tom@rlgvax.UUCP (Tom Beres) (09/29/83)
The following is an interesting story about an ill-fated matchup between
two quality components:
A friend bought the Carver cube power amp (model M400A) and a set of
Infinity speakers. After he hooked them up, when he turned them on he
occasionally got a loud THUMP, THUMP, THUMP coming out of the speakers,
which lasted a long time before it stopped or he turned off the amp.
But either unit worked fine if connected to a different speaker or amp!
Turns out there was a mismatch. The Carver has "smart" circuitry which
checks the load it is driving and senses when it is overpowering a speaker.
If it thinks this is happening, it shuts itself off. The Infinity speaker,
however is a 4 ohm speaker with a capacitive crossover. The combination
presents an unusual load to the amp during power-up. The Carver, seeing
this, thought the speaker was in trouble and shut itself off for a while,
then sensing everything was OK again, turned itself on, and restarted
the cycle all over again, ad infinitum, or close to it.
This did take a while to identify. My friend said both manufacturers
and the dealer were very helpful. The final solution was an 800 ohm,
2 watt resistor for the speaker and factory mods for the amp.
Now everything is fine.
The above is NOT meant to disparage ANY of the products mentioned. All
are excellent products from very reputable manufacturers. The unusual
case my friend ran across was corrected with no loss of quality. I am
repeating the story since: (a) I found it rather humerous how "the best
intentions ..."; and (b) it points out the advantages of buying from
quality firms.
In any case, the views are my own and have nothing to do with CCI, my
employer.
- Tom Beres
{seismo, allegra, mcnc, brl-bmd, we13, gatech}!rlgvax!tom