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2013-03-20 by cg_synth
It's in the notes on the page. >When using 2N3904 and 2N3906 I had to tweak the 2k2 in the resonance part of the circuit (connected to the emitter of the NPN in the amplifier) to compensate for transistor gain. A 15k across it brought it to the point where with the resonance full
2013-03-20 by Steve Inselman
Hello Ken, Which resistor should I change to achieve self-osc in the Steiner filter? I used the 2N2222 + 2N907 transistors. Thanks, Steve [Non-text portions of this message have been removed]
2013-03-15 by Steve Inselman
Hi Ken, Yeah, that was exactly it. Bad CA3080s. Good thing I had extra on hand. Thanks! ________________________________ From: " sasami@... " sasami@... > To: cgs_synth@yahoogroups.com Sent: Friday, March 15, 2013 4:24 PM Subject: Re: [cgs_synth] Serge Wave Multipliers trouble sh
2013-03-15 by cg_synth
Try sweeping it with a DC voltage through a pot. If that works, it's your LFO output. If not, look at common design elements. Do you have the transistors in backwards? (my guess). Are you LM3080s duds? Ken > Hi Ken and all, > I recently completed the Serge wave multipliers and fo
2013-03-15 by Steve Inselman
Hi Ken and all, I recently completed the Serge wave multipliers and found that the 1st and 2nd sections are only picking up the peaks of the LFO waveforms. I'm not able to get any sweeping effects from either section. Am I just not patching in the correct waveforms or is it an in
2013-02-18 by adematteo
Ok so i did 1 side with just reversing the 5089's and am getting the same result.I switched the other side w/ 3904's and what do you know i'm getting a nice upwards slope with the rise cranked cw.So, i guess pairing the 3906 and 3904 does matter. --- In cgs_synth@yahoogroups.com
2013-02-18 by goldencardigan
Ha ha that's awesome! Everytime I think I'm beginning to understand how trannies work in a circuit, I hear something like this and I realise I have absolutely no idea. Cheers Dean --- In cgs_synth@yahoogroups.com , sasami@... wrote: > > Transistors can be funny things. I made the
2013-02-18 by cg_synth
Transistors can be funny things. I made the 116 with every transistor except for the LED drive in backwards. The bloody thing works. Ken >Thanks, i just checked and i'm using 5089's with the 3906 so i'll change those out. >Also, i have the 5089's oriented the same way as the silk
2013-02-18 by adematteo
Thanks, i just checked and i'm using 5089's with the 3906 so i'll change those out. Also, i have the 5089's oriented the same way as the silkscreen which i just realized is backwards to the actual pinout.I thought i checked the pinout of the transistors before installing them so
2013-02-17 by Jason Nanna
Hi, I just debugged a DUSG yesterday that had this very problem. Check your transistors, specifically the NPN's in the current source. I had used 2n3906's in combination with 2n5089's and I got this very behavior. I believe either it was the combination or, much more likely, the
2013-02-17 by goldencardigan
Hi Tony, You should be getting a slow rising voltage as you rightly expect. Cheers Dean --- In cgs_synth@yahoogroups.com , "adematteo" wrote: > > Hi guys, I am noticing that the rise time on my dusg's doesn't seem to have very much effect in a typical way. > > I know this circuit
2013-02-17 by adematteo
Hi guys, I am noticing that the rise time on my dusg's doesn't seem to have very much effect in a typical way. I know this circuit is not a typical envelope generator so i'm curious if it's just the way this circuit works, but if i feed a trigger in and have the rise time set to
2013-02-13 by A S
Actually, I didn't populate the PCB. I bought it from someone that had built it up to that point. I just added the mods and installed it behind a front panel. I agree that this is a very powerful module. I was up late last night because of it! I'm amazed at how useful it is, wear
2013-02-13 by Richarius Molindarius
A little more careful attention is required for building the VCS, USG, DUSG, Negative Slew, Positive Slew and Smooth Stepped Generator. They're all quite specific. To me though, they (the USG and SSG) are a pair of the most powerful analog modules, on the planet. Transistor pinou
2013-02-13 by cg_synth
> Thanks to Dean and Ken for helping me get my VCS issue resolved. Ken, that >22pF cap was the culprit! Thanks for spotting that. > > I noticed that the Exp/Lin switches don't have an effect unless the CV >pots are at something other than zero. Even with no external CV plugged in
2013-02-13 by goldencardigan
Great to hear you've got it working! I know from my own experiences how much heartache troubleshooting a PCB can cause. Cheers Dean --- In cgs_synth@yahoogroups.com , A S wrote: > > Thanks to Dean and Ken for helping me get my VCS issue resolved. Ken, that > 22pF cap was the culp
2013-02-13 by A S
Thanks to Dean and Ken for helping me get my VCS issue resolved. Ken, that 22pF cap was the culprit! Thanks for spotting that. I noticed that the Exp/Lin switches don't have an effect unless the CV pots are at something other than zero. Even with no external CV plugged in. That l
