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2013-04-21 by Sean
Finished building an SSG last night and am having similar issues. Keep popping LM3900s. They go fast and extremely hot! Checked traces (I'll check again) but haven't troubleshooted extensively yet. btw, I used J201 (not J201A) and 50v 10uf Electrolytic (not 25v) and somewhat conc
2013-04-14 by cg_synth
Probably a short on the wire bus to a near by pad. Ken >I got a couple channels on a programmer kicking out a steady voltage near 14.5V , While other channels work fine. Not a big deal, Im sure I can figure it out after the weekend. Just curious if any one else did this before. >
2013-04-14 by meech
I got a couple channels on a programmer kicking out a steady voltage near 14.5V , While other channels work fine. Not a big deal, Im sure I can figure it out after the weekend. Just curious if any one else did this before. d
2013-04-14 by cg_synth
Sounds like there is too much gain somewhere. Your SPAN may not be set propperly yet. Deal with that first. Also make sure you have the right value resistors installed. If you still have problems, increase the 1M resistor to 2M2. >If it's working from about 10'o clock to about 2
2013-04-13 by adematteo
If it's working from about 10'o clock to about 2 o'clock this is normal before it will go into lfo territory. There's a mod i read about somewhere that changed that behavior as well as the fine tune knob to function as you would expect.I don't remember were it was but google or c
2013-04-13 by adematteo
Thanks Dave, this ones been making me crazy ! So, i took my son to his soccer game and got back and fired it up and now both sections are working after popping another 3900 in the stepped section.So either i have a whole bunch of bad luck w/ the 3 different batches of 3900's i ha
2013-04-13 by Dave Kendall
On 13 Apr 2013, at 18:24, adematteo wrote: > So, i'm assuming there's an intermittent short or fragile trace that > i'm not catching ? FWIW, I've been caught by them before - once a *very* tiny sliver of solder bridging things it shouldn't, and another time an almost invisible et
2013-04-13 by adematteo
Well, i did these tests and everything checked out except for pin 3 on both sides i was getting -9.4v. Now here's the kicker, the smooth section all of a sudden started working because as i was monitoring it i pressed on the trimmer for the stepped section, but the stepped sectio
2013-04-13 by djstorm
Hi, I'm working on a cgs48 vco where the frequency knob only works on the middle of it's range. About 50% of the knob travel (25% on each end) causes the VCO to cut out and not function. I have a theory that it's probably somewhere in the cv summing area that is not working corre
2013-04-13 by Adam Scramstad
Thanks Ken! I'll try these tips out this weekend, and report my results. Cheers, - Adam On Apr 13, 2013, at 2:04 AM, sasami@... wrote: > *Worked out on a bit of paper. Try it on one channel before you modify them > all! Sorry, but I really don't feel like ripping the sequencer ou
2013-04-13 by cg_synth
*Worked out on a bit of paper. Try it on one channel before you modify them all! Sorry, but I really don't feel like ripping the sequencer out of my synth again! >CV - To double the output replace the 100k resistors between each inverter >pair with 47k (or solder another 100k in
2013-04-13 by cg_synth
CV - To double the output replace the 100k resistors between each inverter pair with 47k (or solder another 100k in parallel). Other resistor values here will give you different gains. I'm not sure what the max output is at the moment! Gate - Replace 820R near Pulse Out with 100R
2013-04-13 by Adam Scramstad
Hi all, Is it possible to mod the CGS59 A/B to allow a 0-10V output? Cheers! - Adam
2013-04-13 by cg_synth
Okay, those voltages were more or less what I got. Now take a 1k resistor and connect one end to -15. Connect the other end of the 1k resistor to each input pin in turn, and read the voltages. If all is well, they will read around -14.5 to -15 volts. If any read much higher than
2013-04-12 by adematteo
Sorry, that came out as a big garbled mess. 1) +13.54 2) 0 3) -9.23 4) -14.35 5) +11.13 6) -0.113 7) -15 8) -.010 9) 0 10) -.112 11) -.115 12) +13 13) -4.92 (Stepped U5) +12.64 (Smoothed U2) 14) +15 --- In cgs_synth@yahoogroups.com , "adematteo" wrote: > > So all the voltages rea
2013-04-12 by adematteo
So all the voltages read the same on both chips except for pin 13 which i make a note of : 1) +13.54 14) +15 2) 0 13) -4.92 (U5 Stepped) +12.64 (U2 Smooth) 3) -9.23 12) +13 4) -14.35 11) -.115 5) +11.13 10) -.112 6) -0.113 9) 0 7) -15 8)-.010 --- In cgs_synth@yahoogroups.com , sa
2013-04-12 by cg_synth
Seriously, chip frying is indication of serious power routing issues. With the chips OUT, read the voltages on each pin of the socket, then list them here. Ken >Thanks again Ken, and Rich for all the helpful suggestions. >I've triple checked component values at this point,replace
