(http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth2.gif)
the schematic is from:
http://www.epanorama.rackhost.net/schematicsforfree/Audio/Musical/Circuits/Guitar%20Synthesizer.pdf (http://www.epanorama.rackhost.net/schematicsforfree/Audio/Musical/Circuits/Guitar%20Synthesizer.pdf)
and here are the data sheets for the ICs:
http://jameco.com/wcsstore/Jameco/Products/ProdDS/12597.pdf (http://jameco.com/wcsstore/Jameco/Products/ProdDS/12597.pdf)
http://jameco.com/wcsstore/Jameco/Products/ProdDS/45938.pdf (http://jameco.com/wcsstore/Jameco/Products/ProdDS/45938.pdf)
the main thing i was confused about was the power. i went by the datasheets' Vdd for the power and the Vss for the ground. i didn't put anything between the battery and the Vdds. is this correct? and more importantly, would this work? be gentle, this was my first go with layouts and the program.
Thanks!
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if it's not working, here's a link: http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth2.gif (http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth2.gif)
You might want to ground the unused inverters of the 4007.
Quote from: nelson on June 03, 2006, 09:08:23 PM
You might want to ground the unused inverters of the 4007.
inverters as in just the rest of the pins? does it need to happen to the other ic as well?
here is an update. it's a lot smaller, i grounded the unused pins of the 4007 (even though i'm not sure if that's what nelson meant), and i got it down to just 1 jumper. please give me some feedback!
(http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth4_2.gif)
http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth4.gif (http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth4_2.gif)
I think only pin 6 or 8 of the 4007 needs to be grounded. Check out this data sheet, you can see it has 3 inverters, pins 3-5, 6-8 and 9-10. http://pdf1.alldatasheet.com/datasheet-pdf/view/26835/TI/CD4007.html
wow, nice and compact! i gotta buy some chips!! guitar synth stuff is my latest focus. does it do anything? or is it totally dead...? orientation? bad cap? cold solder joint.. ? ;D you will fix it... have no fear!
Only the INPUT pins on the unused sections need to be gnded.
Never gnd the OUTPUT pins, as U are just shorting out the IC.
The rule is: ALL unused CMOS inuts must be tied Hi or Low.
Don't know bout The rest of the PLL.
T
when you complete this, please post soundclips. a dead simple guitar synth would be pretty awesome...
oh i'll be keeping an eye on THAT thread! My microsynth is almost finished but it's a hell of a big build!
Inputs are 3 6 & 10 so just looks like 6 need grounding to me.
I may try this on perf/stripboard as I have the chips .....
Perhaps worth making the 100k a pot to vary the basic frequency, may need a limiting
resistor of 10k or something ..?
MM
Quote from: MartyMart on June 05, 2006, 05:09:57 AM
Perhaps worth making the 100k a pot to vary the basic frequency, may need a limiting
resistor of 10k or something ..?
MM
yeah, i was going to add more 'control' by a basic frequency pot and a pot replacing the low pass filter's 15k resistor. i'll probably wait until this layout is verified, then i'll do that.
explain to me exactly how to add a limiting resistor on a pot. i get really confused when i try to analyze it...
I'm "guessing" values here, but from pin 11 wire a 10k resistor to lug 3 of your 100k pot
and join lug 3 to lug 2 ( variable resistor ) then lug 1 goes to ground.
If this works backwards ( sometimes happens ) then wire it as lugs 1&2 joined with
3 to ground, but version one would seem to be correct.
I'm guessing because i dont know what "zero" resistance would do to the circuit, it
may well be interesting !!
MM.
another update: grounded pin 6, moved and made layout smaller.
