unbuffered CMOS = Troubli-matic ?

Started by petemoore, June 17, 2008, 01:56:13 PM

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petemoore

  I've tested this on only 3 occasions.
  Double D, sounded great on the one side for a time.
  Tube Sound Fuzz type deal, same deal.
  CMOS thing...3 legged dog IIRC, same deal, sounded great for the first time today [alone or driving Rat nuts], made bad noise and died altogether.
  Could be my builds, but that's kind of a thin explanation...possible/unlikely....compared to when using non-CMOS componentry.
  Anyone agree with that statement ?
Convention creates following, following creates convention.

brett

Hi
those CMOS are easily killed by static.  Do you have a nylon or PP carpet?
Definately use IC sockets and pre-bend the legs so they'll go in easily.
Working in my shed in bare feet and only on humid days, the death rate on my 4049s is only about 1 or 2%.  My early DOAs were as high as 20 or 40%.
cheers
Brett Robinson
Let a hundred flowers bloom, let a hundred schools of thought contend. (Mao Zedong)

petemoore

   I always seem to get them in the circuit and have them work ok for a while.
  This 'could' be a PS Problem, hafta check that, all of a sudden noise like resistor from SP touches PS...creeps in slowly than blatant GAaaaaa [hum]...then quits working altogether then works w/hum.
  Very reminiscent of every CMOS I've built [3].
  Works for a while and sounds all CMOS-tubey.
Convention creates following, following creates convention.

earthtonesaudio

I've killed a few inverters in my travels thus far, even in the humid Midwestern summer.  Breadboards are hazardous to CMOS, especially when you're swapping parts with power connected.  :icon_eek:

I don't know why yours would work and then quit later... My only thought is to make sure none of the caps are left "floating."  Especially if you have input jack power switching AND a big capacitor floating (no path to ground, like in the original TSF) you could have a situation.