Building the Meat Sphere

[Taylor]

Cool, glad you got it sorted. Those eureka moments are always exciting. 

[ottopit]

Just a little update...So seems my build has a wider or more "sound options" with under 9 volts I had an outputs that were around 12-14 volts
and i would definitely get different sounds but it seemed easy to "choke" off the whole signal in places I guess gated is a better word.
I setup the colour mod and that really does give you more range on that pot and as someone stated earlier should be manadatory. I'm planning on doing the moog
switch next.
The only thing i couldn't get working yet (besides the LED) and seems like it should be a no brainer is the send/return, I cannot get signal to passthrough
no matter what i try. I have a mono jack for the send and a stereo for the return. So like the build pdf says I go from Send pad to Tip on Send jack then
wire from Send tip to Return ring and Return Tip goes to Return pad, pretty simple but when I probe I get signal all the way from the Send pad->Send Tip->
Return Ring and thats as far as it goes probing the return tip and pad = no sound. I re-melted both of those points many times, even tried a brand new stereo jack
nothing just for the hell of it i switched send and return tips to pad connections still nothing. This has got to be something I'm overlooking but it's driving me crazy  .
So for now I just bypass it.
i'm starting to get used to how these pots interact with the switchs and getting some consistent sounds, man it sounds great especially with delay ( i run a wet/dry/wet rig)
I can play for hours with this thing it puts me in a trace it really is audio nirvana 

[ottopit]

Just curious Has anyone ever tried or thought through what it would take to add a TAP tempo  to something like this?

[DavidM]

Hi Ottopit,

You want to use a jack with a "cut" lug (not a stereo jack, though of course there are stereo jacks with cut).

The cut will be in contact with the "tip" lug when there is no plug in the jack. That would be the "normal" behavior.

WHen you insert a jack, the cut lug detaches itself from the "live" tip.

With a multimeter (or even a continuity tester) and some reasoning, you should get it going in 5 mins tops

BEst

D

[ottopit]

Hi Ottopit,

You want to use a jack with a "cut" lug (not a stereo jack, though of course there are stereo jacks with cut).

The cut will be in contact with the "tip" lug when there is no plug in the jack. That would be the "normal" behavior.

WHen you insert a jack, the cut lug detaches itself from the "live" tip.

With a multimeter (or even a continuity tester) and some reasoning, you should get it going in 5 mins tops

BEst

D

thanks didn't know about those even though i have one laying around i bought frm radio shack a long time ago.Well nice to learn new things. Anyway i wired it up and still no sound only this time the audio gets real faint on the send pad on the board.I tested with continuity setting and all the connections checked out. Maybe something is shorting the signal enough to let just a tiny bit through, i had to crank the amp all the way just to hear it.Then of course bypassing the jacks no problem everything works great.I  know im in the home stretch here so I'll keep messing with it, just a matter of time

[Barcode80]

Just curious Has anyone ever tried or thought through what it would take to add a TAP tempo  to something like this?

since it's envelope triggered, I'm not sure what you would be tapping in...

[ottopit]

Just curious Has anyone ever tried or thought through what it would take to add a TAP tempo  to something like this?

since it's envelope triggered, I'm not sure what you would be tapping in...

I was curious about adding something like this which actually switches between a sample/hold and envelope. Probably too much to change make it work, but I'm a newb so...


http://www.subdecay.com/proteus-auto-filter

[skylab001]

I had been thinking about building one of these based on another sites info, but this pcb looks superb. There are two mods I'd like to add to it 1) an input for foot control, to play it like a wah, 2) an input jack for an external LFO that automatically controls the sweep. If I had to pick either of those it would be the LFO input, and actually these might be doable from just a single input, either/or. If somebody familiar with the circuit might have some ideas as to where to place the jack I'm all ears. I've been looking over the schematic, and I'm pretty sure I have an idea of where it might go, but it seems like there are some builders that know this circuit pretty well already.

[Taylor]

The sweep of the filter's cutoff frequency is controlled by the two optocouplers' resistor component. The two light-dependent resistors need to change their resistance equally and in the same direction to get the sweep.

