SSL4000-6000 "vs" Neve (V) "vs" Harrison "vs" Mci "vs" Amek L-R Master Summ bus

[abbey road d enfer]

The 5532 and 5534 type op-amps require adequate supply decoupling if they are to remain stable, otherwise they appear to be subject to some sort of internal oscillation that degrades linearity without being visible on a normal oscilloscope.

Smells like an urban myth to me...

 

[Andy Peters]

If a scope is not fast enough to easily see a spurious oscillation  you will often see a thicker trace that should normally be a thin line. Sometimes there will be higher distortion (and sometimes a frying noise) when the op amp is oscillating.

Power-supply draw will be higher than expected, too.

 

[JohnRoberts]

If a scope is not fast enough to easily see a spurious oscillation  you will often see a thicker trace that should normally be a thin line. Sometimes there will be higher distortion (and sometimes a frying noise) when the op amp is oscillating.

Power-supply draw will be higher than expected, too.

Not easy to measure in situ, but a chip running hotter than normal with no other explanation may be in oscillation.

More a problem in power amps than op amps but very high frequency oscillation can cause a situation called mutual conduction when the output is trying to pull up and down at the same time. This can be disastrous for power amps and cause them to release their magic smoke..

JR

 

[living sounds]

I've uploaded a comparison of DOAs in the mix bus position here:

http://groupdiy.com/index.php?topic=60321.0