2013-04-12 by adematteo
Thanks again Ken, and Rich for all the helpful suggestions. I've triple checked component values at this point,replaced trannies,ic's,gone over continuity testing and visually inspected the board under a magnifying lens with no luck. There has to be a short or something that i am
2013-04-12 by Dennis Tan
Great that's what I was looking for. I guess I've missed that out from the Doepfer page. Thanks again! Am 11.04.2013 um 14:57 schrieb roglok: > This should help: > www.doepfer.de/a100_man/a100m_e.htm > > Distances on those strips are not metric, but 0.2 inches per hole... > > It'
2013-04-11 by roglok
This should help: www.doepfer.de/a100_man/a100m_e.htm Distances on those strips are not metric, but 0.2 inches per hole... It's an industrial standard, so looking up the datasheets made by Schroff, Rittal, Fischer etc. should give you the same info as the Doepfer page... Where yo
2013-04-11 by Dennis Tan
Hi! I meant the mounting screws for mounting the panels into the rack. I have rack combination from Schneiders Buro. This is what I'm using, http://www.schneidersladen.de/gewindestreifen-m3-gewinde-2 So far, I've made the holes on the panels at x-0.6 and 0.9cm, y-0.4cm. It works
2013-04-10 by cg_synth
Been thinkng about this - The problem may also be caused by putting a voltage on the input pins, which are designed for current, not voltage. Check nothing is shorted to them. Check your resistor values. Maye sure you haven't installed 15 ohms instead of 1M. Ken >Will do.Thanks g
2013-04-10 by adematteo
Will do.Thanks guys! I'll report back when i get this working. --- In cgs_synth@yahoogroups.com , Richarius Molindarius wrote: > > Use a well lit magnified lamp. Especially for that board. Hard to find > small trace breaks and bad solder joints. > > > [Non-text portions of this m
2013-04-09 by Richarius Molindarius
Use a well lit magnified lamp. Especially for that board. Hard to find small trace breaks and bad solder joints. [Non-text portions of this message have been removed]
2013-04-09 by cg_synth
I have no idea why you are seeing what you are seeing. It defies logic. All I can do is give you some trouble shooting tips. Use your eyes (not a meter) to inspect the board. Every track, every part. Do it with the board rotated so you are looking at it afresh. If ANYTHING looks
2013-04-09 by adematteo
Ok, well my different manufacturer theory just went out the window.I popped in 2 more lm3900's from the same manufacturer of the ones i had in that didn't lock up my system and now the new ones are locking the system up. I am measuring 330 ohm resistance between pin 3 (gnd ?) and
2013-04-09 by adematteo
Thanks Ken, All the correct voltages are going to the correct pins (-15v to pin 7 +15v to pin 14) I may have put the 3900 that burned up in backwards ? I checked all the component values and diode orientations this morning.I still have to go through and check continuity throughou
2013-04-09 by cg_synth
Also check you don't have your power rails swapped about. If you have used CA3401 instead of a lm3900, and it's seeing 30V it will go pop too, as they are only good for 15V rails, unlike the lm3900. >Hey guys, I just put together the SSG and it's not working so i tried to switch
2013-04-09 by cg_synth
There are two possible reasons 1) Are you putting them in backwards? 2) they aren't LM3900, despite whatever is written on them. >I forgot to mention i'm getting all the correct power to the correct pins and am not finding any shorts between any of the pins. > >--- In cgs_synth@y
2013-04-09 by adematteo
I forgot to mention i'm getting all the correct power to the correct pins and am not finding any shorts between any of the pins. --- In cgs_synth@yahoogroups.com , "adematteo" wrote: > > Hey guys, I just put together the SSG and it's not working so i tried to switch out the lm390
2013-04-09 by adematteo
Hey guys, I just put together the SSG and it's not working so i tried to switch out the lm3900's after giving the board some continuity testing and looking over the board briefly, i still need to do a lot more troubleshooting but what i wanted to ask about was this, when i switch
2013-04-08 by Neil Baldwin
Thanks Ken. It would seem my SWAMP is then working as expected! :) Neil [Non-text portions of this message have been removed]
2013-04-08 by adematteo
I'm a little confused as well what you are trying to figure out but if you haven't noticed at the bottom of the descriptions page of each circuit under "notes" you'll see the dimensions for the mounting holes on the pcb. --- In cgs_synth@yahoogroups.com , Dmitri SFC wrote: > > "I
2013-04-08 by Dmitri SFC
"I'm building a new system that is 4U / 7 inches in a 17 inch rack rails. What I can't seem to figure out is where should the mounting screws should be. My panels sizes are 4.25" / 4 1/4" or 1.75" / 1 3/4". Any ideas? 4.25" you must be doing Buchla Style. When doing individual or
