Liquid Drive/Distortion+

[Gila_Crisis]

Hi, i wanna build the liquid drive from fuzz central.
but now, i looked at some distortion+ and the LD schem but i don't understand a thing about the opamp. in some schem only pads 1, 2, 3, 4 & 8 are use and in some other 4, 5, 6, 7 & 8. i now on it you can use different opamps such as OPA2134PA, 4558, 731, LM308, etc.... but what's the matter, each opamp has a different pad system?

or simple can i build one circuit and then change the opamp the way i want, or should i always care about the one i use?

[petemoore]

  Either one can be built on the same board, using a 'single opamp', LM741 or other, the circuit uses 1 opamp..or..
  ..1/2 of a dual opamp w/different board to match the pinout assignments.
  See pinouts on data sheets, try lm741 [a single oa], and jrc4558 [a standard dual opamp] the positive inputs are still 'on the bottom' but all pins and V+ are different pins on the single vs. duals.
 

[stobiepole]

Check out the two boards at Tonepad - one is for the MXR Distortion+, the other for the MXR Microamp. The tonepad_distortionplus.pdf (the Mas) design uses a single opamp, while the tonepad_microampdistplus.pdf (the Ampotor) uses a dual opamp. You can build the Liquid Drive on either layout (or the Dist+), depending on whether you want to use a single or a dual opamp. There's another Tonepad design, for the stereo microamp, that uses both sides of a dual opamp to build two microamps on the same board (or two Liquid Drives, if you added the diode clippers, or a mix), which is also pretty handy...

The Liquid Drive is a very nice pedal though. I used the OPA1234PA in it, just because I had a few, and it sounds great.

Chris

[Gila_Crisis]

ok now i see this difference between sinlge and dual opamp.
thank you, maybe i'll work out a pcb where you can use either single or dual opamp. this would be a nice trick.

[petemoore]

maybe i'll work out a pcb where you can use either single or dual opamp.
  I think it'd necessarily have to be 'side by side' or a '2 story' affair, or very fancy switching.
  I used a piece of perf, a socket, and twisty wires to make a 'dual goes in single Oa Slot' converter socket...funkay..