New DS-1 Mod: the 'MIJ-Mod' (vintage MIJ DS-1 sound from post-1994 DS-1)

[5thumbs]

As part of my research for the 'Build Your Own DS-1 Distortion' build doc, I set about researching the differences between the pre-1994, MIJ DS-1 pedals and the post-1994 varieties based upon the M5223AL chip.  I started experimenting with modifying the post-1994 DS-1 to make it sound like the pre-1994, MIJ DS-1.  This experimentation resulted in what I call the "MIJ-Mod."

I have documented the MIJ-Mod in a new main section and the pre-/post-1994 research in a new appendix section of that doc, located here:  http://www.diystompboxes.com/DIYFiles/up/Build_Your_Own_DS-1_Distortion.pdf.


Here is an excerpt from that document, providing the details on how to perform the MIJ-Mod.

"The intent of this mod is to alter the post-1994 DS-1 to make it sound like the vintage DS-1.  I've tested a stock DS-1 modified with the MIJ-Mod side-by-side with a genuine pre-1994, MIJ DS-1 and found the similarity in sound characteristics to be remarkable.

Mod Steps:

1.   Change C7 from 100pF ceramic disc capacitor to a 250pF ceramic disc capacitor.

2.   Change C8 from 0.47μF/50V aluminum electrolytic capacitor to 1uF/50V aluminum electrolytic capacitor; save the 0.47μF/50V cap for the next step.

3.   Remove the 0.068μF film capacitor from C5 and replace it with the 0.47μF/50V aluminum electrolytic capacitor previously removed from C8 in Step 2.


NOTE:  Tantalum capacitors are not recommended for C5 and C8.  BOSS used aluminum electrolytic capacitors in these positions originally, so since we're trying to recapture the sound of the pre-1994 DS-1, I used aluminum electrolytic caps in these positions as well.  Despite their somewhat bad reputation, aluminum electrolytic caps sound pretty good in these positions.  I tried tantalum caps in these positions and they made the distortion sound trebly and harsh.  Tantalum caps can be used in some locations in the DS-1 with positive effect (like Monte Allums does in his DS-1 mods), but they do not sound good in this mod.

Metal film caps may be used in C5 and C8, but please bear in mind that BOSS didn't use film caps for C5 and C8 in the original, so you'll be making a hybrid-of-a-hybrid and might not sound as true to the pre-1994 DS-1 sound as I have tried to achieve in this mod.  I did try film caps in C5 and C8 and they did sound good, but not as close to the original as the aluminum electrolytic caps.

The same goes for using a silver mica cap in C7.  Try it if you want to, but BOSS used ceramic caps in C7 in both pre-1994 and post-1994, which is why they are used in this mod.

I would strongly advise you to try this mod without mixing in any other mods first.  A post-1994 DS-1 with the MIJ-Mod has a sound that is less-compressed sounding than the stock post-1994 DS-1.  The note articulation is vastly improved as well.  You can crank the DIST control with this mod and it still sounds good, unlike the post-1994, where cranking the DIST control results in a bit of a fuzzy mess (in my opinion, of course.)

If you are fortunate enough to own both a vintage DS-1 and a post-1994 DS-1 modified with the MIJ-Mod, if you carefully listen to them side-by-side, you'll notice that the vintage pedal has slightly less bass and sounds slightly more compressed than the post-1994 DS-1 with the MIJ-Mod.  Personally, I like the post-1994 with the MIJ-Mod best, as it has almost identical tone characteristics to the vintage DS-1, but has a less-compressed, higher-fidelity sound that compares favorably with some of the best DS-1 mods out there.  (And yes, I am biased. )  But don't take my word for it, let your ears be your guide to which one is best for you."


As always, if you have questions or corrections, please let me know.  Thanks!

[beatstrat]

Cool.  Love/Hate the DS-1.  I have/keep one, but only use it when it's the only tool in the box that will do the job.

[jimbob]

Awsome!

I think ill buy one soon just for this..And since its only around 39.00 usd.

James

[5thumbs]

Cool.  Love/Hate the DS-1.  I have/keep one, but only use it when it's the only tool in the box that will do the job.

I know what you mean.  The DS-1 space in my pedal board usually provides what I call "church crunch."  Not too ballsy, but more ballsy than my overdrive pedals can/should provide.  I prefer a higher gain distortion for most other things, but the DS-1 is just another useful tool in the toolbox.

