Anybody build their Gristleizer yet, comments on it?

[Taylor]

I doubt the cap rating is causing that, but in general I like to over-spec electro caps because they can fail earlier if their rated voltage is barely above the voltages they're seeing. So 16v for 9v effects.

Any chance one of the electros is in backwards?

[brittney]

I doubt the cap rating is causing that, but in general I like to over-spec electro caps because they can fail earlier if their rated voltage is barely above the voltages they're seeing. So 16v for 9v effects.

Any chance one of the electros is in backwards?

Just checked the orientation of the electro caps around the charge pump, all are fine.
TC7660 appears to work ok on a breadboard (-9v at pin 5) but the neg drops to -2.5v when in circuit.
The chip gets hot too, so thinking theres a short somewhere, can't find anything though, the +9v appears to be ok around the circuit, its 9v at the posts is supposed to be at. The -9v is not. I'm going to replace the electros at the -9v side of the tc7660 to see if that does anything.

Any chance dodgy ICs would cause this drop in negative voltage?

[Taylor]

Getting a bad IC has been exceedingly rare for me, but I pretty much only buy them from places like Mouser. Maybe some of the stuff on ebay or aliexpress is dodgy. Since it's working on your breadboard it's probably OK.

Maybe try checking with your multimeter set to continuity and see if the -9v rail is connected to anywhere it shouldn't be.

[jdb1982]

Got mine up and running after a few years of slacking. Pretty small enclosure but it works. I noticed pulling back my guitar volume to around 8 really cleans up the sound and the thing is wonderfully gnarly wide open.

[Ben_buttons]

Yo! Finally got my Gristleizer pcbs to work without the high pithed whine. The chips that didn't seem to boost the frequency we're maxim1044 1720. I had two lots of this same chip and they both pumped out very noisy whine. Got a third lot of maxim1044 with a different 4 digit number (not 1720). Replaced the chip in two pcbs and they both work great now. here they are!


Thanks for the help!

[tangerine]

I just bought a Gristleizer kit from MusikDing and have scanned through this thread and searched the forum to see if anybody else has built the same kit but I have drawn a blank.

I have some distant experience with electronics and I have built three electric guitars but I'm stalling on this for some reason - maybe because I don't like soldering very much and some of the information seems not to match the components.

Anyway, if anybody has built a Gristleizer kit, have you any tips?

[pinkjimiphoton]

well, mine was from a 3pdt "kit" but was just the pcb.

take your time and you should be fine, it seems daunting, but its not that epic a build really.

usual caveats

read the build doc first. all of it.

start with diodes and resistors.

then caps, electros, sockets etc

be sure to socket the semidconductors so you can @#$% with 'em later

once the board is populated, fire it up and check your voltages.

if they're good, install your semis

fire it up starting with the knobs down low. if it passes no sound, be sure your knobs are oriented correctly. even old pros sometimes get pots wired backwards. if that happens, don't fret, just swap the outside connections to the errant pot.

take your time with it. there's some amazing stuff you can get out of it, but it will likely sound like shit til ya get it dialed in.

remember, everything is a compromise... try and find the best settings for the osc and filter so when ya switch between them you get the best sound.

the good news, is there's not that much to it after the soldering, you should be fine.

have fun and good luck... you got this!

believe me, if i can do it... you probably can too.

[tangerine]

Thanks for the reply and advice.

I had trawled through the thread for a photo of a completely populated board to see if I had understood everything in the documents I have, some are in German but I figured them out. I only found photo as the others seem to have suffered link rot and the one I found seemed to have at least one of the pots connected back-to-front and a different chip in one of the slots. There is nothing to say which way round they go in the slots and they seem to be reversible so that looks like an error waiting to happen.

One of the instructions said something about trimming one of the pots with an oscilloscope which I didn't have but have ordered a DS213 which I hope will suffice and I'm now using the wait for its delivery as the excuse for not starting yet - whilst gradually doing the final assembly on my latest guitar.

I haven't really worked in electronics for thirty years; I feel like I have forgotten all but the basics and back then, hardly anything I worked on (aircraft and ground radio) had an IC. I actually remember the first bit of kit to have an IC and everybody crowding around it like it was a new baby.

[pinkjimiphoton]

can ya post a copy of the schematic and pics of your board? then we can tell ya how to orient the pots hopefully.

[tangerine]

Thanks. When I get to that stage, I will.

[brittney]

Getting a bad IC has been exceedingly rare for me, but I pretty much only buy them from places like Mouser. Maybe some of the stuff on ebay or aliexpress is dodgy. Since it's working on your breadboard it's probably OK.

