Building the Meat Sphere

[Taylor]

Strange. I haven't heard anyone having quite so much trouble finding an IC that works. Has anyone else had a similar experience?

[Strategy]

hey taylor and all. After a year or so of barely poking at my diy setup I have a meat sphere up and running

Random question, is there a trick to getting the rotary switch setting washers to stay put? I use the little setting washers to choose my number of turns for each switch but when I box it up they wiggle loose and I end up with too many positions. I'm ready to try loc-tite or something! is that, or glue, a BAD idea for any reason?? maybe just a little dab of tape so they don't slip around?

I haven't implemented my expression or CV yet. Gonna do it the vanilla way, a switching jack for the expression jack so that the pedal just replaces the pot, and for CV I'm just going to use another vactrol to the intensity pot middle lug or something. yet to be tested...

thanks taylor and all for an amazing project!
Strategy

[kwijibo]

Strange. I haven't heard anyone having quite so much trouble finding an IC that works. Has anyone else had a similar experience?

After playing around I noticed the filter only sweeps in Up mode, and I need a fairly high-amplitude signal to get a trigger even with sensitivity all the way up, so I may have another problem. I've ordered some 1458 ICs from RS to try and rule out anything IC related.

[Strategy]

tonight I alligator clipped a "cv input" to the intensity pot, using an external cv hooked up to a vactrol. odd thing, with adding opto's to a circuit that already uses opto's, it works, BUT, the sound/behavior is super "slewed." the natural musical slide of vactrol based CV is multiplied the way I have this configured. it's musical, but the external cv is almost too subtle at some settings.

I'm using VTL5C3 in both the pcb and in my external cv circuit. Should I use a "faster" opto?- something like VT5C4 or higher?? will it make any difference?

also: is a "sidechain" mod possible in this circuit? it would be cool if the envelope could be triggered by a 2nd audio input.

[nocentelli]

You can already have a different audio trigger source without modification: Just plug the trigger source into the input, plug nothing into the send, but instead plug your guitar (or whatever instrument you want to be filtered) into the return jack.

[Strategy]

wow thanks!!!

right now send/return is bypassed with the jumper, but should be easy to add it back.
thanks!

EDIT: is it possible to wire only the return and not add a jack for send? Or would this cause incorrect functioning for the circuit?

strategy

You can already have a different audio trigger source without modification: Just plug the trigger source into the input, plug nothing into the send, but instead plug your guitar (or whatever instrument you want to be filtered) into the return jack.

[Strategy]

My build is almost done, figured out the issues with the rotary switch setting nuts not staying in place. Also in the end decided still to omit send/return and expression, but keep external CV.

My LED is blinking on and off at a constant interval, even when I'm not playing (when the envelope CV is at rest). Any idea what's the cause??? 

Strategy

[lulu_joe13]

Maybe a short into that circuit? You are missing out leaving off the send return. I use mine with a fuzz and it is awesome.

[Strategy]

I tried the send/return for a while, both for patching in an effect like fuzz and as a possible source of side-chain modulation. I think I just don't have a big need for this really. I still have the holes in the enclosure in case I decide to add them

I'll look for a short in my LED circuit...

Strategy

[Strategy]

I added the CV input as a vactrol to lug 1 of the cutoff pot. this is in parallel with the envelope circuit. The LED is connected to the envelope circuit as well. I can't see any wires touching that would cause a short, maybe the blinking LED is introduced by this additional external wiring somehow?

Strategy

[mthibeau]

I'm not getting a triggered effect. I get clean output when turning the blend all the way to the clean side, so the first TL074 appears to work. The LED will light depending on the positions of the attack, decay and intensity knobs but doesn't seem to change at all with the input signal. The sensitivity knob doesn't seem to have any affect. Pulling the LM1458 stops the LED from lighting under any conditions. I've traced through the circuit from the input and continuity seems to be correct, just that the envelope detector doesn't seem to work.

Any ideas? Are there any common opamps I could try and substitute with? My LM1458s have the National logo and came from Tayda.

Strange. I haven't heard anyone having quite so much trouble finding an IC that works. Has anyone else had a similar experience?

I am facing the exact same problem as kwijibo, I just can't get the envelope detector to work, sensitivity knob does nothing, my three LM1458 ICs were from Tayda as well.

Any suggestions, should I just buy some of the same ICs from a different vendor?

[mthibeau]

It's definately the LM1458 ICs I got from Tayda, I stuck in an NE5532 and the envelope detector works, it's seems to be functional, but not as dynamic as I would expect.

I ordered an MC1458 and should get it in a week, see if that one works better.

Maybe Tayda's supplier is selling them some low quality ICs. I ordered 3 of them from Tayda around December 2012.

[kwijibo]

It's definately the LM1458 ICs I got from Tayda, I stuck in an NE5532 and the envelope detector works, it's seems to be functional, but not as dynamic as I would expect.

I ordered an MC1458 and should get it in a week, see if that one works better.

Maybe Tayda's supplier is selling them some low quality ICs. I ordered 3 of them from Tayda around December 2012.

If it helps, I ordered TI MC148s from RS and they worked the same as the Tayda ones.  I'm also using clone switches so I've desoldered them and ordered some Alphas just in case the switching logic is different.

[mthibeau]

It's definately the LM1458 ICs I got from Tayda, I stuck in an NE5532 and the envelope detector works, it's seems to be functional, but not as dynamic as I would expect.

I ordered an MC1458 and should get it in a week, see if that one works better.

Maybe Tayda's supplier is selling them some low quality ICs. I ordered 3 of them from Tayda around December 2012.

If it helps, I ordered TI MC148s from RS and they worked the same as the Tayda ones.  I'm also using clone switches so I've desoldered them and ordered some Alphas just in case the switching logic is different.

Bummer, you get no envelope detection at all?

I used the plastic Alpha pots, my build is working in both up and down, and I don't need to give it that hot a signal for it to light up with the NE5532 in there, the envelope detection seems just off. I'll post my results when I get my TI MC1458.

[mthibeau]

The TI MC1458 worked perfectly, the ones from Tayda must be faulty (I tried all three of them). Builders beware, they didn't work for me. I got an NOS TI chip from from ebay and it worked like a charm.

Not sure if this is normal, but I really have to hit the strings pretty hard, even with the loudest humbuckers I own, to get the envelope to open, I have been playing it with a SHO in front of it now and it sounds great!

Is there a way to mod it so it can be a little more sensitive to input? I'll re-read the entire thread and see if it was mentioned.

[1878]

I built mine yesterday but it doesn't sweep. Luckily, I'd socketed the optos because I seem to have problems with them whenever I use commercially bought versions ?!?! I replaced them with an LED/LDR combo & noticed the LED's weren't reacting in a 'sweepy' way. They get brighter/dimmer when I turn one of the controls (sensitivity I think) but that's it.

I can hear differences in tone when I play with some of the switches & controls so it seems not to be triggering. I've tried lots of different settings but nothing. Any ideas where to start ??

Thanks in advance.

[Taylor]

Which dual opamp are you using?

[1878]

I'm using a LM1458N. I bought 3. The second worked for a short time.

[1878]

I've fitted an MC1458 & rolled my own vactrols. It's working now !! I'm gonna box it back up & spend a bit of time getting to know it.

Just to clarify...

Range - 4 positions
Up/Down - 2 positions
Range - 4 positions
HP/BP/LP - 3 positions

Thanks.

[Taylor]

Range has 3 positions IIRC. Maybe somebody who's built it more recently will correct me if I'm wrong. Glad you got it working!