(http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth4_3.gif)
http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth4_3.gif (http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth4_3.gif)
thanks for that, marty. i'll work on that.
i haven't tested this at all. i don't have the chips yet, but once i get to a good layout point, i'll etch a board, get the chips, then test it. also, i hope you guys aren't expecting too much from this circuit. it's not a real synth...
yeah! I was thinking that 100k should be a pot too, that was what I had in mind...Man, thanks for the layout, I was scoping out the schematic for this the other day and thinking it looked interesting and next thing I know you've posted this layout. Cool, I ordered those IC's, I'll let you know when I get it built, looks weird aka cool...
if it sounds like a synth, it's a synth... ;D
ok i know im gonna get flack for this lol,
and as a concession i'll admit that i'm not someone who has tested the latest greates guitar synth technology available...but for me, analog "wave folders" and other weird guitar signal manglers
have an immediacy and a certain sensitivity that make them sound "better" than some REAL guitar synths i've heard... give me one "synthy" sounding effect that reacts to my playing and gives me some touch sensitivity and still posesses some of my strings envelope complexity and you can keep all those lifeless midi "note followers". i'd rather have a TONE i can use than a bad approximation of a flute or violin... however i would LOVE a GOOD violin tone, i just wonder if it's a question of trying to derive a more complex signal from a less complex one... ie. is there enough attack information in a pluck to describe all the different variations in a bow.. ? but i digress,
I hope this circuit works out, seems like in effects design -simplicity is popularity!
and this layout is very easy on the eyes, can't wait to hear it's personality! 8)
hey choklit,
Your circuit is really a "pitch follower".
4 a GuitarSynth, U need envelope triggers & filters & VCAs.
The article says "similar to a synth".
The LowPass filter gets rid of upperharmonics that would false trigger the PLL.
Then the squared-up up guitar frequency goes to the PLL input.
The PLL tries to "lock into" the input freq.
The output of the PLL, Pin 4, is a SQuare wave.
The SQwave out usually should have a buffer opamp.
So, what U will have out is a SQuare wave at the guitar frequency.
Still, an interesting soundmaker.
afn
T
i only named the layout after it's author's article. i don't think "Guitar Synth kind of" would be a good layout/effect name.
anyway, no harm done because i don't believe anyone here thinks it's a real synth.
update: added pads for two pots. i'm not sure if they will work (that is if the layout does), and if they do, they might be backwards. i pretty much guessed on the VCO pot. i guess we'll see...
(http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth5.gif)
http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth5.gif (http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth5.gif)
let me know if this looks like it won't work, because it probably won't. thanks!
can you post some soundsamples?
look interesting.
i haven't made it. i'm just in the process of the layout.
I built this last night using the most recent layout (with the ground trace added back to pin 8 of the 4046 that went missing after the first revision) and it's not working.
I think the problem lies in the 4007 which is listed as a complimentary pair plus inverter. First, the layout shows no connection to ground for Vss (pin 7). Second, I don't see how connecting a resistor across pins 3 (gates of complimentary pair) and 5 (source/drain of same pair) with no other connections to the other pins of the pair will make an amplifier. Same for pins 10 and 12 (same configuration). I think pins 2, 11 and 14 have to go to V+ and pins 4, 7 and 9 (plus pin 6) have to go to ground.
I'll give that a shot and see what happens.
Edit: okay I tried that and at least I'm getting some sound out of it now. I'm getting guitar signal out of pin 12 of the 4007, although I can't hear anything at pin 5 or pin 10. Output at pin 3/4 of the 4046 sounds kind of synthy but most positions of the frequency and VCO pots give just a sustained pitch out, not related to the input pitch of the guitar, pitch controlled by the frequency pot. VCO and frequency pots have to be all the way down to have any control of the pitch by the guitar, maybe a little bit of control with the VCO turned up somewhat. Do yourself a favour and wire up a volume pot (I used a 100k) at the output. This puppy is LOUD.
i knew it was a bad idea to post this before i was done...
i was hoping no one would try it before i did. anyway, thanks for coming back with suggestions, and i'll work on getting the thing working. if you find anything else out, please let me (and the rest of us) know. thanks!
have you tried it without the pots? 1) put a jumper connecting pads 1 and 2 of pot 2. 2) replace R4 with a 100K. 3) put a jumper connecting pads 1 and 2 of pot 1. that should get it back to the schematic in those areas. maybe you'll have more success going more toward the schematic than what i added. after we get the original circuit going, then we can add. let me know!
either way, here's an update with an added level pot and some flaws of mine fixed. it also has rick's suggestions:
(http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth6.gif)
http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth6.gif (http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth6.gif)
As Rick points out, the 4007 needs power connections: pin 14 connected to V+ and pin 7 to ground.
