Anybody build their Gristleizer yet, comments on it?

[Skruffyhound]

I finished mine this evening (bar the box - which makes four without an enclosure in the last week )

Mad little effect. I wasn't overly impressed when I fired it up, but now 5 hours later and I'm still tinkering with it, I think that says something about how many tones and nuances there are, and I haven't even started adding other effects to it.

I had to flip the LED round to get it to light up and change out the 4K7 resistor to a 1K. I've got ticking on many settings but I'm hoping that shorter wires and shielding in/output will sort that out. The extra 10uF cap had no effect on ticking and may actually have made it slightly stronger, it also had a radical effect on the tone -so there was another round of tweaking, in the end I left it off for now.

This circuit makes some great sounds but is probably not very stage friendly. Every channel change you have to re-bias, adjust guitar volume/tone, amp and effect level and maybe switch pickups to get the best out of it. Fun to tweak, but not maybe so much fun while the audience is waiting impatiently.

Don't even think about leaving the bias as a trimpot, it needs to be outside the box. I couldn't find trimpots small enough to get four side by side on this board anyway. Taylor did a great job with the PCB's beautiful to build on, but that would be my one criticism, that the trimpots could have been given a bit more space.

There is too much treble on many settings so it needs to be EQ'd to deal with that, if anyone has any good ideas where to squeeze a cap into this circuit to take a little of the top end I'd be interested in suggestions.

That's it for now, I'm happy. Thanks Taylor for the PCB's, Josh for getting the ball rolling with a great build report and of course Roy Gwinn
for designing it in the first place.

The Threads ;
http://www.diystompboxes.com/smfforum/index.php?topic=79012.0
http://www.diystompboxes.com/smfforum/index.php?topic=79078.0

[jacobyjd]

It's definitely a fun effect--I haven't built one on Taylor's board yet--too much other stuff going on.

However, for your 'too much treble' problem--I'm assuming this is on the VCF side of things--try backing off on the depth pot. I found that doing this lowered the frequency of my dry signal, so it sounded like a fixed wah, without depleting the higher frequency end of the LFO sweep.

My only complaint with the first one I built is that it can't handle much of an input signal without distorting harshly--however, there's a ton of gain on tap at the output. With this in mind, I might fiddle with the input--maybe use a fixed voltage divider or something to drop the front-end gain.

[Taylor]

I had to flip the LED round to get it to light up and change out the 4K7 resistor to a 1K. I've got ticking on many settings but I'm hoping that shorter wires and shielding in/output will sort that out. The extra 10uF cap had no effect on ticking and may actually have made it slightly stronger, it also had a radical effect on the tone -so there was another round of tweaking, in the end I left it off for now.

This circuit makes some great sounds but is probably not very stage friendly. Every channel change you have to re-bias, adjust guitar volume/tone, amp and effect level and maybe switch pickups to get the best out of it. Fun to tweak, but not maybe so much fun while the audience is waiting impatiently.

Don't even think about leaving the bias as a trimpot, it needs to be outside the box. I couldn't find trimpots small enough to get four side by side on this board anyway. Taylor did a great job with the PCB's beautiful to build on, but that would be my one criticism, that the trimpots could have been given a bit more space.

There is too much treble on many settings so it needs to be EQ'd to deal with that, if anyone has any good ideas where to squeeze a cap into this circuit to take a little of the top end I'd be interested in suggestions.

Thanks for this.

Arg you're right, the LED is labelled backwards. I will need to change it on the PDF. The LED resistor is going to be different for everybody depending on what LED you use - what color did you use?

Strange about the ticking. I didn't have much ticking to begin with, but the cap fixed what ticking there was. I saw someone mention somewhere that a smaller value would be better. Were you able to set yours up using a scope? If your ticking is really bad you might not have the LFO tweaked quite right.

Sorry about the trimpots, I thought I had made them work for different varieties but I always use these:

http://www.mouser.com/Search/ProductDetail.aspx?R=T73YB102KT20virtualkey61330000virtualkey72-T70YB-1K

and they fit with some extra room.

Let's make this the build thread; everybody can post their questions, comments, build reports and photos here.

Edit: ok, the PDF has been updated.

http://www.aronnelson.com/gallery/main.php/v/Taylor/

[Skruffyhound]

backing off on the depth pot

Thanks Josh, I'll check it out.

distorting harshly

Ha Ha, you're not kidding, that's why I'm tweaking the bias the whole time, but my gut feeling(without having looked at it too closely) is that the differences in how hot your signal is are minimal (hard strum/soft strum) its just that they are accentuated exponentially by the gain structure of the circuit, so you would have to interrupt  that somehow and when it differs with each channel that leaves you doing something similar to twiddling with the bias. You have the Mrk 1 version however, maybe there are some differences.

Let's make this the build thread; everybody can post their questions, comments, build reports and photos here

.
Good idea, I'm really interested in how it turned out for everyone else, and what mods people will figure out.

I used a green LED, ultrabright 5000MCD, about 1 lumen if I assume 30 degree beam. They are not very powerful in reality, but I thought it might be more pleasant than a really in-your-face powerful colour. Soothingly indicative.

I had my new scope on the signal, but just as a general indicator, and I tuned by ear using your instructions from the build Pdf. I think it's really clear where the sweet spots are. However, you could always pull back a bit to loose some ticking, but by doing that you lose the best of the effect. I will wait until I shield the in/out, then the switch if necessary and finally the rotary switch if I really have to, before I tame the effect down. I wired the rotary with 3 strand ribbon on a connector socket, quite fiddly, so I'm loathe to do that again, but that could be the problem.

the cap fixed what ticking there was. I saw someone mention somewhere that a smaller value would be better

OK, I'll try it out.

