Anybody build their Gristleizer yet, comments on it?

[Taylor]

I doubt you've got that in wrong, the pin marked 2 in the datasheet should be in the center hole.

Since you've got a 6-position switch, it's going to have 2 setting that don't do anything. Do the other 4 work? I guess you don't have a scope, eh? If you have the ability to interface your music stuff into your computer, there are a couple of good free scope plugins like this one:

http://bram.smartelectronix.com/plugins.php?id=4

It would help to know if what you've got going is right.

[Strategy]

Taylor, I'll try that scope plugin, that's a good idea. That will be a good test for the trimmers.

I'm not sure what's up with the unused pins on my rotary switch...! Maybe I'll just break down and order one of the more familiar 3P4T, 'closed' style switches

- Strategy

[Strategy]

I'll also try to post some video this weekend of running a drone through the pedal and turning the 2P6T...

- Strategy

[Skruffyhound]

     I can't say that the trimmers on my build had the effect that Josh mentions above. They clearly have a sweet spot, as I remember, it was somewhere close to the middle of each. After tuning using the 500 Hz signal from my 50 dollar scope (beginners luck or good judgement, not sure which) I have pretty much got the ticking under control, though sadly at the expense of the indicator LED. With the LED in the circuit, well ... TICK, TICK, etc. Just waiting for a lower consumption Opamp before I go back and wrap up things. I promise to post pic's when I'm done although I may still be a while, this effect is really a keeper, so I want it to look nice, but although I'm technically OK with materials I'm not much of a graphic artist. It's taking me a while to decide on a design.
      As a reference I went back to Josh's sound clips and compared. Mine sounds very similar I think. Of course the best test would be if Josh built his and A/B tested with the old one, but I guess he has other plans for this.
     As a little aside, I have a tremulous lune on the breadboard adding some buffering and a wet/dry mix + phase shift amongst other things, anyway I found that I could get it to self oscillate in a very synthy way. After enjoying that for a little while a light bulb came on in my head and I grabbed the Gristleizer from the shelf . This effect is very cool in alot of different contexts. I felt like I had just invented electronic music.
     

[Strategy]

Build update:
I swapped out the 2p5t for a 3p4t cannibalized from a dead project. It is definitely less confusing to use this switch, there are fewer weird sounding 'unused' positions.

The triangle wave setting is pretty much not modulating the effect though. I get great square, up ramp and down ramp waves but no triangle whatsoever. I will try to check it out on a scope to see if there's a weak modulation at this setting if any, but I'm thinking there's not. If I can track down which components are responsible for the triangle wave output, I'll see if there's a mistake there: any ideas?

even without the triangle section this is a powerful sound slicing tool, really enjoying it. I want to see if I can trouble shoot that bit before I box it up, any feedback is hugely appreciated!
-strategy

EDIT: to clarify what the triangle setting sounds like, I would say that on VCA, it sounds like unmodulated signal with some very faint ticking. On filter, it sounds like a fixed wah with some very faint ticking. Its clearly going through the circuit and is gained up but, just not being modulated.

[Taylor]

And you've adjusted the trims and bias knob while listening to the triangle? It sounds to me like the bias is set wrong and the triangle is modulating outside the range that does anything. If you can scope it, it makes understanding what's up so much clearer.

But if you've got everything but triangle you're pretty close. If it's not a matter of the pot settings it would just be to do with the Rs and Cs on that switch tap.

[Strategy]

I've tweeked the trims and bias while on Triangle setting but I need to give it a little bit more rigorous/systematic test this way.

The first thing I'll probably do though is double check my resistor & cap values (and continuity) in line with the switch tap for triangle. What is the best way for figuring this out? ...use my meter to figure out the switch taps, then see what's in the path from there to the IC, right? It is tempting just to reflow solder on anything that looks sketchy, its amazing how touch ups can resolve random issues like this.

DIY has been somewhat trumped the past week and probably until the 30th as a I race to the finish line on my new album which I hope to turn in to kranky by the 30th. Building pedals makes some good procrastination though, this has taken about 3 years and, there's lots of boring stuff like editing audio at this point. Soldering trouble shooting and wiring = great procrastination!

- Strategy

[thereverend]

my futurlec order finally made it into my mailbox. hopefully i'll have this up and running by the weekend.

[svstee]

Built mine and got it running. Ran into a few problems, though. Wasn't paying attention and reveresed + and -, cooked the MAX1044. Fixed that and tried again, then noticed I forgot the diodes!

Working now, but it has a few issues:

When I put the Dpdt switch up, it changes the sound like in the clips, but it also makes it REALLY trebly. Think out of lipstick pickups + phase switch + rangemaster treble. Totally unusable.

The Level pot does nothing at all.


Could either of these be because of damage from my earlier mistakes?

[jacobyjd]

Built mine and got it running. Ran into a few problems, though. Wasn't paying attention and reveresed + and -, cooked the MAX1044. Fixed that and tried again, then noticed I forgot the diodes!

Working now, but it has a few issues:

When I put the Dpdt switch up, it changes the sound like in the clips, but it also makes it REALLY trebly. Think out of lipstick pickups + phase switch + rangemaster treble. Totally unusable.

