As most of you know I'm a huge fan of DOD effects. The Overdrive Preamp/250 has been one of my favourite overdrives since .... forever. It was one of the first overdrives I bought when I started playing guitar and as I was already a big fan of the MXR Dist+, this little yellow box, which is electronically very similar was instantly familiar.
I've written lots about these boxes before for my own versions and a blog about a shootout with several different models available. As I've said many times before my personal favourite version of this box is the early to mid 80's one with the 351 IC which, to my ears, is the most musical and harmonic. Now, I know there';s people out there shaking their heads and calling me names as the early grey version is the most collectible and by far the most expensive version of this OD, but, I like the 80's one.
I have made grey versions before but they are the '79 circuit that was essentially the same as the first of the yellow versions (DOD changed the colour, not the circuit) and with the price of these earlier grey versions getting out of control, and with the news recently that DOD/Digitech were being closed down by their parent company Harman, I thought I'd make some of these early grey versions with a twist.
This circuit here is the very first, infamous 7 resistor grey 250 circuit introduced in 1977, hence it's called the ODP777. While there are several different versions of these early grey boxes it appears that the first of them shipped with a somewhat simpler 7 resistor (and 4 caps) PCB with silicon diode clipping. As far as I know the DOD never had germanium diodes like the early MXR Dist+'s which suits me fine as I'm not a huge fan of the germanium Dist+ either. Again, I'll take an early 80's silicon "block logo" MXR any day.
So, I thought I'd make a first generation grey box 250 as people are asking over $1000 for originals now, although you can pick up early yellow ones for considerably less, and as I wrote in past blogs, I rate the Chinese re-issues AND, even though it's not my favourite, the newer (2013) DOD re-issues highly and would use any of them live. The current (just deleted?) sparkle finish re-issue is actually closer to a grey box version with LED, Boss style 9V and true bypass.
This early version is very nice, and slightly different to the other '79 grey version I make. This one has nice harmonics and bottom end with a treble that cuts through nicely. The other 250's all have this, just in different amounts. This versions does clean up nicely though and shows the "preamp" part probably nicer than the later versions. With the gain down and the volume up it's a great clean preamp, which got me thinking (that's rarely a good thing) that it would make a great actual preamp.
I put in a mini toggle to take the clipping diodes out of the circuit and BAM!!!
I have had mini toggles in my ODP and Tymexars before and while I like them, this circuit just keeps the bottom and mids intact really nicely and has SO MUCH output it's crazy good. The Dist+ pulls out bottom end as you wind the gain up, which is great in that circuit with the diodes but it thins out the tone without clipping. This circuit keeps everything there and just has heaps of clean headroom that clips the IC at the very end of the gain pot travel essentially giving you massive amounts of clean boost.
This pedal uses the "obligatory" LM741 IC like the originals but I have socketed it so you can try your own versions if you like.
The original 250 is a GREAT overdrive preamp into a lot of different amps, especially into old Marshalls and Oranges and works well with single coils and humbuckers. Like the Dist+ it keeps humbuckers "clean" and tight while saturating them in distortion and both the Dist+ and the 250 are great with P-90's. The 250 is also great on bass and this version as a preamp is even more versatile on guitar and bass.
These (obviously) aren't in my usual handmade stainless steel enclosures as I was trying more to replicate the original aesthetic as well and are in these powdercoated Hammond 125B enclosures which are almost the same size as the originals. They are all hand made here by me on my custom Tym PCB's and have Boss 9V adaptor plugs and, LEDs and true bypass.
I'm not sure if this will be regular Tym effect and I'm thinking of making a version in the smaller MXR size enclosure without the mini toggle for those who want the straight up OD/Pre for a pedal board. We'll see how these go?
I've made 10 of these that will be in the shop on Sunday all going well.