The schematic assumes you know how an inverter is wired up. Pin 1 needs to connect to pin 5...won't work without that connection
The unused inverter could be used for a millenium bypass. Need a pulldown on the input. Can't see the layout, but might need one on the output too.
With the 4046 they've chosen to use the first phase detector, which is a bit of an odd choice if you ask me...who knows!
Ah, now I can see the output. You need a large cap there plus a pull down resistor on the output. I'd have to check the data sheet to see what the VCO output can source but it might be an idea to use the spare inverter as a buffer (not biased as an amp, logic type buffer).
Edit. It would be better to divide down the output...or set up the spare inverter as an amp with gain a lot less than one (output is going to be a tad huge) and use it as a buffer.
PS you can run a trace under C1 to connect pin 1 to pin 5
Was I right about the extra V+ and ground connections or should V+ only be connected to pin 14 and ground to pin 7?
Sorry Rick, didn't see that bit.
QuoteI think pins 2, 11 and 14 have to go to V+ and pins 4, 7 and 9 (plus pin 6) have to go to ground.
Yes, absolutely right.
gez,
thanks for all of that info. i don't know what half of it means, but i'll learn. so, after i connect pins 1 and 5, what exactly do i have to do to make this work?
you're saying either a large cap and a pulldown resistor on the output, or divide down the output. both of these to decrease the huge output of the circuit? if this is correct, how exactly would dividing down the output be accomplished?
thanks again for the help, i'm just not as experienced as you.
Well that made some difference. I can get a reliable output from it now. I don't think the PLL is being triggered very well, I'm mostly getting squeaks and squawks but if the pots are set to give the original settings it sounds fairly synth-like, in a kind of massively overdriven, heavily compressed sort of way. I wonder if what I'm hearing is just the output of the 4007 with the PLL not actually being triggered?
Putting a volume pot on the output is the same as dividing the output down. Wire the output of the circuit to one end of a 100k pot, the other end of the pot to ground and the wiper becomes the new output.
did i do that right on the last layout? the volume pot.
on the pot, pin2 usually is the wiper.
input would be at pin1.
gnd would be pin3.
output would be pin2.
as pin 2 goes "towards pin 1", volume is increased, until pin2 = pin 1 = max volume.
Normally U would have a resistor divider to keep the level in the 1-2V range.
afn
T
thanks!
okay, here's an update. i connected pins 1 and 5 of the 4007, the level pot should work now, i changed the cap values to uFs instead of nFs, and i also made a different layout without the 2 pots i added. this should help us get this thing working, then we'll work with those. maybe this layout will work a little. thanks to everyone helping!
(http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth7.gif)
http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth7.gif (http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth7.gif)
(http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth7nomods.gif)
http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth7nomods.gif (http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth7nomods.gif)
i also deleted the past layouts so there's no confusion.
Quote from: RickL on June 08, 2006, 12:29:06 AM
Well that made some difference. I can get a reliable output from it now. I don't think the PLL is being triggered very well, I'm mostly getting squeaks and squawks but if the pots are set to give the original settings it sounds fairly synth-like, in a kind of massively overdriven, heavily compressed sort of way. I wonder if what I'm hearing is just the output of the 4007 with the PLL not actually being triggered?
No, you're hearing the output of the 4046. All this is really, is a circuit to square up your guitar signal, so it should sound very similar to a lot of comparator fuzz circuits. The difference here is that the output of the PLL will have exact 50:50 duty cycle so that might give it the edge in sounding a little more synth like.
I'm surprised they chose the first phase detector as it likes to see nice straight square waves, not manky approximations from the output of a 4007. You might get better triggering if it were wired up to use the other detector.
Quote from: choklitlove on June 08, 2006, 12:11:48 AM
you're saying either a large cap and a pulldown resistor on the output, or divide down the output. both of these to decrease the huge output of the circuit? if this is correct
You already have a pot on the output so, as Rick pointed out, that'll divide down the output. I don't follow layouts very well (only my own) so I got confused by the pin numbers on the pot (I use PCB mount, so pin order would have to be different from yours). Anyway, you need a cap on the output to block DC, followed by a pull-down resistor to avoid switching pops. You also need a pull-down on the input for the same reason. If you're not sure what I mean check out RG's switching article etc over at Geofex.
okay, thanks for the info. i read the article, and there's a lot of good info. one of the only questions i have is: how do you determine the values needed for the resistors and caps? any pointers on how to do this?
also, does this mean i need both a cap and a pulldown on both the input and output? or just both on the output and just a resistor on the input? sorry, but thanks for your help and patience with my learning.
