Hello, I am trying to build a sub-oscillator module for a Yamaha CS10 analog synthesizer.
I am using the Yusynth schematic, adapted for modern CD4013 chips (the transistor is setup as common emitter).
This is the original schematic :
https://yusynth.net/gear/CS10_en.html
(https://imgsh.net/i/j8pC9YF.png)
This is the layout I have drawn from it :
(https://imgsh.net/i/Vn3JWXd.png)
The circuit is very simple, and it is already wired to the synth.
My concern is that I don't hear anything coming out from the sub-oscillator circuit so far :
When I am an audio probe, I can hear the original signal coming to the CD4013 pin 3, but i hear nothing coming out from pins 11 and/or 12 (which are supposed to be the -1 and -2octave out) if i'm not mistaken.
I have checked the voltages with a multimeter, and this is what i am getting :
pin 01 : 14,98v
pin 02 : 15,04
pin 03 : 7,93
pin 04 : 0,07
pin 05 : 14,98
pin 06 : 0,05
pin 07 : ground
pin 08 : 0
pin 09 : 15,06
pin 10 : 0
pin 11 : 15,02
pin 12 : 15,05
pin 13 : 0,02
pin 14 : 15,06
Do these values seem correct ?
I don't have a spare CD4013 to swap and check with another chip:(
Thank you in advance for any hint:)
what does your datasheet tell you about the transistor orientation in your layout, please? that's for a start.
Quote from: duck_arse on October 07, 2023, 10:37:44 AMwhat does your datasheet tell you about the transistor orientation in your layout, please? that's for a start.
That i'm not the smartest guy on earth ? :icon_redface: :icon_biggrin:
With the transistor in the right direction (i'm so dumb : I previously made a couple layouts with the 2N3904 in the right orientation, and turned it 180° the other day :icon_rolleyes: ), i'm getting some octave down signal from the 4013 pins, but not from the synth...
I will investigate the wiring further, because something lmight be wrong there...
(Also, one thing which surprises me is that when I check the circuit using an audio probe, sometimes the octave down sounds are clean, and sometimes "wobbly")
Ok, I'm suspecting either a dodgy 4013 or a dodgy socket or a badly soldered veroboard (but the solders looks fine) : when "just" testing the circuit, I can't hear anything, but if i push on the top of the chip with my finger, I can hear the sound...
There was a thread about a similar problem on Modwiggler. Basically, the modern 4013's are a lot faster than the old ones and it screws up some of the old synth sub-osc circuits because they're fast enough to react to capacitively-coupled spikes from other pins. The SH-101 one was the example in that case, I think. This is the thread:
https://modwiggler.com/forum/viewtopic.php?t=221841
The TLDR version is that the fix is to add a 1K resistor between D and Q! and a 100n cap from D to ground.
HTH
Wonderful, Electric Druid, thank you so much for the hint!
When you mean "D" and "Q", which pins exactly do you mean?
(there are several)
(https://www.build-electronic-circuits.com/wp-content/uploads/2020/08/4013_Pinout-white.png)
From this picture, it seems to be D=pin9 and Q=pin13?
(https://www.muffwiggler.com/forum/userpix2/46505_flipflop_1.jpg)
Ok, from this schematic, it's pin 2 to 5 and pin 9 to 12
(https://www.muffwiggler.com/forum/userpix2/16047_shapers_divider_section_1.jpg)
The schematic shows polarized caps, is it required?
Also, the schematic seems to call for 2.2k resistors, while you suggested 1k : which would be the difference?
(https://imgsh.net/i/K1cDbyY.png)
This is what I am coming with...
Quote from: snk on October 07, 2023, 06:06:42 PMOk, from this schematic, it's pin 2 to 5 and pin 9 to 12
(https://www.muffwiggler.com/forum/userpix2/16047_shapers_divider_section_1.jpg)
The schematic shows polarized caps, is it required?
Also, the schematic seems to call for 2.2k resistors, while you suggested 1k : which would be the difference?
Yes, exactly. The modern chips require that you deliberately *slow down* the feedback from the !Q output to the D input (on either flip-flop, hence the choice of pin numbers).
