Anybody build their Gristleizer yet, comments on it?

[Derringer]

I've got the bias and depth cranked up, but not all the way, there are sweet spots on both knobs

at points during the clips I'm hitting an octave up before the gristleizer and delay after it

But yeah dude, I don't know if mine is 100% "right" but I dig

thanks for the kind words

and thanks for the info on the rotary

[Taylor]

Hmm, it does sound like trem and filter at the same time. I think maybe what's happening is that the LFO has a really large sweep and it's cutting between the area where it's audible and then "outside" the proper range. When it cuts outside the range of audibility it kills the signal which creates a tremolo in sync with the VCF.

That, or you built it "wrong" and it sounds better that way.  

I think it's a matter of how the LFO is set: I'm guessing that those sounds are available somewhere in the tweaking of the trimpots. I need to go mess with mine a little more. I have to confess that I haven't fired it up since the day I built it to verify the PCB. Aside from the weird sounds, which are great, I think the G-izer makes for one of the best tremolos I've ever used. That FET gives it a precise feeling of control that you don't get with an opto-based trem.

Awesome clips, Derringer!

[Skruffyhound]

But...wtf is going on with yours--it sounds like you've got BOTH VCA and VCF going on there. I'm hearing tremolo and filter going at the same time. I want that.

+1
Can you find out what you did "wrong" so we can all do it

[Derringer]

I'm very confident that all the wiring and components are correct. I really took my time with it.

play with the shape and offset trims. I really didn't do much with them. Before I plugged a guitar into it, I ran a 1Khz sine in and scoped it on the output. I tried to get a triangle wave, but couldn't so just left that pot randomly adjusted, same with the offset. Now at that time, I also didn't know where to have to rotary pot set.

so ... just play with it. Start by turning the bias up till the sound gets loud and distorted. This is pretty high up on the bias pot. Bring the level down to compensate. Then, turn up the depth pot till you can hear some 'squawk' happening. 

[Taylor]

You should be looking at the LFO waveform on the scope (tap it from the + pad of the "optional 10uf" cap), rather than the output, to see a triangle. The output isn't ever going to look like a triangle using a sine wave input.

[Derringer]

ok, this part is over my head right now

should I still send a sine wave into the circuit?

I have the optional 10uf cap installed, I should still be able to tap off the + side right?

do I need to adjust my scope from how I currently have it set (to read a 1kHz sine) to read the lfo waveform?

thanks

[Taylor]

Well, first, it could be that your mis-adjusted waveshape control is what's giving that nice sound, so it's up to you whether you feel you need to tweak it any further. If it ain't broke...

I don't know what kind of scope you're using, and I'm not experienced with anything but my cheapo digital scope. But you don't need to send a signal at all into the circuit. What you're looking at when tweaking the waveform is the LFO, which is a free-running oscillator that's going all the time, even without any signal input to the circuit. You might need to set your scope for DC coupling to see the LFO properly.

Yes, you should be able to see it even with the optional cap installed. You can see the signal at the center lug of the Depth knob as well. So that's the LFO, and that's what should look like a triangle in one of the switch positions (which one is triangle actually depends on which way you read the wiring diagram when you wired it - you can look at the switch as if it's drawn from the bottom or the top - both will work the same, just with different positions for the different waveforms).

It should look like a square wave, a ramp wave going up, a ramp wave going down, and then the last wave that isn't one of these three is supposed to look like a triangle, but it probably won't when you first look at it.

[Derringer]

I fiddled with the scope a bit with no luck, so I tried the tune-by-ear method and I think I got it. I definitely found which rotary position is affected by shape trim.

Overall sound is still pretty much the same. I'll fiddle some more with the scope tomorrow and see if I can get it that way too.

thanks

[Taylor]

If you had the scope setup to look at audio frequencies, you'll need to turn the time scale on the scope slower to see the LFO.

[Derringer]

that would probably be the "sweep time/cm" adjustment then ... cool
thx


and pics




not my neatest build, but there's nothing shorting out and the lid closes easily

[Ry]

Got mine running this weekend  .  What a beast, this is a great pedal, much more fun than I imagined it would be.  I love how dirty it can get with the bias knob tweaked.

This one will get a spot on the pedalboard!

Thanks to everyone involved!

[Strategy]

Gristleizer got a test run at band practice today. AWESOME...I used this on farfisa organ and it was REALLY complementary with keyboards. In fact, I would say some of the clipping I got on hitting guitar chords pretty loud- sort of not an issue with the organ, which is dynamics-free. Rich chords and drones sound awesome through it.

We recorded but the takes aren't in the band FTP yet, when they are I'll try to isolate a little snippet and post it here.

- Strategy

[Taylor]

Cool, I don't have my Farfisa anymore, but it's a fun and peculiar instrument. They have a very distinct sound, more rich than the goofy console organs with built-in rhythms, but still a little goofier than a Hammond. A Farfisa through the Gristleizer is a neat idea indeed. I'll be interested to hear that.

[jacobyjd]

I put an order in last week for parts for 3 of these babies--we'll see what I can come up with Working on my box layouts now.

[Strategy]

I've had my farfisa for almost 20 years (woh that makes me feel old...I'm going to be 34 this year) and it's been in almost all my bands. Pretty stoked. What's weird about Gristleizer is...The filter sounds like a PHASER. Or very phase like in character, as though it is sweeping within a similar range to some popular phasers. I can't get more scientific than that, though.

