Distortion 250 parts and variations?

[cylnplnt]

I am preparing to build the Distortion 250. Planing to stick to the current build doc for a D+ style result. I plan to socket C1,C2, and C4 to experiment with cap value and type(for mojo). I’ve seen those are commonly changed in mods. I came across an old thread on here documenting a 250 Gray Box spec build. It called for a 22u Electrolytic(positive lead in left pad) in C4. I was wondering if I could use a tantalum(1u) in C4 with the same consideration of having the positive lead on left(nearest the op amp)?

I’m also wondering about the mention of other parts lists for the various DOD 250s. Are they listed somewhere on the site? My build doc only has one list.

Very curious about how different the Gray Box parts are. The differences between the schematics of the “standard” 250 and D+ seem to mainly be the absence of the cap at C1, and different clipping diodes. The Gray Box has different values throughout. Might have to build another that way too.

Thanks folks! Here are the gray spec subs from Mr. PedalPCB.

Add 25pF cap across R2

R3 47K
R5 470K
R6 20K
R7 20K

C1 2n2
C4 22u (positive lead in left pad)
C5 2n2
C6 10u

D1 1N4148
D2 1N4148

Gain C500K
Volume A10K *I used an A100k here*

 

[spi]

Personally I wouldn't use a tantalum for audio coupling (mostly due to word of mouth on this). Although since this is a distortion pedal I doubt it would matter.

And there's definitely no mojo in them.

 

[spi]

I’m also wondering about the mention of other parts lists for the various DOD 250s. Are they listed somewhere on the site? My build doc only has one list.

Drivestortion Project File.pdf (dropbox.com)

 

[cylnplnt]

Drivestortion Project File.pdf (dropbox.com)

Thanks for this. Really cool to see the different versions lined up like that. Feeling like I definitely want to do a separate 250 build now. Definitely more variance from the D+ than I’d thought. I went D+ first due to my general preference for germanium clipping. Now I’m curious about how the other values, like the resistors, affect the sound. I wonder if the choice of clipping diodes is what determined the difference in the other part values between the 250 and D+?

 

[cdwillis]

The silicon and germanium diodes are going to make the biggest difference. I posted a chart that had a bunch of different 250 version values if you search the forum.

I'd change the volume pot from a10k to a100k for increased volume output. The 10k resistor adds to one side of the voltage divider created by the 10k pot and decreases the maximum volume. This is a bigger deal with the germanium diodes than it is with the silicon diodes. Also do not use a b1m pot for the distortion control. MXR used c500k and the sweep is way better. I found the linear 1meg pot to be basically unusable except for a tiny portion of the sweep.

 

[cylnplnt]

The silicon and germanium diodes are going to make the biggest difference. I posted a chart that had a bunch of different 250 version values if you search the forum.

I'd change the volume pot from a10k to a100k for increased volume output. The 10k resistor adds to one side of the voltage divider created by the 10k pot and decreases the maximum volume. This is a bigger deal with the germanium diodes than it is with the silicon diodes. Also do not use a b1m pot for the distortion control. MXR used c500k and the sweep is way better. I found the linear 1meg pot to be basically unusable except for a tiny portion of the sweep.

Already got the a100k. Thanks for the heads up on the C500k. I realized that’s actually what was in the kit I did as practice leading up to the build I’m doing currently. Glad you suggested that before I started this build. Got one in the mail now.

 

[BuddytheReow]

Considering the part count, it may be worth your while breadboarding this and modding to your taste. If it helps there's a nice breadboard tutorial on it.

TUTORIAL - Distortion 250 - MXR Dist + - The Modder's Dream!

Damn, I miss breadboarding. The ability to make a circuit on a whim without sacrificing solder or anything else except your time. My wife is out for most of the day hanging out with her family for a girls' day, so I thought I would lock myself in the basement and get things done around here...

forum.pedalpcb.com

 

[CR0SSBL4DE]

From the Effects Layouts DRIVESTORTION documentation: