Anybody build their Gristleizer yet, comments on it?

[ren]

Hi Taylor & the ticking pals,
unfortunately the guys from endangered audio didn't reply to my mails. Probably they get pretty much questions like these.
Of course I will be glad, if you have an idea how to help me. 
I've read the whole thread. Removing the LED had no effect. Solder a cap to pin 4 and 11 of TL074 isn't possible, because the EA-schematic uses completely other ICs, as yours does.

[Taylor]

On the TL074, pin 4 is power and 11 is ground, so just look up the datasheet of the ICs they use and if you want to try the cap, put it across the power and ground pins of the chip, minding the proper polarity if using a polarized cap.

[Skruffyhound]

If it's ticking in bypass haven't you got a solder bridge somewhere? sounds like the tick must be getting into your ground for it to do that, just speculating (I'm not an EE)
Check out Oldschoolanalog's comments on changing the IC above, I have no ticking on mine, but of course it's not the same board.
Good Luck

[ren]

Putting a large value cap at the V+ and V- pins of the single op amps had not any influence on sound.

Endangered Audio sent me 6 (no double or quarter ICs) parts of UA741 instead of the LM741, which you can find in their assembly guide.
Maybe these op amps cause the ticking? I've read the data sheet, but I don't know, which is the significant value (consumption).

To bridge the bypass switch is some kind of difficult, because the two eyelets on the PCB are a few centimeters away from each other. Soldering a cable between them, there is the same "antenna effect" that the bypass switch caused.

Thanks a lot for helping me so quickly! 

[ren]

I will replace the UA741/LM741 (supposedly the same) with TL061 single op amps.
The bypass wires will be replaced with coaxcables (shielded).
I'll keep you posted.

[ren]

I replaced all UA741 with TL061. Ticking is a little bit more quiet, but still unacceptable.
Shielding the bypass-switch wires didn't help very much too.

[Skruffyhound]

    I'm sorry, I don't really have any good advice for you, it would seem there is a chance that some of the problem lies in the layout or your wire routing. I don't think it's really the biggest issue here, but when you used shielded wiring, did you remember to ground the shield at one end.
    Presumably the EA guys built a prototype that didn't tick, check their build info again.
    I assume you have tried all the above "fixes" simultaneously.
    Good luck

[ren]

Your advice wasn't that bad. I actually forgot grounding the shield.
Now my Bypass is absolutely clean, without any ticking or other noises.
Engaged, the LFO is still draining, but that's no problem.
I also tried the grounded circuit input true bypass schematic, but this was noisy too.

Thank you for your help! 

[Skruffyhound]

Great, glad I could help with something

[Derringer]

here's a little improv gristleizer based jam my drummer and I got into a little while back


100924 gristelizer.mp3 - 1.85MB

and if zshare is being lame for you the way it is for me atm

http://www.megaupload.com/?d=5BMVDSG0

[digi2t]

My Gristleizer is finally done. Took me a while to troubleshoot because of a bad trace on the board. Don't worry Taylor, my bad. I'm a noob at this, but it sure gets your brain box working. Wacky effect, but deadly when combined with a fuzz pedal (Tycobrahe Octavia in this case). VCF mode, along wth the Octave on, can get crazy.



Here's a look at the guts...



Don't think I'm going to paint it. Just leave it dull, and grey, and keep everyone guessing. Same for the Tyco. They'll be my twins on the board.

I also included two expession pedal jacks for depth and speed. I'm thinking about maybe MIDI'fying this sucker, but I might make another one on veroboard and experiment on that one. We'll see....

I'll post sound clips when I have some time.

[Taylor]

Looks great!

[digi2t]

Thanks Taylor. Your PCB really is the cats ass, just that I ruined one of the traces between a diode and a resistor when I was debating which diodes I would use. Luckily they were right next to each other, so a small jumper (after hours of head-thumping troubleshooting) was called for.

To tame it down for guitar use (especially when I run fuzz pedals along with it) I found that adding the "4" to the 1 & 2 equation for VCA adds a bit of high end filtering. Especially if you go to exteme bias setting, the ticking is less noticable. I added a small toggle switch for this, it switches between the stock 1,3, or the tamer 1,3,4 in VCA mode.

