[sdiy] noise source crap out

[Tim Ressel]

Yo,

I don't think the caps are the problem. Here is how my
coffee-addled brain would approach it:

Step 1: Check power supplies on the opamps
Step 2: Ohm out the ground connections
Step 3: Inspect the board for cold joints etc.
Step 4: Flex board and listen for output changes
        --> if you hear changes, re-solder all joints
Step 5: If you have a scope, look at outputs of amps.
Look for distortion, heavy dc biases, clipping, etc.
Step 6: If the opamps are socketed, swap opamps one at
a time.
Step 7: Swap the transistor

Questions, queries, posers:

All outputs affected? Or just one?
Varies after turn-on? Or constant?

Hope that helps.

--TR

*******************************
When in doubt, gulp a Hexuccino
*******************************

--- Magus Ship <elmystico at earthlink.net> wrote:
> "All of a sudden" my homebuilt noise source, which
> is based on the
> Electronotes and ASM-1 designs has crapped out. 
> What used to be a rich hiss
> has become a futzy stream of what sounds like badly
> band pass filtered pink
> noise.  Around this time the ground connection at my
> power supply became
> desoldered (unrelated? related?).  My question is
> whether the transistor or
> the filter caps to get pink and Random Low Frequency
> outputs would be the
> problem.  Is it possible that a transistor that
> provides good noise can
> change or crap out over time?  Or is it more likely
> that a cap or a bad
> connection in the filters would produce this effect?
> thanks as always.
> Gavin 


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