Anybody build their Gristleizer yet, comments on it?

[fegg]

hi these are the outputs from a pc scope of my gristleizer can't seem to get the triangle any better adjusting the shape trimmer
also I have no idea about the offset adjustment.
  I'm using a mono guitar lead into the pc sound card the end I'm probing the circuit with is unshielded wire to ground
and shielded to the + pad on the optional 10uf cap or centre lug of depth pot, both produce the same output,
anyone have any comments?


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[fede409]

Hello, I present my version of gristleizer, I just need to remove some tick tick, I hope it increases the value of decoupling caps. I used the PCB gaussmarkov. I thought about changing the value of BIAS pot to 500k for better control. Am I right?

I want to thank Roy Gwin for making public this great circuit and everyone on the forum.

Cheers!

Sorry for my bad English.
From South America (Argentina) Federico.

[Skruffyhound]

Nice work Federico. Control knobs are interesting.

BIAS pot to 500k

I'm too lazy to check the schem, but if the original pot was smaller than 500k then you might get the opposite effect. In some situations you can change to a smaller pot to get a longer control sweep. Try it. The other possibility is to change the taper you are using. If you check in the start of this thread I think I ended up using a rev log for bias after Dave (oldschoolanalog) suggested it.
Good Luck

[bassesofdeath]

A question regarding the use of 4 position rotary switches. Has anyone use the Mode Switch For The Q-Tron OR Stereo Polychorus from Small Bear, for a wave form selector?

[glops]

Great lookin' box for a great circuit.

[fede409]

Hello, I remove the tick placing the caps between v + and v- of the integrated circuit as discussed before, but I have to remove a whistle coming from the ICL7660, to place instead of max1040, I could not find it!!!
It happens that the 7660 is not exactly like the 1040. 7660 to create a negative voltage produces a frequency oscillations that can be heard, while the 1040 does not.
I hope my comment is useful for someone.

[gigimarga]

Hello,

I've just finished a Gristleizer and I can't find any informations about how to set the BIAS trimpot...the LFO waveforms are OK all, but the effect it's too weak...when I modify the BIAS trimpot it becames harder, but distorted...I used a 2N3819 FET.

Thank you all!

[TheVoiceOfSaturng]

I just finished my Gristleizer this evening and even got to make some noise with <a href="http://soundcloud.com/recompas/gristly-noodle">here</a>.

I'll post the guts photo shortly.  I initially had the 10uF cap that was optional installed and found that it severely changed the shape of the waveforms.  Chopping it off get me some nice waves on the scope.

I also added a CV input to the circuit.  Instead of connecting the outer leg (not the one connected to ground) of the depth pot to the board, I put a switch in that connection that allows me to switch either the internal LFO signal or and external one into the depth control.  Easy mod and very handy for modular synth nerds!

-T

[Dumpster Diver]

 HI, I'm new to this blog and also DIY circuit building. (thanks for having me on!) I'm a little stumped right now on my Gristleizer Kit I bought from Endangered Audio (Todd Kelley's design V.2)
First of all, What's up with the Smashing guitars webpage? No one is replying to my E-mail (so I can't exactly find any direct answers)  I have found the PDF diagram was a nightmare once I began to probe my board.
I can't get in contact with anyone From EA, to even ask for service (I'm a novice builder)...I think I could be pretty screwed. Right away There was an inconsistancy with C13 on the diagram, and the PCB (the polarity of the cap was one way on the board, and then the other way on the PCB)...once I began my troubleshooting, Switching it out had absolutely NO effect on the circuit...that means I'm not even accessing 75% of my PCB right?  so far I've made a few faults, The LED was backwards and also my mode switch got wired backwards in a hurry...there must be a few more things that I put in backwards in that case, but Again, the Diagram I got is next to impossible to read!!!
The point of panic for me was that I have accidentaly deleted my E-mail sent from Todd (yes, that was a full-retard move!!!) I could have SWORN there was a tiny tidbit of information from him personally that was not included in the PDF file....something perhaps like a jumper point near C12 and C11? I was left with a few extra resistors and about 2 inches of wire, maybe a few of my friends Resistors somehow got mixed into my assortment during the long-winded building session? either that OR Todd sent me a few extras by mistake? another thing worries me is that the IC's didn't come in a static bag, and some of them could be no good from the get-go.
(there are a few holes in the PCB where nothing is Labelled and it looks like I missed something totally obvious!) That being said, I will post what I can about the symptoms, and get some photos taken fo-shiz!


