Meatball / McMeat Layouts with on-board switches

[jota.ventura]

Hi.
This is a replica from the original, the image is mirrored. I've narrowed down the sides a bit to fit into a box like the one proposed by pssst at pisotones. Measurements are 170 x 87,5 mm. I've adapted the pot pads to fit alpha 16mm pots, and also added the pads for R6 and D3 as ChanchoPancho said.
Now I'm trying to put the components in place, I'll tell you when done.

[ringworm]

You've connected all the filtering caps together as they come out of the filter switch, they shouldn't be like that.

[jota.ventura]

Oops. I've just seen it.
I shouldn't work at night, the errors appear at day.
Now I think it's correct.

[jota.ventura]

Ok. I think I've finished the layout:

The names of the components are based on the schematic by joep. R.led (that doesn't appear at the schematic) may be 2k2. I forgot to label D1 and D2, the diodes connected to pins 12 and 13 of the tl074.
I have a doubt about the leds connected to R10-11-12. While in the joep schematic their negative poles are connected together and the positive ones go to the resistors, in this photo there seems to be a + sign just in the opposite way:

I'm trying to imagine how it would affect if they were inverted...
Any clue?

[jota.ventura]

However, looking at the photo I think I see (by the shape of capsules) that the leds are positioned correctly according to the schematic by joep, contradicting the + sign on the pcb. Or maybe this is not a + sign, it's small and the image is not high quality...

[jota.ventura]

I've arranged a bit the position of the rotary switches because they were too close to the edge of the box, you can see it in the image of the post #100. The one in post #103 has not changed, but it's only intended for the components position.

[ringworm]

Ok... I got mine built at the weekend so am wanting to compare notes. I used my pcb (page 4 i think) and jota ventura's layout they're pretty much the same. I've checked for broken traces shorts, bad joints etc and it all looks good.

It definitely works... but I have a number of questions/observations regarding how it works:

Sens pot - mine needs to be maxed to get the effect to trigger and in the 'Up' position my indicator LED isn't as "active" as it should be. I've read nearly all the threads on this board and a few others beside and this seems to be a recurring complaint in relation to guitar output ( I have a Jazzmaster with Seymour Duncan "vintage" SJM-1s, a low output guitar I guess). In the 'down' position my LED is nearly always on and can be dimmed/brightened with the Intens pot, is this correct?
Attack & Decay pots - just begining to figure out how these work together but again only a small usable area within the first third of each.
Colour - again a recurring complaint, mine also does very little and only makes a tonal change in about the last 20%. I might do the mod on this that is out there.
Intens - this seems to be working fine and depending on all the other settings has a a wide area of use.
Blend - Again this seems to work as reported with the volume dip/phase effect somewhere in the middle.

My trigger section seems to work fine Off/Full/Half as I say in the 'Down' position the light is nearly always on and i need to do a whole lot of tweaking to get a usable sound, this responds better to slow chords than single notes.
My filter section seems to work fine but the higher range settings need tweaked in other areas to get usable sounds, they are very high as ChanchoPancho points out.

My biggest concern is how hard it is for my guitar to trigger this effect, I have the parts to build a Micro Amp, would this help out?
Are there any resistors that could be swapped out to increase the sensitivity or the input of the signal? Or could the resistors on the input of the vactrols be swapped out for another value, any suggestions?

I'll post my voltages for comparison. Apologies though, I'm using a regulated 9v power supply

At input: 9.12 V

TL074
1 4.20
2 4.20
3 4.15
4 8.41
5 4.15
6 4.20
7 4.20
8 4.20
9 4.20
10 4.15
11 0.00
12 1.50
13 4.19
14 4.19

MC1458
1 2.01
2 1.93
3 0.00
4 0.00
5 1.50
6 1.94
7 1.94
8 8.41

Vactrol1
1 (-) 0.00
2 (+) 1.52
3 4.52
4 4.52

Vactrol2
1 (-) 0.00
2 (+) 1.52
3 4.52
4 4.52

[Skruffyhound]

Congratulations, it's kind of a slow cooker this thread, but everyone is gradually getting there.

Sorry, but I'm no help for you at all as yet. I've delayed this build until I have my UV/photoresist process up and running, almost done now.
I have parts already and I'll be on this within the next 2 weeks, but thats an eternity right!

My question(s) to you would be - how sure are you that your traces are good, and if you are sure of the PCB, then do you think there's something fundamentally wrong with the layout or can we tune this by switching out components.

I guess I'll do what I should do with every build and breadboard first.
I'll post back as soon as I get somewhere.

[ringworm]

I've checked the traces with a magnifying glass and back-light, they seem fine. Like I say, this works, but it's a matter of details in how it works and I think it's a case of tuning rather than the layouts not being 'correct', given that they're traced straight from the original pcb. I'm using vactrols and wonder if that affects the circuit in some way.

[jota.ventura]

Sens pot - mine needs to be maxed to get the effect to trigger and in the 'Up' position my indicator LED isn't as "active" as it should be. I've read nearly all the threads on this board and a few others beside and this seems to be a recurring complaint in relation to guitar output ( I have a Jazzmaster with Seymour Duncan "vintage" SJM-1s, a low output guitar I guess). In the 'down' position my LED is nearly always on and can be dimmed/brightened with the Intens pot, is this correct?