Sorry about the trimpots

No Problem, while I was searching my pile of old audiophile junk I found a huge stash of Alps trimpots that I hadn't seen before, so my Gristleizer has more mojo now even if they have to lean over a bit to fit in.

Thanks guys, I'm enjoying this effect a lot.
Aston

[Skruffyhound]

I am really having fun with this
Probably the most interesting pedal I've made, Clarinot cubed was good too, but I'm working on filtering for that before I'll really be happy.
Anyway, tried a bunch of different caps from pF values to 100uF, no effect on ticking but it becomes apparent that a possible mod might be to put switchable caps in this position, I'm getting a lot of different tones out of this. I need to be a bit more systematic and see if they are available elsewhere, there's easily 50 different settings on this thing.
Also a little interested to implement a dying battery pot on the whole circuit and see how that interacts with the bias. 

[svstee]

I am really having fun with this
Probably the most interesting pedal I've made, Clarinot cubed was good too, but I'm working on filtering for that before I'll really be happy.
Anyway, tried a bunch of different caps from pF values to 100uF, no effect on ticking but it becomes apparent that a possible mod might be to put switchable caps in this position, I'm getting a lot of different tones out of this. I need to be a bit more systematic and see if they are available elsewhere, there's easily 50 different settings on this thing.
Also a little interested to implement a dying battery pot on the whole circuit and see how that interacts with the bias. 

Gristle Factory anyone? 

[svstee]

Hey, I just got my board in and had  question. If you look at the image of the PCB Taylor posted in the Gristleizer PCBs for sale thread;


you can see a lot of small holes. There is one between the 47K and 470K resistors to the right of the TLO72 and one that would be under the 47K resistor left of pin 3 of the TLO72. What are these for? Sorry if there is a really obvious answer here, are they jumpers or what?

Thanks!

[Skruffyhound]

They are just junction holes for the traces, you don't need to do anything with them.

[tiges_ tendres]

Hey, I just got my board in and had  question. If you look at the image of the PCB Taylor posted in the Gristleizer PCBs for sale thread;


you can see a lot of small holes. There is one between the 47K and 470K resistors to the right of the TLO72 and one that would be under the 47K resistor left of pin 3 of the TLO72. What are these for? Sorry if there is a really obvious answer here, are they jumpers or what?

Thanks!

All they do is allow for the traces to run between the bottom and top side of the board. 

[svstee]

That's good, I was a bit worried. So I don't have to do anything with them, correct? Apologies, I'm kinda new to PCB's... Vero forever! 

[frequencycentral]

PERF forever! 

[Taylor]

So I don't have to do anything with them, correct?

Correct, as mentioned, they are just little wormholes that bridge the 2 sides of copper. Nothing goes in them.

[svstee]

PERF forever! 

Somehow I expected that, fanboy.   

[Roy]

I've got my two boards (thanks Taylor) and I plan to put one together completely standard as a reference, and then if there's anything I think could be better I'll put those mods onto the other.

Im sure this is really obvious if I just looked properly, but where is the schematic? I was looking for how exactly the MAX1044 was wired up (this doesn't feature in the original) and a pin list for the ten way connector. Also the connections marked 1234 in the top right, and where are the grounds for the input and output taken from? The optional capacitor - what does that do?

It's a very compact board. I like small.


Roy Gwinn

[jacobyjd]

Roy,

Have you checked out the PDF project file? It has a wiring diagram and full schematic--check out the first post--it's linked there

[Roy]

Thanks Josh, I've got it now.

http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=41718

That optional capacitor isn't mentioned on the schematic. Tracing, it is between the DEPTH wiper and ground, so rounding off the edges of the modulation waveform. That's what the (rather poorly designed) low pass filter R15/C5 and R16/C6 was supposed to do. I shall have a good look at this and see if I can come up with something better.

Roy

[Taylor]

Sorry about that Roy; since your boards were gratis, you didn't show up in my Paypal list of people to send the link to.

I'll have to add that cap to the schematic, you're right.

There is only one ground on the board, this follows the convention I've been using that the ground from the board, the output jack, and the power jack should all be tied to the input jack ground tab. This is start grounding, and while I'm not certain if it's really necessary for pedals, it does seem to be the common convention these days.

Looking forward to your thoughts.

[svstee]

This is start grounding,

Is that similar to making something jumberable?

Sorry, I had to...

[Taylor]

[Skruffyhound]

OK, well no real joy on the ticking front.
Small value nF and pF caps have some effect on certain settings in the optional cap spot.
Shielding Out/Input was not successful, and I don't think there is any point shielding anything else.
I've built the "fast and not so dirty sine generator" on the breadboard and set the triangle wave with my little scope. I'm getting  a small amplitude on a small screen (JYE Tech 50 dollar scope) so it's not super precise, but my big scope has blown a tiny fuse that I'm having trouble sourcing.
The single biggest improvement has been ripping the LED out completely, after trying several different substitutes.
I've checked the orientation of transistors and FET.
On a whim I changed out TLO72 for TLO62 and I think I got a slight reduction in tick, although my limited understanding of this circuit suggests that it is not logical.
I may begin to change out the rest of the IC's,transistors and Fet, but as both effect and all controls are functioning correctly it's a bit redundant.
I've spent the last four hours reading about decoupling, I'm wondering if I can get anything useful out of splitting TL074 back into two Opamps with further decoupling, but I'm a bit out of my depth here, so I would appreciate any suggestions.
It's still a useful effect with useable settings, but the tick is getting on my nerves
Love to hear about any other builds