DOD OD 250 Variations

[Baktown]

All,

I've developed an interest in building all the different versions of the DOD OD 250, and I want to make sure that I understand what those different versions are.

As near as I can tell, here are the versions that were made:

77 Grey
80's Yellow
Yellow Reissue
YJM 308

Am I missing anything?  Is the Yellow reissue the same as the 80's Yellow?  I'm also trying to build a comparison chart between all the different versions.

Thanks in advance.

Axl Bundy

[MartyMart]

You seem to have that right, some more info here : http://www.analogman.com/dodmod.htm
Seems the re-issues are "close" to the Old yellow's and some of those were "exact" copies of the
original '77 Grey 250 circuit - later yellows and the reissues have more low end "mud" which is cured on the YJM308 version
- this seems closest to the 77' Grey 250 original.
There's not much between the 250/Dist+ and Ross Dist , I like the "Liquid drive" by Phillip @ Fuzzcentral, which is
an improved "combo" of all of these influences.
MM.

[cab42]

There was a thread not long ago where all the the variations were shown with perf layouts: http://www.diystompboxes.com/smfforum/index.php?topic=52113

Unfortunately the layouts are gone, but you might find something of interest.

Edit: They were moved to the gallery: http://www.aronnelson.com/gallery/v/tungngruv_0/DOD-OD250/

Regards.

Carsten

[stopstopsmile]

how would you add a tone control to one of these?  I am thinking of picking up the tonepad microamp board and making a dist+ but I want to add a tone control.  And a good one not just a simple filter. 

[petemoore]

  I have a Tonepad board, it was on the pedalboard for a while, big dist+ fan, I need to rework that board [w/treble pot] and give it a second shot at where the RAT is now Residing.
  When I whipped it together and plunked it into plastic RS poopbox, it just didn't like it.
  I need to rework that board, to have a greater grind factor, nice T/B balance with tight Bass.

[Mark Hammer]

how would you add a tone control to one of these?  I am thinking of picking up the tonepad microamp board and making a dist+ but I want to add a tone control.  And a good one not just a simple filter. 

Define "good one".  Do you mean a 3-band EQ?  Do you mean a Big Muff type filter?  Do you want boost or only cut?  What kinds of tones do you want to be able to achieve?

Keep in mind that many types of tone controls will involve selectively bleeding off signal to ground.  That means that if you want to still have a hot output signal AND tone-shaping, you will need to add a gain recovery stage of some sort.  At a certain point, obviously it stops being a DOD250 and turns into something else.  If you're fine with that, so am I; whatever it takes to nail the desired sound and functionality.  But if you somehow want to stick closely to "classic" DOD250 tone yet still shape the sound a little more, you may be limited in your choices.

[stopstopsmile]

mark specifically i like the muff control and i like the tone control you and jack did.  but i have no clue how to implement them in a build yet. 

I want to play around with something new, I am not so stuck on retaining the same sound as I am already modding it up a bit to begin with. 

[Baktown]

All,

Thanks for all the good info.

I can't seem to find schematics pertaining to the different versions of the 250.  Does anyone have the schematic specifically for the 77 Grey version?  I found what looks to be the right one, but it has quite a few different components than the Vero layout as drawn by Ulysses.  I assume that Ulysses created his layout from the original schematic, so maybe this isn't the 77 schematic?  See below...

[Hamfist]

The great thing about this circuit is that it doesn't need a tone control.

how would you add a tone control to one of these?  I am thinking of picking up the tonepad microamp board and making a dist+ but I want to add a tone control.  And a good one not just a simple filter. 

[tungngruv]

I can't seem to find schematics pertaining to the different versions of the 250.  Does anyone have the schematic specifically for the 77 Grey version?

Not sure what happened to my 77' layout. I'll repost when I get home in the same gallery.

All info from JHS

Using this layout:



- add a .0022uf to the input to ground, {can be connected right alongside the .01uf input cap}
- lose the 10uf cap
- change 4u7 to 22uf
- diodes are 1n4001
- change .001uf  output cap to .0022uf
- 500kB and 100kB instead of the later reverse log pot

JHS also recomended matching the 22k resisters as close as possible. Hope that helps.

