The (new) Gristleizer - mods?

[BluffChill]

I recently built a Gristleizer! I saw a few other threads about this but they're all now very old.
I bought the PCB from Fuzzdog - shop.pedalparts.co.uk. It's a great board. I built two actually - the first one in a stompbox, and the second one in a neat little instrument enclosure I found in a local electronics store for a couple of quid.

Pic:


Couple vids:

I love this enclosure - it was so easy to work with compared to poking around in a 1590BB. Top row knobs are speed, depth and level, bottom row are bias, shape and offset (I forget the order of the last two, might be the other way around) and the big knob is the waveform selector. Top switch switches between VCF and VCA, bottom switch is wired for true bypass. There isn't a 9v battery option yet.

I was thinking about adding a few modifications as there is a lot of space on the back panel. My ideas were LFO out (one that's quite easy to do - I think you can just take it from the centre lug of the depth pot) but also I wondered if you could easily do some sort of speed in or a trigger, to be triggered from an external synthesizer with a CV/Gate output (I have a Korg MS20). Other ideas I had were modulating the bias with the speed pot, I have no idea if this would work. I'd love some sort of patching bay at the back where you can plug things into each other like on a synth. If anyone has any ideas, I'd love to hear them!

[mightlife]

Did you get anywhere with this?
I'm interested in doing the same.
Cheers.

edit - Also, how did you get the shape and offset on there as well? Was it difficult? Sorry, I know that's subjective, but the original schematic doesn't seem to be set up for them to be accessed on the 'front panel'.

[BluffChill]

I did - managed a half decent vero build working backwards from the schematic (which seems to have disappeared from the internet...) I will post it soon. Managed to get CV control and LFO out too, which worked quite nicely.

[Ben79]

I'd be interested to see this...

I've got the board and an MS10.

[BluffChill]

OK here it is. I know it's a very messy layout but I was kind of a novice. But I can self-verify it, but it could do with a second look. I was surprised there wasn't already an existing Gristleizer layout until I tried to make one!

[The Crooked Man]

Sorry to resurrect an old post like this, but I'm wondering how to do CV mods on my Fuzzdog Gristleizer, too.  The post above doesn't have links or images, unless I'm missing something?

[PRR]

> doesn't have links or images

Use "Quote" to check for links not rendering properly. This seems to be PostImg but at its OLD .org URL. Change the .org to .cc and open in new tab. You get this:
https://postimg.cc/TKpPHzgN

[Rob Strand]

The LFO sounds like it could to do with a bit of help, either exponential or sine-ish smoothing.


For reference,

FuzzDog docs,
http://pedalparts.co.uk/docs/Gristleiser.pdf

Original article

[The Crooked Man]

Not seeing what exactly I'd have to tap to get a CV input here, though.  Am I missing something obvious?

[Rob Strand]

Not seeing what exactly I'd have to tap to get a CV input here, though.  Am I missing something obvious?

The point A on the original article is essentially LFO out/CV in.

There's some low-pass filtering before the JFET which you can mentally bundle with the LFO if you really want to. 

[ThermionicScott]

"The New Gristleizer" sounds like a long-lost Coil album.   

[The Crooked Man]

Not seeing what exactly I'd have to tap to get a CV input here, though.  Am I missing something obvious?

The point A on the original article is essentially LFO out/CV in.

I'm not seeing a point A anywhere in one these images. 

[Rob Strand]

I'm not seeing a point A anywhere in one these images. 

See,
- original article, page 560, Figure 1
- right-hand side, wiper of Depth pot VR4.  Wire is marked "A"

[antonis]

More clear now..?? 

[The Crooked Man]

I'm not seeing a point A anywhere in one these images. 

See,
- original article, page 560, Figure 1
- right-hand side, wiper of Depth pot VR4.  Wire is marked "A"

Wow. I have absolutely horrific eyes, but even so, I have no idea how I missed that.  Thank you!