best value/type pots to be shared by dod 250 and dist+ in same housing

[geezer15]

Hi I have built a grey dod250 and an mxrdist + both on vero. I originally thoughti might be able to build 1 circuit and swit ch a couple of componants in and out to create the 2 different pedals but there are too many variations. (the layouts are even different) now I would stilllike to house them in the same pedal and switch between the circuits. Now they both require different value pots. Can any one suggest pots I can usethat will work for both circuits?

1) Dist+   http://www.aronnelson.com/gallery/main.php/v/DRAGONFLY-LAYOUTS_0/album17/album06/mxr_dist_plus_001.jpg.html?g2_imageViewsIndex=1

2) dod 250 http://www.aronnelson.com/gallery/main.php/v/ulysses/ulysses_layouts/ulysses_77_grey_dod_od_250/ulysses_77_grey_dod_od_250_1_0.gif.html


MXR+ shows       10K Vol  and 1M Drive
Dod 250 shows    100k vol and 500k Drive I'm not sure what C and A mean but I was going to use log for volume and lin for drive.

Thanks
Pete

[Steve Mavronis]

A=Audio Log, B=Linear Log, C=Reverse Log

Here are what the DOD 250 Overdrive (all versions) use:

Gain - 500K Reverse Log (C500K)
Level - 100K Audio Log (A100K)

Here is what my first version 'block logo' MXR Distortion+ uses:

Distortion - 500K Reverse Log (C500K)
Level - 50K Audio Log (A50K)

I think some Dist+ also used 100K Audio...

[petemoore]

  Talking about Dist+ / OD250 topology, electromechanical variable resistive dividers:
  The Volume pot wafer as assigned puts an R between signal path and ground, 10k loads the circuit, 50k is ok, 100k is fine. Audio Taper recommended.
  The gain pot should be not-audio-taper.
  The original gainpot value was chosen for this intending to use the Distorter circuit as a semi-clean boost.
  Since the gain is max when the gainpot is jumpered [or turned fully CCW] and 50k feedback R cleans it up more than necessary, I have 50kL pot there for the OD250.
  The ''what was D+ but the grade improved" dirtbox has just preset D+circuit gain setting R, but Jfet pregain-booster 'volume knob' is the gain - supergain adjustment knob since it is used to 'hit the diodes' hard/harder.
  I found using tweeked circuits for clean mooted out the need for a major gain reducing/big potvalue [1m or 500k], so instead of having no-use clean available near the CCW side of the pot, I have 'shaved dirt' there, and then between CCW and CW settings is a 'fine-tune-dial' that adjusts between hard clipping and harder clipping dirts. Although the larger pot value covers the entire range from notsvery clean through max Dist, the range of my 50k is covered by about 1/10th turn of the 1 meg pot...makes it impossible to dial in accurately/visually or even by ear...too touchy/sensativey !
  If the Dist+ is deemed a good booster you wouldn't wanna lose the low settings either, I thought of using a switched pot so min. setting could introduce a 470k resistor or whatever for major DIST+ cleanup.
 

[geezer15]

Thanks Steve thats helpful. i'll go with C 5ook and A 100k for both then.

[Steve Mavronis]

If this helps too, here is a thread where I posted re-drawn schematic I made from my real 1980 MXR Distortion+ reflecting the actual offboard wiring inside the pedal as well as the circuit part values.

http://www.diystompboxes.com/smfforum/index.php?topic=90241.0

Steve

[Quackzed]

actually upping the volume pot value in a distortion + is a really common mod for a stock unit. due to the pedal being slightly below unity at low gain with stock ge diodes in the clipping section.

[Steve Mavronis]

Well since he's making a hybrid 250/Dist+ clone, C500K and A100K will be his best combination.

[tubelectron]

Hi,

What's important is the C curve (reverse-log, reverse-audio RA) for the overdrive/distortion pot, otherwise you won't have progressivity in the setting, having all the effect unspread and located near the maximum clockwise.

A+!

[Quackzed]

Yeah, i agree.
c500k and a100k for vol. i just meant that people tend to bump the dist + volume pot up to 100k anyway, so its not a 'compromise', rather it solves a potential volume loss problem.i wasnt suggesting any need for a higher value than 100k tho..

[geezer15]

Thanks guys. will complete over weekend, with some luck. I will post some pics when finished. Trying out some decal labeling.

[geezer15]

Here are pics of the unfinished pedal. The circuits are still wired to seperate jacks, pots etc from testing, I will wire into the housing in the next couple of days. I like the decal lettering its just a shame the edges of the transfer are still visible through the laquer. Waiting for a C500k pot to arrive. I only have a C1m which I guess would do.



http://s1228.photobucket.com/albums/ee448/geezer15/?action=view&current=IMG_8464.jpg&newest=1

http://s1228.photobucket.com/albums/ee448/geezer15/?action=view&current=IMG_8465.jpg&newest=1

[deadastronaut]

with decals/waterslide its best to do the whole face...then you wont see them edges..

[geezer15]

Ah yes!

Mind you I dont think I could plan it out on one sheet probably get the measurements all wrong. Easier just to put the labels on when its finished but I might have a go.

I just printed off an A4 sheet of various labels ie Vol, Tone, in, out etc. In various colours, fonts and sizes to cut out and use on future projects. I thought the edges would 'disappear' once lacquered as the transfers were thin.
Should have known that was too simple lol.

Pete