Anybody build their Gristleizer yet, comments on it?

[Taylor]

BTW, it's not a noobish question at all (and those are fine anyway). The vast majority of guitar effects run on a single-sided supply.

I would actually be interested to know why this circuit was designed with a bipolar supply. Usually this is to increase headroom, but to my ears the Gristleizer has very low headroom - the opamps distort quite readily (though I use a bass with a built in preamp, so the output is hot). This means that, using a single 9v supply, the circuit would be even more distorted, but I don't really understand why it's like that.

The gain of the first stage is 11, which I guess is kind of a lot. Seems like maybe different values could be chosen for the resistors around IC1/1 to cut this down a bit. Just thinking out loud here...

[skweeegor]

Yeah, the fact that all the other effects I've used/built didn't require their own supplies confused me a bit. Generally I'd go with the "try it and see" method for any unknowns but that's not the best idea when power is concerned.

[kelmark]

Hi fellow builders,

I'm building up the Gristleizer from Taylor's PCB , and I'm having trouble laying my hands on the 470uf Cap from my substantial component supply and my local parts store, the only 470uf caps I can find locally is: a. dipped Tantalum (which is polarized) or b. 470uf radial Electrolytic Cap. So my question is this;  can I use either of these above caps  and if so how should I wire them in given that they are polarized, or should I keep looking for one on-line or should I wire couple 220uf ceramic cap in series and be done with it. Or am I missing something obvious here. Any advice will be appreciated

And BIG Thanks to Taylor for suppling the PCB on this wonderful project!

Kelmark

[jacobyjd]

The electrolytic is what you want--you'll have to check the schematic for the polarity--it should be noted there.

[Taylor]

Hi fellow builders,

I'm building up the Gristleizer from Taylor's PCB , and I'm having trouble laying my hands on the 470uf Cap from my substantial component supply and my local parts store, the only 470uf caps I can find locally is: a. dipped Tantalum (which is polarized) or b. 470uf radial Electrolytic Cap. So my question is this;  can I use either of these above caps  and if so how should I wire them in given that they are polarized, or should I keep looking for one on-line or should I wire couple 220uf ceramic cap in series and be done with it. Or am I missing something obvious here. Any advice will be appreciated

And BIG Thanks to Taylor for suppling the PCB on this wonderful project!

Kelmark

There aren't any 470uf caps in the G-izer. There is a 470nf, though, which is the same as .47uf. I don't like to use values with decimals on the PCBs because sometimes people don't see the period.

So what you need is a .47uf, which is more properly written as .47µf, or 470nf.

uf/µf=microfarad
nf=nanofarad
pf=picofarad

1uf/µf = 1,000 nf = 1,000,000pf.

Hope that helps!

[kelmark]

Hi fellow builders,

I'm building up the Gristleizer from Taylor's PCB , and I'm having trouble laying my hands on the 470uf Cap from my substantial component supply and my local parts store, the only 470uf caps I can find locally is: a. dipped Tantalum (which is polarized) or b. 470uf radial Electrolytic Cap. So my question is this;  can I use either of these above caps  and if so how should I wire them in given that they are polarized, or should I keep looking for one on-line or should I wire couple 220uf ceramic cap in series and be done with it. Or am I missing something obvious here. Any advice will be appreciated

And BIG Thanks to Taylor for suppling the PCB on this wonderful project!

Kelmark

There aren't any 470uf caps in the G-izer. There is a 470nf, though, which is the same as .47uf. I don't like to use values with decimals on the PCBs because sometimes people don't see the period.

So what you need is a .47uf, which is more properly written as .47µf, or 470nf.

uf/µf=microfarad
nf=nanofarad
pf=picofarad

1uf/µf = 1,000 nf = 1,000,000pf.

Hope that helps!

I'm sorry I meant the .47uf cap that is labeled  470nf on the pcb.  Is this a electrolytic? if so how is it orientated? Caps kinda screw it my head anyway... Thanks for the help!