2K2 is going to provide even more smoothing/slowing down than 1K. If you go with too large a value, you'll find the sub-octave effect doesn't work beyond certain frequencies, but as long as it covers all the stuff you care about, a bigger value is probably better.
HTH
QuoteMy concern is that I don't hear anything coming out from the sub-oscillator circuit so far
From that I suspect the input square-wave doesn't have sufficient swing. For the original application of a mod the square-wave is nice and clean and swings virtually rail to rail. Not an audio signal. It's not clear if the intended input swings negative. The diode protects from negative swings but is there negative swing? In some circuits with negative swings you might find a series cap on the input. It all depends on the details.
Have you got the R and S inputs on the first gate grounded? The schematic has three pin numbers but only one connection. All those pins need to be grounded.
QuoteThe schematic shows polarized caps, is it required?
Also, the schematic seems to call for 2.2k resistors, while you suggested 1k : which would be the difference?
This schematic has a Schmitt-trigger front-end which might make the circuit more sensitive However the aim of the Schmitt-trigger and the 2k2 +100n filters is about making the circuit more robust.
If you aren't hearing anything you aren't even getting the clock on the first gate to trigger. If you were hearing something and it was glitchy then perhaps the second circuit would help.
If we knew what the square-wave input was it might be possible to make a better suggestion. A one transistor inverting switch might work. This idea but maybe different values and put a reverse diode across base and emitter for protection; can also put a resistor across base and emitter to tune sensitivity.
Supply voltage not important at this point. Point O would connect to the clock input.
(https://i.stack.imgur.com/hH2Ju.png)
With diode:
(https://i.stack.imgur.com/BPFko.png/)
Thank you all for the help, that's very valuable.
QuoteIf we knew what the square-wave input was it might be possible to make a better suggestion.
I am going to give a bit more information about the synth and the mod :
- The synth is a vintage analog synth made by Yamaha in the late 70s. You can find the service manual here : https://www.synthxl.com/yamaha-cs-10/
(https://syntaur.com/images/CS10.jpg)
It's lovely, but the single oscillator design doesn't help getting deep basses...
- The Sub-Osc mod was designed by Yves Usson (Yusynth) (https://yusynth.net/gear/CS10_en.html), who later designed the MiniBrute. The good point is that it's a talented and well-respected synth designer... The bad point is that he did the mod on his very own synth... 30 years ago : it's a one-shot, not a commercial product, and back in the days he may have used the older version of the CD4013, which may explain why his schematic doesn't work anymore "right out of the box" and requires some tweaking.
Quote2K2 is going to provide even more smoothing/slowing down than 1K. If you go with too large a value, you'll find the sub-octave effect doesn't work beyond certain frequencies, but as long as it covers all the stuff you care about, a bigger value is probably better.
Thank you. I will start with 1k.
I can try with Mylar 100nF caps (instead of polarized electrolytics)?
QuoteIf you aren't hearing anything you aren't even getting the clock on the first gate to trigger. If you were hearing something and it was glitchy then perhaps the second circuit would help.
When I am applying a small pressure on the chip with my finger, I can hear the -1 and -2 suboctaves coming out of the chip, so i am suspecting either a bad socket or a faulty CD4013. I have ordered some more 4013, and I am willing to rebuild the circuit if required (but first I'd like to know what works and what doesn't and if the schematic is fine before building another wrong layout). :icon_lol:
Ok. I build another veroboard, with the additional mods (1k resistor + 100nF electro cap). I used another CD4013 (which I borrowed from another circuit).
The result is strictly the same :icon_sad:
No sub-octave sound, unless if I touch the chip and push it slightly, i often get a buzzy squarewave (but not a clean one).
The build is not the same, the chip is not the same, the socket is not the same... the issue is the same :-\
Quote from: Rob Strand on October 07, 2023, 10:40:43 PMHave you got the R and S inputs on the first gate grounded? The schematic has three pin numbers but only one connection. All those pins need to be grounded.