Quote from: choklitlove on June 08, 2006, 03:58:16 AMhow do you determine the values needed for the resistors and caps? any pointers on how to do this?
The pulldown on the input is in parallel with the impedance of the input stage. To prevent loading it's best to make the resistor as large as possible. I'm pushed for time so don't want to go into the detail of it all, but there are many posts on all this by RG in the archives. Between 1M - 4M7 should do (latter would be a good choice seeing as the circuit already uses them). No need for another cap at the input as it already has one (DC is being blocked).
For the output, you don't want the pulldown resistance to be too large as a voltage large enough to cause pops might develop across the resistor (Electrolytics tend to get used and their leakage is higher than the smaller caps used for input stages). How large you make it all depends on the output impedance of the circuit. In this case there's a pot, so there's no need for a further pulldown resistor. You do need a large cap though, to block DC. between 1u - 10u should be fine. Again, best search for RG's posts on all this as he explains the whys in detail (don't have the time, sorry).
Edit:
Examples (didn't read thru but should help - search for input/output impedance if you still have questions):
http://www.diystompboxes.com/smfforum/index.php?topic=38132.msg269538#msg269538
http://www.diystompboxes.com/smfforum/index.php?topic=42049.msg303686#msg303686
http://www.diystompboxes.com/smfforum/index.php?topic=26755.msg178604#msg178604
http://www.geofex.com/Article_Folders/impednc.htm
thanks a lot gez! shit, that's a lot of information. "Having thought through this once or twice, most people sigh, and just use 1M." and that's exactly what i'll do. at least that's what i will try first.
also, "For mechanical switches, put a 100K to 4.7M (exact value does not matter) resistor from the "outboard" end of both the input and output capacitors to ground."
so i think 1M will work fine for the input. now, for the output, you said i have a pot, so that will pull that down, but i still need a cap. between 1u and 10u. i'll try 1uf at first. thanks again!
okay one quick question: i thought (for some reason), these capacitors at the input and output to block dc needed to be electrolytic. am i wrong about this? the reason i ask is that you said the existing cap i had at the input would work. thanks again!
i'll take your word for it. here's an update with the pulldowns and capacitor and all that. maybe this one will work...
(http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth8.gif)
http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth8.gif (http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth8.gif)
(http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth8nomods.gif)
http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth8nomods.gif (http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth8nomods.gif)
Cap 6 needs to be between the output (pin 4) of the 4046 and lug 1 of the pot. If an electrolytic is used, the + leg connects to pin 4 and the - leg to lug 1.
Otherwise, looks good.
since pin 3 and 4 are connected, running it from the 3rd like i did should be the same, right? if not, why?
Quote from: choklitlove on June 08, 2006, 03:46:16 PM
okay one quick question: i thought (for some reason), these capacitors at the input and output to block dc needed to be electrolytic. am i wrong about this? the reason i ask is that you said the existing cap i had at the input would work.
All caps block DC. Electrolytic caps are only used because there's nothing else that can be made that small with such high capacitance, so when you need a big cap electrolytic is all you have really. It's best to make output caps large as you have no idea what the input impedance of whatever follows is. If it's low, then a small cap is going to limit bass. Inputs with high impedance (not really the case here incidentally) don't require such large caps, so electrolytics can be avoided.
Quote from: choklitlove on June 08, 2006, 04:15:27 PM
since pin 3 and 4 are connected, running it from the 3rd like i did should be the same, right? if not, why?
No problems, do it (I just used the given pin on the schematic to keep things simple).
Sorry, I think it was ok in the first place...all these damn components obscuring traces! Hold on, I'll check again.
Maybe it's an optical illusion, but on my monitor it looks as though pin 4 is still connected to lug 1. :icon_confused:
If not, my apologies. If so, cut the link.
