Distortion+ or DOD250 perf layout

[mmaatt25]

Hi,

I can't find any perf layouts for the either the MXR Distortion+ or DOD250, I know there very similar so either would do.  There are a couple vero/stripboard layouts, but to be honest i hate using that stuff, perfboard is much tidier and more compact.

There may be reasons why I can't find the layouts, like MXR/DOD don't want them posted, which is fair enough.

Many thanks

Matt

[petemoore]

 There probably are some in the LGallery.
  Maze of myriads when it comes to finding any particular thing in there.
  For the DIST+ I found the ROGroove's perfboard template and pencil to be educational for the circuit, making layouts etc.
  It can be made small or smaller, and that will fit in small box.
  A few built, having access to 1 set of diodes...perhaps a diode selector switch, Treble or some kind of tone control.

[Steve Mavronis]

Here are some page links in the gallery of perfboard layouts for what you want:

Dist+/250 layout for the standard single opamp
http://www.aronnelson.com/gallery/main.php/v/Burnt-Fingers-stuff/Layouts-and-schematics/dist_single_opamp_perf_002.gif.html

Dist+/250 layout for the standard single opamp with asymetrical clipping -
http://www.aronnelson.com/gallery/main.php/v/Burnt-Fingers-stuff/Layouts-and-schematics/dist_single_opamp_asymetrical_clipping_perf_001.gif.html

Distortion + perf layout -
http://www.aronnelson.com/gallery/main.php/v/jdub/Distortion+_+perf+layout.PNG.html

[mmaatt25]

Many thanks, my search wasn't broad enough

[mmaatt25]

There's a resistor R9 value 100R on this layout:
http://www.aronnelson.com/gallery/main.php/v/Burnt-Fingers-stuff/Layouts-and-schematics/dist_single_opamp_perf_002.gif.html
what does it do, why's it there?

I can't find this resistor on any schematic!

Many thanks

Matt

[Steve Mavronis]

There's a resistor R9 value 100R on this layout... what does it do, why's it there? I can't find this resistor on any schematic!

The 100 ohm resistor is on some gray DOD 250's according to gut shots I've seen. I included it in my schematic (but labeled as R4 instead) for the gray 250 clone that I'm building. I'm not sure why it's there either. Maybe some sort of voltage related adjustment?

[Ronsonic]

R9 in the layout works with C3 filtering / decoupling the DC in from the power supply.

In Steve's drawing it doesn't do much of anything. Missing cap on board or drawing, is my guess. But I didn't build it or draw it so....

[Steve Mavronis]

I've seen other people's drawings with an extra cap with that 100 ohm resistor but any extra cap was not on the late 70's gray 250. When I started out doing research to make a clone I studied the source - the actual PCB from all the photos I could find - in an effort to reverse engineer it because I didn't trust any schematic because there were so many variations. My schematic matches what is on the gray 250's that have the 100 ohm resistor connected to V+. But some gray 250's have it and some don't.

[Ronsonic]

I get the impression they were pretty loose about how these were made. Thanks for the confirmation on that variant.

[mmaatt25]

Hi,

I've completed both DOD250 and MXR Distortion+ both have been made around the above perf layout above, but using component values from the GGG schematics.

I haven't got any 500k reverse log pots, but searching the forum Mark Hammer suggests that a 50/100k log/lin pot works as well, which would be better log or lin?


Many thanks

Matt

[mmaatt25]

Hi,

I've completed this two of these, Dist+ & DOD250 (with appropriate values) using this perf layout, http://www.aronnelson.com/gallery/main.php/v/Burnt-Fingers-stuff/Layouts-and-schematics/dist_single_opamp_perf_002.gif.html

Both are not working, I'm pretty sure that the voltage divider is wrong in this layout. It shows R3 from pin3 of IC to R4, R4 to 9V+, R5 & C3 and then R5 & C3 to Ground.  I think it should be R3 to R4, R5 & C3. Then R4 to 9V+ and R5 & C3 to Ground.

Hope this makes sense!! Otherwise I need another debug session.

Many thanks

Matt