Tone control for the Cupcake?

[jubal81]

I've got a Cupcake board ready to be built and I'm wondering if anyone has a good way to add a treble boost/cut for it. I currently use a Janglebox, which has a three-way tone switch and I'd love to have an OS clone with variable treble control.

[stecykmi]

one simple way might be to have a switchable input cap, kind of like the Rangemaster. The stock RM value of 0.005uF is really small though, you might want to try something a little larger. Then put the stock value on the switch.

You'll have to experiment to get it sounding how you'd like though.

[jubal81]

one simple way might be to have a switchable input cap, kind of like the Rangemaster. The stock RM value of 0.005uF is really small though, you might want to try something a little larger. Then put the stock value on the switch.

You'll have to experiment to get it sounding how you'd like though.

That's a good idea. I was hoping to do it with  a resistor so I could use a pot, but it might be even better to put some different caps on a rotary switch.

[bigmufffuzzwizz]

I was looking at the schematic earlier and I'm guessing R2 and C3 form a low pass filter. If that is what those are for, you would be able to switch the order of them to change it to a high pass filter. A switch with HP/LP would be really cool. Maybe someone else could verify it as I'm still learning too. 

[stecykmi]

I was looking at the schematic earlier and I'm guessing R2 and C3 form a low pass filter. If that is what those are for, you would be able to switch the order of them to change it to a high pass filter. A switch with HP/LP would be really cool. Maybe someone else could verify it as I'm still learning too. 

I don't think it is a LP filter since nothing's going to ground. I think it has to do with the gain compensator circuit. Compressors are fairly non-linear circuits so it's difficult to tell what's going on.

I don't see any good candidates for a hp/lp switch in the circuit, at least not with stock values. A lot of the caps are for DC decoupling or AC bypass caps for amplifiers.

[bigmufffuzzwizz]

I see so its gotta go to ground to be a filter. Then that would leave the input cap as the most effective way to change the circuit to more treble/bass.
What about R11 + C7? Isn't that a filter?

[stecykmi]

Well R2 and C3 are a filtering something for sure, but it's not a clear cut low pass in the sense than it may not directly affect the output signal, it more than likely affects the frequency response of the compression.

Any time you have a cap it's going to act as a filter. One way to think of caps are frequency-dependent resistors; when frequency = 0 (which is just DC voltage), resistance is infinite and when frequency is infinite (which is only possible theoretically), resistance is zero. That's true for any cap, no matter the value.

R11 seems to be there to decrease feedback since it's acting as a voltage divider with R4. C7 is acting as a low pass filter, but it's value is pretty large (4.7uF), so it is more than likely there as some sort of stabilizer cap. I'm not entirely sure of it's purpose.