Weird observation in the ongoing testing process is that ticking seems dependent on input and output gear. I had my guitarist test the gristleizer with his Sunn/Orange 4x12 setup. The ticking was really loud. On organ and played through a Fender DeVille clean channel the ticking was totally undetectable. Really weird. I keep thinking I will add the de-ticking cap, but every other time I use the thing the ticking seems more or less apparent and I can't really nail it down.

- Strategy

Cool, I don't have my Farfisa anymore, but it's a fun and peculiar instrument. They have a very distinct sound, more rich than the goofy console organs with built-in rhythms, but still a little goofier than a Hammond. A Farfisa through the Gristleizer is a neat idea indeed. I'll be interested to hear that.

[thedefog]

I'm posting on this thread since the other one I was posting to is a little dated (dec 27th).

I built my Gristileizer using the board that jacobyjd used in his initial post. At first I was having issues with the lfo speed. It was not getting slow enough (averaged a sweep around 1/2 a second at lowest settings). I remedied this by placing a 680k resistor at the input. Now I get a very slow sweep, which sounds like the other demos I've heard.

Currently, I'm trying to remedy the excess distortion in the circuit created. I'm assuming that it is the nature of the effect, but I'm not entirely certain. I've tried different resistor values on the initial input opamp, as well as the output opamp, but due to the other values in the circuit it doesn't function properly when I change the gain factor. I don't really know enough to figure out what is necessary to lower the overall output without adversely changing the way the circuit functions. Does anyone have any thought on this one?

[jacobyjd]

This weekend I populated my Gristleizer board (this is to be build #2 of 4). Still have to solder it all together. However, I wanted to post my 1590BB layout mockup for everyone to check out.



I'll be using the right-angle pots from Futurlec, so mounting them on the side of the enclosure seems logical. The drawing isn't to scale, but I'm pretty sure everything will fit just fine. I'm hoping to put together a cool graphics layout together for this one--probably using Rick's overlay technique. I'm also considering using the extra pole of my rotary switch for LED indicators for each waveform. We'll see though.

Hopefully tonight I can solder all the board components/pots After that, I'll lay out and drill the enclosure. This one will probably get a white undercoat, then a parts retrofit, then graphics, then assembly! I'm pretty excited to get this one up and running 

After this, I'm looking at making one with some LFO mods--preferably a slow LFO to modulate the speed of the main LFO--similar to what some of the 4ms LFO add-ons do.

[thedefog]

I'm posting on this thread since the other one I was posting to is a little dated (dec 27th).

I built my Gristileizer using the board that jacobyjd used in his initial post. At first I was having issues with the lfo speed. It was not getting slow enough (averaged a sweep around 1/2 a second at lowest settings). I remedied this by placing a 680k resistor at the input. Now I get a very slow sweep, which sounds like the other demos I've heard.

Currently, I'm trying to remedy the excess distortion in the circuit created. I'm assuming that it is the nature of the effect, but I'm not entirely certain. I've tried different resistor values on the initial input opamp, as well as the output opamp, but due to the other values in the circuit it doesn't function properly when I change the gain factor. I don't really know enough to figure out what is necessary to lower the overall output without adversely changing the way the circuit functions. Does anyone have any thought on this one?

Changed R22 to 100k and that seemed to tame the input volume enough without adverse affects on the effect.

[jacobyjd]

I'm posting on this thread since the other one I was posting to is a little dated (dec 27th).

I built my Gristileizer using the board that jacobyjd used in his initial post. At first I was having issues with the lfo speed. It was not getting slow enough (averaged a sweep around 1/2 a second at lowest settings). I remedied this by placing a 680k resistor at the input. Now I get a very slow sweep, which sounds like the other demos I've heard.

Currently, I'm trying to remedy the excess distortion in the circuit created. I'm assuming that it is the nature of the effect, but I'm not entirely certain. I've tried different resistor values on the initial input opamp, as well as the output opamp, but due to the other values in the circuit it doesn't function properly when I change the gain factor. I don't really know enough to figure out what is necessary to lower the overall output without adversely changing the way the circuit functions. Does anyone have any thought on this one?

Changed R22 to 100k and that seemed to tame the input volume enough without adverse affects on the effect.

I'll give that swap a try on my current build--I was down w/ the flu for 2 days, but I should be able to finish it by the end of the week. If that fixes the distortion, then awesome   I've been thinking about putting in some sort of pre-gain control, whether it be a switch or a pot to allow me to overdrive the effect or not. I kind of like it in some situations, but not in most--it kind of takes away from anything using just a clean sound.

Anyway, here are a couple pics of my build so far--most of the drilling is done. I had to alter my original layout idea, since the input jack would've been a little too snug w/ the pots--this would work with a straight cable, but with a 90deg head, it would be a pain. The jacks are going to go side by side on the audience side of the enclosure, with the DC jack snugged directly beneath the pcb. Still a bit cumbersome, but it all fits

[1878]

I've finally got the time and parts to put this thing together next week. The Endangered Audio model has a footswitch for the VCA/VCF control. Have any of you succesful builders out there done the same ?? Is there any point ??