Sorry, Rob, I'm not following you : what do yo mean by "
R and S"?
you have the datasheet in front of you, yes? observe the drawing of the flip flops, two square boxes with pins/legs sticking out of them. ALL the pins of flipflop one will have "1" on them, and all the pins for flipflop the second, with nary a scent of imagination, will have "2" in their names.
each FF will have a D data input, S set input, R reset input, Q output, !Q bar|not Q - an inverted Q output, and a CLK clock input. look how the circuit presents the connections for a divider - an output fed back to an input, of the same half.
ALL unused INPUTS of a cmos chip, ALL CMOS CHIPS, must be taken to a logic level. this rule is not negotiable, cannot be overruled by some web guy telling you otherwise, is not negated by a wrong drawn circuit diagram. a level can be high or low, supply voltage or ground voltage. to get your flipflops to work properly, and it might be your finger effect proving this, you need to connect all the S pins and all the R pins to ground, because that's what the datasheet tells you.
obvs supply and ground is common to both FF's. you probably should be using poly/mylar/plastic/ceramic caps for the slowdown timings. stay with the parts you have at the moment, you will get them working right eventually.
Thank you so much, Duck Head (and sorry Rob for being a bit thick).
I was looking at the colored pinout posted above, which doesn't feature "R"...
With this one it's better :)
(https://www.eleccircuit.com/wp-content/uploads/2020/06/CD4013-pinout.png)
Quoteyou need to connect all the S pins and all the R pins to ground,
Ok, so I see that pins 8 & 10 (flipflop #2's Set & Reset) are already grounded, but not pins 4 & 6 (flipflop #1's Set & Reset).
I will put them to ground and let you know how it goes.
Quote from: duck_arse on October 08, 2023, 09:47:20 AMyou need to connect all the S pins and all the R pins to ground, because that's what the datasheet tells you.
It works!
Thank you so, so much Duck Head, Rob Strand, Electric Druid! :icon_cool:
[insert hippie, flowers, hurrah emojis]
I would have one last question : the audio out from the mod circuit is supposed to be wired to the square wave mixer pot.
It's nice and tidy because you don't have to mess the original pcb (or remove it from the front panel).
But the issue is that if I mute the square wave, the sub-octave also gets muted. I wish I could for instance have the sawtooth wave + the sub-octave mixed together, without having to have also the regular square wave...
I will browse the synth schematic (https://www.synthxl.com/yamaha-cs-10/) to find another possible place to put the output from the sub-osc circuit, but i'm open to suggestions (because my knowledge is quite limited and I wouldn't want to damage this venerable synth).
(the plan B would be to wire the sub-osc out to a jack socket, and then put a jack cable into that socket, going then to the audio in jack... but it is not very elegant, as I would very much prefer a solution where everything is inside the chassis, and permanently wired).
Hello
Ok, I found a good place (imho), I am putting here the screenshots from the schematic and the circuit for future reference.
Again, thank you so much all for your help and good advices : I am so glad to have this mod working, and I couldn't have managed to make it work without you.
(https://imgsh.net/i/DLyVKrO.jpg)
Yes, you can see on the part of page 6 of the schematic that you posted how the various signals (Ext/Noise, Pulse, and Ramp) are mixed with 68K resistors and 10K linear pots (A10K). Then they all go down that VCF-SI connection to the filter on page 9.
Yves' circuit uses 220K resistors and a 47K pot (probably to match levels a bit better - the 4013 puts out a full 15V signal) so it gets wired into the same spot as the others.
Ok, so the synth got back in its wooden case, with the faceplate screwed, etc. So far so good... until I noticed and odd behavior :
- First, everything is fine, the -1 oct sounds great, the -2 oct sounds great, in tune, etc.
- Then, after a couple seconds of using it, both octaves get shifted + 1 oct (so -1 becomes not shifted, and -2 becomes -1 octave), and while the -2 sub-osc sounds good (even if "only" playing 1 octave below instead of 2), the "previously -1 subosc" sounds thin and nasal (just like if the pulse width got maxed).