Maybe try checking with your multimeter set to continuity and see if the -9v rail is connected to anywhere it shouldn't be.

So I got somewhere with this this evening. The two trim pots I had in were 220R instead of 220k 
Effectively bridging the +9 and -9v

I pulled both out this evening (after burning up a TL6770) and after replacing the charge pump the negative rail is much closer to -9v.
Also, the board was drawing 0.2A until the TL6770 fried!!

So hopefully once i get the new trims in it should be ok. I'm pretty sure I've wired the pots backwards too...

[brittney]

I'm pretty sure I've wired the pots backwards too...

I don't have the board to hand, but pots are wired like this.
Does it look ok?

Cheers

[Taylor]

I'm pretty sure I've wired the pots backwards too...

I don't have the board to hand, but pots are wired like this.
Does it look ok?

Cheers

Yep, that's right.

[tangerine]

can ya post a copy of the schematic and pics of your board? then we can tell ya how to orient the pots hopefully.

I have populated the board and soldered everything and things are falling into place.

I was a bit confused by a conversation in this thread as people seemed to be discussing images which I could not see, then I realised that Ghostery was blocking about half the images. So, I'm now going back through the thread to see the photos I have missed.

[tangerine]

I have everything connected and everything looks okay - except I can't fit everything back in the enclosure!

However, I don't seem to be able to get any substantial sounds out of it apart from a clicking which naturally varies with the speed control, as does the LED. The speed only seems to have a small sweet zone - most of the range is so fast that it is a buzz and the last 10-15% is in a pulse range to the point where it is so slow it almost stops.

The level is reversed and the difference between the bypass level and the full pedal level is scary.

The depth and bias pots don't seem to do very much, I adjusted the trim pots and there was some effect but I wouldn't like to try to identify what it was.

Likewise the VCA/VCF switch but I don't readily know which position is which.

Apart from boosting the output, the audio that the pedal is creating seems to be on top of the input rather than modulating it.

The kit I got from MusikDing had a five position selector switch rather than four which I believe I have connected appropriately given that it has an extra position but given that I'm not getting any modulation, doesn't seem to do anything either.

I wasn't sure about a couple of things. The pots I received with the kit were not all exactly the same as on the board, in the kit there were 1 x A10K (speed), 1 x B10K (depth), 1 x C100K (bias) and 1 x B100K (level). The notes which came with it indicate that C100K should be used for the bias.

Also, one of the ICs supplied was not as specified, the MAX1044 seems to have been substituted with an IC identified:

7660S
CPA2
L901AAN

I don't know much about ICs but the notes say that if any other IC is used to disconnect pin 1 and I have tried it with pin 1 both connected and disconnected.

Has anybody else experienced anything which might point me in the right direction, please?

[Taylor]

Were you able to get your scope and go through the waveform trimming procedure?

Tweaking procedure:
 The shape trimpot is used to shape the triangle wave. If you have an oscilloscope, view
the waveform and tweak the trimpot until it most closely resembles a triangle wave. If you
don't have a scope, turn the speed and depth up high, and tweak the trimpot while playing
your instrument. The trimpot should be set at the point that sounds the smoothest.
 The offset trimpot sets the center of the LFO sweep. Set it so that the waveform is
centered around 0v. If you don't have a scope, set the speed to medium, the depth high,
and set the offs

Also, can you verify with a multimeter that your 7660 IC has approximately -9v at pin 5?

[tangerine]

Thank you very much for your reply.

Firstly, the voltage at pin 5 on the 7660 is +8.85v. I'm pretty sure that the input power is the correct polarity because the LEDs work.

I connected the oscilloscope and fed a sine wave signal from an app on my iPad through the Gristleizer and tried what you suggested but there was no effect from any adjustment apart from the level control which at a certain point sent the display a bit haywire. I wasn't listening to the output so I can't describe what it sounded like.

Here is a photo of the oscilloscope display. It is a DS213 and can save screen captures but it is not recognised by a Mac and I can't retrieve them so I resorted to primitive methods.

The blue trace is obviously the input and no matter what position the shape selector was set on, the output was a square wave. I think it is worth noting that the input scale is 50x the output scale; i.e. 0.5v vs 10mv. As I mentioned, no adjustments to any pot or trim pot made any difference apart from the level control.

[duck_arse]

The kit I got from MusikDing had a five position selector switch rather than four which I believe I have connected appropriately given that it has an extra position but given that I'm not getting any modulation, doesn't seem to do anything either.

might we see a photo of the switch you received?

further - power off, pull the IC1 if socketed, then measure the resistance between pins 8 and 9 as you switch the rotary switch. list results. then measure between pin 8 and the "3" lug [clockwise?] of the depth pot as you switch work. list results.

