!???? New kind of mojo from jrc4558D?

[charbot]

A couple of weeks ago I built a Dr Quack/ Nurse quacky hybrid envelope filter on a  layout I designed.      Its basically a Dr Quack with a  added attack, range and delay controls.  I had used a jrc 2068DD dual op amp, chosen arbitrarily because it was cheap and I didn't know too much when I bought it.   It works and sounds great however...
      last night after finishing a TS-clone ( first time i ever heard one ...wow!) I started tinkering with the Dr Quack. Since they were already out, I thought Id see what the "magical" 4558D sounded like in there.  So i pop the 2068 out of the socket and put in a 4558. It sounded pretty good, maybe better.   The problems began when I tried to swap back the original 206b for comparison.  When I turned on the amp there was a LOUD, shrill, siren-sound.    even with the vol on the amp is down all of the way.   
    So I am thinking...... I must of broken something or someting is touching something it shouldn't.... No, everything looks fine.    Maybe the op amp was damaged when I removed it... I put the 4558 back in  ......
IT works... so the problem must be with that 2068 that was originally in there, right ?  Nope. I tried a couple of brand new ones   right out of the pack.  Each one gave me that same  head-splitting noise (not the good kind). 
That Noise.... every time that noise....So but when I put in that damn 4558.... PRESTO it works!. Remember the 2068 had worked and at least sounded decent for weeks!
I am still too frustrated to do any testing with a dmm, but I have arrived at two possible conclusions: The 4558 has either "possessed" my auto wah ... or after working with 4558, the Dr Quack "refuses" to function properly with any another op amp.   
     
Maybe I shouldn't question the black arts.... the circuit works and sounds good, thats whats important right?
Any thoughts, suggestions, or spells are appreciated. thanks

[343 Salty Beans]

or maybe you electrostatic murdered your 2068s. When you're handling op-amps, touch a grounded piece of metal before you actually touch it. Your body slowly builds up static electricity, and if you have enough n your body when you touch an IC, you can damage it so that it doesn't function properly.

That's why I keep my ICs in this fancy anti-static foam, not in a big bucket with a bunch of other ICs. it's well worth the investment, cuz you don't have to worry about murdering half your ICs if you're rummaging around in the 'spare op-amp' bin.

But you said you tried new ones...and that mojo tale is good for campfires.  I dunno what to tell you.

[charbot]

or maybe you electrostatic murdered your 2068s. When you're handling op-amps, touch a grounded piece of metal before you actually touch it. Your body slowly builds up static electricity, and if you have enough n your body when you touch an IC, you can damage it so that it doesn't function properly.

That's why I keep my ICs in this fancy anti-static foam, not in a big bucket with a bunch of other ICs. it's well worth the investment, cuz you don't have to worry about murdering half your ICs if you're rummaging around in the 'spare op-amp' bin.

But you said you tried new ones...and that mojo tale is good for campfires.  I dunno what to tell you.

Yeah... thats what I thought ...the first couple of times....  but If any static kind of thing happened to the 2086s it would have happened to the 4558.. It was handled the same ant tossed back on my junk heap/ desk in between swaps. 

is that sound characteristic of a fried op amp?

ooh!  I just remembered.   ive experienced that noise before....
I built a bobavia on perf board  (another layout of my own design)
In normal mode, it  worked but when I flipped the "spinal tap" mod switch...WEEEERRRRRRRRRR
there it goes.   

[jonathan perez]

maybe you popped it in backwards?

[LyleCaldwell]

Long shot - you have a bad joint on a cap or whatnot somewhere that induces oscillation on the 2068 but not on the 4558.  The joint was fine at first, when you were using the 2068 successfully, but became stressed at some point.  Go over all the joints with the iron and a dab of fresh solder if they aren't visibly perfect.

[charbot]

Long shot - you have a bad joint on a cap or whatnot somewhere that induces oscillation on the 2068 but not on the 4558. 

hmmm...  ill check that tomorrow... thanks