The Level pot does nothing at all.


Could either of these be because of damage from my earlier mistakes?

I'm assuming you're referring to the VCF mode being trebly. Mine is very treble-heavy as well, but not as bad as yours sounds.

To tame some of that, I roll back the depth control on mine. With depth at minimum, it sounds like a fixed wah. I like mine about half-way.

The extra treble might be tameable with some cap changes.

[svstee]

I'll try rolling off the depth. Which caps should I be looking at? I'll probably make it/them switchable.

Any thoughts on the Level pot? Thanks!

[Taylor]

The level pot is really straightforward, just a voltage divider on the output. The only thing I can think is that you've got some bad solder joints.

You don't have both a level trimpot and a level panel pot, right? The level and bias should be either a trim or a panelmount pot, not both.

[jacobyjd]

I'll try rolling off the depth. Which caps should I be looking at? I'll probably make it/them switchable.

Any thoughts on the Level pot? Thanks!

Can't answer the cap question without some time to look at it, sorry.

However...if your level pot does nothing, there's something wrong. the circuit should have a TON of gain available.

[Skruffyhound]

You don't have both a level trimpot and a level panel pot, right? The level and bias should be either a trim or a panelmount pot, not both.

Wow, good guess Taylor. I was staring at the schem trying to imagine how it could not work whilst still letting signal through before I saw you'd answered.

I've got some low current consumption opamps now so I'll try them, and make a last attempt to save the indicator LED by changing to an ultrabright with a much higher current limiting resistor. Otherwise I'm very satisfied, tuning with a scope reduced the ticking to almost nothing after the removal of the LED, and that's without any additional caps. Dave told me he also ditched the LED, and he's using the brute force cap mentioned earlier in the thread and has no ticking. Super effect, I'm using it alot.

[Strategy]

Build report continuation for me:  SUCCESS

I had to mess around w/ the trims a lot before I "found" triangle wave.

Need to add/experiment with LFO out mod now.

wish list mod, low priority for now:
- CV input to LFO speed...possible? or expression pedal input in parallel w/ speed pot? this is above my head for now

Will be a couple weeks before I can put it in enclosure, will post pics when I do.

The pedal sounds great with stage center spring reverb after it, or big cheese before it, haven't tried it yet w/ other pedals yet or with my various keyboards.

Re: ticking, it could have been the eq setting on my mixer, but I could swear that when i did locate the trimpot sweet spot, my ticking reduced slightly. And I'm not using the tick reduction cap. This might be voodoo, I was not systematic about checking this.

- Strategy

[Taylor]

wish list mod, low priority for now:
- CV input to LFO speed...possible? or expression pedal input in parallel w/ speed pot? this is above my head for now

The Speed pot pans between GND (slowest speed, I think) and -9v. I think doing an expression pedal would involve sending -9v to the pedal, dividing it with the pot inside, and sending the divided voltage to lug 3 of the speed pot (where -9v went before). Make sure you disconnect this lug from the -9v pad. This would actually be series, not parallel, so the panel mounted pot would control the maximum range that the expression pedal could sweep through. Parallel would be like mixing any signals - could be done with a passive mixer.

CV is the same idea, you want to send a negative voltage to lug 3 of the speed pot. I can't really give any more specifics than that because I'm fairly ignorant of what kind of voltages most synth stuff is working around. I think it's usually 0-5v or -5v to 5v, so a CV going down to -9v may not be available in many systems. I guess if you're working with a modular, you can amplify a CV.

Please note that the above is for "sending you in the right direction" of research - I'd suggest you look into these ideas a bit before you try them. Just a little disclaimer so I'm not liable if you fry your board. 

[Taylor]

You don't have both a level trimpot and a level panel pot, right? The level and bias should be either a trim or a panelmount pot, not both.

Wow, good guess Taylor. I was staring at the schem trying to imagine how it could not work whilst still letting signal through before I saw you'd answered.

Looking at this again, it occurred to me that the board does not state explicitly that the level and bias should be either a trim or pot but not both. I never thought to make that clear because it was obvious to me, but it may have tripped some people up. Did anybody else not know that? We haven't heard back from SVStee, so I don't know if that's his problem, but I can't really figure out how sound could be coming out if the level pot doesn't work. Having both level pots in would surely screw things up, though.

[svstee]

No, I don't have both a level trim and pot. I thought that one was obvious too, Taylor. I didn't check the pot, there must be a fixed resistance. Thats the only way I could see it working the way it does.

Any idea what caps I should be looking at to tame treble?

[jacobyjd]

Build report continuation for me:  SUCCESS

Fantastic, man! Once calibrated, it's a really solid effect

[Strategy]

OK, so having done this to another effect recently, I would say a prime mod for this pedal is expression pedal to LFO rate. Using one of those 6-pin Neutrik stereo switching jacks. I'm out of those but will post a mod pic when i do it.

The great thing is this is a 10K pot and most expression pedals are 10K meaning you should get the full range sweep with pretty much whatever you put in there.

This is easier than implementing CV to LFO rate for sure, and gives you the ability to speed up that LFO without having to reach a hand away from your guitar to turn the knob...

- Strategy