2013-02-12 by A S
Good catch! I think I might have a 22n cap at home. I'll try it tonight. Thanks! Andrew On Tue, Feb 12, 2013 at 12:55 AM, sasami@... > wrote: > ** > > > I looked at the photos. > > Looks like a 22pF where you should have a 22nF (0.022uF) next to TL072. > Other side of TL072 - pin
2013-02-12 by cg_synth
Expo mode is feeding a changing voltage back into the unit. There will be some change in it's frequency as a result. > Here's something strange. I just hooked it up again. In cycle mode, if the >fall and rate switches are in expo mode, raising the Fall CV or Rise CV >pots will in
2013-02-12 by cg_synth
I looked at the photos. Looks like a 22pF where you should have a 22nF (0.022uF) next to TL072. Other side of TL072 - pin 7 resistor should be 8k2, not 22k as marked on the PCB. Ken _______________________________________________________________________ Ken Stone sasami@... other
2013-02-12 by A S
I measured the cathode voltage of the diode. It's at +15V while an input voltage is present. If the voltage is lowered to near zero (when Pin 5 goes up to +4.2V), the cathode drops to +11V. On Mon, Feb 11, 2013 at 10:23 PM, A S synthasaurus@... > wrote: > > Okay, I replaced the d
2013-02-12 by A S
Okay, I replaced the diode and with no input, the voltage at Pin 5 of the TL072 is +4.2V. I also tried replacing the TL072, but still get the same results. Andrew On Mon, Feb 11, 2013 at 10:04 PM, A S synthasaurus@... > wrote: > > Thanks Dean. I just measured the voltages. With a
2013-02-12 by A S
Thanks Dean. I just measured the voltages. With a decreasing input (slowly decreasing from +5V to 0V), Pin 5 of the TL072 follows the input until the input drops into the 10s of Millivolts. Decreasing the input lower causes the voltage at Pin 5 to immediately jump to +3.74 volts.
2013-02-12 by goldencardigan
Hi Andrew, Please ignore my last rant, it wasn't aimed at you in anyway. It looks like you've got your pot wiring right. Check the Diode connected to Pin 5 of the TL072, next to the two 220k Resistors on the schematic. With nothing connected to the Trig or Input, you should have
2013-02-12 by A S
Here are two pics (Left and Right PCB shots): http://imageshack.us/a/img826/7277/vcspcbleftside.jpg http://imageshack.us/a/img811/5241/vcspcbrightside.jpg Andrew On Mon, Feb 11, 2013 at 9:28 PM, A S synthasaurus@... > wrote: > Hi Ken, > Sure did. I used 100K resistors there, and
2013-02-12 by A S
Hi Ken, Sure did. I used 100K resistors there, and I used this for the two 1n caps: http://www.mouser.com/ProductDetail/EPCOS/B32529C102K/?qs=sGAEpiMZZMv1cc3ydrPrF1iYn56hZ3YmhsEj8dPJEuE%3d Thank you, Andrew On Mon, Feb 11, 2013 at 9:06 PM, sasami@... > wrote: > ** > > > Re lockin
2013-02-12 by cg_synth
Re locking up, have you seen the modification to replace the 10n caps with 1n in the cycle switching circuit? 150k also go down to 100k. Ken >Hi Dean, > Thanks very much for the reply. Regarding EG operation, I'm okay with the >fact that the pots will work "in reverse" if wired w
2013-02-12 by A S
Here's something strange. I just hooked it up again. In cycle mode, if the fall and rate switches are in expo mode, raising the Fall CV or Rise CV pots will increase the freq. output up to the 12 o'clock position. Going past that position, the freq. will decrease slightly. If the
2013-02-12 by A S
Hi Dean, Thanks very much for the reply. Regarding EG operation, I'm okay with the fact that the pots will work "in reverse" if wired with cycle mode's audio freq. in mind. Speaking of cycle mode, it does work as an oscillator in this mode, though I'm not sure if it works in the
2013-02-11 by goldencardigan
Hi A S To me it sounds like you need to check your pot wiring. Have another read of the wiring list and confirm your connections, as a lot of people have had problems with this. Can you tell us which connections you have used for the Rise, Fall and respective rate pots. Just for
2013-02-11 by A S
Hello, I have a CGS75 Rev 0.0 where the Rise and Fall pots don't give typical EG slew rates. For the following symptoms, I'm using a square wave output from an LFO set about 1 Hz to the input of the VCS. The output of the VCS is driving a VCO FM input, so that I can hear what the
2013-02-08 by Steve Inselman
My mistake as I assumed. I was reading the instructions wrong... Thanks Ken. These VCOs sounds great BTW. ________________________________ From: " sasami@... " sasami@... > To: cgs_synth@yahoogroups.com Sent: Friday, February 8, 2013 5:21 PM Subject: Re: [cgs_synth] CGS VCO calib
2013-02-08 by cg_synth
You are trimming the main output to on OCTAVE higher, not 1 volt higher. You need to listen to it, not read it with a meter. Ken >Hello, > Could anyone help me w/ which output I should calibrate to 1v higher than the 1v in to the 1v/oct input adjusting the Span trimmer?? >It is t
2013-02-08 by Steve Inselman