2013-04-07 by Dennis Tan
Hi there, this is a little off topic, but maybe someone could shed some light in this. I'm building a new system that is 4U / 7 inches in a 17 inch rack rails. What I can't seem to figure out is where should the mounting screws should be. My panels sizes are 4.25" / 4 1/4" or 1.7
2013-04-07 by cg_synth
Octave buffer - When the inputs to OCT A,B and C and NOTE A,B and C are all Low (0V), the output should read 0V. Set OCT A, B and C High (+15). Adjust Oct Adj trimmer until the output (OUT) is 7.0V. Set OCT A,B and C and NOTE A,B and C all to Low again. The output should read 0V
2013-04-06 by Stephen Richards
Hi Ken and all I have had the MARSH panel built for about six months now and have never done any calibrating. So today , i'm trying to have a crack at it. Firstly , the CGS41 diatonic converter. The documentation say the two trimmers, octave buffer and note buffer, need adjusting
2013-04-05 by cg_synth
>I was also planning to do just that. (The 1k resistance would just to quiet down the signal...?) The 1k resistance is so you don't blow the stuffing out of it when a patch cord hits a panel. _______________________________________________________________________ Ken Stone sasami
2013-04-05 by cg_synth
You would need VCAs of some sort, be they Vactrols followed by buffers, SSM2164 or whatever. Ken --- In cgs_synth@yahoogroups.com , "ctujoao" wrote: > > I was also planning to do just that. (The 1k resistance would just to quiet down the signal...?) > On the other side: If I want
2013-04-05 by ctujoao
I was also planning to do just that. (The 1k resistance would just to quiet down the signal...?) On the other side: If I wanted to put the gain of each band under CV control, is it realistic to do it with TL07x somewhere around the potentiometer? Or should I look at the vactrolin
2013-04-04 by cg_synth
The manual/(ON) position of the switch is allow you to manually force a stage to be High (requires the clock to be working - it is a dynamic process). The idea is you toggle it on and off to program in a pattern. The Loop/ON position then turns on the feedback loop, sending the l
2013-04-04 by neilbaldwin70
Hello all, I posted a similar question over on Muff's but I thought I'd try here too as there seems to be a great deal of knowledge (and Ken's attention!) on here :) Basically I'm trying to test my SWAMP build and am totally stumped by some features of the Comparator section so i
2013-04-03 by adematteo
Great tip Ken,thanks. The more i think about it, it might be nice to have individual control over both sides so i'm still deciding which way to go. --- In cgs_synth@yahoogroups.com , Loscha wrote: > > That is a bit more elegant than my idea. > Maybe try that one first! > > On 4/2
2013-04-01 by Loscha
That is a bit more elegant than my idea. Maybe try that one first! On 4/2/13, sasami@... sasami@... > wrote: >>If you wired up the two resistive elements across, say, a 9v battery, >>and then hooked each of the sweeping legs across both channels of a >>scope, you'd get a pretty a
2013-04-01 by cg_synth
>If you wired up the two resistive elements across, say, a 9v battery, >and then hooked each of the sweeping legs across both channels of a >scope, you'd get a pretty accurate measurement of the two tapers. A plain old multimeter would do. You want the voltage between the two wip
2013-04-01 by Loscha
If you wired up the two resistive elements across, say, a 9v battery, and then hooked each of the sweeping legs across both channels of a scope, you'd get a pretty accurate measurement of the two tapers. /ErJ On 4/2/13, adematteo adematteo@... > wrote: > > > Individual control ov
2013-04-01 by adematteo
Individual control over left and right may be the most economical way to go but i think i will order a hand full and do as you suggest to see just how off they are. Thanks Ken, all food for thought. --- In cgs_synth@yahoogroups.com , sasami@... wrote: > > Thoughts: > > You could
2013-04-01 by cg_synth
Thoughts: You could make some "switched attenuators" instead of using pots - basically dual gang rotary switches with 1% resistors between each step. That of course gets very expensive. You could buy a few pots and test them, and see how bad they really are. Maybe you can pic the
2013-04-01 by adematteo
Hey guys, I would like to build a stereo version of the res. eq. The idea would be to build a desktop box that i can run my master bus from my mixer through. I was wondering if anyone could offer any practical advice as far as getting close to the same response from both boards ?
2013-03-20 by Steve Inselman
Okay, I just assumed that it only applied when using 2N3904 and 2N3906 transistors. Thanks again Ken, Steve ________________________________ From: " sasami@... " sasami@... > To: cgs_synth@yahoogroups.com Sent: Wednesday, March 20, 2013 7:32 PM Subject: Re: [cgs_synth] Steiner VC