**Gristleizer Build Report!!!** Sound clips for normal people inside!

[jacobyjd]

Well everyone, here's my much-overdue build report on the Gristelizer. I went into this project finding almost no information on exactly what the heck this thing was supposed to sound like. Obviously I had no clue what the terms VCF and VCA actually meant to my ears. Also, there are precious few sound clips/demos of it out there (here's the best one I could find: http://www.youtube.com/watch?v=37zXCmsGZFk), and there are NO non-experimental sound clips that I could find.

Hopefully this build report will give everyone who is like me a better idea of what is going on with this effect.

Summary:

The Gristleizer is a multi-LFO-shape VCF/VCA modulator. For other noobs, VCF is something like Dano's Optochopto (search it!)--it sounds like a wah with an LFO working the treadle. VCA is a tremolo. That's it and that's all.

Controls:

VCF/VCA Mode Switch--This chooses between VCA and VCF mode.

Volume--It's the volume control...if you need me to describe it, then go somewhere else

Bias--for VCA, it's basically the intensity of the effect--from weak and pathetic to clipping the opamps. For VCF, it sets the balance between bass and treble at each end of the LFO sweep. Too much bass distorts the opamps harshly. This control is meant to be a trimmer, but I'd say it's absolutely essential to have outside the box.

Depth--Depth is interesting. For VCA, it's pretty standard for a tremolo depth pot. For VCF, however, the less depth you have, the more you get the bottom end of the LFO sweep--meaning if you have depth at 0, it sounds kinda like a fixed wah you can't really adjust. It's a cool easter egg for some applications.

Speed--The slowest speed setting gives you about a 3-second LFO sweep. We're talkin' SLOW. Dime the speed pot and it's almost to fast to perceive without the Depth all the way up. HUGE speed range.

LFO Shape Switch (Ramp Up, Triangle, Ramp Down, Square)--This chooses the different LFO shapes--pretty self-explanatory...the only thing to note here is that you lose some volume on the Triangle setting, since to jank the LFO into a triangle, it loses some of its depth. This is where the bias pot comes in. If you use Triangle, bias it a little hotter. From my experience with the different shapes, the Triangle setting is the one I keep coming back to--it's the most melodic one in both the VCF and VCA modes.

First Impressions:

Can easily get wild, clips harshly if you bias it hot, can get LOUD, definitely more lo-fi settings than the average bear...erm...effect.

Build Notes:

1. there's an extra pad for the FET on the gm layout--it definitely skips a hole, so check the schematic before you cut the leads. I didn't, and I had to relocate it to the underside of the board. No biggie--I only had one of those

2. Everything on the switch wiring layout on the gm Project PDF is correct...except: you need to jump A1 and B1 together.

3. You need a separate power supply--this beast runs on +/-9v. I used the gm bipolar power supply project, based on R.G.'s schematic. Anything that'll get you +/-9v will do. I used a MAX1044 with good results. I also ignored the input jack power switching portion of the project, which is not needed if you're not using a battery.

4. The gm project uses single opamps--I'm sure this could be improved, but I'm cool with my cheapie 741s 

5. Like I mentioned before--move that Bias trimmer to an external pot

6. The other trimmers are to tune the Triangle LFO shape. Mine were pretty good in the middle--this should take minimal adjustment. Keep these as trimmers.

7. Watch your wiring--the LFO can get ticky (even w/ some bleedthrough to the bypassed signal) if you're not careful. The higher you crank the Bias control, the worse it'll get.

8. I added the LFO rate LED mentioned in the comments on the GM site--no ticking problems there--uses a separate NPN transistor to switch an LED based on the LFO. Read it carefully, then draw your schematic from the description. I messed it up the first time...

