Building the Meat Sphere

[nocentelli]

[Beo]

Thanks Leo, I put in the jumper (which I now know as the colour mod) and it made a big difference. Thanks!

[Govmnt_Lacky]

Did Taylor ever fix the layout to include the missing electro cap that is on the originals?

[Taylor]

I've never changed the PCB layout, but I think what you're referring to is an error in the schematic, not the PCB itself. That is something I should fix in the docs but the PCB doesn't have any missing parts as far as I know.

[Govmnt_Lacky]

I've never changed the PCB layout, but I think what you're referring to is an error in the schematic, not the PCB itself. That is something I should fix in the docs but the PCB doesn't have any missing parts as far as I know.

You are missing a 10uF electro between the Send and U1D Pin 14. On your schematic, you just have a solid connection between the two. On the original units, there is a 10uF electro between the them. The positive side towards U1D Pin 14  

Is it on the PCB? If it is... it is just a paperwork drill...

[Taylor]

Yes, it's on the PCB. Yes, only the document needs to be updated.

[Beo]

Yes, it's on the PCB. Yes, only the document needs to be updated.

The documentation threw me off a bit during my debugging. For example, I noticed some inline pots and resistors that were in opposite order on the PCB. For the Colour pot, it looks like the 1k5 resistor terminates to ground on the schematic, but it in fact connects to vref correctly on the PCB and the vref notation is missing in the document. None of these are big deals, especially now that I have a working build, but a doc update could help future builders. I'd recommend discussing and showing the colour mod in the pdf, as it really seems to be an essential/mandatory mod. The green diffused LED/LDR combo would also be a good recommendation in the doc. Showing the fourth No Connection poles for the Range switch would also help confirm there are four switch positions for that control. Of course this thread is essential reading as well!
Thanks for the great pcb Taylor.

[Taylor]

OK, well, the missing cap is fixed, new file is here. I will try to work on more extensive updates.

edit: Actually, let me throw this out: I am extremely busy at the moment, I no longer have the original schematic files, and doc creation has never been my strong suit anyway. So if anybody reading this would be up to make some nicer-looking docs with updated content in exchange for dollars or PCBs, please message me.

[suncrush]

Is there a way to mod this pedal so that it works as a fixed wah, in addition to working as an autowah?

[tremelo68]

I finally, after a year of letting it sit on the shelf unfinished, troubleshot it and got it fully working. Now I hear the reason why it is so loved. What an amazing filter. Very musical and full of tone options.

Did the Moog mod and that is worth adding for sure. Also, used 5mm green diffused LEDs, as the vactrols were not doing it for me. 

This forum has been very useful. Thanks for the info.

[nocentelli]

Is there a way to mod this pedal so that it works as a fixed wah, in addition to working as an autowah?

The bandwidth switch (the one that switches between a larger and smaller value input cap to the envelope section) should be an on-off-on arrangement so there is one position where the guitar is disconnected from the envelope detector. This will give a fixed eq setting that you can adjust with all the filter controls (lp/bp/hp, colour, intensity, range, up/down, and blend).

[suncrush]

I apologize if this has been answered (but hey, it's a long thread!)

It looks like the loop is only engaged when the pedal is on, so that any effects you put there can only be used when the filter is engaged.  Is that right?  Am I reading this wrong?

[nocentelli]

That's correct, but you can modify the bypass wiring so pedals in the loop are active whether or not the filter is engaged. The drawback is that you need to wire the guitar input direct to the input buffer, and use the footswitch to direct the loop return signal either direct to the output (bypass) or through the filter section to the output (filter engaged): This now means that the guitar signal is permanently buffered, I.e. not true bypass. This may or not be an issue for you.

[yvarg]

If you're willing to add another small board inside your enclosure, you can create the effects-loop-though mod without forcing the guitar's signal through any of the filter's buffers. I used a DPDT relay that's triggered by the extra pole of a 4PDT stomp switch used for the normal effect on/off. It's just a complex way to add another pair of contacts that are triggered by stepping on the stomp switch. It's not elegant, but it works!

Speaking of mods, has anyone come up with a way to make the Blend knob more effective at blending the wet and dry signals?

[nocentelli]

It's mentioned some way back in the thread that the phase relationship through the filter opamps makes the lowpass blend less effective than the bandpass. I'll have a browse back through, as I only use it on lowpass, and there's a noticeable dip in the middle.

[yvarg]

That makes more sense. I, too, only use it in the lowpass mode, and that blend knob would be pretty useful if I could get it to work.

[add4]

Ok i'm digging out my meat sphere after a looong time and i want to finish populating it and making it work
i'd like to centralize all the things i found in the thread so far

- Moog mod: which is not mandatory
- Colour mod which involves putting a jumper between pin 2 and 3 of the color pot. IT IS NEEDED TO HAVE A CORRECTLY FUNCTIONAL COLOUR POT (right?)
- don't use vactrols, use green diffused leds and ?? LDRs? (does anyone have a reference? places to buy the correct ones?)
- LM1458 required to make the envelope work painlessly

is there anything else? could anyone point me to the correct LDRs?

thanks

[bcalla]

I can answer a couple.
Moog mod - I recommend this.  I did test it with guitar, and at some Meatball setting, low notes can become unpredictable as noted above.  The Moog switch brings it back under control.  That said, the Moog switch is not noticeable at most settings.

I used LDRs from Tayda.

[Govmnt_Lacky]

Diffused LEDs and Tayda LDRs are good. Make sure the LDRs can get to 2M dark.

Make sure your 1458 IC is known good. Don't use Tayda or eBay clones. Go with a reputable seller for these. Bad or out-of-spec 1458s will cause the pedal to not function properly.

[Fine Mechanics]

Just finished my build, but unfortunately it's not working.

When the effect is engaged I get clean signal when blend is below 100%, the LED triggers/flashes along with the envelope but I don't get any wet sound. The only issue I can find on the board are with the little holes meant to be left empty to the top right of the 47u cap above the LED (I'm looking at the side of the board with text where the components are mounted). I accidentally lifted the pad on the top of these two holes after trying to get rid of some solder that had fallen into the hole. The lower hole also has solder in it but I didn't attempt to clear this after lifting the pad on the top hole.

Any ideas what could be causing the issue? Unfortunately I don't have a VM/audio proble to hand to post readings/explore where audio may be dropping out myself.

I'm using a pair of vtl5c3/2 vactrols. LM1458N and TL074CN. Any help that you could offer would be hugely appreciated at this stage!!