I didn't notice that previously, either because :
1- it wasn't happening and boxing the synth along with the add-on circuit made it happen;
2- when the guts of the synth were out, I didn't play enough with it to hear the issue (but really I don't think so);
3- Once boxed, I spent more time with the synth, tweaking every parameters, and one combination of parameters made this happen (it would be odd, but that might be something to consider)
One thing I find surprising, is that it doesn't happen right at the beginning, just after powering the synth on, but it happens after roughly 10 seconds, and the scenario is 100% reproducible.
It's like something needs to "charge" (?) and starts acting weird after it's charged (?)...
I will obviously open the synth again to check what can be wrong, but if these symptoms could give anyone a clue about some directions to investigate, I think it might help me troubleshooting this :)
QuoteOne thing I find surprising, is that it doesn't happen right at the beginning, just after powering the synth on, but it happens after roughly 10 seconds, and the scenario is 100% reproducible.
Yes, there's got to be something in that.
To me it's still unclear where the squarewave input is connecting in the circuit. If it's AC coupled the 10 seconds could be related to the coupling cap charging up via the transistor and shifting the point in the square-wave where the CMOS gate clocks. That would fit the scenario you see.
You really need do a deeper analysis and look at the signals with an oscilloscope, especially those around the input transistor on the mod ckt.
Putting that aside, and assuming you are just getting clock glitches you could just try adding one of those RC networks between the /Q output and D input on the first 4013 gate. If the trigger is getting stuffed up like I mentioned earlier it's not really the right solution, even if it works!
please post the circuit diagram as you have it now. sounds like a clock input going floaty, or else glitching input.
Quote from: Rob Strand on October 10, 2023, 05:20:04 AMlook at the signals with an oscilloscope
DC coupled. What rises like the tide?
Quote from: duck_arse on October 10, 2023, 09:49:21 AMplease post the circuit diagram as you have it now.
Here it is : https://www.swisstransfer.com/d/c7dde5eb-4197-41c8-90b5-77cc82ad2b57 (https://www.swisstransfer.com/d/c7dde5eb-4197-41c8-90b5-77cc82ad2b57)
(else, it can be found in the link posted above : https://www.synthxl.com/yamaha-cs-10/ (https://www.synthxl.com/yamaha-cs-10/) )
And here, just the VCO schematic, exported as a JPEG (you can find it on the PDF linked above) :
https://www.swisstransfer.com/d/71329b27-8c89-4dea-9237-1ad2d03f3862
And this is the layout i used (it's not very clean, as it was still a "work in progress for personal use" : the two red lines going to a red circle were the links I added afterwards to link pins 4 & 6 together and to ground)
(https://imgsh.net/i/0DGEfnN.png)
Quote from: duck_arse on October 10, 2023, 09:49:21 AMsounds like a clock input going floaty, or else glitching input.
I have run out of time today, hopefully I can reopen the synth tomorrow and work further on it. I wish I can fix it without too much issues :)
Are your connecting the the SQ in input of your circuit to TP4 on the Yamaha schematic? ,or are you connecting it further ahead where the 10k+1k5+68k meet. You should use TP4 as it is a clean full-swing signal. The other point is low level and could even be corrupted by very small amounts of signal feeding back from the other outputs.
It would probably be a good idea to wire the ground of your circuit to the ground side of the 1k5 resistor - ie. a ground in the vicinity of IC8 (IC8a, pin 1, 2, 3).
Quote from: duck_arse on October 10, 2023, 09:49:21 AMplease post the circuit diagram as you have it now. sounds like a clock input going floaty, or else glitching input.
(https://imgsh.net/i/0DGEfnN.png)
no, not the whole thing, I was wanting to see what you thought the circuit for this thing you built was. there is some further strangeness I can see on your board, but without your circuit, I dunno what's supposed to be and what's not.
Quote from: duck_arse on October 11, 2023, 09:05:49 AMno, not the whole thing, I was wanting to see what you thought the circuit for this thing you built was. there is some further strangeness I can see on your board, but without your circuit, I dunno what's supposed to be and what's not.