I hope I'm looking at the right circuit diagram.

[tangerine]

Thanks for your reply.

Here is a photo of the switch I received. I just noticed in the notes from MusikDing that it says the switch is DP6T, I miscounted. The BoM notes say:

Switch - 3P4T or DP6T rotary (Waveshape. Only 2 poles and 4 throws are needed)

I guess that when I have got it working, I'll put jumpers on the spare throws so that there are no dead switch positions.

I'm sorry, I only just got your revised reply. Whilst I was away taking the photo, I decided to reassemble a guitar which was sitting there so I haven't got the other answers right now, I'll go back later, but by IC1, I assume that you mean TL074 as it is the only one with >8 pins.

[pinkjimiphoton]

I have everything connected and everything looks okay - except I can't fit everything back in the enclosure!

  boy... been there. i always test first then assemble in the box. as long as your voltages to ground are copacetic at obvious test points like sockets, etc, usually you're good to go.

However, I don't seem to be able to get any substantial sounds out of it apart from a clicking which naturally varies with the speed control, as does the LED. The speed only seems to have a small sweet zone - most of the range is so fast that it is a buzz and the last 10-15% is in a pulse range to the point where it is so slow it almost stops.

good, that means your oscillator is working properly. does it work in both modes? am and fm? <"trem" or "filter"> if so, you got it.

The level is reversed and the difference between the bypass level and the full pedal level is scary.

pot is backwards, indicates the effect is working properly, it should be stupid loud when cranked.

The depth and bias pots don't seem to do very much, I adjusted the trim pots and there was some effect but I wouldn't like to try to identify what it was.

your gristleizer is working properly from your description. turn the depth and bias down to just about off. right now the effect iws set above your hearing range,m and you're probably annoying every dog in a six block radius.
you need to drop the range down lower.
odds are all your pots are backwards if the volume is.
anyways think of the depth as an ultimate wah sweep that goes so high it dissappears but you can tell its there in an annoying earwiggy kinda way. turn it dow to the opposie side of where it does that. suddenly the guitar will be unmistakeable.
turn the speed to slower while testing this shit.
now when you adjust the bias it will also change the tone and effectively work almost like a fuzz gain, both these pots need to be approached low n slow to get the "feel" for it.
once you can hear the guitar, it'll become obvious. right now the filter is likely set so high it almost dissappears completely.

Likewise the VCA/VCF switch but I don't readily know which position is which.

one will produce a wah kinda sound
thats vcf, voltage controlled filter, an envelope follower
the other will do slow throbs to pseudo ring moduation and weird electronic "harmonized" sounds... if ya get the righ rate and range going, it sweeps the filter at the right range where it modulates between "about" a minor third, and, again, "about" a fourth... so it sounds like a sus 4 chord on anything, or by adjusting a little more almost get 3rds and 7ths which is sick. if i had a workin webcam i'd get video...

anyways, i'm thinking its working, but not how you expected.
also, each waveform will need different settings to function well.
we need tom w to make a chip to compensate for this, lol...
but i think its working but ya can't tell cuzza the wiring, and i think you got confused about pinout.. really depends on how you mount your pots, board mount or flying leads etc..

Apart from boosting the output, the audio that the pedal is creating seems to be on top of the input rather than modulating it.

see above. filter is above audio range

The kit I got from MusikDing had a five position selector switch rather than four which I believe I have connected appropriately given that it has an extra position but given that I'm not getting any modulation, doesn't seem to do anything either.

should be able to set the stop on it to 4 positions if you unhdo the nut and the washer under it. uusually it has a stop in it you can move to adjust how many thows.

I wasn't sure about a couple of things. The pots I received with the kit were not all exactly the same as on the board, in the kit there were 1 x A10K (speed), 1 x B10K (depth), 1 x C100K (bias) and 1 x B100K (level). The notes which came with it indicate that C100K should be used for the bias.

thats cuz they want to take advantage of the taper of the reverse audio pot... basically a 10k audio pot "backwards" in feel that still rotates clockwise for the bias... i think i used a linear in mine. same settings in both, just easier to dial in with the reverse audio.

Also, one of the ICs supplied was not as specified, the MAX1044 seems to have been substituted with an IC identified:

7660S
CPA2
L901AAN

I don't know much about ICs but the notes say that if any other IC is used to disconnect pin 1 and I have tried it with pin 1 both connected and disconnected.

you need to connect pin 1 to pin 8 if you hear a high pitched whine. it seems to happen with a lot of charge pumps........ some this will cure.

Has anybody else experienced anything which might point me in the right direction, please?

hopefully this will help ya get it sorted a little