DOD Overdrive Preamp/250 Part 1

 

I've been a huge fan of these for years now. Before all the "boutique" overdrives on the market, these were IT. I had one permanently on my board for years along with an MXR distortion plus, which is a VERY similar circuit but these two pedals are worlds apart in their tone and reaction to different types of pick ups and amps.

While most of the time I used these pedals I ran them into a old solid state amp ala Bob Mould, this Overdrive Preamp works extremely well into valve amps, extremely well.


 

For some reason it's one of the few pedals I ever really regretted selling. I remember selling it through my shop with the original box and paperwork, and even when I sold it I had reservations. So years later I'm talking to a friend of mine who makes awesome pedals and collects DOD stuff and I mentioned how I had one of these but regretted selling it. I told him how I might buy one back and see if they were as good as I remembered. He told me that original grey versions were fetching up to $600 and old yellow ones could get $400? ........... And then I found out they were no longer made in the Chinese reissue version................. Great !!

After lots of research and looking I managed to find an old yellow one (an '81 in fact) for almost nothing AND found a couple of re-issues brand new for a great price. I've had a YM308 (Malmsteen signature model named after a Ferrari) for a while and it never impressed me compared to my memory of them



It turns out the YM is "based" on a vintage one with several different components, not least of all the legendary "all important" LM741 IC as used in some of the vintage ones. My '81 has a 351, which on paper is essentially a straight replacement, and the most common chip used in the 80's. I socketed the PCB in my original so I could "test" the difference between these two chips.

They are VERY similar in tone and gain with very little discernible difference between them. The reissue, like the YM uses the now legendary 4558 dual op amp with only one side being used. This, and the difference in caps and resistors makes the YM a different beast indeed with less bottoms and more "clang"


  

The Chinese re-issue is actually pretty darn good. Very close to what I remembered and VERY close to the original one. Closer in fact than the YM version. If I only had access to the re-issues, after this shootout I would be more than happy with one of them for live use. They're well made, look the same and have that tone.

So, it got me thinking. Why then is the original going for SO MUCH now ? Sure, they're rare compared to say a Boss OD1, but ............. ?

Being that I already make MXR Distortion +'s I thought I'd look into why the older versions of these are so sought after for their tone. Maybe that LM741 has a secret ? I use 741's in my Dist + circuit and I have a good supply of old and new 741's. To be honest I don't mind the Dist + circuit with TL071's, which most people say is too sterile, but the 741 is a great IC in that circuit, there's no doubt.

The DOD 250 is essentially the same circuit with a few less components and different values but the design and layout is obviously heavily "borrowed"



Working from my original and lots of info from the net I came up with a great sounding version of this little circuit, and it is a great sounding OD. It doesn't have the "balls" of the Dist + but nicely pushes the signal into first a slightly asymmetrical distortion and then a very symmetrical squarewave. While I always wanted the Dist + to go to 11, this circuit is very nice on most settings, not needing full gain to sound nice. With the volume up and the gain down, it's a great little Preamp "boost" that you can introduce just the right amount of "dirt" into. It's a very different drive depending on what pickups you use too, which to me is a good sign for OD's.

So all in all it was time well worth spending on getting familiar with this little pedal again. I will be making some of these in a Tym version VERY soon, so stay tuned for more details.

PART TWO

Jul 24 2013 Written By: Tim Brennan