Oh, ok : I haven't drawn such a thing (and never attempted to draw a schematic :icon_redface: ) :
- I took the Yves Usson schematic, and drawn the veroboard layout.
- Then, I changed the transistor to common emitter (to fit modern CD4013);
- Then, I added the suggestions Electric Druid pointed me to from the MW thread (adding 1k and 100nF to stabilize the octave down);
- Then, I added the "pin 4 to pin 6 to ground" wires (because without it, it wasn't working at all). It isn't drawn on the veroboard layout (it was added afterwards), and I used resistor legs on my build.
I can try to draw a schematic, but it would be my first attempt (so expect even more errors than in my actual circuit, ah ah), and I will need some time to figure out how to draw such a thing :icon_redface:
well I'm'a wondering why you have IC pin 1, which is an output pin, connected to +15V in all the layouts you have shown. it looks like it is, anyway. and a proper working circuit would never connect an output pin to either supply or ground, would it?
I'm also wondering why we have all missed that to this point.
also, a circuit diagram please. then we can see if you are taking outputs from Q's and using the !Q outputs only for clocking the data pin. all this stuff seems to count when something isn't quite working.
Quote from: duck_arse on October 11, 2023, 10:16:52 AMwell I'm'a wondering why you have IC pin 1, which is an output pin, connected to +15V in all the layouts you have shown. it looks like it is, anyway. and a proper working circuit would never connect an output pin to either supply or ground, would it?
I'm also wondering why we have all missed that to this point.
You're absolutely right :icon_eek: :o :icon_redface:
This is the original schematic, drawn by Yves Usson and taken from his website :
(https://imgsh.net/i/xN5zxRP.png)
https://yusynth.net/gear/CS10_en.html
(I need to go back to work, but will go back to the troubleshooting board and drawing board later this evening)
Thank you again so much !
I made a cut in the veroboard so that the +15V doesn't go to pin1 anymore. I had good expectations, but sadly it din't improve things.
Quote from: Rob Strand on October 10, 2023, 10:31:28 PMAre your connecting the SQ input of your circuit to TP4 on the Yamaha schematic? or are you connecting it further ahead where the 10k+1k5+68k meet. You should use TP4 as it is a clean full-swing signal. The other point is low level and could even be corrupted by very small amounts of signal feeding back from the other outputs.
It's connected to IC8, pin1, so it's TP4, right?
(https://imgsh.net/i/i7OU3hp.jpg)
Quote from: Rob Strand on October 10, 2023, 10:31:28 PMIt would probably be a good idea to wire the ground of your circuit to the ground side of the 1k5 resistor - ie. a ground in the vicinity of IC8 (IC8a, pin 1, 2, 3).
Thank you for the tip, Rob.
Yes, I double-checked with a photo I took before wiring (and featuring a yellow dot where i soldered the input) and the schematic, and i wired the square input just after pin1.
(https://imgsh.net/i/zSgAhKc.png)
Quote from: duck_arse on October 11, 2023, 10:24:11 AMalso, a circuit diagram please. then we can see if you are taking outputs from Q's and using the !Q outputs only for clocking the data pin. all this stuff seems to count when something isn't quite working.
Reading that again, and comparing the 4013 datasheet pinout to my layout, and it seems that i made a mistake : I may have mixed Q and !Q, as (if I read you correctly) the 220k resistor coming from Q and going to switch 1 should go to Q (pin1), not !Q (pin2).
(but if I read the original schematic, both Qs -pin1 & 13- are unused, so I think i blindly followed the schematic)
(https://imgsh.net/i/3rNCwFY.png)
Quotewe can see if you are taking outputs from Q's and using the !Q outputs only for clocking the data pin.
On the schematic, both Qs are unused.
Audio out is coming from !Qs (pins 2 & 12)
Would you suggest another kind of wiring?
Quote from: snk on October 11, 2023, 03:49:56 PMI made a cut in the veroboard so that the +15V doesn't go to pin1 anymore. I had good expectations, but sadly it din't improve things.
It needs to go to pin 14 instead, otherwise there's no power to the chip. Previously it went through pin 1 to pin 14, which isn't right, but at least it finished up in the right place!
