Boss DS-1 Distortion - Ultra Mod - - Modded by Keeley
Boss DS-1 Distortion - Ultra Mod - - Modded by Keeley

DS-1 Distortion - Ultra Mod - - Modded by Keeley, Distortion from Boss.

All user reviews for the Boss DS-1 Distortion - Ultra Mod - - Modded by Keeley

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Average Score:4.8( 4.8/5 based on 6 reviews )
 5 reviews83 %
 1 user review17 %
Not satisfied with those reviews?
heads on fire01/28/2012

heads on fire's review"What a surprise!"

Boss DS-1 Distortion - Ultra Mod - - Modded by Keeley
*With the diode Toggle Switch you have the DS-ULTRA! Huge tube like tone, switch back and you have the classic Seeing Eye Mod (SEM) version of the pedal for high gain, tube like distortion!
*Extra mods to increase the distortion range at maximum settings.
*Mods to correct the bass response and give you a fuller, more powerful tone. *Perfect for Strats now with this mod!
*Comes with Cool Knobs!
*Toggle Switch Up - Our Standard Seeing Eye Mod.
*Toggle Down - Adds another LED to the clipping circuit for a Large Fat Tone.


This is a great pedal! Keeley takes the homely little DS-1 and turns it into a sexy fire-breathing beast. The modifications increase bass response, distortion range, sustain, and attack with this pedal. It's like plugging into a dimed Marshall JCM900, only at a low volume! Honestly! The build quality from Boss is fantastic - this could be thrown off of a building and still be just fine. The additional mods from Keeley look to be incredibly stable as well from a durability standpoint - I've had no issues with mine.


This thing sounds awesome! The two ways I've enjoyed using this pedal are as a boost for solos into an already distorted amp signal, and for a gnarly dry distorted tone when used in conjunction with the amp's clean channel. As a boost, it screams - the notes just sing out with abandon, sustaining as long as I want them to. As a dry dirt box, it gets some great rhythm tones from AC/DC to 90s alt-grunge.


I'm thoroughly impressed, because this modification has taken a humble $40 Boss pedal and elevated it to the status of a superdirt! Robert Keeley is a genius of modern guitar electronics, and that he could make this pedal sound good is a testament to his skill and ingenuity. A+, Highly recommended.

Hatsubai's review"Much more versatile"

Boss DS-1 Distortion - Ultra Mod - - Modded by Keeley
This is probably the most famous DS1 mod out there. Keeley is one of the top modders in the field, and he has all kinds of pros using his pedals. The DS1 has always been one of those "go to" distortion boxes, but I always found it to sound very "pedal" like, if you know what I mean. Keeley helps fix this issue, and he also adds a nice switch so you can get even more tones out of the thing. The pedal still has your standard gain, tone and level knobs, but it also has a two way switch to allow you to select between different diode settings.


The pedal is still very much like the normal Boss in that it's housed in an indestructible housing. These things have seen all kinds of abuse throughout the years, and they always seem to handle whatever is thrown at them. The layout of the knobs is slightly different on the DS1 compared to other pedals such as the SD1 and whatnot. Instead of the tone being in the middle, the level is in the middle. This is something to keep in mind in case you've never used one of these things before. The manual is kinda useless now that Keeley modded it, but it's not really needed as these are very simple to use.


Like I said before, the standard Boss DS1 always sounded a bit thin and boxy to me. I could never get a really great tone out of it. The Keeley helps fix this issue, and it makes it a lot more usable. The biggest thing about this is the extra switch that allows you to select between the Seeing Eye mod and the extra LED that you can add in the circuit. You won't be able to physically see the LED, but it's added to the clipping section to give you a more aggressive tone. I'm a huge fan of using LEDs in the clipping section, and I tend to use this mode the most out of all of them.


