Anybody build their Gristleizer yet, comments on it?

[Wingnut]

Here's a pic of the finnished Gristliser, mine was a musicling kit, so there's 6 positions on rotary switch I labelled them D for distortion as you get a grainy distorted signal with no modulation, I will add some diodes to one of them to give a different flavour. Thanks to Taylor for his tireless effort helping everyone out on this massive thread.

[Taylor]

Looks good! I think it was 11 years ago this month when the first run of this PCB was made. Definitely didn't expect people to still be building them all this time later.

[Ben N]

Hang on, Taylor, mine is still at the populated board stage. 

[lulu_joe13]

Taylor, Halloween this year was a cover of Bela Lugosi's Dead and I probably used your Gristleizer on every track. I think I have built 3 of yours and given them to my fave musician friends. There is nothing like it.

[Taylor]

Taylor, Halloween this year was a cover of Bela Lugosi's Dead and I probably used your Gristleizer on every track. I think I have built 3 of yours and given them to my fave musician friends. There is nothing like it.

Awesome! Obviously the main credit goes to Roy Gwinn for designing the thing way back when, and Chris Carter for popularizing it.

Hang on, Taylor, mine is still at the populated board stage. 

Oof! Well I'm sure you'll get around to it...  I have something that I'm working on still, that I originally wrote the code for in 2010. And I have an acoustic musical instrument that I bought wood for in 2007 that I still keep telling myself I'll finish some day.

[tangerine]

Is anybody still following this thread? There doesn't seem to be a more active thread on the topic of the Gristleizer so I hope nobody minds me resurrecting it.

I had to abandon my original Musikding build as it wasn't getting anywhere and it was driving me insane. I put dismantled most of it, put it in a box and forgot about it for three years.

And now, I have a bit of time and cleared my head, I thought I'd give it another go.

I took a bit of a different approach as my last attempt didn't look like I would ever get it in the box (and I still need to make a few small adjustments before I do - or I might try a bigger enclosure if I get it working) but I have rebuilt it with the pots board mounted which means that the controls are all probably back to front. It seems to be partially operational but it doesn't sound much like I expected it to. I am only getting a fuzz effect and a background beating buzz which varies with the Speed knob but only a small area of the pot's sweep is usable - the LED flicker shows that it is either a blur for half the sweep and so slow, it seems to be off altogether. But the guitar tone is not affected by the Speed control at all. The Depth and Bias knobs don't seem to do anything - I added trim pots to all the controls and have swept through all of them.

If anybody has the patience to offer some advice, I'd be grateful.

[rankot]

It's still on my todo list, so, unfortunately, I can't help.

[eh la bas ma]

I built the musikding kit. This circuit features a Bias control. It allows to adjust and to calibrate the modulation for each waveform.
I suggest to wire it to a pot instead of a trimmer.

If the Bias isn't slightly adjusted when changing the waveform's rotary switch's position, the effect will be weak or fuzzy. There is a narrow effective range on the bias pot's rotation.

If I remember correctly, there are 2 trimmers, Shape & Offset, which are also useful to calibrate the modulation, affecting the bias pot itself. It's not easy to find settings allowing a strong modulation for each waveform : some careful listening and patience are required with these trimmers.

This detail can be disturbing at first, when you discover the effect. Throbbing Gristle's musical atmosphere is even more disturbing.

[tangerine]

Yes, I have a pot on the Bias but the PCB had a space for a trimmer for each pot so I thought why not have one on each.

My last attempt, there seemed to be an issue with the waveform selector switch which never got resolved. I have completely rewired it and checked the continuity within the switch and to the board but absent any effect, it is difficult to know if it is working or even if it is the problem. I'm guessing that the two centre pins on the switch connect the selected waveform generator to the oscillator somehow and I'm 99% certain that everything is connected correctly.

Sounds like I need to have a long play with the trim pots.

Yes, I used to listen to TG in the 70s.

[eh la bas ma]

I also notice, on my build, the 2N3819 is oriented opposite to the pcb silkscreen : round side toward TL072.

[PRR]

If the Gate pin is the center leg, it can go either way.

[tangerine]

I haven't had much success tweaking the trim pots but I noticed when I had the Speed control at a point where the LED was flashing slowly enough for me to see the wave shape, no matter which position the switch was in, it was making the same sawtooth ⁄| shape but the output wasn't changing.

In summary, I'm still just getting a lot of fuzz but no oscillation on the signal.

[pinkjimiphoton]

you guys inspired me to pull mine out ...

https://www.youtube.com/watch?v=iQVVpbTP8jQ

[Taylor]

Some folks had been asking if I'd restock the Gristleizer, so I got some more in!

http://www.musicpcb.com/pcbs/gristleizer