Moving tone stack in es100 rebuild and remove reverb?

[Shrimpfarmer89]

Howdy all,

my question is this, I’m looking to rebuild a Randall es100 and want to have a tone stack for each channel, if I move the tone stack from later in the circut and add them onto the chain where the master volume is, is that a possible thing to do by just moving the same circut without having to drive the preamp section more? I can understand if I need to, I just can’t figure out how much is nesscesary to power that section. The other thing I’d like to do is completely take the reverb section out of the build, could I do that and use the transistor that is in the beginning of the reverb circut to drive a graphic eq? Let me know, I’m sure there are a few steps I’m missing in this whole ordeal to hit my endpoint. Thank for the read.

[J M Fahey]

Leave as is and buy/build an amp which does what you want.
Serious.

Plan B: add what you want at the effects loop, but don´t murder that PCB, you will not be able to mod it into what you want and probably just lobotomize it.

Plan C: learn to enjoy it, as-is. Killer amp.

[vintagekiki]

Plan C: learn to enjoy it, as-is. Killer amp.

[Shrimpfarmer89]

By rebuild I mean from scratch, I don’t have one of these amps and I wouldn’t dare touch an original that’s like destroying a wyeth painting.

what I’m saying is from a scratch build from bought parts, I want to get rid of the reverb circut all together and just pass it to the power amp.

and

use the transistor that is already at the reverb area and pre prescence knob to run a graphic eq.

it seems like in other things I’ve read you can move the ton circut up to where the volumes are with ease and

Don’t (?)

have to add another transistor to power that larger tone section.

I don’t have the money to buy one of these and want to make one for myself with little bits I want.

[vintagekiki]

There is no need for any intervention on the Randall es100.
You can connect any guitar effects so and Graphic eq to jacks Effects Send / Return.

If you want to make a DIY amp like Randall es100, information is here

https://www.ssguitar.com/index.php?topic=4086.0
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https://www.diystompboxes.com/smfforum/index.php?topic=79923.0

https://sites.google.com/site/plexilandia/preampfromhell.rar

[J M Fahey]

By rebuild I mean from scratch, I don’t have one of these amps and I wouldn’t dare touch an original that’s like destroying a wyeth painting.

what I’m saying is from a scratch build from bought parts,

Now we´re talking.
Yes, on a custom build you can do what you want.

If you want the full Monty, just thinking aloud, kinda busy now, there you have two channels alternatively (or concurrently) feeding the same gain strip , EQ, Reverb, etc.

I would duplicate the common section, use each first stage to always drive its own, so you have two full, independent channels end to end, and simply switcch one or the other output to feed signal to the power amp.

talk about independence!!!

They might even have 2 separate send/receive Loops, each its own graphic EQ, or add it to just one channel, you are painting on an empty white canvas.

Think about it and post your ideas here, it can be an interactive project.

[Shrimpfarmer89]

Excellent! So my thoughts are these:
I am moving that tone stack and presence controls into the pre amp section of the amp.

I found a schematic named the “preamp from hell”
which is basically the same preamp as in the eg100 original schematic.

this scematic uses 24 volts to run its circut, and it has the tone stack in it and the presence knob in it as well.

the original circut in the es100 runs on the same amount of voltage, interestingly enough l, so I guess I don’t need to add more voltage at the line out of the power transformer to power the preamp section.

So I guess I’ve answered one of my questions, about that tone stack not needing more voltage to be run if it is moved into a preamp.

however, if I was going to create an amplifier from scratch in a totally new never before built amp, to figure out the voltage needed to run that circut, would I just figure out the amount of resistance and capacitance I was going to put in that circut to clean the current, and then use the ohms law to figure out how much voltage
I would need to power it?

so there’s one part of my question.


second part, is I want to add the graphic eq into the build as well.

in a post before there was talk of putting it in the fx loop stage, which is where I’m going to wire it in.

the voltage. Needed to run the circut I’m looking at building is around 16-20 volts.

so theoretically i will have to bring voltage in from the power transformer and run I through a resistor/ capacitor to clear the dc signal, and use a transistor to facilitate the voltage that will run the eq circut correct?

in the original es100 schematic there IS a transistor where the reverb tank is, (which I am removing) can I use that transistor to power the circuitry of the graphic eq? If so, do I put the eq circut closer to the power amp and after the transistor? Or farther away from the power amp in the chain, and before the transistor.

will these voltages are basically the same voltages as on the original schematic, so what I am thinking is I won’t have to change the power stage at all to get more power out of the amp to drive the speakers or the preamp circuts? (Am I correct?)

thank you for the help! I just need some clarity with what I am thinking about proceeding with. Much appreciated.