Hello,
While trying to spot mistakes, I am trying to figure out the best way to wire the chip, while keeping in mind what Duck_arse wrote : "we can see if you are taking outputs from Q's and using the !Q outputs only for clocking the data pin."
- The Yves Usson schematic I used (because it is designed for the Yamaha CS10), doesn't use pins 1 & 13, so Q is not used. Therefore (or from what i'm assuming), it is using !Q for both clocking the data pin and outputting audio.
Then I have searched the web to see how other sub-osc designs used the same chip (CD4013) :
- On the DIY site from Parasit Studio, !Q is also used :
https://www.parasitstudio.se/building-blog/cmos-workshop-part-3-octave-down
(https://www.parasitstudio.se/uploads/2/4/4/9/2449159/4736159_orig.png)
- On the Electric Druid site :D, his study of the venerable SH-101 shows that Q are used :
https://electricdruid.net/a-study-of-sub-oscillators/
(https://imgsh.net/i/2yXGrcE.png)
Which would be the best way to do? keep the original design to stick to the original schematic (even if we found some flaws in it), or do things "by the book", and route the outputs from Q to the audio out (while keeping !Q for clocking)?
I guess Duck_Arse was implying that the latter would be better, but since english is not my native language, i'd like to be sure :)
Quote from: ElectricDruid on October 12, 2023, 03:53:45 AMQuote from: snk on October 11, 2023, 03:49:56 PMI made a cut in the veroboard so that the +15V doesn't go to pin1 anymore. I had good expectations, but sadly it din't improve things.
It needs to go to pin 14 instead, otherwise there's no power to the chip. Previously it went through pin 1 to pin 14, which isn't right, but at least it finished up in the right place!
Mega :icon_redface:
Quote from: snk on October 12, 2023, 08:55:55 AMQuote from: ElectricDruid on October 12, 2023, 03:53:45 AMQuote from: snk on October 11, 2023, 03:49:56 PMI made a cut in the veroboard so that the +15V doesn't go to pin1 anymore. I had good expectations, but sadly it din't improve things.
It needs to go to pin 14 instead, otherwise there's no power to the chip. Previously it went through pin 1 to pin 14, which isn't right, but at least it finished up in the right place!
Mega :icon_redface:
yes, this. I thought you would have seen. so, please tell us you have added the supply volts to the supply pin.
a circuit diagram. WE ALWAYS start with a circuit diagram, then we are all talking the same language. and you must draw the diagram correctly, with electric and not mechanical details. so all your IC pin names are included on the circuit diagram, along with the pin numbers. just drawing the diagram will stop dumb problems and answer some questions.
(https://imgsh.net/i/j8pC9YF.png)
so you posted THIS, but said you had changed it around the transistor. and then someone posted this
(https://www.muffwiggler.com/forum/userpix2/16047_shapers_divider_section_1.jpg)
it was YOU! and said that was the original. allright, but what is the circuit you are building? we get confused about things, because they don't all match up.
see - the two transistor circuit takes a signal, inverts and inverts it in the schmitt [Rob et al - please correct me on that]. your original also doesn't invert the signal, but your modded version with collector connection
will invert.
alright. the flip flop clocks [does work, changes state] on the positive going edge. then Q and !Q go opposite states. !Q has to go to the data or it won't divide, but you can also use the !Q output as THE output. but the two transistor circuit doesn't, it uses the Q output.
ok. so a few things - your
from the !Q is going to be opposite level of the original
from the Q. it will clock the next stage different edge to the original [relative to the inputted signal], and the final output will also be opposite of the original. and loading a data line can sometimes play silly with cmos, depending what it connects to. so if !Q does the data and Q does the driving, the two don't mix/load/cross over/mess up.
now none of this might be making a jot of difference to the circuit, but your build isn't working, and we don't yet know why. we don't know if the circuit is correct for logic cause you haven't showed it to us yet. and we don't know if the build is wired right yet, cause THAT follows from the circuit.
it all follows from the circuit diagram. any form - pencil on paper is fine - but the circuit as you intend to build it. please.