Pics:





Sound Clip:

http://www.zshare.net/audio/65463389045694e7/

Chain--Telecaster bridge pickup>Gristleizer>ART tube preamp>Audacity>VST Cab sim

Legend--
Clean Riff
Clean Chord
VCA Ramp Down Riff
VCA Ramp Up Riff
VCA Square Riff
VCA Triangle Riff
VCA Triangle Chord (adjusting from max speed downward)
VCF Ramp Down Riff
VCF Ramp Up Riff
VCF Square Riff
VCF Triangle Riff
VCF Square Chord (adjusting from max speed downward)

Special Thanks:

John Lyons did that gorgeous custom powdercoating job for me--BUY HIS ENCLOSURES. DO IT NOW!

Bluesdevil etched me the PCB--thanks a lot man!

gaussmarkov.net provided the project files for the effect and the power supply.

certain_ant--commenter on the gm project page--provided the flashing rate LED solution

Links:

gm Gristleizer Project: http://gaussmarkov.net/wordpress/circuits/gristleizer/

gm Bipolar 9v Power Supply Project: http://gaussmarkov.net/wordpress/circuits/bipolar-9v-power-supply/





I think that about covers it. Enjoy!

[rousejeremy]

Awesome. If this was Facebook, I'd give it a Like.

[loss1234]

which schematic did you use?

looks really good!!

thanks

[jacobyjd]

which schematic did you use?

looks really good!!

thanks

Check out the link to the gaussmarkov project page--you can either just get the schematic, or you can download the entire project pdf

Glad you dig it!

[frank_p]

Nice build report and nice project !

[nosamiam]

Thanks for the report! I'm working on one too. I can't listen to your clips right now but I will when I get a chance. Like you, I jumped in not really having any idea what it sounds like. I was just intrigued by the story of the last working original biting the dust.

I'm just waiting till payday to order the pots, rotary switch, and enclosure.

I have 5 pots and 1 trimmer on my version. I used gaussmarkov's schem but did my own layout. I'm in the middle of breadboarding but will probably just build it before I finish the breadboard. I hate breadboarding.

For power, I came up with this:



It's the Millenium Bypass and the charge pump. Not verified yet, but it should work.

[Brymus]

I must say its EXCELLENT.
I liked (am intrigued by)the sound of VCA down and square,and all the VCF clips except the chord,which is all just IMO,but I could see myself playing that pedal for hours with all those sounds.
BUT that pcb looks so freaky clean and pro,I thought it was fiberboard you drilled and wired underneath until I read it was etched.
I wish I could build all my stuff on PCBs like that.
The enclosure is like everything John does excellent.
Thanx for sharing -its build reports like this that make this forum so useful.

[jacobyjd]

Nice build report and nice project !

Thanks!

I must say its EXCELLENT.
I liked (am intrigued by)the sound of VCA down and square,and all the VCF clips except the chord,which is all just IMO,but I could see myself playing that pedal for hours with all those sounds.
BUT that pcb looks so freaky clean and pro,I thought it was fiberboard you drilled and wired underneath until I read it was etched.
I wish I could build all my stuff on PCBs like that.
The enclosure is like everything John does excellent.
Thanx for sharing -its build reports like this that make this forum so useful.

No problem--glad to share!

In retrospect, I probably would have been better off doing the VCF chord with the Triangle wave--it sounds much better. I was mainly just trying to exhibit the LFO speed range.

With several of the LFO settings at high speed in VCF mode, it sounds like your guitar is blowing a raspberry Kinda cool for lead stuff.

Also, one thing my sound clip doesn't illustrate is how great ALL the settings sound going into a distorted amp. Even a hot-biased VCA setting that distorts the opamps in an ugly way sounds awesome, since it acts as a booster on an LFO into your amp.

[John Lyons]

Cool! Looks good and sounds neat.
I can see how the distorted bits along
witha distorted amp or pedal will get
some great sounds.

