McMeat debug: Envelope ain't working

[Coriolis]

OK: I swapped the 1458 for a 5532, and most of the envelope flutter disappeared. Interesting. I wonder if the 1458 is actually fried, or the 5532 is just doing a better job under the same crap conditions?

C

[ulysses]

are you using leds/ldrs?

in mine i used leds and ldr's and i used a battery to build it/test it. it worked fine untill the battery started to lose voltage and then it started to sound distorted, trigggering badly.

when i plugged in a psu 9v+ the trigger kept going off becasue the leds were way to bright and when they went really bright (when i played loud) the sound would go heavily distorted (not in a good overdrive way) like the rails had been pushed to far. i even blew a 1458. what i had to do was increase r11 and r10 to 470R. this stopped the leds getting to bright.

it does sound like you have wired the up/down switch incorrectly. if you are using a variable switch make sure you pull the pin, turn the switch all the way left then put the pin in position2.

i dont know what else to try.
cheers
ulysses

[Coriolis]

I'm using VTL5C3's for the opto's.

when i plugged in a psu 9v+ the trigger kept going off becasue the leds were way to bright and when they went really bright (when i played loud) the sound would go heavily distorted (not in a good overdrive way) like the rails had been pushed to far. i even blew a 1458. what i had to do was increase r11 and r10 to 470R. this stopped the leds getting to bright.

It certainly seems like the envelope is somehow too sensitive. I have a scratchy selector switch on my strat, and maybe the cable I'm using isn't what it used to be, and these things could false triggers  I guess.
Maybe I'll try messing with R10 and R11, like you said.
I'm pretty confident I'll get the switching right at some point. 

Thanks for the tips!

C

[chunks717]

I removed sweep switch, hard wired one position, and got it working that wayfirst,
just to make sure wiring was not the problem..........turns out that was part of it.
also, I switched IC to lm358.....this worked where my nte 1458 "equiv" did not.
all sounds great now..........................just some thoughts.................
also, this was the first i heard a downward sweep....its really great! (if subtle)

[charbot]

Congrats chunks!

Ive been following this thread for the last week or so because I was about to build the mcmeat too.  By the time I got the parts Id ordered, I was getting worried that this one would end up being an expensive lesson on why I should stick to projects that reflect my current skill level.  To my complete surprise, this sucker worked on the first try. it even works with my homemade vactrols.  This is amazing because my vactrols are only in the ballpark range of the vtl5c3's.  I only tested and matched the "light on" resistance and added a 1k resistor to the photocells to achieve aprox. 1.5k ohms.   I also had to use a NTE 778A to replace the 1458.  I have never heard an original meatball, but one this sounds amazing.
Im sure it would sound even better with the proper optoisollators. Next order i make I will get some  and a 1458 to swap around to see whats best.
Good luck guys, if I can do it, you can.  I am really just a beginner so I cant offer any sound advice, but if everything is wired right and no component is fried, it has to be mechanical( in the switch)
 
    BTW, all those knobs and switched are just as confusing after the box is wired and working.  If you are using the pisotone wiring diagrams,the rotary switches are wired correctly, but I believe that two of them are switched around from their placement on the original meatball: the range and the bandwidth.
Can anyone confirm this? Anyway, I have them switched. The one with the caps has to be the four position hi-lo and is the top right one.   
Im beginning to understand how the coltrol;s interact and can dial in some interesting sounds, but I think that it will take many hours of tweaking to discover the full range the this effect can produce.