QuoteIt's connected to IC8, pin1, so it's TP4, right?
Yes that the one.
QuoteOn the DIY site from Parasit Studio, !Q is also used :
https://www.parasitstudio.se/building-blog/cmos-workshop-part-3-octave-down
The 10k's alone are enough if the input signal truely has noise or glitches. The 10k's can help very narrow glitches from ground bound or parastic effects.
Quoteso you posted THIS, but said you had changed it around the transistor. and then someone posted this
This circuit with the 100nF caps and 2k2 (which is 10k and 22n) between D and /Q can help when the input signal has the glitches.
Quotesee - the two transistor circuit takes a signal, inverts and inverts it in the schmitt [Rob et al - please correct me on that]. your original also doesn't invert the signal, but your modded version with collector connection will invert.
Yes, the (original) buffered and Schmitt version don't invert but a single transistor switch will invert. I was thinking early on the phase isn't such a big deal for an octaver.
FYI, for the Schmitt version the resistor R60 + C5 doesn't look right to me. The diode direction D2 looks OK. I'd be thinking a resistor across the diode and the existing R60 replaced with a short.
Sort of like this, but a ground version instead of a +V version, Which would then produce a narrow positive pulse.
(https://i.stack.imgur.com/8R5ub.gif)
Another thing: From what I can see the synth outputs swing +/-. The circuit with the Schmitt-trigger is only single supply. Powering the CD4013 from +/- V will get the swing but the voltage is too high. You still need to get the clock pulse swing right and also make sure the Schmitt triggers at 0V, which it probably doesn't as is. Anyway there's some incompatibilities.
Duck, thanks for keeping this thread rolling.
well Rob, it turns out my flipping flopping has the same problem. I haven't finished building the circuit concerned: I had a cap to fix, but not the R as well.
https://www.diystompboxes.com/smfforum/index.php?msg=1257634
in my spray last night, I forgot to point out that the emitter driving the clock drives high and floats low, whereas the modding colector drives low and floats high. and the clock clocks on the high going, so that might be another of the things that might add to not working.
can't wait to hear about the proper connected +15 volts and pin 14, tho.
Quote from: duck_arse on October 13, 2023, 10:05:08 AMwell Rob, it turns out my flipping flopping has the same problem. I haven't finished building the circuit concerned: I had a cap to fix, but not the R as well.
https://www.diystompboxes.com/smfforum/index.php?msg=1257634
in my spray last night, I forgot to point out that the emitter driving the clock drives high and floats low, whereas the modding colector drives low and floats high. and the clock clocks on the high going, so that might be another of the things that might add to not working.
can't wait to hear about the proper connected +15 volts and pin 14, tho.
The cap to ground thing can work in some cases. The final 470pF is quite a high value. A resistor before the cap might allow for a smaller cap as it forms a proper glitch filter. For the circuit posted in this thread with the 100pF cap trigger circuit a cap to ground won't work since the cap to ground will kill the trigger pulse. The feedback R + C method is a little more deliberate and robust in the sense that it blocks any clock glitches for a defined interval after the initial clock pulse.
Quote from: duck_arse on October 12, 2023, 10:52:59 AMit all follows from the circuit diagram. any form - pencil on paper is fine - but the circuit as you intend to build it. please.
+1 agree. This is a really good discipline to get into. For a long while I wondered why my circuits didn't work. Then I started actually recording the changes I'd made, and it rapidly became obvious why things weren't working!
You should have a *complete* schematic of what you're doing *before* you even try to build it. And once you build it and modify it *you make sure* to notate those changes on the schematic you printed out and had on your desk while you were building. You did do that, right?!? Ok, 'course you did! How could I doubt you?!?
This kind of discipline about documenting *exactly* what you have on the breadboard in front of you is *crucial*. *Thinking you know* isn't good enough, because you're almost cetainly wrong in some detail or other. So the only way to manage it is to be absolutely rigorous about recording the circuit as you modify it so you know what you have and what you're listening to.
HTH
Quote from: ElectricDruid on October 13, 2023, 09:34:51 PM...documenting *exactly* what you have...