I also added a 22k (I think... if I remember correctly, adjust to taste!!) resistor between the wiper of the bias pot and ground. Aurally, it seems to tame down a bit more of the hiss, and shifts the region of the bias somewhat.

I found that tuning this baby on a scope is the best way to go. Hands down, bar none. This tends to align the shape / offset / bias relationship best. With the bias knob set just in the right zone in VCA mode, I can shift between any waveform now and get that wave, without having to readjust each time. When I tuned it by ear, I had to constantly tweak the bias knob every time I changed waveform. Luckily, our electrical department had a PC based scope on hand (Hantek DSO-2090), which they were nice enough to lend me. Think I'll buy one though, for around 150$ it's a great tool. I used multi-turn trimmers for the shape and offset, this allows you to really hone in on the adjustment. Surpisingly, I found the bias knob much more of a trimmer in VCA mode than anything else. It has a much wider use in VCF mode, especially when the depth is set down low. I did use the reverse log 1M pot, as you suggested in your build notes.

To isolate the jacks from ground for the expression pedals, I used special swaged fiber washers, made by Switchcraft. They have a little shoulder machined into them, thus by drilling the hole a bit larger (7/16"), the shoulder sits snug into the hole and insulates the jack from ground. You use 2, one inside, one outside. They're only 1/32" thick, so most jacks will be long enough to get the nut on. In this case, I even got the metal washer on. Digikey part number is SC1147-ND, at 0.45$ each. I used 9-pin w/DPDT stereo switching jacks, from guitarelectronics.com. 6.95$ each.

As for the IC's, I ended going with ONSemi's MC33078PGOS, and MC33079PGOS. I tried 4 different sets (TL, TLE, MC3307, and LM613 series), as an experiment, and found this set to works best sound wise. They were the second cheapest as well, just above the TL series, and about 3 to 5 times cheaper than the TLE's and LM613's. Go figure. Take it with a grain of salt, that's just my ears.

As a precaution against cross-talk I also shielded some of the input and output wires. Nothing fancy, just gutted some 4 conductor Belden cable, wraped the wires in the foil, and slipped the outer casing over the works. Didn't notice any difference to tell the truth, but since the meter was running (my boss hates it when I say that LOL)...

There you go. For someone as technically challanged as I am, I'm quite pleased with the result. I even got to fiddle with an ocilloscope for the first time ever. Even moreso with the fact that I discovered this great forum. Thanks to one and all for any info I had to dig up. In a way, you all had a hand in this build. Thanks again.

[aleister]

  I just finished a gristleizer build and after a couple problems it seems to be quite a cool pedal. This thing can go from subtle to over the top real quick.  Mine seems to have a whole lot of gain also, I really have not gone past 1 o'clock on the level pot.      Now I have a couple questions.  I assume the led is mandatory in this circuit?  I am not an led guy so I left it out and after about 3 minutes of messin with knobs I blew up the 2n3904, yup smoke, cracked case and all. So as precaution I also replaced the 2n3819, which was my last one ,with a 2n5457 and after a bit of knob messin I could see an orange glow from the bias pot when I turned it all the way down, then the smelly smoke came. So I then checked the pinout for the 5457 and saw that the gate and source were reversed. So after I replace that correctly and changed the pot it seems to be working as it should except for one thing, the led stays on even when i have the effect in true bypass. I will give it a critical eye a bit later cause I really just want to make some noise right now. I was just wondering if anyone may have experienced anything similar with their gristleizer builds?

[Taylor]

Unless you wired the LED on the board through your bypass switch, it does not turn off when the effect is bypassed - you need a second LED for bypass or you need to switch the emitter of the transistor with your switch.

It seems weird, but at the time I did this PCB design (about a year ago) I was under the impression that switching the flashing LED with the bypass switch would lead to bad ticking. So the idea at that time was that you'd use a second LED for bypass indication.

The other thing is that many people who build the Gristleizer (probably most people actually) don't build it as a pedal, and often there's no bypass at all for tabletop boxes and modular synth gear, so having an LED bypass switch would be confusing.

In hindsight I might do it differently, but it's always a compromise when designing a PCB that will be used in many different contexts/formats.

I assume the led is mandatory in this circuit?  I am not an led guy so I left it out and after about 3 minutes of messin with knobs I blew up the 2n3904, yup smoke, cracked case and all.