Quote from: gez on June 08, 2006, 04:20:06 PM
Maybe it's an optical illusion, but on my monitor it looks as though pin 4 is still connected to lug 1. :icon_confused:
If not, my apologies. If so, cut the link.
i know, it's weird. there's no trace, the cap's just shaded on the negative side, so it's hard to see. maybe i'll upload a pcb soon, but i've been avoiding it so far because the project's not done. i hope we get this thing going. thanks for all of your help!
Quote from: choklitlove on June 08, 2006, 04:25:25 PMmaybe i'll upload a pcb soon, but i've been avoiding it so far because the project's not done. i hope we get this thing going.
Good idea. I haven't really checked the layout over that thoroughly, but just glancing over it things look ok, so it should work as intended (though that might not be that great).
Man, I've been following this thread with interest, eagerly awaiting those IC's in the mail so I can try this thing, keep us posted. I'm gonna do a vero layout from your layout and the schematic. And no my expectations aren't too high, lol, but I tend to like things that sound weird...
this layout is still not verified. please don't expect it to work yet...
(http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth8pnp.gif)
http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth8pnp.gif (http://i49.photobucket.com/albums/f295/choklitlove/guitarssynth8pnp.gif)
Can't wait for it to work! my microsynth is giving me a hard time troubleshooting...
where's rick? i won't be able to get the parts until sometime next week, so i'm curious if the revisions we've made since his last post will make his work. i wish there was a store that carried those ic's. i'd have the sumbitch working by now.
rick!!!
I haven't done anything else to mine since my last post. I should try adding a cap at the output but I don't think it will make much difference. Mine doesn't have a pulldown resistor at the input but that won't effect the sound either. I'll try to get to it this weekend. What I've got so far may be as good as it gets.
I'm in the last stages of training to do a half Ironman on the July 1st weekend and my weekends tend to be filled more with sweat than solder.
Update - I added a 1uF non-polarized cap at the output and fiddled some more with it and it appears to at least somewhat work.
With no input from the guitar (i.e. guitar plugged in but not playing anything) it oscillates all by itself, pretty much random noise like you might hear when twiddling the dial on an AM radio late at night.
Single notes from the guitar mostly silence the random stuff and seem to follow the pitch of the guitar reasonably well. With the VCO and Frequency pots turned down it sounds like a square wave distortion. Turn up the Frequency and some overtones start to creep in. If you turn the Frequency pot up too high (smaller resistance) it won't trigger and you're back to random noise. Turn the VCO pot up and you get more overtones and less square wave. Turn it up too much and you're back to random noise.
It works better above about the fifth fret, especially with the pots turned up and it doesn't like chords. The only way I can imagine using it live is with a noise gate set with a fairly high threshold, or turning it on exactly when you hit a note and never stop playing until you turn it off.
I guess it sounds a bit like an analog synth, more so with the pots turned up a bit. It will never be more than a novelty but it was easy to build and you'll have the only one in town.
that sounds about right. in the article it states that if the 15K resistor at the VCO is increased, it will oscillate without any input. well, i'm glad that it works at least a little. when i build it, i'll try it without the mods, and maybe i'll get it to be a little more functional. thanks rick!
how is this coming along? any news or improvements?
i have just made a full layout and it's here: http://geocities.com/worthekik/guitarsynth.html (http://geocities.com/worthekik/guitarsynth.html)
unfortunately, it's still not verified. the ics should be here by the end of the week, then i'll get crackin first thing. i'll post here as soon as i have any news. thanks for the interest and help everyone!
Hey choklit,
200dpi dosen't give U a "size" of the picture.
Just print the layout reduced/enlarged until the ICs line up on their tenthinch (.1) centers.
afn
stayDIYing
T
Quote from: toneman on June 21, 2006, 10:51:10 PM
Hey choklit,
200dpi dosen't give U a "size" of the picture.
Just print the layout reduced/enlarged until the ICs line up on their tenthinch (.1) centers.
afn
stayDIYing
T
i realize that. i just put that because that gets you close. i also put the actual dimensions of the board so people can scale it themselves. i will eventually put the board in a pdf that's scaled.
Has anyone verified this layout yet?
I'm curious about building this for my brother for Christmas, so I thought I'd get a head start now.
yeah , while we are on a roll of verifying your layouts :)
Quote from: marmora on September 26, 2006, 06:06:48 PM
Has anyone verified this layout yet?
