and GREEN channels of my RG100ES?  Is it as simple as replacing a resistor and/or cap, and if so, which one(s) and what values?

I've included an excerpt from the schematic with this post for anyone who would care to show me what components need to be changed or added.

Thanks in advance-

J M Fahey

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Re: RG100ES GAIN mod?
« Reply #1 on: April 07, 2011, 02:27:50 PM »
They are already using all the gain possible.
I suggest you build a clean boost pedal (MXR MicroAmp or similar) and use it up front when needed.
You *might* insert an extra FET stage in the Red channel, but it will most certainly need major PCB surgery, plus further debugging to solve the certain hiss/hum/ground issues it will add, so the external help becomes the best option.

BMWFREQ

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Re: RG100ES GAIN mod?
« Reply #2 on: April 07, 2011, 02:47:28 PM »
What would the result be if the values for R22 and/or C17 were tweaked?  Any idea??  Also, what if I added a cap accross R5 on the Green channel???

mensur

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Re: RG100ES GAIN mod?
« Reply #3 on: April 08, 2011, 02:47:08 PM »
You can devalue R22 to 1.5K, C12 to 1uF, and go the same with R23 C21, but there's possibility of oscillation.Why would you need more gain on the clean?

J M Fahey

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Re: RG100ES GAIN mod?
« Reply #4 on: April 08, 2011, 10:31:21 PM »
Quote
What would the result be if the values for R22 and/or C17 were tweaked? 
If you mess with R22, you mess with the bias. Why would you do it?
If you lower C17 you lose bass; if you increase it the sound will probably muddy or fart, with no extra gain in "useful" guitar frequencies.
Quote
Also, what if I added a cap accross R5 on the Green channel???
You would turn it into a second Red channel, lacking the clipping diodes to boot.
I fail to see the advantage of doing that.
What part you don't understand about "it's already tweaked to the max?"

joecool85

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Re: RG100ES GAIN mod?
« Reply #5 on: April 12, 2011, 08:04:25 AM »
I'm with Juan that you should just put a booster or OD/dist pedal in front of the amp if you need more gain.
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tra

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Re: RG100ES GAIN mod?
« Reply #6 on: April 30, 2011, 12:45:16 PM »
I'm with Juan that you should just put a booster or OD/dist pedal in front of the amp if you need more gain.

According to Grady Champion (Dimebag's guitar tech), Dimebag would put an MXR EQ in front of the amp and crank the mids to act as a boost, but then he would scoop the mids with a Furman EQ in the FX loop. He said in an interview that there was so much gain that they needed to dial in a gate just right because if that gate opened you'd get howling feedback.