Hmm, no, there shouldn't be any need to put the LED in. I ran mine without the LED for some time. I'm guessing there was something else going on, but diagnosing it would take longer than loading in the LED.

[aleister]

OK, I understand now. This probably would have been crystal clear to me had I not had a torched transistor. I was under the assumption that something else had gone wrong.  When morning comes I do want to trace through the circuit in some good light and see if anything is really amiss. I am hoping that I just had a dodgy transistor and i am sure this happens from time to time, although this is a first for me. Otherwise the circuit is giving me some great sounds and I don't think I have scratched the surface yet. Thanks for the help Taylor.

[digi2t]

I personally did not mess with the board (flashing) LED myself. I did add LED's for bypass and VCF mode, but I took my power directly from the adapter, and wired these through 3PDT footswitches. I need the LED's because I've got so much shit at my feet, I need to see at a glance what's on, or not. Besides, I do a lot of rythym based stuff, and I run through an Adrenalinn 2, and a Boss Slicer, so the little flashing LED is a bit of a God send. Especially that fact that it's always flashing even when the effect is bypassed, this allows me to somewhat syncronize myself with whatever beat I've got going before I kick it in.

aleister, your units gain is about on par with mine. I put numbered knobs on mine (easier to record and recreate settings), and I don't go much past 1.5 or 2. I get the feeling that if I crank this sucka, I could play it with a 2X12 cab... direct.

Now.... can we make a tap tempo version of the Gristleizer. With MIDI. That can accept MIDI clock signals. If it's not too much to ask...

[boblob]

Just did one of these on good old vero/stripboard using a layout based on the one over at gaussmarkov, but taking the bias pot offboard. This is the one using the 5 discreet LM741s. I built this for table top use, with toggle switches for bypass and VCA/VCF modes and added a bypass indicator LED. I also took the input impedance up a fair bit using the resistor values suggested by gaussmarkov.

Works well, and is sounding like it ought to, but oscillator ticking is a problem (it bleeds through in bypass a little too on the ramp up/down settings, with the bias and levels cranked). Not sure is anyone has answered this (just read through this thread and didn't see it - appologies if it's bindun) elsewhere, but where on the schematic does the optional de-tick 10uf cap go on Taylor's schematic?

I have tidied up the wiring, which hasn't really helped and have adjusted the shape and offset trimmers as best I can (by ear and DMM - I don't have a 'scope). I've also tried placing a big electrolytic around the supply pins of IC1 and IC3, which doesnt help either. Would like to try  the de-tick cap next (if someone will kindly tell me where it goes), then sheilded wires for the in and out.

Over at gaussmarkov, Roy Gwinn (the man himself), reckons that ticking will most likely be a layout problem - specifically the location of the "integrator cap" (I think he means either the 470nF in the feedback of IC1 or the 2.2nF across IC3). Since ticking is a problem on vero, Taylor's and it seems Endangered Audio's layout I think there's other issues too.

Soundwise, the VCA is a really decent tremolo, the VCF sounds pleasantly burbly if a little harsh on the treble side. As others have mentioned - an external bias pot (rather than an onboard trimmer) is pretty much essential. There's an overall lo-fi sound that I guess is partly down to the LM741s, which I like. Not managed to get it to self oscillate (even with that big LFO tick). I'd have a lot of use for this if I can tame the pesky LFO ticking.

[boblob]

Just to add - re-read the thread and see that according to Roy, Taylor's de-click cap is supposed to be between the depth wiper and ground, providing an extra bit of filtering before the stock low-pass filtering arrangement of R15, R16, C5 and C6. Just tried this, but hasn't helped with my ticking problem.

Looking at gutshots of Chris Carter's Gristleizer, it looks like he's used shielded cable for board out to level pot (http://www.flickr.com/photos/yurisuzuki/4140697611/in/set-72157622768379175/#/photos/yurisuzuki/4140697611/in/set-72157622768379175/lightbox/). Looks promising - according to EA (and I think CC has said similar), they managed to de-tick theirs without any additional filtering - maybe this is what they are obtusely referring to, simple shielding. Something else to try, at least. Shielded cable on the depth wiper - board might also be an idea...

[boblob]

Another quick update - sheilded cable on the output seems to have had minimal impact. However, I have managed to get it to self-oscillate (yay! a first for diystompboxes Gristleizer builds?) by tweaking the offset trimmer and bias.