Keeley Electronics DS-1 Seeing Eye Mod

Robert Keeley’s name has grown substantially over the past couple of years and with good reason: he’s an electrical engineer by trade blessed with a musician’s ear for good tone. That combination has proved to be a blessing for his business, Keeley Electronics, and has earned Robert the reputation of knowing what sounds good and being able to build those tones into his final products for his customers.

BOSS DS-1I became interested in one of Keeley Electronics’ latest modified pedals, the Boss DS-1 Seeing Eye Mod (SEM) after learning that pro players Steve Vai and Joe Satriani were using it. Well, I’m no Steve Vai or Joe Satriani on guitar, but was still very curious about Keeley’s transformation of the DS-1, which happens to be among Boss’ oldest and longest-lasting pedal designs.

If you’re familiar with the stock DS-1 pedal, its distortion is moderately heavy and its tone definitely accentuates the higher frequencies, especially as you increase the distortion control. This can make for some ice-pick piercing treble distortion, especially at louder band-practice and gig levels, which probably also explains the reason why Steve Vai and Joe Satriani set there unmodded DS-1s to relatively lower-gain settings and used the unit’s volume control more as a boost. All in all, the unmodified DS-1 sonically when used as the only source of distortion is more suited to that of the bedroom-player or user who wants the effect at lower volumes.

Keeley Electronics’ Boss DS-1 SEM was designed to correct the original’s shortcomings both in tone and distortion quality. The intention of the DS-1 SEM was to not only increase the amount of gain available, but also make it usable, smoother gain through careful tuning of the tone control network. Beyond tuning the DS-1 SEM for better tone through new values of parts, many of the original unit’s parts were discarded and substituted for premium components such as tantalum capacitors. To increase initial gain, Keeley incorporated a unique diode in the circuit, which doubles as the "Seeing Eye". As notes or chords are played, the light-emitting-diode flashes and pulses with equivalent intensity as your guitar signal. A cool look certainly, but very useful – in fact, this type of clipping is used to help "gain up" even the most famous of amplifiers such as Marshall’s Jubilee series amps, first introduced in 1987, and reissued in various forms since then.

So how did the DS-1 SEM perform? Extremely well to these ears. As a player of tube Marshall amplifiers as well as various quality guitars, etc. over the years, it’s almost embarrassing to admit how close this DS-1 SEM will simulate the higher-gained distortion sounds that modern Marshalls and other amps can produce. The distortion is smooth and has good harmonics – the extreme sterility that can occur with the stock DS-1 when cranking up the distortion control – is gone. The ability to smooth out the tone so it’s not "ice-pick" trebly is also there. Certainly there are plenty of highs on tap if you want them, but I found the DS-1 SEM most comfortable when setting the tone to about 11:00 when used with my Vox AC30’s Normal channel.

I also tested the DS-1 SEM through a Hiwatt set for a warm clean tone and it functioned perfectly there as well; very usable high gain when kicked in. I do have to make clear though that this is not a pedal aimed at the classic rock or blues sounds – it’s much too aggressive for that. In fact, for classic rock and bluesy sounds, a tube amp with overdriven power tubes is a must for the majority of the tone, though kicking on a pedal is a nice "helper" to bring out thicker rhythm or solo tones. A power tube stage has a dynamic response in its compression that is unique to power tube distortion.

This pedal is definitely tuned for harder rock and modern metal types of sounds and if you’ve got a humbucker-equipped guitar, the DS-1 SEM will love you that much more for it. Priced at just $95 for a brand new DS-1 SEM, with a full warranty through Keeley Electronics, the DS-1 SEM is a great choice for those seeking contemporary high-gain distortion tones. Check out Keeley Electronics at for a full lineup of modified and original design effects.

Note to LegendaryTones readers: Because of my personal association with Robert Keeley (who also serves as the chief designer of the LegendaryTones Time Machine Boost), I felt it was important to tell everyone that this story about the DS-1 SEM was not transferred into a full review with product ratings due to potentially being labeled as being biased (against other distortion units). So I avoided any direct comparisons. The story’s purpose here really anyway is to serve as an informational piece and is my true unbiased opinion of the DS-1 SEM, which happens to be very favorable. While it can be argued by some perhaps that a write-up of this kind could still be written or presented in a biased fashion, I should state a couple of points on this issue: 1) my personal integrity is worth much more to me than "making up a story and saying I like something that I truly did not", and 2) Because I really enjoyed this pedal and think that many people would benefit from its use, it would be a disservice NOT to write about it just because some people may feel that there is bias of some sort. I can assure you that in this article, there is none.

So in the end I opted to tell the story – the DS-1 SEM’s a good one folks – no b.s. there!


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