#1
I've decided to go ahead and build the famous Ruby amp. Seems fairly easy to build, and i will hopefully learn a lot from it in the process.

My actual question is would it be possible to add some basic EQ controls to it? Just Bass, Mids and Treble?

Any help would be hugely appreciated

Many thanks, Joe
#2
I'm pretty sure its possible but as to how I'm not really sure. Maybe just wait til some of the smart cookies get here. They could probably help you out.
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#3
adding a tonestack will cost a ton of gain.
you'll lose 10dB overall, 20dB in the midrange.
you can make up for part of that by reconfiguring the FET
from a common drain to a common source design.
but that alone might not be enough
it could still be somewhat anemic.
more likely, one additional stage will be needed.
Meadows
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#4
Woah, i didn't realize how much dB you loose. Would a simple "tone" knob (ala Valve Jnr.) be better/easier? I may just leave it to be honest. Probably isn't worth all the trouble.
#5
As Someone said above, a tonestack will cost you gain. However, you will likely have less gain loss with a single tone knob or a two knob stack than a three knob stack.
Here is a site with some good schematics of several flavours of tone stacks: http://amps.zugster.net/articles/tone-stacks
I haven't built a Ruby (yet), but I did put the Moonlight tone in my Valve Junior and am pleased with the result.
#6
So a two knob stack would be okay then? I really don't want to loose too much gain. Also, where would i place it in the schematic? I haven't properly read that website yet, so forgive me if it tells you.
#7
The Ruby is a super low output amp... I would not be doing anything that jeopardizes some of the output.

It was designed as a simple amp and that's how most people use it. I think your trying to make too much out of it.
#8
Quote by Rum Monkey
So a two knob stack would be okay then? I really don't want to loose too much gain. Also, where would i place it in the schematic? I haven't properly read that website yet, so forgive me if it tells you.


You're essentially replacing the volume control, with the tone stack (which includes a volume control).

So the volume inputs and outputs, are now the tone stack's inputs and outputs.

I personally feel a ruby has too much gain in stock form, so a simple tone control and volume stack would be perfectly fine. I wouldn't do more than that though.
#9
I have no experience with the Ruby, so I don't know what your results would be. I was just saying that the less tone knobs you have, the less gain you lose. As I said, I have the Moonlight single knob from that website in my VJ. The gain loss is definitely noticeable, but the VJ still has plenty of output. I wired it to a push-pull pot so that I can pull the tone knob out of the circuit and have normal gain when I want it. You could always do that, or use a separate DPDT switch.