-J

[Dumpster Diver]

Ok, This is the best I can do verbally to explain the problems with the Gristleizer.
So, the Square wave seems to be working better than anything else , The 'speed' pot has no effect on the other 3 waveforms in either VCA or VCF (the only waveform that "flashes" is the square in VCF, and the first ramp in VCA) what's interesting is that VCA mode doesn't produce any self-oscillation. I'm getting a bit of effect in VCA but nothing sounds like that Gritty texture I know I should be getting out of it. As I've mentioned before...my C13 has been soldered both ways and produced no change whatsoever.(meaning something isn't making connection, and I'm not accessing most of my board, or I've got a bad component)

There is also something WEIRD..sometimes when I am playing with the VCA/VCF mode switch and selecting waveforms with the rotary simultaneously, the Flashing waveform will sometimes Jump from the square wave position (hard right) back to the FIRST position (hard left) and vice-versa.
when I was calibrating the shape and offset, I first noticed that my Triangle wave was totally jagged and broken as with everything BUT the square wave.
Like I said, that's all I have to go on for now, I've tried both 18VAC and 9VDC with no change.
I'm looking to speak to someone who had similar problems or perhaps built this same kit with better luck than me.
I have no URL Address, so I will have to E-mail you PHOTOS if you think you can help?

also should add; I'm more than willing to pay good $ for professional service!

Things are starting to get a little restless.
For all it's worth, the truth is hard to swallow at this point, It would have been cheaper and quicker just buyng the pre-built $375 Gristleizer. I spent a month bussing around and living hard, spent well over $400 bucks on food and transportation...I'm not licked yet though...

if you can get me going I would be forever in your debt!

-Jules

[Taylor]

Hi Jules, this thread is mainly about building the Gristleizer board available at my site, musicpcb.com. I'm not really familiar with what the guys at EA have done with their version, and they have flamed me for talking about their board so I'm not too keen on dealing with that again. I can say that their version of the circuit is not the same as mine.

I'm not even sure if they make their schematic available to people who haven't bought their kit, so you'd probably need to find some people who have worked with their kit and circuit to really give you specific help.

[Dumpster Diver]

yeah, I was looking to find someone else out there who had built The EA Kit with more success than me.

thats too bad, I guess I'm not going to be making any progress at this point, total impasse.

I just sent an E-mail to Todd Kelley, If there's a bit of luck there, I will let you know.


your board looks awesome BTW!

[PerryLevy]

Hello Taylor,

I need some help with setting the Trim pots on the SHape and Offset.  I have purchased an oscilloscope and measured using the LFO from the 10uF optional cap and I only can see the waveforms for Ramp Down and Squarewave (1st and 3rd position on my switch respectively).  The second position on my switch shows what looks like a Triangle wave but only when I turn my Depth knob all the way down.  The fourth position on my switch shows no waveform at all either with the Depth knob or Bias Knob in any position.  I have also used the scope attached to the center lug on the Depth pot and still there is no waveform.

Why can I not see the waveform on the fourth position on my switch?

I'm guessing that is suppose to be my Triangle waveform.

I have double checked all my wiring and the pedal sounds great except for the fourth position.

Thanks in advance for your help.

[Taylor]

Hi Perry, unfortunately it's been about 2 years since I built mine so I'm a little fuzzy on the details of how the scoping went. I would recommend reading the waveform from the depth pot wiper. Second, if you don't get any LFO signal in the fourth position, it's probably due to a bad solder joint around those parts or a faulty wire connecting the switch to the board. Try reflowing those joints.

[PerryLevy]

Thanks for the input Taylor.

I have checked the switch connections are correct, the solder joints are good.

Does anyone else have any input on why I can't see a waveform when in the fourth position of the switch?

Thanks!

[samE]

hello, I almost finished another gristleizer but i am having some problems. all of Wave shapes work except for the triangle, when set to triangle the sound has no shape to it with any setting, it simply sounds bypassed. I checked my wiring and it seems ok. would it be something specific that would course this fault?

any help would be amazing, as you can probably tell from my other questions, i am some what of a super noob .

thank you in advance.
sammie

[Taylor]

If everything works except one waveform, you likely have a bad solder joint somewhere in the waveshaping (lower left of the board) section, or perhaps a bad wire going to the rotary switch. Try reflowing those joints. You may also just need to adjust the trimpots a little more.

[samE]

ok, thanks ill try that.....

[Strategy]

I just modded my Gristleizer by adding vactrols to the filter depth/cutoff and lfo rate pots. Sounds awesome! A little funky, a real kludge way to implement control voltages, but very musical.

will post audio/pics maybe a diagram as soon as I get the thing all put together in the enclosure

Strategy

[Taylor]

Apparently Buchla used optocouplers for a lot of their CV stuff, so... there's a good line to tell yourself and/or anybody who remarks at the slow/imprecise CV.  You were going for that vintage Buchla organic feel.