Building the Meat Sphere

[Taylor]

Right, doesn't matter. But you need to be sure to use the enclosed plastic type. The metal rotary switches will fit physically but will mess everything up because they're connected differently.

[Vince_b]

Thanks Taylor. I have bought the right ones from Smallbear.

[Vince_b]

I have another question, this time about the vactrols. The led (the side with the square leads) should be soldered on the side where there is a "+" on the pcb, but should the marking on the vactrols be visible when soldered in place or should it be against the pcb?

[Taylor]

Which vactrol are you using? It will depend on the part, but the datasheet for whatever you're using will show the proper orientation.

I normally use NSL-32s, and these have a dot showing the negative LED lead. If you look at the datasheet for the Vactrols, there is a drawing showing that there's an angled corner indicating the cathode (negative) lead.

[thedefog]

Taylor,

Beautiful work! I ordered the PCB from you today and just put in a parts order from small bear as well. I've been waiting for this baby a long time now. I see a future permanent spot on the pedal board. Just under $100 for all of the parts too, awesome deal!

[Vince_b]

I have done a drilling template. It can be downloaded here: http://www.box.net/shared/kiekb8vs26p8rya9qexr

1. When you print it, make sure that "page scaling" is set to "none".
2. It's easier to mount the switches and pots on the enclosure before soldering them to the pcb. If you try to solder everything on the pcb before mounting them on the enclosure it might be harder to make each components fit in their holes.
3. The rotary switches are a bit taller than the legs of the pots so you will need to bend them a little bit to make them long enough.

[thedefog]

Thanks for the template! That'll help a bunch. Now let's see some custom artwork!

[bassesofdeath]

Has anyone tried using MC4558CP1 op amps? I have a box full of these and wanted to use them all.

[thedefog]

Has anyone tried using MC4558CP1 op amps? I have a box full of these and wanted to use them all.

Standard dual op amps won't work on this apparently.

On another note, anyone planning on implementing Expression pedal control on this like the original?

[Vince_b]

I want to implement the expression pedal control but I'm not sure yet how to do it.
There is a wiring layout on this website http://www.pisotones.com/Meatball/psst/meatball-psst.html but it's in spanish and it use a jack that have 8 lugs and I don't really understand what is going on.

[MarcoMike]

8 lugs are because those are switched jacks. imagine the upper and lower rows of lugs as a separate DPDT, actuated by the jack, when inserted.
anyway, I always thought decay and intensity were not worth being controlled by an expression pedal.
what I did is wiring the expression pedal as a CV source: +V on the hot lug, ground on the third and CV on the wiper. this way you have a +9V - 0V cv out of your expression pedal. when the exp pedal is connected, its CV substitutes the output of the 1458, just before the intensity pot (which is now used to limit the V applied to the vactrols)

[Vince_b]

I understand why Pedal1 (decay) would need this kind of jack but it looks to me that Pedal 2 (Intensity ) only needs a mono jack isolated from the enclosure, right?
But anyway I will probably wire it like you said. Just to make sure that I understand: I need to connect 9v to the tip, CV on the ring and ground on the sleeve. Is that it? By the way, I never used an expression pedal so I'm not really sure about how they work.
And also, where is the CV on the pcb (or on the schematic)?

[Taylor]

The CV is coming out of the pot, not from the board.

So, assuming a Moog type expression pedal, 9v goes to the jack ring, ground to the sleeve, and the divided voltage (CV) comes from the tip and goes where the output of the envelope section was.

[MarcoMike]

few more details came into my mind:
as the CV "user" is, say, low impedence, you will find that the exp pedal pot value makes the difference: too high resistance will end up in a very poor linearity. I ended up buffering the CV with an opamp, as I 1/2 available (the other one is for phase inversion on LP)
just pay attention and don't fry the vactrols!! do all your tests with a series resistor from expr to effect or the intensity pot at min, if you follow the wiring I suggested.

[Vince_b]

The CV is coming out of the pot, not from the board.

What I wanted to ask is where the CV as to go on the board?

the divided voltage (CV) comes from the tip and goes where the output of the envelope section was.

This is precisely what I want to know. Where is the output of the envelope section?  Where should I solder the CV from the jack to the board?

Sorry for all those silly questions but I'm not familiar yet with the way that this kind of effect works.

[Taylor]

I'll go ahead and draw up a diagram as I'm sure others want to add this too. Should have it this evening.

[ryanuk]

Hi

Appreciate that the PCB is available to buy , but are there transfer files available for the top/bottom layers for DIY PCB builders?

RyUK

[Taylor]

No, this PCB is not designed for home etching and would be nearly impossible to etch even with very good resolution equipment at home.

However, if you Google search, some people have done layouts for this that are meant for home etching.

[GodSaveMetal]

No, this PCB is not designed for home etching and would be nearly impossible to etch even with very good resolution equipment at home.

However, if you Go ogle search, some people have done layouts for this that are meant for home etching.

Mr. Taylor I´ve made PCB fiberglass two layers, it no easy but if you are experienced you made it, please post the two side PCB for etching at my risk!! OK?? thanks man it great you work!!!!!!!!

[Taylor]

Roberto, as I said there already are some layouts for this, see the Pisotones website, and I think in the Wiki at the top of this forum and by using the search feature on this forum there are a few threads with different layouts already posted. These layouts would be much better suited to making at home - there's no reason to use mine. There are some places with 6 mil trace spacing etc.