I bought my first DS-1 used at a local guitar shop, didn't like it much, modded it with Monte Allum's DS-1 mod and liked it a lot more.  Bought the second one to try Monte's DS-1 Rectifier mod...and liked it.  Got my third one as a "gift" from one of the kids I work with...it was dead and needed rehab; nursed it back to stock condition and used it as the mule pedal for the MIJ-Mod.  Got my fourth so I could have a "stock" post-1994 DS-1 for testing purposes.  Bought the fifth so I could have a vintage MIJ DS-1 for testing purposes.  I think I now have enough DS-1 pedals to last me the rest of my life.

To be honest, as much as I like the DS-1, I don't LOVE the DS-1.  However, it's what about 90% of the kids I work with have, so love them or not, I've had to get comfortable with them in order to modify/fix them.

BTW, I got the last post-1994 DS-1 new on eBay for $32.95 w/shipping.  You can't always find them that cheap on eBay, but you might get lucky and save a few bucks if you keep your eyes open.

[soulsonic]

Thanks Brett! I've got a DS-1 that I've messed with modding before, but I wasn't too happy with how it came out, and now I'm looking to un-mod/re-mod it to be more what I'm looking for, so your copious notes in the "Build Your Own DS-1" document are very much appreciated. You and Muhammad have done a great job with it!

[zombiwoof]

Can anyone point me to a layout of the current DS-1 with the component numbers on it to help with this mod?  There's a layout in the document for the board to use in the build, but I don't know if it corresponds to the stock board.

Thanks,
Al

[5thumbs]

Can anyone point me to a layout of the current DS-1 with the component numbers on it to help with this mod?  There's a layout in the document for the board to use in the build, but I don't know if it corresponds to the stock board.

Thanks,
Al

The 'Stock DS-1' layout in that doc exactly matches the post-1994 DS-1 layout, right down to the component labels.  The only difference between that layout and the BOSS layout is miqbal put in a DIP8 op amp, rather than the SIP8 used by BOSS.

Same goes for the 'True-Bypass' layout in the doc, except that the TB layout omits the components in the input/output buffer and flip-flop switching circuit.

So the component labels apply to miqbal's 'Stock' layout, my 'True-Bypass' layout and BOSS's post-1994 layout.  You can use the schematic/layout information in that doc and have it apply to your BOSS DS-1.

[zombiwoof]

       "The 'Stock DS-1' layout in that doc exactly matches the post-1994 DS-1 layout, right down to the      component labels.  The only difference between that layout and the BOSS layout is miqbal put in a DIP8 op amp, rather than the SIP8 used by BOSS."    etc.........

Thanks for the info!  I was recently thinking of getting one of those, since I've never had one, now I think I will.  I was aware that most people say the recent model needs mods to sound good, so your mod sounds like the one to do.

Al

[5thumbs]

Thanks for the info!  I was recently thinking of getting one of those, since I've never had one, now I think I will.  I was aware that most people say the recent model needs mods to sound good, so your mod sounds like the one to do.

I'd position the MIJ-Mod as a "starting point" mod.  I've built some other mods that are pretty cool in the degree they change the character of the DS-1, so there is still a world of innovation out there that extends beyond the MIJ-Mod.  To me, this mod just restores the better, original voice of the DS-1 to the post-1994 pedal.

Folks should feel free to mod on top of the MIJ-Mod, but change their approach slightly to not change the MIJ-Mod components to keep that vintage DS-1 sound.  I like my MIJ-Modded pedal quite a bit, but like all stock DS-1 pedals, it is a bit too fizzy at max gain for my tastes.  I'm sure I'll play with the clipping diodes to cut the fizz a bit, but that's about it.

I guess it comes down to this: If you like the DS-1, you'll like the MIJ-Mod.  If you have never liked the DS-1 (and have heard/tried the vintage DS-1), the MIJ-Mod is nothing new.  If you've never heard a vintage DS-1, the MIJ-Mod is an opportunity for you to hear that tone for about $0.25 in parts.

