741 modified Dist+

[DailyDovetails]

The distortion plus was the first pedal I successfully made. I used the PPCB board.

This is my take on the distortion +. It isn’t exactly what I was hoping for but I’m thinking of it more like a prototype. I will probably play with changing pot tapers and I will also fix the pots that don’t work in the direction I think they should. It always feels confusing to get the pots to work the right way in the Pcb layouts.

High and low are just high and low pass filters and it also has some clipping options. There is a bit of odd unidentified fizz which both sounds cool and is a little annoying. I think it might be related to either the power supply or the chip, I’m unsure if it’s origin.

 

[Harry Klippton]

It's probably the diodes

 

[Feral Feline]

Is one of the "clipping" options "no diodes"?

That may help narrow down the hiss.

Maybe tack on Mark Hammer's StupidlyWonderfulToneControl (with AMZ's mods), see if that dulls the hiss.


However, this is a build report, not a trouble-shooting thread...



Very impressive boards you're making for yourself.

I find it difficult to implement that style of knob; your use of them here nails it!


Very cool and clean build.

 

[DailyDovetails]

Is one of the "clipping" options "no diodes"?

That may help narrow down the hiss.

Maybe tack on Mark Hammer's StupidlyWonderfulToneControl (with AMZ's mods), see if that dulls the hiss.


However, this is a build report, not a trouble-shooting thread...



Very impressive boards you're making for yourself.

I find it difficult to implement that style of knob; your use of them here nails it!


Very cool and clean build.

What's funny is the "hiss" is only when playing and it seems to be there even when set to LED and with the gain down. It's a sound I haven't really heard in the other builds I have done. It's kind of like a distorted overtone for lack of a better term. I will see if I can try to capture it and share.

I had wondered if it was power supply related as I used a single 1Uf cap in the power filtering stage per the https://www.electrosmash.com/mxr-distortion-plus-analysis schematic. I noticed Robert's version has an additional 47Uf cap there and I don't seem to have that noise with that board.

 

[Feral Feline]

Blu-Tack on a 47µ would be a quick check, or just tack-solder on the 47µ — if the hiss is still there, I'd try pulling the LEDs for just op-amp clipping to see if that gets closer to the heart of the matter.

You have both soft (Sw1) and hard (Sw2) clipping?

 

[DailyDovetails]

Blu-Tack on a 47µ would be a quick check, or just tack-solder on the 47µ — if the hiss is still there, I'd try pulling the LEDs for just op-amp clipping to see if that gets closer to the heart of the matter.

You have both soft (Sw1) and hard (Sw2) clipping?

Not a bad idea. I think I am going to build another of the boards soon with a few changes. One of the cool things about using the crimped connectors is I can pull the board and replace it with another no soldering required.

Just hard clipping like this.