Yes this is correct. I've tried and increased the value of the sens pot, and it seems to help a bit, but not enough.

Attack & Decay pots - just begining to figure out how these work together but again only a small usable area within the first third of each.

The decay pot must be higher than attack to get the effect.

Colour - again a recurring complaint, mine also does very little and only makes a tonal change in about the last 20%. I might do the mod on this that is out there.

This is the correct behaviour.

My trigger section seems to work fine Off/Full/Half as I say in the 'Down' position the light is nearly always on and i need to do a whole lot of tweaking to get a usable sound, this responds better to slow chords than single notes.
My filter section seems to work fine but the higher range settings need tweaked in other areas to get usable sounds, they are very high as ChanchoPancho points out.

Yes, it's not a "plug'n'play" pedal, it needs lots of tweaking.

My biggest concern is how hard it is for my guitar to trigger this effect, I have the parts to build a Micro Amp, would this help out?

I have the same problem. Yes, a microamp should help, but I hope there's any other solution.

Are there any resistors that could be swapped out to increase the sensitivity or the input of the signal? Or could the resistors on the input of the vactrols be swapped out for another value, any suggestions?

I think the problem is that we use vactrols instead of leds like the original, but I've tried it also with leds and it was the same...
Maybe increasing even more the sens pot, or bypassing R4, or maybe bypassing R9... ??
Mine works well, but I've got to hit the strings very hard and I'm not comfortable with that, I hope we find a solution.

[gmr1]

I gotta tell you, if they're all like this - this is one finicky pedal. I have a real one. I've had it for years (I got it new, and it's serial #73, or something like that...). Same guitar, same settings, different days - Sounds different. Sometimes it triggers perfect, sometimes It wants me to play with it for a half hour until it'll allow me to get the sound I want. The rotary pots also are missing the washers to keep them locked to the # positions on the graphic (never had them, I'm assuming they usually do?)... so that gets crazy sounds if you go outside of those settings. I'd really like to build a clone, and sell the original (it's mint and early, must be worth a fair amount), but it seems like the clones act just as nutty. It's a shame as when it's dialed in - amazing... but I could never trust it enough to put it on my live board.

[ringworm]

this is one finicky pedal.

So the originals are as temperamental? The harmony central reviews back this up also. Yeah, I don't mean to imply that this build doesn't work, cos I've gotten some great sounds out of it but 'finicky' is definitely the word.
Any chance you'd post a set of voltages from the original for comparison? I made mine in the 'auto-wah' setting from the manual.

Maybe increasing even more the sens pot, or bypassing R4, or maybe bypassing R9... ??

Could be worth a try. I thought maybe R10 and R11 could change to suit the vactrols better.

[gmr1]

Any chance you'd post a set of voltages from the original for comparison? I made mine in the 'auto-wah' setting from the manual.

Sure, no prob. I'll try to get that done before the end of the week.

[ChanchoPancho]

this is one finicky pedal.

So the originals are as temperamental? The harmony central reviews back this up also. Yeah, I don't mean to imply that this build doesn't work, cos I've gotten some great sounds out of it but 'finicky' is definitely the word.
Any chance you'd post a set of voltages from the original for comparison? I made mine in the 'auto-wah' setting from the manual.

Maybe increasing even more the sens pot, or bypassing R4, or maybe bypassing R9... ??

Could be worth a try. I thought maybe R10 and R11 could change to suit the vactrols better.

I did change teh pots in the vactrols section and it didn't make any sound change I even bypass them and no change.

[jota.ventura]

I did change teh pots in the vactrols section and it didn't make any sound change I even bypass them and no change.

What pots? Don't you mean resistors? R10 and R11 maybe?
Anyway, thanks for sharing your experience.

[ChanchoPancho]

Yes the Resistors, sorry, my bad. Have you tried it?

[ringworm]

I built the micro amp and using it in front of the effect the difference is night and day. I need a box for this now, I keep playing with it.

[jota.ventura]

Yes the Resistors, sorry, my bad. Have you tried it?

Not yet. I've been busy with other things.

[chicago_mike]

Ive been on the road for a few weeks so never got to finish this thing..hows everyones units working?

[ringworm]

Hi Mike. I've been having fun with mine after an unsure start. It's been on top of my amp for about 3 or 4 weeks now, still no enclosure and numerous repairs for excess fiddling!



It's taken that long just to get a feel for what all the different controls do and how they respond to one another. I think the response could be better, it's nowhere near as sensitive as my neutron build but I'm playing with it more than I play with that so go figure. I built a micro-amp to go in front of it and that really makes a difference to the response but i often play without that also. Without the amp my response starts to kick in around 2/3rds of the way around Sens, with the amp I'll get response before the half way mark. The only mod I made was the 'colour mod' that had been posted when the original McMeat layout was being built here. That just involves joining the traces between the wiper pad to lug 3 on that control. It greatly improves the useful range of that effect. I also made a board for the jacks and have tested the send channels. They work. I've not got an expression pedal so I haven't had a chance to test those jacks out.
I built it with my own 'Albondiga' pcb but I'd recommend jota.ventura's as his pot pads are bigger and he's reduced the width a little to fit in a 7" enclosure. I used his layout as a reference and it's good.