In article , Eiron
wrote:
Trevor Wilson wrote:

I rescued a Rotel RA930AX amp from the junk shop. The manual says:
"Do not use speakers that have a very high capacitive load, say over
0.1 microfarads, as it may cause a damage to the power amplifier
section."

So I shan't be connecting it to my ESLs. Any idea what would happen?

**Actually, you're likely to experience fewer problems with the Rotel,
than with most other amps. I am a Rotel service agent and part of the
testing procedure I use on ALL amps (except Naim of course) is to
connect a 1uF cap across the load, to check for instability issues.
Rotels do not exhibit problems.


**Typo alert! Sorry. That would be a 0.1uF cap.

Thanks. So it's a power issue rather than instability. I have mislaid my
ESL handbook but I seen to remember that it presents a similar load to
16ohm in parallel with 2uF. It should be OK if I keep the volume down.

The matter may be more complex pun :-) that that...

A model of the impedance of the ESL57 is described on the 'Audio Misc'
pages on the 57 and 303. IIRC It was common to test amps for suitability by
using a load like 8 - 16 Ohms shunted by 1 - 2.2 microF. However sometimes
*smaller* capacitances might invoke instabilities which don't appear with
large capacitances. Hence unless the amp is specified as 'unconditionally
stable' there might be a risk.

Slainte

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