"An old proverb says that 'the faintest ink is more powerful than the strongest memory.'"
QuoteYou should have a *complete* schematic of what you're doing *before* you even try to build it. And once you build it and modify it *you make sure* to notate those changes on the schematic you printed out and had on your desk while you were building. You did do that, right?!? Ok, 'course you did! How could I doubt you?!?
It's also a good idea to add: a title, version numbers and dates on schematics and files.
Dates and versions is something missing from a lot of DIY'ers stuff. If someone fixes something (eg. layout or schematic) it's hard to know what is old and what is new. If you look at some threads on FSB threads the only thing holding the chronology together is the date of the post. If someone quotes an old post with an old/obsolete schematic, or attaches an old version of the schematic, it screws up the chronology. When thread gets to 20 pages it's painful to piece things together.
I pretty much write dates against all my handwritten notes and notes on the computer. It makes it a lot easier to go back to something and re-assemble all the info. Writing the aim of what you are trying to do is very useful, also a summary which rolls-up what you have worked out so far (saves deciphering 20 pages of notes).
I've learn the usefulness of stuff over time.
Hello all
Thank you for all the wise words and advices :icon_biggrin:
I was away for the weekend, but tomorrow I will go back to the drawing board and draw a schematic as advised, before drawing a veroboard layout.
I'm used to veroboards (I build them from verified layouts, and tweak a couple components to my tastes), so getting into schematics seems quite a steep learning curve, but it will obviously be a great occasion to learn and know what I am doing better :)
Hello,
I have drawn a schematic of what (I think) I want to build.
I took the Yves Usson schematic, added the 1k + 100nF cap to ground (to slow down the chip as advised), wired the transistor as common emitter (to suit modern CD4013 chips), and used the Q and !Q as advised.
As it is my first schematic drawing, it might feature some errors : I have checked it twice and twice again, but things get fuzzy pretty quickly when you're such a newbie :)
I hope it's not too ugly :icon_lol:
(https://i.postimg.cc/8j31CpKW/Yamaha-CS10-SUb-Osc-Schematic-Yann.png) (https://postimg.cc/8j31CpKW)
[sorry for the somewhat blurry picture, I had poor light conditions and could not take the photo while being perfectly in front of the paper sheet]
Quote from: duck_arse on October 12, 2023, 10:52:59 AMok. so a few things - your from the !Q is going to be opposite level of the original from the Q. it will clock the next stage different edge to the original [relative to the inputted signal], and the final output will also be opposite of the original.
This part is a bit technical, and I'm trying to get it right : when you write "opposite level", do you mean like "anti phase", which might create some PWM (taking a full, deep square wave, and converting it into a thin, nasal pulse sound)? Or is it something else?
yer diagram - on the B section, you have the slow down cap before the resistor. the resistor first against the !Q, then the cap against the D as in the A section. your level pot is at the very least odd, if not wrong. the hot signal at the pot top [CW], ground at pot bottom [CCW] and the volumed signal out from the wiper. I'm not sure the use for that extra 10k on the pot, either.
the Q or !Q is probably me overthinking things. it may not matter at all. it won't/shouldn't get all PWM, or even PMU, on you.
and yes, I now see that's the way that pot was originally. it isn't the usual way to do volume - it perhaps is providing a constant loading for mixing the two stages in the full, original circuit.
Ok, so I made a verobaord layout out of the schematic I wrote... and.. it's working :icon_mrgreen:
I am sooo happy, I just spent 15 minutes with the synth, and the sub-oscillator is adding so much to its potential!
Thank you very much to all of you, I managed to make the mod I wanted... and I learnt a lot from your input (dealing with schematics, etc). 8)
(https://i.postimg.cc/gnW5CNNw/Yamaha-CS10-Sub-Osc-v5-verified-OK.jpg) (https://postimg.cc/gnW5CNNw)
Good stuff.
For those 1k + 100n networks, 10k + 10n would be preferable for a CMOS gate. It's just a minor nitpick. In this ckt it's not a bit deal, if it works leave it.