Vintage MIJ DS-1 pedals are selling for $75 and up on eBay, so the MIJ-Mod is a bargain for most, unless you want to own a vintage DS-1 for its collectability.  I had to buy a vintage DS-1 so that I could validate this mod against the original.  Had I not done that, folks could easily refute my claim of this simple, inexpensive mod very closely capturing the character of the old pedals.  YMMV, but I've done my best to cut through the bovine scatology and myth surrounding the vintage DS-1 versus post-1994 DS-1.  Hopefully your ears will like it as well as mine.

[5thumbs]

FYI, I added my D4/D5 clipping diode mods to the DS-1 build doc, calling it the 'MIJ-Mod PLUS'.

In a nutshell, I replaced D4 with a series combo of 1 each of 1N4002 and 1N34A diodes.  I replaced D5 with a NPN silicon transistor (I used a 2N3859A, but any common silicon NPN should work) with the base->emitter acting as the clipping diode.  The resulting sound was a reduction in the fizz I mentioned in the earlier post, while at the same time still retaining its striking similarity to the vintage MIJ DS-1.

You can read more about the MIJ-Mod PLUS at the usual location: http://www.diystompboxes.com/DIYFiles/up/Build_Your_Own_DS-1_Distortion.pdf.

Thanks!

[dan5150]

This is a great doc. Thanks so much for sharing!

-Dan-

[5thumbs]

Folks, if you're building a DS-1 from this doc, please check the value for C8 in the 'Stock DS-1' and 'True-Bypass DS-1' schematics.  C8 is supposed to be 0.47μF/50V for the post-1994 DS-1 and 1μF for the MIJ-Mod and MIJ-Mod PLUS DS-1.

We had some confusion early on about this value.  Unfortunately, the value for C8 remained documented at 1μF in many of the versions of this doc so far.  I think I've finally got all this worked out, so please grab the latest version of the doc to pick up the latest corrections.

Sorry for the "version hell", but this often happens when you have multiple contributors working on a technical document (who have busy full-time jobs.) 

-Brett

[miqbal]

 

[5thumbs]

Greetings once again!  I've come up with the third and likely final mod in the MIJ-Mod series.  It's called the "Mondo-MIJ" and it is a high-fidelity version of the "MIJ-Mod" that builds upon the previous two "MIJ" mods.  The resulting distortion is really exceptional, particularly considering that it is coming from the humble DS-1.  I've demo'd the prototype to a couple of my guitar buddies and they were very impressed with the Mondo-MIJ by itself.  They were especially gracious towards it when comparing it to the stock pre-1994 DS-1, stock post-1994 DS-1 and MIJ-Plus DS-1 pedals I let them play side-by-side with the Mondo-MIJ DS-1.  (I'm now building additional Mondo-MIJ DS-1 pedals for them...an understandable consequence and a flattering result at the same time.)

The original "MIJ" mod was designed to replace only the minimal number of components necessary to make the post-1994 DS-1 sound like the pre-1994 MIJ vintage DS-1. The "MIJ-Plus" mod was designed to remove some of the "fizz" from the "MIJ" mod by increasing the proximity to clip in the D4/D5 clipping diodes. The "Mondo-MIJ" mod is designed to bring a higher fidelity sound to the "MIJ"-type mods through the use of film capacitors, an upgraded op amp and a more sophisticated clipping circuit. Admittedly, this is probably the last of the "MIJ"-type mod series. To extend the mod much further than the "Mondo-MIJ" will take the pedal in a direction that will likely be inconsistent with the tone shape and note articulation that endear the original MIJ DS-1 (and hopefully "MIJ" modded) pedals to guitarists worldwide.

You can find the "Mondo-MIJ" mod instructions in the 2-26-2008 version of the 'Build Your Own DS-1 Distortion" document located here: http://www.diystompboxes.com/DIYFiles/up/Build_Your_Own_DS-1_Distortion.pdf.  Pages 18-21 are the specific pages related to the "Mondo-MIJ".

NOTE:  If you have questions how to wire "Part 3" of the Mondo-MIJ, please post on the thread http://www.diystompboxes.com/smfforum/index.php?topic=64731.0 and I'll answer them as best I can.  The new clipping circuit in the "Mondo-MIJ" is a bit more complex than your average "diode swap" mod, but the resulting distortion is well worth the effort.  Jack Orman's articles on alternative distortion saturation controls are to be thanked for giving me the inspiration for the clipping circuit mod in the "Mondo-MIJ".  (Thanks, Jack!)