Liquid Sunshine Report & Vero Layout

[kurtlives]

Here is the schematic for the Subdecay Liquid Sunshine - http://www.subdecay.com/schemls.gif
Volume pot is 100K(A), Hi Gain pot is 10K(B) and Lo Gain pot is 100K(B)

Breadboard this last night...
With 3 MPF102s with drains biased to approx 4.5V DC. I wasn't all that impressed... The low end was very flat, boring and weak. There wasn't also a ton of gain coming from this circuit. I think I was hoping the low end would be a bit more active sounding. This was on my 75W SS test amp, maybe on my tube amps things will sound better.

After a while of transistor swapping I ended up Q2 and Q3 as 2N5457 which added a bit more gain. I liked this a bit more. I also changed the 10K source resistor on Q3 to 4K7 for a bit of added grit. I also increased the second coupling cap (the one leading to the gain pot) to 22nF for a bit more bass and fullness.

Had no issues with feedback or oscillation. I think if I built this I would add a switch to break or make the feedback loop, cool variations in tone there.

Whats the purpose of the Q1 stage? It's it a buffer isn't it. If you ditched the buffer isn't the input of Q2 still high impedance and not load down the signal?

After playing around with the circuit some more today...
With the feedback loop engaged and the Hi Gain cranked the circuit did oscialte. The Lo Gain control affect the frequency and such but it seemed like the Hi Gain control was the one that start the noise. I liked the crazy noises I could make though, found it very musical. When I build this I will include a feeback loop switch for these reasons.

Should be noted that I tested the circuit today with a proper tube amp. Things sound much better, low end was solid.

Here is my vero layout that is not verified... Can someone please look it over? I might have an issue with C2?



Thanks...

[kurtlives]

Lots of errors in last layout....Here is a new one. Still not sure if C2 100pF is correct.