Anybody build their Gristleizer yet, comments on it?

[eeliyx]

Could you post a picture of your PCB and wiring?

Is your MAX1044 outputting negative 9v at pin 5?

Here are the voltages of pins 1 to 8:

9.03, 5.4, 0, -3.27, -8.37, 4.36, 5.72, 9.04

Can you check with a continuity meter that the negative terminal of your power supply is connected to GND on the PCB, your enclosure, and the sleeves on your 1/4" jacks?

From what I tested, it's all connected to ground. The output jack it grounded through the case.

I contacted the seller about the pinout of the 2N3819 I was sent because I found conflicting information online.
Gonna test if the voltage at the charge pump changes when I turn up the depth next.

[eeliyx]

After some more days of testing I'm still none the wiser.
Can someone give me some keywords to research about the kind of oscillator used in this circuit and how the different waveforms are achieved?
If anything, this whole ordeal made me really want to understand Opamps in detail.

[pinkjimiphoton]

sounds like the switching to me, too... but at least for testing purposes, you need a ground on the output jack or nothing is gonna work right. even in the case, it may not be grounding the output. even tho it SHOULD ground thru the enclosure, it doesn't mean it always does. and without the ground to the output, the circuit can't possibly work right.

still thinking its working above the audio range, maybe a pot or two are oriented backwards?

[Taylor]

After some more days of testing I'm still none the wiser.
Can someone give me some keywords to research about the kind of oscillator used in this circuit and how the different waveforms are achieved?
If anything, this whole ordeal made me really want to understand Opamps in detail.

I'm not sure the right name for this kind of oscillator, but the two opamp stages on the bottom left of the schematic are the actual oscillator, and the one on the bottom right is the waveshaper that creates the different waveforms. The way the schem is drawn makes it really hard to follow what the actual waveshaper stage looks like in any one configuration. If I have time I would like to redraw that section as four separate images so we can all see more clearly how it works at each switch position.

It's also been almost 10 years since I built mine, and I don't have it anymore, so some of the details have slipped my mind!  As the Dudeist Monk above says, for now I'd recommend running a ground wire to your output jack just to be sure. If I haven't posted some new schematic images here in a few days, please feel free to bump the thread to remind me.

[eeliyx]

For anyone who wants to play around with a circuit model, I built the LFO stage in this online circuit sim.
https://falstad.com/circuit/circuitjs.html
Just save this as a txt and open it in the online applet.

[duck_arse]

the two oppie osc is a schmitt trigger/integrator type. plenty on that config hereabouts ....

[telebiker]

Just save this as a txt and open it in the online applet.

This page is no longer available. It has either expired, been removed by its creator, or removed by one of the Pastebin staff.

[telebiker]

I'm curious, has anyone faced up to the issue when the effect has hi-freq hissing noise while on? It's loud enough to be clearly hearable, however, the wet signal is louder and also very clear. And hissing increases when something exists in the input jack.

[telebiker]

I'm curious, has anyone faced up to the issue when the effect has hi-freq hissing noise while on? It's loud enough to be clearly hearable, however, the wet signal is louder and also very clear. And hissing increases when something exists in the input jack.

Can it be grounding problem?

[Chahmann]

Hi everyone, first time posting here, I recently built my Gristleizer and am having trouble with it... everything works fine except the definition of the different waveshapes and the depth (let me clear out that the depth pot works fine, but the actual depth is not that deep, on max it´s pretty mellow)... i think the rotary switch may have something to do with it, and the fact that i used an NTE451 instead of the suggested 2n3819, the pinout is different, thats fine, i managed to solder it the required orientation, BUT i noticed the current draw is 30 mA instead of 50, dont know if that affects. Also in "filter mode" it produces a very high pitched low volume hiss kind of noise,  and also noticed that the -9 volt pin on the MAX1044 outputs arund 7 volts instead of the same value of the positive... everything seems to be working except that it doesnt sound as deep as the videos ive seen... i will post a picture later tonight for you tu see... i hope i can get help here, Thanks in advance

-Chali Hahmann

[Taylor]

I would recommend using the 2n3819. Because this circuit uses the JFET in its narrow linear region rather than as a switch, the specific device characteristics do make a difference in the modulation results, so the lack of depth seems to point to that.

Regarding the high pitch noise, check that the MAX1044's pins 1 and 8 are connected to each other with a continuity meter. The chip has a frequency boost feature that sets the switching frequency above audio range, but if they're not connected it would be audible.

[Chahmann]

I would recommend using the 2n3819. Because this circuit uses the JFET in its narrow linear region rather than as a switch, the specific device characteristics do make a difference in the modulation results, so the lack of depth seems to point to that.

Regarding the high pitch noise, check that the MAX1044's pins 1 and 8 are connected to each other with a continuity meter. The chip has a frequency boost feature that sets the switching frequency above audio range, but if they're not connected it would be audible.

Thanks a lot mate, will check and probably come back for revision.... Ugh, gotta look for or order that 2n3819...as for the max1044, i hope it is what you said....aaand the rotary switch i think there´s something going on there, anyways , I´ll be back. Cheers

-Chali

[Chahmann]

as mentioned before here are the images, cant take a pic of the frontside of the board caue the leds are glued in place so they act as mounts... if you can spot any mistakes please tell, thanks in advance
-Chali

[telebiker]

What a nice enclosure.

[pinkjimiphoton]

now mine don't @#$%in work

ain't life grande? lmao

[telebiker]

I'm curious, has anyone faced up to the issue when the effect has hi-freq hissing noise while on? It's loud enough to be clearly hearable, however, the wet signal is louder and also very clear. And hissing increases when something exists in the input jack.

Regarding the high pitch noise, check that the MAX1044's pins 1 and 8 are connected to each other with a continuity meter. The chip has a frequency boost feature that sets the switching frequency above audio range, but if they're not connected it would be audible.

Checked MAX1044's pins 1 and 8 and they are connected. Just wondering, what else can cause hi-freq hissing noise?

[telebiker]

I'm curious, has anyone faced up to the issue when the effect has hi-freq hissing noise while on? It's loud enough to be clearly hearable, however, the wet signal is louder and also very clear. And hissing increases when something exists in the input jack.

Regarding the high pitch noise, check that the MAX1044's pins 1 and 8 are connected to each other with a continuity meter. The chip has a frequency boost feature that sets the switching frequency above audio range, but if they're not connected it would be audible.

Checked MAX1044's pins 1 and 8 and they are connected. Just wondering, what else can cause hi-freq hissing noise?

Hello everyone! Want to fix this issue with high pitch noise. Do you think that it's worth to change potentiometers and ICs?

[BetterOffShred]

Make sure your 1044 I'd the scpa variety. Needs the "s" or they will make high pitched whine in audio devices

[telebiker]

Make sure your 1044 I'd the scpa variety. Needs the "s" or they will make high pitched whine in audio devices

Didn't know that. Mine is cpa only. However, not sure, where to find MAX1044SCPA. Is it possible to use TC1044SCPA or ICL7660SCPA instead?

[bluebunny]

Is it possible to use TC1044SCPA or ICL7660SCPA instead?

Yes.