The pedal is pretty solid, but it's expensive compared to the dirt cheap DS1s you can find all throughout Craigslist and/or eBay. It's a decent gain pedal, but I still can't truly get used to using the DS1 as a primary gain pedal. I much prefer amp distortion. It's hard to choose between this and the Analogman version as they're both different takes on the same pedal, but I find the Keeley one to be a bit more modern sounding.
Audiofanzine FR11/03/2008

Audiofanzine FR's review

Boss DS-1 Distortion - Ultra Mod - - Modded by Keeley
(Originally written by mikeosoft/translated from Audiofanzine FR)

Same as the original but with a "pseudo-bypass" switch that allows me to recover the sound of the original pedal. (I call it "pseudo-bypass" because I changed some parts of the circuitry that have little to do with the bypass)


Same handling as the original pedal.


It still amazes me, I bought the original pedal and modified it with a kit I bought on the web. The modification I made is simply brilliant! It adds warmth to the sound, I would even dare saying it turns a solid-state amp into an all-tube amp. I noticed that the sound is much better with a transistor amp like the Randall RH150G3 than with an all-tube Peavey 6505 for example.
The sound is really mind-blowing when I use the clean channel of my Randall amp and the clean booster.


I've been using it for 1 week and it's perfect to get that modern rock sound.
Combined with the amp's overdrive channel (gain set to 0), it adds some real power.
A lasting product that combines the reliability of a stompbox with transistor-based tube simulation. Are we getting to the point where we can avoid tubes without having to resort to digital technology?

pierre745's review (This content has been automatically translated from French)

Boss DS-1 Distortion - Ultra Mod - - Modded by Keeley
C a distortion


3 buttons and a switch


Awesome with a Cort kx custom and di marzios.G hate to try with EMG's.


I was looking for the sound of guitars hero style neal schon, john mitchell, steve rothery .... and well, I'm comblé.Je do not know the original pedal but has changed its ...
You pay by paypal, it receives an email of AR and all by Chronopost one receives in 1 week (bring in for customs chronopost otherwise keeps the toy (41 euros for 130 euros in much product + port)).
Honestly, there are so many pedals that have disappointed me .... I can not believe to have found one that suits me so well ...

brui2fon's review (This content has been automatically translated from French)

Boss DS-1 Distortion - Ultra Mod - - Modded by Keeley
This is a BOSS DS-1 modified by Robert Keeley
the CONTRL are the same: tone, dist, volume
Keeley changes several components, see his website:
and adds a miniswitch, to switch between two modes of distortion


C obviously very simple and super easy to use
records provided, BOSS and Keeley, offer many examples of rglages


The Keeley mod has nothing ave see the pedal base
the sound is much more open, broad and ample hot
it replaces a perfect channel amp a little winded
grain sings wonderfully
c a pedal register trs "rock n roll", it is less suitable to the metal and blues but we can do it anyway, APRS and regalges depends on your gear
it sounds a bit "harsh" enough ie sharp, acute, but lowering the tone does not pose a problem to balance the sound
I IDAL, unwanted in a LP Junior P90 faded in for the good old stuff to the phone etc., c pr IDAL's really that I saw no vox AC30 lol


I just know I wanted to finally buy the quality Keeley
I believe following and I will take other

raphaon's review (This content has been automatically translated from French)

Boss DS-1 Distortion - Ultra Mod - - Modded by Keeley
Pedal DS1 (Taiwan) changes with a common switch on / off Keeley.
Pedal steel strapping


Rglagle simple
level button
Tone button
Button gain
keeley switch


Keeley modified by the distortion is much better than the pedal base (not hard), the pedals will change much potato. Still, for me the sound of the DS1 is not my prfr but the ds is that I put in my BB Preamp parrallle Xotic from home (I wonder vritable sense.
For me the DS1 alone is too noisy. Caution is noted that I do not work directly on my amplifier but GX700 (multi effect rack) to link my PC.

DS1 Ultra yes but with you!


I've had 2 days
if I had the choice again no problem I would.
Come and listen the sound, I use it in some of my components (coupled with Keeley DS1 Ultra)