Meatball / McMeat Layouts with on-board switches

[chicago_mike]

That looks really really cool. I still have 2 mcmeats to finish but after that Ill do one of these. 

[chicago_mike]

Hey Jota, when you said the image is mirrored, do I mirror the image for printing or just go ahead and print it?

Using clear transfer sheets on all my builds now and black light bulbs. flawless method but the sheets are not cheap.

[jota.ventura]

Well, I don't know about that method, I always draw my pcb's with a pen.
I don't remember what I meant by 'mirrored', but the drawing corresponds to the copper side of the PCB. If you look at the post #92 in page 5 you'll see it.
I'm glad to see that my work is useful for someone.

[chicago_mike]

coolness. Thanks. You just draw right on the pcb? damn!

[jota.ventura]

Yes. It's not that difficult, I use a marker specially designed to draw on pcb's and then an acid bath.

[chicago_mike]

I just place the sheet on a sensitized board and bathe it in blacklight. a few minutes and piping hot ferric chloride or amonium persulphate.
Yours actually takes some talent.

[ulysses]

hey all

first of all- well done to all you guys putting so much effort into this one- good to see group involvement-

the mcmeat was (if i remember correctly) my second ever gtr pedal build. it was quite easy on the board, but fiddly to wire. i managed to squeeze it into a 1590bb (without a foot switch).

can i just say for newbies considering this build- there is a lot of mojo around all lovetone pedals, and not all of it is deserved- the meatball is an auto filter with many knobs for fine tuning- if you are a filter nut this may be the build for you- but like the univibe to the voodoovibe, you will likely get just as good a sound and "easier use" out of the mutron III. the mutron III is a much easier build, and will deliver a very similar sound without the "fine tuning knob" complications. as i said "if you are a filter nut" this may be the pedal for you- if you are looking for auto filer that sounds just as good as the meat ball but with ease of use, go the mutron III. to be honest i wish i had not bothered with the meatball given how difficult it is to use. i cant remember who or when (and i didnt bother researching it), but someone told me the meatball was a hacked mutron III.

check the mutron III at pisotones (if its still live). they had audio samples there when i built mine. also check the mutron micro v which is an even easier build-

cheers, ulysses.

[ChanchoPancho]

Hey guys, I have some news... In my latest posts I said that the frequencies of the filter were too high and I've been trying to correct that issue. I'm lowering the value of R6 (1M8) so the gain of the detector stage is lowered as well. I'm still experimenting with different values so when I have de definitive one, I'll let you know.

[ChanchoPancho]

I've been trying to view the plot of the colour mod but i can't find it. Where the hell is it?!

[chicago_mike]

Colour mod??

[ChanchoPancho]

Yes, i red that shorting lugs 2 & 3 of the colour pot, improves its response and I also red that somewhere there's a plot showing what this mod does. If anyone have info about this i'd appreciated.

[ChanchoPancho]

Hey guys, after a lot of time experimenting with the meatball I found a way to correct the frequencies that were too high specially in the up mode:
I replaced R9 (330) with a jumper. This way more current draws into the vtl's leds.

I also found after playing a lot with it, that some pots are ment to be always on the max position like Sens And colour.
This are the settings for the pots i find more convinient:

Up mode:
Sens: max
Attack: min - 9 o clock
Decay: min - 12 o clock
Colour: max
Intes: min
Blend: max

Down Mode:
Sens: max
Attack: min - 9 o clock
Decay: 12 o clock
Colour: max
Intes: min
Blend: max

I'm not 100% happy with the sound. I think it's still to "treblely" so I think I'm going to change the filter caps (C9-C16)
I'll let you know if something comes up.

[chicago_mike]

What I did with the mcmeat pdf version, is get a 6 position rotary for the range control. Since I dont have sccess to a 4 position.

Then I copied the the range control from the Supertron schematic. And just increased the cap size to tase really.

[ChanchoPancho]

Wow I didn't know that one. It sounds really great. Here it is a page that describes the whole project (for the ones that didn't know it, like me) http://msswartz.tripod.com/supertron1.htm

Mike, what cap values did you use finally? From your post I understood that you used larger values than the supertron. I'm asking to save some time... thanks in advance.

[chicago_mike]

Try as high as a .047 and go down from there. Dont have my mcmeat close to me.

[ChanchoPancho]

Hey, I got news again. And I must correct the thing I posted before. R9 must be increased to get lower filter frequencies.
I replaced it with a 1k resistor and replaced the intensity pot as well. I'm trying with a 5kB instead of the original 1KB.
With this higher value you can get very low frquencies, so low that i think 5k is maybe too much. I think I'm going to put a 4k7
in parallel with it so I can obtain a value around 2k5.

That's it for now...

[phoganuci]

Does anyone have a final confirmed debugged version of the pcb and layout images posted in replies #59 and #73?  I have seen people discuss problems with these since their original posting, and although ringworm posted corrections, the layout image has since disappeared from the original post.  I am interested in getting a board together and starting the project soon and this looks like the best starting point to me.  Any help is greatly appreciated, as always!

[Skruffyhound]

Ringworm recommended the Jota Ventura version because it's slightly compressed to fit in a smaller box and had wider traces. I was about to use the ChanchoPancho version with Jota's layout.... when I had an unfortunate etching accident. Now I'm again waiting to see the upshot of Chicago mike's suggestion. It seems a bit mad to have three pots that are on max all the time, so if that's the case I may have to look at changing the PCB or the circuit or making a monstrous hybrid with the supertron. This thread keeps rolling on but it doesn't seem like anyone is really satisfied yet, so I'm biding my time with this one. Good work from everyone though, sorry to be lazy in this thread, I promise I'm pulling my weight on some other projects.

[phoganuci]

Skruffyhound,

Thanks for the reply.  I saw the pcb and layout on replies 100 and 103, but I had one immediate concern about the agreement of the images just from eyeballing the two.  It appears to me that they are slightly different images, in that line coming from D6 touches one of the unused poles of the rotary switch in the layout but not on the pcb image.  I doubt that this would have any effect, since this is an unused pad.  I was just worried that there might be some other smaller difference that I have not seen yet.  Regardless, I am set on using this design and layout.  I am going to go through the Mcmeat 1.1 Joep layout and compare these two and compile a list of questions.  I will be back with any issues I find (if any).  Thanks again!

Patrick

[jota.ventura]

Phoganuci, both drawings are ok, but the last version is the one on post #100. I only moved slightly the rotary switches and the bypass led in order to be more symmetric in the box.
Go ahead