Good work!

john

[loss1234]

i sure feel dumb for overlooking the schematic!

i thought the link was just for a pcb layout

for those interested in another way of getting +/- rails for this project,
I have been having a blast with
the DC to DC chips sold by mouser.

not super cheap but with one chip and a 5v reg (or a 5v diode)
you can drive over 10 opamps with true +/- 15 volt rails

thanks

[nosamiam]

i sure feel dumb for overlooking the schematic!

i thought the link was just for a pcb layout

for those interested in another way of getting +/- rails for this project,
I have been having a blast with
the DC to DC chips sold by mouser.

not super cheap but with one chip and a 5v reg (or a 5v diode)
you can drive over 10 opamps with true +/- 15 volt rails

thanks

What should I search for, or do you have a part #? This sounds cool!

[bluesdevil]

Finally a real build report for this goddamn thing!!! Many thanks for the superb effort, Josh.
I made my board at the same time, but still need the rotary switch and JFET. I'm actually thinking of making it a non-stomper.... maybe something to set on the amp with controls and switches on the front so I can twiddle the knobs without bending over.

[jacobyjd]

Finally a real build report for this goddamn thing!!! Many thanks for the superb effort, Josh.
I made my board at the same time, but still need the rotary switch and JFET. I'm actually thinking of making it a non-stomper.... maybe something to set on the amp with controls and switches on the front so I can twiddle the knobs without bending over.

That's not a bad idea--I know the one in the youtube video is built that way.

However, that video is a little misleading in some aspects--I thought this thing would self-oscillate. It does not--you have to have some sort of input, so take that into consideration. I could see that setup working well for some crazy feedback manipulation, or you could probably mod it pretty easily to oscillate.

I may end up hooking mine up to my cacophonator to do some cool ambient stuff, just to see what I can come up with.

[ehofherr]

  That looks and sounds awesome!  I watched that vid the other day and was intrigued. 

[nosamiam]

Finally a real build report for this goddamn thing!!! Many thanks for the superb effort, Josh.
I made my board at the same time, but still need the rotary switch and JFET. I'm actually thinking of making it a non-stomper.... maybe something to set on the amp with controls and switches on the front so I can twiddle the knobs without bending over.

That's not a bad idea--I know the one in the youtube video is built that way.

However, that video is a little misleading in some aspects--I thought this thing would self-oscillate. It does not--you have to have some sort of input, so take that into consideration. I could see that setup working well for some crazy feedback manipulation, or you could probably mod it pretty easily to oscillate.

I may end up hooking mine up to my cacophonator to do some cool ambient stuff, just to see what I can come up with.

Yep, that's what I was thinking. Put something in front of it that self-oscillates.

[Taylor]

Seems like feedback from the output of IC5 to its + input would make it oscillate, no? Add a pot to control amount of feedback...

[Dan N]

Nice. Elvis in Hawaii.

How about grabbing that bias knob and showing us Elvis at Sun.

[jacobyjd]

Nice. Elvis in Hawaii.

How about grabbing that bias knob and showing us Elvis at Sun.

Not sure what you mean by that...

[bluesdevil]

Finally a real build report for this goddamn thing!!! Many thanks for the superb effort, Josh.
I made my board at the same time, but still need the rotary switch and JFET. I'm actually thinking of making it a non-stomper.... maybe something to set on the amp with controls and switches on the front so I can twiddle the knobs without bending over.

That's not a bad idea--I know the one in the youtube video is built that way.

However, that video is a little misleading in some aspects--I thought this thing would self-oscillate. It does not--you have to have some sort of input, so take that into consideration. I could see that setup working well for some crazy feedback manipulation, or you could probably mod it pretty easily to oscillate.

I may end up hooking mine up to my cacophonator to do some cool ambient stuff, just to see what I can come up with.

Yep, that's what I was thinking. Put something in front of it that self-oscillates.

Josh misunderstood my comment. I'm going to put mine last in the effects chain and just sit it on top of my amp to make twiddling with the controls while playing easier.
   Having it self oscillate to make a self contained noise unit isn't a bad idea either, though!!

[DougH]

Sounds great! The VCF stuff reminds me of the old leslie simulator circuit, from which I think the original Phozer was based on. Psychedelic, man...