Saxxy synth kazoo

[petey twofinger]

i am really curious about the circuit above . i ordered the parts for a tim escabedo pwm distortion . i will say i am fuzzy on how to read that schematic  , the sections on the bottom that is . what exactly would this circuit do , replace the "sho boost" that is shown above ?

let me see if i have this right , the pos 9 volts goes to the pins on the chip on the bottom section , it aslo goes to a cap then to ground .

the chip is a 4049 , any more details on it ?

the capacitor substitutions you mentioned are for the 10 cap that is right off the input .

do i have all this right ? so what exactly is the advatage , or what is it doing , thanks ES ! sorry for the noobish questions .

[joelindsey]

Thanks for posting that, earthscum! I just got a handful of 4049's and this seems perfect for the job.

i will say i am fuzzy on how to read that schematic  , the sections on the bottom that is . what exactly would this circuit do , replace the "sho boost" that is shwon above ?

what chip is that ? what exactly is the advatage , or what is it doing , thanks ES !

It's a CMOS CD4049 hex inverter. That is to say, six inverters on one chip. I could be wrong, but this appears to have three stages, U1C a 10x boost, U1B another boost with some low pass filtering, and U1A a unity gain buffer. Am I right about that Earthscum? The amount of gain depends on the ratio of the resistor on the input and the feedback resistor. So if Rinput is 100k and Rfeedback is 1M gain = Rfeedback/Rinput The section on the bottom are for the leftover inverters. I think people often tie the inputs to V+ or ground so the chip doesn't overheat or something.

[Earthscum]

It's a CMOS CD4049 hex inverter. That is to say, six inverters on one chip. I could be wrong, but this appears to have three stages, U1C a 10x boost, U1B another boost with some low pass filtering, and U1A a unity gain buffer. Am I right about that Earthscum? The amount of gain depends on the ratio of the resistor on the input and the feedback resistor. So if Rinput is 100k and Rfeedback is 1M gain = Rfeedback/Rinput The section on the bottom are for the leftover inverters. I think people often tie the inputs to V+ or ground so the chip doesn't overheat or something.

Yep, pretty much. It goes 10x gain, integrator, and a buffer. Tie unused inputs to ground or V+ so that the outputs go to high impedance, and don't have a chance to oscillate. Pretty much, you're looking at a pseudo=sine wave that is reaching as close as it can to each rail. Best to use a CD4049UBE. The cap from positive to ground should go from pin 1 to pin 7, underneath the chip (I try to put then inside the socket recess, otherwise under the board works fine... ceramic caps aren't any thicker than a lead after trimming it).

It really does a number for keeping an apparent "compression" on the signal, sustaining it longer, and cleaning up a bunch of the overtones. And, once you build it, you realize how simple it really is, especially compared to an op amp solution. I just don't like the hiss of them, but in circuits like these, that isn't much of a concern.

[tiges_ tendres]

(Edit: I guess you already knew about the Duct tape mod, but as I can't access TGP at work I had no idea it was the same thing.  Sorry)

That's one way.

Here is another! (Not my video, but sounds great!)

Signal chain:  Guitar>Mini amp>Speaker of Saxxy Synth>Headphone jack out to amp.

From the comments:

It's pretty low tech. I have a mini 9.v amp facing upwards directly into the mouthpiece/mic of the Saxxy. I put the amp in a cardboard box and then used half a roll of duct tape to hold it all together. I placed half of a small rubber pool ball around to base of the Saxxy to help funnel the sound of the amp to the mic and to help control bleed to the room sound outside. I'm plugging my guitar into the mini amp and then out via the Saxxy's headphone output to my main amp.

[petey twofinger]

sorry to resurrect this zombie thread i should prolly wait till i have more to share , but wth .

i messed with it yesterday , first trying a lil 386 amp front end , it worked ok , but it had tracking issues , big time , and when it did respond , well it was modulating or warbling a bit , like previously mentioned . luckily enough i had a cd4049ube here so i tried out Earthscums recommendation  , and it worked very nicely . the warble was gone , i could actually track a low E , albeit a bit of a delay on that open E but that seems to be par with this sort of thing . i was using my kids mini start , its so small , perfect for at the bench , position 4 with the tone rolled back seemed to work the best .

switched to " my " guitar , a fernandes with actives / sustainer , and it started misbehaving , didnt track as well the volumes weren't as consistent either . ran out of time so today , back in there and see if i can switch the cap to a 15nf or something different value to make it match up with fernando a lil better .  that might have to be a switchable mod , so it is more flexible on the input . i am guessing its the first cap , the ten nf that i will swap out . i know i saw a few times , this trick were you use a transformer on some circuits , like a fuzz face , i believe , to make the input more universal or stable ... i wonder if that is what would do the trick ?

on a lot of amps have 2 inputs , one for active pick ups , one for lo out put , whats the deal there ?

next will be trying to use the additional stages of the cd4049ube to serve as  a buff n blend so i can still get dry guitar out as well as synth .

then maybe the filter from the WSG ... its 741 based ... hmmm ( noisey ? ) . any recommendations for a " better " simple filter ?

http://electro-music.com/forum/phpbb-files/thumbs/t_741_odd_filter_849.jpg

this is really fun lil project , thanks Earthscum , you really saved the day here !! and good luck to anyone here looking to find a saxxy , highly recommended lil device to hack . try the second background track , then play " low rider " with the saxx on high ...

Earthscums recomendation :

[petey twofinger]

so today i tried a weird sound generator filter on it . i took earthscums suggestions and used the 4049 extra chanel for a blend and it worked well with a 100k pot so i could get straight tone as well as synth .

i also breadboarded a wsg filter but for some reason it just didnt sound right . the filter worked fine , i tried a few op amps and the 741 seemed to have the least distortion . the problem is that the saxxy output is to hot , i tried using the speaker output , vs the headphone output with lil success . i also changed the input resistor on the wsg filter all the way up to 25 meg . i am at a loss here . its either dull sounding or distorted . i am guessing its impedance mismatching ? i cant find a schemo for the saxxy either .

http://electro-music.com/forum/download.php?id=26622

going to have to spend more time with it . maybe try a q n d filter next ... ? but ...


any suggestions ?

[petey twofinger]

would something like this work ? i am just shooting in the dark here , so any feel free to turn the light on for me , if you would please




should i measure the impedance of the ins and outs to get an idea where i  am at ? i never did this , i do it with the units on , and just use an ohm meter  ?

i noticed on the board , a smd lm386 amp chip ? maybe i should try tapping off the input of this chip , for the input of the filter circuit ?

[petey twofinger]

made some progress , video is LOOONG !

http://www.youtube.com/watch?v=dOt5rMyLcgg&feature=youtu.be

[timd]

Sorry for hijacking this thread Petey - but I found something at the thrift store that made me think of your project. While most likely not as cool as the Saxxy, I present the Merry Okee:

While this product has an unbearable name, it could be great as a possible guitar pedal. I'm looking to get a faux steel drum sound for the guitar.