Hello, Could anyone help me w/ which output I should calibrate to 1v higher than the 1v in to the 1v/oct input adjusting the Span trimmer?? It is the second step in the "setting up" section in the notes. The waveforms are unaffected by the Span trimmer unless I am doing something
2013-01-31 by cg_synth
Soldering them to the resistor leads sounds like a plan. That should give you some structural support as well as a good connection. Ken >Hi Ken > >I finally got a hold of the 1uF BP electros for the CGS113 and it turns out the pins are too wide to fit through the PCB !! > >I meas
2013-01-31 by Stephen Richards
Hi Ken I finally got a hold of the 1uF BP electros for the CGS113 and it turns out the pins are too wide to fit through the PCB !! I measured the pins width at 0.8mm. I have a 1mm drillbit but am a bit worried about damaging the PCB traces , as i only have a handheld drill ; no d
2013-01-26 by Stephen Richards
There are instructions for calibrating the VCO here : http://www.cgs.synth.net/modules/cgs48_vco.html The second paragraph deals with Span trimmer calibration. ________________________________ From: Steve Inselman steveinselman@... > To: CGS cgs_synth@yahoogroups.com > Sent: Sund
2013-01-26 by Steve Inselman
Hello To adjust the Span trimmer what output should I connect to for calibrating the voltage? I tried the waveforms but the span trimmer had no effect on the voltage. I also tried the other 1v/oct but it is connected to initial freq wiper. Thanks, Steve [Non-text portions of this
2013-01-19 by cg_synth
You need to connect the 0V from the 5v supply to the 0V of the +/-15V supply. Ken >Thanks for the answer. > >I think the problem is that I have two separate PSU's for +/-15V and +5V >and they are not connected other than through the AC lines and the corresponding >main earth line
2013-01-19 by Joachim
Thanks for the answer. I think the problem is that I have two separate PSU's for +/-15V and +5V and they are not connected other than through the AC lines and the corresponding main earth line. I measure 5V between the 'digital' ground of the +5V PSU and the 'analog' ground of th
2013-01-18 by cg_synth
Yes, the 741 output should do that to turn the relays on. Next, look at the collector of the transistor. That should go down to near zero volts. If it does, then you have problem with the relays, RCD, or the trackwork between them. If it doesn't, check the emitter really is conne
2013-01-18 by Joachim
Hi, yesterday I tested a PSU (+5V, +/- 15V) with a CGS63 Power Supply Delay but at the and of the relays I get no voltage. I get +14.2V at pin 6 of the 741 (the output) and nothing at the link near RCO so my guess is that I have a faulty BC 338. Or is the +14.2V wrong there? I ha
2013-01-14 by achtung_999
To be frank, I hardly use the modem option. It is not an essential process in my way of working[?] On Sun, Jan 13, 2013 at 3:30 AM, A S synthasaurus@... > wrote: > ** > > > Thanks for the link to your demos. It seems that the real ring modem allows > one of the inputs (is it the
2013-01-13 by A S
Thanks for the link to your demos. It seems that the real ring modem allows one of the inputs (is it the carrier?) to appear at the output. Is this correct? I just re-read some of the text on Ken's page. and this seems to be the case. It also mentions that since the real ring mod
2013-01-13 by achtung_999
It's single sideband modulation, it sounds different. You can hear the difference here at my blog: http://ernstvanderloo.com/?p=24 grtz Ernst On Sun, Jan 13, 2013 at 2:16 AM, A S synthasaurus@... > wrote: > ** > > > Hello, > Can anyone shed some light on the real ring modem? > >
2013-01-13 by A S
Hello, Can anyone shed some light on the real ring modem? http://www.cgs.synth.net/modules/cgsrmodem.html What are the advantages of connecting two ring mods in this manner? Thanks [Non-text portions of this message have been removed]
2013-01-10 by adematteo
Well i guess i'll check my led's from now on.I don't know how i ended up with it but i just have a bag of random led's and somehow it ended up in there. Feeling good this thing is working now ! --- In cgs_synth@yahoogroups.com , sasami@... wrote: > > >HOLY COW, i figured it out a
2013-01-10 by Richarius Molindarius
Now I'm stumped. The flashing LED where it is in the circuit, couldnthave been responsibkw for the entore problem. .. Could it? Im wondsring there if it actuallt IS CAUSing (oops) a problem by trying to deag 20 mA to Ground from the opamp. On 2013-01-09 6:39 PM, sasami@... > wrot
2013-01-09 by cg_synth
>HOLY COW, i figured it out and i want to tell you guys but i really hope this doesn't earn me some sort of nickname because i'm pretty sure this may be a first. Last year I was fixing on of JH's phasers with the two lightbulbs in it. One globe failed, so I hunted around until I
2013-01-09 by adematteo
HOLY COW, i figured it out and i want to tell you guys but i really hope this doesn't earn me some sort of nickname because i'm pretty sure this may be a first. Some how i used an led that is i believe a flashing led, i'm not quite sure but it does look to have a small black thin