[Mark Hammer]

The great thing about this circuit is that it doesn't need a tone control.

how would you add a tone control to one of these?  I am thinking of picking up the tonepad microamp board and making a dist+ but I want to add a tone control.  And a good one not just a simple filter. 

That would depend on what you're feeding it, and what you're feeding it to.  Keep in mind that while the "native" tone of the unit may well be just right with one guitar and a given amp, switching it on may well elicit undesirable components from subsequent stages using a different amp.  A hotter output signal will almost invariably provoke at least some additional harmonic content from the amp, and if one has the amp set for a sparkling clear clean tone, kicking in the 250 may be excessively bright unless you turn down the treble on the amp.....which of course you can't do while you're taking a screaming solo.

So yeah, I would agree with you that very often you don't need a tone control....but sometimes you do.

[petemoore]

  The basic dist engine sounds just great, I tried more of the 250 values [dropped the r of the 1m bias resistors to about 35k, preferred.
  .01uf cuts bass about right.
  Treble control I use on it instead of the diode LP filter cap, depending on amp volume, what else is 'in' [I like to drive or have the Dist+ driven by boost often enough], I find the simple pot added to the slightly larger diode cap gets used and is very effective at reaching the right amount of treble rolloff, making it easier to find the small difference between enough and harsh HF output with varying external circumstances.
  Going far as to preset and eliminate the gain knob, use a bypassable pre-booster [and guitar] volume to adjust the gain, keep the added treble control.

[BubbaKahuna]

I can't seem to find schematics pertaining to the different versions of the 250.  Does anyone have the schematic specifically for the 77 Grey version?

Not sure what happened to my 77' layout. I'll repost when I get home in the same gallery.

All info from JHS

Using this layout:

Slick, but I tweaked it to eliminate the jumper. I don't like jumpers, just a fetish of mine. 



Cheers,
- JJ

[tungngruv]

Nice JJ, why didn't I think of that?

As far as a tone control, I bet the input cap blend control on Joe Gagan's Easy Face:

http://www.aronnelson.com/gallery/d/7304-2/EZFacewBlendCap.jpg

would give some variation in tone without affecting the great sound of this OD.

[petemoore]

  Thanks to Toney for the gifts, the DIST+ is in a DOD EQ box [with EQ slider openings covered in copper], LED and 3 knobs.
  With a .0068uf cap > 22k pot across where the LP cap goes across the diodes, barely goes to just not quite enough treble [CCW] to what's probably no rolloff, or, just about right, the cap is hanging off the potlug, easy to increase it's value or reduce the pot value, subtle control, fine tunes the zone I want.
  I dropped the divider resistors from 1m to about 45k, I'm definitely preferring these values.
  100k output pot and it's got good boost.
  BTB si's for clipping are mounted in the PCB.
  A mod for making the signal swing at the diodes either pulled up toward + or pulled toward - might be a way to assymetricize the clipping with the same diodes in place.
  I had/used a Ochre MXR + box for over a decade, main [only] Fuzz.
  The buzzing sound of a cable in the carpet alerted me to look at the cable tip on carpet where the missing MXR was. [OUCH !!]
  Built Dist+'s, some died, some got lost in the PcB shuffle, I had one in a wood box on PB for years, all modded out w/OS Comp with it. [Still had the 1m divider resistors, I would opt to smaller values now]. It got all charred, smoky, and died.
  Toney sent me the PCB, built and boxed, just wasn't right.
  Now that I've had a couple days to think on and rework it, I've got it distorting the amp really nicely, and at various volumes..turning down the 100k volume pot has a voicing effect.
  Oh...only 22k pot on the gain, just enough to drop it back a few notches and dull it down some, subtle for a gain control, about the way I like that Dist+ knob to work, could go a bit lower though.
  Tight bass, loud leads, super for distorting chords.

[Baktown]

Thanks to all for the good ideas!  I didn't realize this was such a popular build!

Axl