I'm curious about building this for my brother for Christmas, so I thought I'd get a head start now.
i will be working on this in the next couple of days, and i'll post here with results. thanks for the interest!
keep an eye on this page: http://geocities.com/worthekik/guitarsynth.html (http://geocities.com/worthekik/guitarsynth.html)
alrighty...
i have built it. there are some things that maybe someone can explain so we can make this layout work nicely for everyone.
using this layout:
http://geocities.com/worthekik/guitarsynth.html (http://geocities.com/worthekik/guitarsynth.html)
initially, there was no output. however, i found out, and i don't remember how, that if i put a 100K resistor between lug 3 of of both the VCO pot and the level pot this happens: there is a nice output, but neither pot does much of anything when turned (i realize that it is taking the signal straight to the output). however, the Frequency pot sounds awesome and does a great deal when turned. this excited me and made me think that this layout isn't dead yet. i will continue to experiment, but maybe someone can help me out quicker with some answers or suggestions. thanks to everyone!
nothin?
i'm watchin too. i want to make this one for some noisy buddies of mine.
i wish you luck. maybe this bump will help...
has anyone built this?????
Quote from: nag hammadi on October 01, 2006, 04:42:06 PM
has anyone built this?????
i have. it's just got a few problems (a couple posts up). when i use the resistor thing, it has a really cool sound. i just want to know why it does what it does when i do what i do.
i wrote a rap
awwww snap!
hippity hop and whatnot.
I've had my eye on this circuit for a while now... I was skeptical that it would work at all... seems too easy... I'm glad you got it up and running, even if it's not as expected! Does it track ok, is it musical, or is it more like a ring modulator- all dissonant and wierd?
i am dissonant and weird
Yeah, wierd = good(usually), but a pitch-to-voltage synth is priceless, especially if it actually works! Then you can get wierd in a very musically useful kind of way... especially if you can use an adaptation of this circuit to possibly output CV to an analog synth or 2...hehe
i don't have the project handy, and if i try to remember what it was like, i'll get it confused with the other project i made last night. sorry. i'll post after i play with it again.
if you're interested in the guitar synth, you might like the pulse wave here: http://geocities.com/worthekik/pulsewave.html (http://geocities.com/worthekik/pulsewave.html)
it's really easy and it sounds cool.
Hey, nice layout of the PWM! That's another one I've had my eye on... Actually I'm after bass synth, but I learned long ago that usually the difference is usually a cap or 2, maybe not even that... provided it can even track low frequencies of course...
Quote from: choklitlove on October 01, 2006, 02:20:00 AM
alrighty...
i have built it. there are some things that maybe someone can explain so we can make this layout work nicely for everyone.
using this layout:
http://geocities.com/worthekik/guitarsynth.html (http://geocities.com/worthekik/guitarsynth.html)
initially, there was no output. however, i found out, and i don't remember how, that if i put a 100K resistor between lug 3 of of both the VCO pot and the level pot this happens: there is a nice output, but neither pot does much of anything when turned (i realize that it is taking the signal straight to the output). however, the Frequency pot sounds awesome and does a great deal when turned. this excited me and made me think that this layout isn't dead yet. i will continue to experiment, but maybe someone can help me out quicker with some answers or suggestions. thanks to everyone!
still no ideas?
What exactly are you after? It sounds as though you've got it working.
If you redraw the schematic (showing this resistor between the lugs etc) it would be easy to make suggestions for improvement (I find layouts hard to follow) if that's what you're after.
Thought I'd bump this to see if any ground has been made. Just looked through my box of stuff and i've got all of the required parts... wondering if I should start ??
Thanks everyone
When you mentioned how it behaves better above the fifth fret, it made me think of octave up circuits. I wonder if a smallish(.05) cap to ground at the input (to approximate neck pickup/tone rolled down) would aid in the tracking. I recall tracking pedals that got confused by too much high frequency content, or perhaps some diodes to ground clipping to square up the signal your feeding the chip.?
these are just ideas to try, ??? sometimes you just have to try some random things and something will 'work' and then go back and try to figure out how or why. :icon_twisted: