a couple notes on ressurecting roland 80017a vca/vcf ic's <junos, gr700 etc>

[pinkjimiphoton]

and off topic for Jimi...I found a Ludwig Phase II for a surprisingly reasonable price.  It was always my holy grail of pedals and really the last one I built.  It needs some love to sound as good as the clone we (mostly you) worked so hard on...and I'm terrified to open it after reading your experiences with wires constantly breaking.

no terror necessary, YOU can DO THIS! if I  could do it, hell, anybody could!!!

if ya need help, its here.. the wires didn't break as much as just come loose. they're best soldered to the board imho. the spade connectors they used wiggle loose with time.

i'd start with replacing all the electros. odds are that will fix most of it.

i am stoked for ya!! really cool pedal!

[snk]

the sh101 was cool, the first "strap on".... but it was a mono synth if i recall correctly. i sold mine about about 5 years ago finally. lotta fun. but it was more of a mono analog as i recall, the juno was way better

"apples and oranges", as we say... Yes, the SH101 is mono, so when it comes to playing chords, well, errh, you have to get the Juno 
But for "alive" basslines, the SH101 is very good, it has a more "vibey" feel than the Junos which have a rather "straight" sound. The SH101 is more acid, the Juno are deep and solid.
From a technical point of view, afaik, the 101 is a "synth on a chip" kind of synth, using CEM also featured in other synths from other brands. The Juno use the proprietary IR3109 chip, which sounds awesome.

[pinkjimiphoton]

yeah, to me, the two big ones were moog and arp... their filters were astounding.

but man, tell ya what... rolands could get REAL close to either... magical!! i couldn't believe the sounds i got outta that thing last nite. it was insane!!

now i'm bumming cuz i really need to refurb the gr300 before taking it out... needs all the electros replaced of course. but that causes downtime, and i never wanna play a normal guitar again after last nite, lol

that said, the v 1.5 firmware for my gr700 is on the mail truck now, as soon as its delivered, i'm gonna install it. also gotta see if the two damaged chips my bassist roger repaired work!

[ElectricDruid]

The SH101 does use a CEM3340 as its oscillator, but the filter is still Roland's IR3109 filter chip. It's a quad OTA on a chip, basically - I can't remember if the exponential convertor is on the chip or external off the top of my head.
The SH101 has a little clipping diode network in the resonance feedback loop which I think might account for its acid sound (totally agree Jimi - it has the most liquid squelch of any filter I know). It adds distortion to the feedback, but that feedback is then filtered so it never sounds crunchy, and that clipping provides limiting which allows the synth to howl without going totally crazy.

[pinkjimiphoton]

thanks tom, now i wanna add diodes to the thing 

as it turned out, i bought the firmware upgrade chip kit off the bay for 30 bux. brought it from v 1.2... fairly early ... to 1.5, the final version.

man. BIG difference. tracks better, faster on the low notes.. actually sustains notes and chords n stuff now, much better aminal.

that said, the replacement chips i ordered are no good.

the ORIGINAL chips, however, work GREAT after being de-gooped and repaired between my bassist roger and i... he did the delicate SMD stuff for me at work, replaced a missing cap and ran a jumper where i'd messed a trace up on one chip, and re-soldered the pins of one of the chips, i had lifted the middle two off their pads trying to get the goop out from under the pin leads. if that shit is anywhere that's conductive, its a bad thing.

i even fixed one of the chips myself, i grafted in a missing smd cap ... well, mostly obliterated cap, i really was overzealous trying to get the goo off til i figured out i had @#$%ed up

680p cap soldered in, back in business. sounds freeking phenomenal.

the chips i got on ebay tho, they have issues, or maybe they're just not compatible with my particular machine (?)

both chips would jump around in pitch during decay. even switching them to different sockets made no difference, it stayed with the chips. one wasn't as bad as the other... about 3 seconds into the decay it would start to warble, then jump up an octave... the other about 2 seconds in would first glitch up an octave, then just jump all over to random notes. not useable, unfortunately.

he said he tested them and burned them in, and i believe him. but maybe they were a better "fit" in his synth, or maybe he just plugged 'em in to see if they worked and didn't really try any long notes. short and fast stuff, no problem. but i'm a sucker for big long chords with huuuuuuuuge - ass filter sweeps.

the chip that was most unstable also manifested noise on just whatever string socket i tried it with, when the synth was turned off completely from the guitar, just that one string you'd hear crackly noise/distortion coming thru the guitar signal. even with the volume of the guitar off.

of course, at one point a pin got stuck and broke off, so i had to replace it which probably means i'm stuck with them, or at least that one <in which case i'll ask roger to de-solder, de-goop and re-solder with fresh caps and see if i can salvage it.

i got a great deal, 45 a piece, but its not a great deal if they don't work right. contacted the vendor about a return. had already left them great feedback.

of course, crickets so far

ya GOTTA get the goop out from under the chip pins. or at least slice with a single edge razor so they can't have any continuity at all. makes a huge difference. all 6 chips i started with are working perfectly now, so the next step is to re-calibrate now that all the chips are in their sockets... after all the jacks are in their boxes?

also, found a trick for ground loop issues with the gr300 after dicking around with it extensively most of the day... if you try and run your guitar and synth separately in two audio chains, there's two problems... the big one is a ground loop, made my normally almost silent pedalboard sound like a blown transformer buzzing.
so forget the "guitar only " out on the synth... but just for a minute.

the fix i found was to run the guitar out jack from the synth controller itself <the guitar> to my guitar rig, and the output of the "mixed" signal to the keyboard rig.

hum problem solved... but now the volume control on the guitar doesn't work right for the guitar signal. you can't kill the hex fuzz completely, and if you want nothing from the synth, well, too bad, there, buster, cuz even with it rolled all the way to guitar, and the synth off, the guitar sound keeps coming thru the keyboard rig. and the hum is still there, tho less, at least.

so i figured, this is a roland product, i betcha a doob to a donut that if i plug a cord into the guitar only output of the main synth, the gr300 itself, that maybe it would "think" the signals were separated.

bingo. now the guitar volume works for the guitar and synth as a master, as it should.  and to bring up the synth, you just roll the mix knob from guitar to synth. put the switch on synth only, and you're in business, way less hum, way less noise, and you can turn up or down or mix the ratio of guitar to synth from the guitar itself.

so in the end, i just plugged in a spare right angle 1/4" plug into the guitar only output of the synth, plugged the 1/4" output of the guitar into my normal pedalboard, and the 24 pin synth cable into the synth.

a little weird with all the extra cabling, but it sounds great and now it seems to work more intuitively.

one caveat to anyone who dare try this ... the gr300 is a monster. for some reason, roland didn't put a volume control on this thing, and they probably should have. so do yerself a favor and use a volume pedal. way easier that trying to mix from the guitar, the synth volume just overpowers the guitar volume, even with the gain mod from wayne's site.

anyways... onwards n upwards n stuff....