Korg X-911 Analog Guitar Synthesizer (With Demo Recording)

[chromium]

Did I mention I'm a synth nerd yet today?   

I just picked up a neat little "effect" - a Korg X-911 guitar synth. 



These were only built for a short time (~1981), probably didn't sell too well, are pretty scarce as a result, and this one had seen better days!

This isn't like most of the stomp-box synths (Electro Harmonix Micro, Boss SYB-5, etc..) that are basically octave/fuzz boxes with filters.  This one is actually a real analog synthesizer, based on some of the same circuitry used in Korg's venerable MS models.  It is designed to track the pitch of an input signal (guitar, bass, mic, another synth, etc...), trigger its internal sounds, and match the pitch of the notes you are playing.  It has built in distortion as well, and many of the "synth" functions you would expect - envelope generators (for shaping tone over time), portamento (glide between notes), adjustable touch sensitive dynamics, a resonant low-pass filter (for tonal sweeps and "wahhhhs"), and a couple of oscillators (the sound generators). 

That's a lot of "stuff" stuffed into a small package!



This one came to me (relatively) cheap, as it was busted.  One of the pots was broken and seized up, it wouldn't trigger properly (due to a bad  IC), and an LED was shattered/burned out.  I found a schematic online, sorted everything out, and now it works like a champ!  I still need to tweak its "intonation" a bit.  There are a number of trimpots inside that have influence over this.  Adjusting them to track pitch properly seems like more of an art than a science (that's what I was working on in that pic above).

That said, I'm *really* blown away by it's tracking ability!  I have a late model Roland guitar synth setup too, and being that this old Korg doesn't even have a dedicated/specialized pickup or anything, it does a *very* respectable job tracking notes. 

Even with bass!!  (althogh you'll want to stay up kinda high on the 'board for the best results)

I was jamming with it a bit last weekend, and ending up recording a little improv song to demonstrate some of the sounds it can make.  All the synth parts in this song were made by the Korg, and "played" using the Alembic Distillate (and SG special on a couple very minor parts).  There's some normal bass in the middle, which is also the Distillate.  I used a compressor to smash the input signal a bit, to help even out the dynamics so the Korg could do its best job possible with tracking pitch.  I ran the Korg into the Space Echo, and then thru the Alembic F2-B preamp.  Here are some shots of the setup:





Oh yeah- and the song:

[Barklessdog]

Sounds great. I like the synth melody part in the middle.

[chromium]

Thanks!

I've always been fascinated by the synergy of guitars and synthesizers.  It's the ultimate effect/sound-processor!  That stuff was relatively new, and so out of reach when I was a kid.  Although I never had the know-how to design circuits from scratch, I read a lot of books and cop'ed elements from other peoples schematics/projects and tried building my own stuff.  Like this one that I managed to hang onto after all this time:





That box used distortion to fuzz out the input signal, and then trigger a synth filter and envelope generator to shape each note that you played.  I had bread-boarded up a pitch following oscialltor at one point too, but it didn't work well enough (nothing like that Korg!) to make it into permanant form. 

I still lust after some of those early guitar synths, like the , Roland GR-300, the Condor, or the "signal processor" types - like the Ludwig Phase II and those Tom-Oberheim-built-Maestro effects.  I actually just won one of those this morning - because I can't pry myself from Ebay long enough to avoid such temptation!  At least I buy low... problem is that I don't sell.  It's kinda like home equity.  Money I'll never see again.  Ever.   

This one is the Maestro W2 Woodwind Synthesizer.  Looks like grannies' old Wurlitzer organ:



I'll be subjecting you all to more proggie sounds from it soon!

[Barklessdog]

Wow, that pretty cool stuff.

I always wanted a Ludwig phase. It's like a transformer robot!
Way too pricey today though.

I have this Man O Meter box from work. It would make a cool pedal housing. Its a meter for a spray booth to measure air flow.

[Barklessdog]

You know I own a Korg N-1 synthesizer that has all the instruments sampled. It sounds great, but it's too easy and just does not have that old analog vibe. I stop using it. Its to easy to just press a button and not work to get a cool unique sound.

Samples are just cheap & easy to me, vs created sounds.

[chromium]

Love that Binks enclosure!  I get a kick out of some of the DIY effect that guys sell on Ebay.  I've seen stuff built inside of Altoids tins, cigar humidors, tupperware, etc...

I have the schematics for the Ludwig Phase II.  Someday I  might try to build one - there's no way I'm paying 2-3K for one.  Spec-wise, it's actually a lot like that Maestro I just bought - fuzztone, tremolo, filter - and the Maestro adds octave effects.  Wish somebody would post some samples of the Ludwig.  That way I would know if it would be worth the time and effort.  With its towering stature and lightshow, it's still the coolest looking pedal, though!  I just can't believe the prices...

[hieronymous]

Finally got a chance to listen to "squelch" - sounds great! That first bass line - is it simultaneously outputting the fuzz sound and the squelchy sound?

[chromium]

Finally got a chance to listen to "squelch" - sounds great! That first bass line - is it simultaneously outputting the fuzz sound and the squelchy sound?

Thanks!  That bass sound was part dry signal (heavily compressed), and part pulse-wave from the oscillator tuned an octave lower.

It has an oscillator like the MS-20 keyboards - where you can have multiple waveforms on different octaves output simultaneously from just the one oscillator.  There's a block diagram of its internals here that shows at a high level how its layed out.

Unfortunately, the way they have this thing designed, you can't use *both* of the oscillator outputs at the same time *and* mix in the dry or fuzz/distortion signal - which is kind of a bummer.  Probably a just sacrifice made for cost and/or front panel space.  It would sound pretty crazy having (essentially) two oscillators in unison running along with the bass signal.  Those old MS synths do that punchy, buzzy bass sound really well.

[chromium]

Oh - and I should mention too that those crazy blips at the beginning were from running my hand over the roundwounds.  The synth hears that, can't figure out what notes you are playing, and goes completely spastic.  Great fun!   

[Barklessdog]

I love it when you give Mr Roboto spasms

[chromium]

http://www.youtube.com/watch?v=4S_i2tziV_U&feature=related

[ramone57]

that robot clip was funny, Joe.  good one!