NPD!!! - Keeley SD-1

[coldwar1977]

Finally pulled the plug and got me a Keeley modded version of the SD-1.

And it sounds sweet!
I was already a fan of the stock version, but this is a whole different beast.

Well, the tonal difference is highly noticeable to say the least! A big surprise to me.
I don’t know much about the technical side of things, but apparently the Keeley version features some seriously upgraded key components (capacitors, resistors, different main chips - stacked), resulting in:

1. much quieter operation (almost zero hum)
2. improved bypass (no more "bleeding through" when level/gain are cranked
3. more low end (bass) and a fatter overall tone (which is great if u choose to use the sd-1 as a standalone overdrive)
4. more “clarity” (which means even complex chords won’t sound mushy)
5. a bit more volume level on tap (which is welcome if you use it as a boost in front of an already overdriven amp)
6. a very sensitive and more effective Tone control (it not only effects treble, but also the behavior of the midhump)

The Keeley SD-1 also has a two-way toggle switch to choose between two types of overdrive, but so far I only care for the loudest mode

All in all, a great pedal!
It sounds much more muscular than an "ordinary" SD-1 (there's definitely a hint of Plexi/Marshall going on), which makes it perfect for all kinds of classic rock.

Any more lovers of the Keeley SD-1 here??

[coldwar1977]

Forgot to say:
IMHO this pedal is best suited for singlecoil guitars (bridge pup).
Its fatness and strong low end might be a bit much for certain "darker" sounding LP/SG/... style guitars.

[jonhart]

I love my Keeley SD-1. It's my main drive pedal, and for the moment it's actualy my only drive pedal. It's hard having it by itself, but it gets the job done. I usualy boost it with another OD in front of it for leads, but my other drive pedal broke so I'm looking to build a BYOC 808.

[11 Gauge]

Originally Posted by coldwar1977

1. much quieter operation (almost zero hum)

I never understood how folks are getting hum from a SD-1. It has to be one of the lowest noise pedals I've tried.

If anything, any tiny amount of hum or thermal noise is only exaggerated because the buffered bypass switching is silent. And - you're only going to hear noise like that at home in your living room.

Now - if the SD-1 had hum like a stock Big Muff, I'd totally understand. Or thermal noise (hiss). But there is a LOT more gain with something like a Big Muff, and it uses transistors, which don't have as good of noise rejection.

The SD-1 is a low gain drive box with a decent stock chip with a low noise floor. If anything, it has used the dual layer "DD" 4558 chip that LOWERS the noise floor versus a "vintage" "single D" 4558 chip.

Bottom line - what is this hum that I hear folks talk about? And unless you have the drive control pegged, would you hear anything considerable? I wish more pedals were as quiet as the SD-1 when it comes to ALL types of noise.

[telefunken]

I've been looking at getting one of those. I almost pulled the trigger yesterday, this thread isn't helping me.........AAAARGH!

[coldwar1977]

@11 Gauge: you're right Keith, the SD-1 is not very noisy to begin with. I was indeed thinking of a situation where the gain is maxed (and in direct comparison to my Bad Monkey). But now there's even lower noise!

@Telefunken: just do it, chances are great you'll love that pedal

[11 Gauge]

Originally Posted by telefunken

I've been looking at getting one of those. I almost pulled the trigger yesterday, this thread isn't helping me.........AAAARGH!

If money is an issue, the 5 Star Mod has been available via Overdrive Spider on the Web for probably at least 5 years now:

http://www.docstoc.com/docs/69425466...VERDRIVESPIDER (scroll down for the 5 Star mod instead of the others)

...I see they've actually moved these docs, cleaned them up, and offered an option to actually download a printable PDF. Pretty cool.

Apparently, Keeley used to have these mods posted on different web pages here and there. I did find where someone saved the exact Keeley verbiage:

"***** SD-1 5-Star Ge Mod ****
Board Number, New part, Old part, Reason
C10 --> Metal Stack Film 1uF, remove electrolytic, increased fidelity,
C7--> Metal Stack Film 1uF, remove electrolytic increased fidelity,
R6 --> 2.4k ohm metal film, 4.7k, increased distortion
C3--> 0.1uf metal stack film, 0.047uf, fidelity and bass response
C2--> 0.1uf metal stack film, 0.018 fidelity and bass response,
R2--> 620k ohm metal film, 470k ohm, increased input impedance, better bypass,

Add 47pF cap across diodes in clipping section to smooth out distortion, just like TS9. On some older units, short out D3 and the 470 ohm resistor in the power supply section to increase the voltage to the circuit. This increase the headroom and gain. Newer units have it shorted already. Here is the tricky part of our mod, take a germanium (Ge) transistor and use the Base-Emitter junction (legs) of the device and use it in place of D6. If you use a PNP transistor, the Base will be the negative or cathode side, the Emitter will be the anode. Here is a diode drawing Cathode---|<----Anode. This increases the amount of distortion produced by the pedal, it also sound really nice. Try this! Don't leave it out! It's fun. Get your Ge transistors from Steve Daniels http://www.smallbearelec.com

If you want to drill out the LED and install a 5mm big job, change R30 to a 1.2k-3.3k ohm depending on brightness and battery drain you want, replacing the stock 3.9k ohm."

So if money is an issue, you could have someone install the parts for the 5 Star for you. Possibly not a beginner's mod, but pretty easy and straightforward.

IMO, the most critical parts of the 5 Star that make it "what it is" are the diode changes, and the fairly standard "2X gain mod" thing.

Note that most folks think it's not necessary to go to the trouble of using a germanium transistor as a diode, and Keeley may even be simply using a diode instead of a transistor now, too.

Either way, I thought the Overdrive Spider was pretty well known at this point, just like the Seeing Eye/Ultra Mod for the DS-1 by a whole host of web-savvy folks.

[valvestate]

Originally Posted by coldwar1977

I don’t know much about the technical side of things, but apparently the Keeley version features some seriously upgraded key components (capacitors, resistors, different main chips - stacked), resulting in:

1. much quieter operation (almost zero hum)
2. improved bypass (no more "bleeding through" when level/gain are cranked
3. more low end (bass) and a fatter overall tone (which is great if u choose to use the sd-1 as a standalone overdrive)
4. more “clarity” (which means even complex chords won’t sound mushy)
5. a bit more volume level on tap (which is welcome if you use it as a boost in front of an already overdriven amp)
6. a very sensitive and more effective Tone control (it not only effects treble, but also the behavior of the midhump)

Don't want to sound like a prick but you just basically described the BOSS OD-3 especially #3

[coldwar1977]

Originally Posted by valvestate

Don't want to sound like a prick but you just basically described the BOSS OD-3 especially #3

Yep, but still they sound quite different.

The OD-3 is a great sounding overdrive - probably one of the best stock pedals out there - but imho it hasn't got the punch nor the singing mids of a Keeley SD-1.

I've tried them both side by side (along with several other pedals) before I bought the KSD-1.