[Taylor]

I used a boxed metal film cap, like so:

http://rocky.digikey.com/weblib/Panasonic/Web%20Photos/New%20Photos/ECQ-UV%20SERIES%2015.0H,17.5L.jpg

I generally use these for anything smaller than 1uf, electrolytics for bigger than 1uf, and ceramic for really small values like 27pf.

Definitely don't use an electrolytic there, any kind of film or ceramic cap is ok if you can't get the boxed film caps.

[Derringer]

Would running the flashing LED through the main stompswitch so that it doubles as an off/on indicator be bad procedure?

It would most likely cause a nasty pop because of the current rush right?

[jacobyjd]

Ok--I finally started to look over this board for my second Gristleizer build--I'm still a Futurlec order away from all the parts I'll need (haha), but I might as well start planning now.

Here are my build constraints:

1. I'm going to fit this into a 1590B. Yeah, you heard that right.

2. Because of condition (1), I'm going to have to work around that whole rotary switch problem by using an on-off-on dpdt for the LFO switch, omitting 1 of the LFO shapes (It'll probably be the rev. sawtooth).

That's pretty much it. Because of the board-mounted pots, I'll be able to pull this off, I'm pretty sure. I still need to check my measurements. I may also have to go with a DPDT and a buffered bypass, OR a millennium setup on a daughter board. I'll ring in with other issues as I work on the project.

[Strategy]

You *might* be able to keep your switch profile low without sacrificing an LFO waveshape setting. I couldn't see any toggles with enough poles/throws (though I think they do exist) on Mouser just doing a quick browse, but there's also slide switches. Of course this gets into 'new part' territory- figuring out pinouts, how to mount in enclosure, etc'- maybe this isn't super helpful, but something to consider...

- Strategy

EDIT: I meant to include this link...http://www.mouser.com/Electromechanical/Switches/Slide-Switches/_/N-5g2x?Keyword=3+pole+switch&FS=True

Just a selection of slide switches...

Ok--I finally started to look over this board for my second Gristleizer build--I'm still a Futurlec order away from all the parts I'll need (haha), but I might as well start planning now.

Here are my build constraints:

1. I'm going to fit this into a 1590B. Yeah, you heard that right.

2. Because of condition (1), I'm going to have to work around that whole rotary switch problem by using an on-off-on dpdt for the LFO switch, omitting 1 of the LFO shapes (It'll probably be the rev. sawtooth).

That's pretty much it. Because of the board-mounted pots, I'll be able to pull this off, I'm pretty sure. I still need to check my measurements. I may also have to go with a DPDT and a buffered bypass, OR a millennium setup on a daughter board. I'll ring in with other issues as I work on the project.

[Strategy]

A followup to my LFO output mod: I can see what is happening with the LFO output. When a cable is inserted into the LFO output the LFO is not injecting as much voltage into the circuit. Effectively bringing it to the front panel means sacrificing LFO depth of the LFO signal.

If anyone can suggest a way to possibly prevent/circumvent this, that is great- my understanding of electronics is probably too elementary to brainstorm a way around this issue...

- Strategy

[Taylor]

A followup to my LFO output mod: I can see what is happening with the LFO output. When a cable is inserted into the LFO output the LFO is not injecting as much voltage into the circuit. Effectively bringing it to the front panel means sacrificing LFO depth of the LFO signal.

If anyone can suggest a way to possibly prevent/circumvent this, that is great- my understanding of electronics is probably too elementary to brainstorm a way around this issue...

- Strategy

You could add another dual opamp to buffer and amplify the LFO signal. Try non-inverting opamp amplifiers:

http://www.play-hookey.com/analog/non-inverting_amplifier.html

Here you can calculate the gain you need:

http://tangentsoft.net/audio/calc.html

Or you can make the 2 resistors the 2 sides of a pot and you can have variable gain.

[Strategy]

thanks Taylor, I suspected I'd have to add a buffering feature like this- a good experiment!
- STrategy

[Taylor]

Would running the flashing LED through the main stompswitch so that it doubles as an off/on indicator be bad procedure?