The envelope section puts out a DC voltage that changes based on the playing dynamics. So to control the sweep with an external control voltage you'd just need to connect your CV in parallel with the output of the envelope section. It'll be the outer lug of the intensity pot, that's not connected to the 330r resistor. I don't know much about external CV sources, so you may need to play around with voltage dividers to get the sweep in the right range.

[skylab001]

Thanks Taylor, that was about where I was figuring it would go. So out of curiosity, how close does the meat sphere come to the original pedal which it was based on? Has anybody done a side by side?

[DavidM]

Hi,

I have been comparing the Mu-Tron III schem to the Meatball and noticed the resistors in parallel with the LDRs in the Mu-Tron are both 220K, whereas the Meatball has 220K and 120K.

Any clue about this?

Thanks,

D

[pedalgrinder]

It's interesting that there is when i read through the forum pages a bit of a problem with a few of them triggering properly. I've often wondered why on u2b rather than unity with the wire between pins 6,7 put a pot or trimpot so you can adjust the gain a bit higher on the lm1458 i figure they use this for it's naturally high gain in the first place but i keep thinking you could essentially use any op amp if you were able to adjust the gain and turn it up to the desired level that triggers correctly for your set up. I could be way off and iam sure someone has thought of this allready but i couldn't find it within these pages. Has anyone tried adjusting the gain to see if a better trigger happens?

[charmonder]

It's interesting that there is when i read through the forum pages a bit of a problem with a few of them triggering properly. I've often wondered why on u2b rather than unity with the wire between pins 6,7 put a pot or trimpot so you can adjust the gain a bit higher on the lm1458 i figure they use this for it's naturally high gain in the first place but i keep thinking you could essentially use any op amp if you were able to adjust the gain and turn it up to the desired level that triggers correctly for your set up. I could be way off and iam sure someone has thought of this allready but i couldn't find it within these pages. Has anyone tried adjusting the gain to see if a better trigger happens?

For what its worth I tried a MC1458 in the place of the lm1458 and it had a very strange result.  It seemed the envelope would never decay. I could only trigger the sweep higher and higher and have to reset the power to get it back down, but maybe I messed something else up...     




I should post my results pretty soon, I made a daughter board with 4 buffers  to allow a better mix knob, ( seems to lose a ton of volume at 50% ). And these buffers allow notch filter and all pass filter


For everyone that wants to add an lfo to the pedal you might take advantage of the two unused positions in the up down switch.

[charmonder]

looking at the schematic, is the filtered signal inverted?

[thecolorfield]

Hey all, this was first build ever and to my surprise I soldered it up, plugged it in and everything sounds great! There is one small thing that is confusing me...For some reason I can't get the LED to light up when the envelope is triggered. I have a 4k7 resistor in the RLED spot and I'm using a 5mm waterclear blue LED. From the pictures on this forum it looks like I just solder the Anode/Cathode right onto the PCB, which i have tried with no luck. But then there's the Build PDF which seems to be saying to solder the Anode to the PCB and the Cathode to the middle lug of the 3PDT switch. I have tired both ways and still no luck....Everything else is fine, but the LED, what am I overlooking?

p.s. I can also report that I used a MC1458L instead of the LM1458 and its working fine.

-Brian

[Vince_b]

If you solder the LED right on the pcb it will light up even when the effect is bypassed this is why you should wire it to the 3PDT like what you've seen on the build document.
I don't know why your LED doesn't work. Try it outside of the circuit only with a battery and a limiting resistor, maybe you have burned it.

[thecolorfield]

thanks but my understanding of it is correct, right?

[Vince_b]

Yes I think that your understanding of it is good but make sure that you have a wire that goes from the cathode to the middle-middle lug and also a wire that goes from the pcb (LED NEG) to the middle-top lug of the 3PDT.
First, check to be sure that your LED is correctly wired according to the build document and make sure that it ain't burned. If it still doesn't light up try a limiting resistor with a value a little bit lower. In my build I used a 3k resistor (clear orange LED) and the light is pretty dim. Maybe 4.7k is to high for your LED in this circuit.

[thecolorfield]

sorry I'm new at this, a shorting jack is the same as a switching jack right? Would this work for the return in the MeatSphere?

http://www.mammothelectronics.com/4SJK104M-p/610-1006.htm

[Vince_b]

Yes this is what you need for the return.