I don't think a DIY solution would be better than the miniDSP. It has a 400MHz floating point Sharc DSP.
Maybe you can get something to work with a ADAU1701 or similar DSP, but it wont be better than the miniDSP
If you just want to implement filters for an soeaker system, should be ok. Keep in mind the IC limitations, the first 3 I can think of are:
- You only have 2 outputs, so the limit is a two way speaker, or HPF for stereo signal.
- Not enough processing power for coeficient calculation, just...
For softer clipping, you can add a resistor in series to the diodes. Make the resistor equal to R1, and it should behave like typical soft clipping (gain of 0db at min gain)
On an inverting opamp stage, the noninverting input is connected to a DC reference (noted on most pedal schematics: Vref, Vbias, V/2, etc) in between the power rails of the opamp (+Vcc and -Vee).
In the case of 9v powered pedals, the opamp is working with Vcc=9v and -Vee=0v. That makes the...
The most difference will be the ones on IC2A. The last stage.
For the first one, you can just ignore the switch. Give a chance to asymmetric clipping, it will give more natural dynamic response (softer transition from clean to clipping)
It's based on the Orange Squeezer compressot + mods. https://forum.pedalpcb.com/threads/wampler-ego76.21266/post-276368
All orange squeezers have a trimpot for bias.
Gain comes from these 2 stages:
For the IC1A stage, I would use 2 LEDS in parallel (with opposed polarities) on the R4 (is an inverter opamp stage, so is hard clipping, even in the feedback loop),
And for the IC2A stage, I would add a current limiter resistor to the output and use 2 LEDS on...