It would most likely cause a nasty pop because of the current rush right?

This would be a good idea. I think I mentioned it in the other thread. I don't really think there would be a pop, at least no more than the usual LED switching arrangement.

Ok--I finally started to look over this board for my second Gristleizer build--I'm still a Futurlec order away from all the parts I'll need (haha), but I might as well start planning now.

Here are my build constraints:

1. I'm going to fit this into a 1590B. Yeah, you heard that right.

2. Because of condition (1), I'm going to have to work around that whole rotary switch problem by using an on-off-on dpdt for the LFO switch, omitting 1 of the LFO shapes (It'll probably be the rev. sawtooth).

That's pretty much it. Because of the board-mounted pots, I'll be able to pull this off, I'm pretty sure. I still need to check my measurements. I may also have to go with a DPDT and a buffered bypass, OR a millennium setup on a daughter board. I'll ring in with other issues as I work on the project.

Josh, I don't know if you've considered this, but there are some very low profile rotary switches that are meant to be surface mounted. They have very thin bodies, and I think they're available in 3P4T. If that interests you I can bust out the Mouser catalog and give you some part numbers. The only thing is that they often don't have mounting hardware, since they're not meant for panel mounting, so you'd have to epoxy it to the case.

[jacobyjd]

Thanks for the suggestion, Taylor--I'm going to stick with either the toggle or slide idea--I don't really use all the wave shapes anyway. If I have to scale back to 2 (Square and Triangle), then I can live with that. I'd really like to fiddle with an on-off-on wiring scheme to squeeze 3 out of it though--I'll see what I can come up with

I'm still planning on building a 3rd that has all the features and more in a few months

[Taylor]

I can't seem to make it work...well, it's still a kick ass pedal! If anyone comes up with a replicable scheme for exp pedal input using a 'known quantity' pedal like the Moog, and can sketch a quick diagram of it, I'll try again later. Now to try the LFO out mod!

- Strategy

This should work.

[Strategy]

I'll try it soon Taylor, thanks a million!

the oval shaped end of the switching jack in your drawing represents the insert end of the jack, correct?

Now off to order some more switching jacks and pick up a Moog expression pedal!

- Strategy

[Taylor]

the oval shaped end of the switching jack in your drawing represents the insert end of the jack, correct?

- Strategy

Yep.

[Derringer]

some clips of my first start-up

http://www.zshare.net/audio/72611071428208bc/

http://www.zshare.net/audio/72611110edfa8704/

It fired right up for me. There's some tic, even when bypassed, but not enough to irritate me. I play noisy rock music anyway so a little sputter is no big deal.

I put it on the scope and had trouble making a triangle wave.
What selection should I have the rotary switch on for the triangle? Yeah I know ... put it on the triangle selection ... but  which selection is that?

As a tremolo this thing is sick, and a flip of the vca/vcf switch sends the sounds into orbit!

I'll post some pics as soon as I figure out how to get my laptop to upload them ... it's balking everywhere, gmail, photobucket, imageshack etc ... just flat out refuses to upload.

[jacobyjd]

some clips of my first start-up

http://www.zshare.net/audio/72611071428208bc/

http://www.zshare.net/audio/72611110edfa8704/

It fired right up for me. There's some tic, even when bypassed, but not enough to irritate me. I play noisy rock music anyway so a little sputter is no big deal.

I put it on the scope and had trouble making a triangle wave.
What selection should I have the rotary switch on for the triangle? Yeah I know ... put it on the triangle selection ... but  which selection is that?

As a tremolo this thing is sick, and a flip of the vca/vcf switch sends the sounds into orbit!

I'll post some pics as soon as I figure out how to get my laptop to upload them ... it's balking everywhere, gmail, photobucket, imageshack etc ... just flat out refuses to upload.

I think the triangle is the 2nd position, IIRC.

But...wtf is going on with yours--it sounds like you've got BOTH VCA and VCF going on there. I'm hearing tremolo and filter going at the same time. I want that.