Can anyone help with a spot of advice?

I'm in the process of buying a 2nd hand Arcam Alpha 10P. The, extremely
honest, seller called me the other day to say he'd come across a problem
with it whilst demo'ing the 10 integrated he's also selling. He said that
the buyer wanted him to turn it past 50%, and when he did so, the 10P
switched itself into standby. The unit had just been started, so it
shouldn't have exceeded any heat limitations.

He's swapped out all cables (I've seen a shorted speaker cable cause this
sort of thing before) but it still happens, whether the power amp is hot or
cold.

The manual suggests it might behave like this at high levels if the speakers
are low impedance and/or the source is particularly loud (e.g heavily
compressed rock, off CD). Even so, 50% volume sounds a bit low for it to
start happening (even if it is 'kin loud).

Any thoughts? Normal behaviour in circumstances I'm hardly ever likely to
experience? Or the sign of an amp that's on the way out? Any advice would
be greatly appreciated.

Regards,

Deep C

In article , Deep C
wrote:
Can anyone help with a spot of advice?

He said that the buyer wanted him to turn it past 50%, and when he did
so, the 10P switched itself into standby. The unit had just been
started, so it shouldn't have exceeded any heat limitations.

The manual suggests it might behave like this at high levels if the
speakers are low impedance and/or the source is particularly loud (e.g
heavily compressed rock, off CD). Even so, 50% volume sounds a bit low
for it to start happening (even if it is 'kin loud).

Hard to say for sure without more information. I am not sure what is meant
by "50% volume". Most volume pots have a semi-log law. Do you mean rotated
to be half-way between fully-up and fully-down? If so, I'd guess it is
actually about -20dB down on fully-up. However in itself this may not tell
us much unless we also know what source was used, and what signal levels
(and shapes) were being played into the amp. Also, if the cutout is a
current limiter/trip we'd need to know something about the impedance
properties of the speakers being used as well as the details of the signal.

The 'volume control' allows you to adjust the overall 'gain' of the amp,
but how loud the result is - and how much current / voltage are output -
depends on other factors like those I have mentioned.

As a result, the above may not establish that you will have any problems.
Will depend upon what you play, how loud you like it, what the impedance of
your speakers is, etc. Hence unless the amp is checked in some way, you can
only really tell by trying the amp in circumstances equivalent to those in
those where you would be using it.

FWIW with most of the amps I use, until/unless I modify them, the working
volume settings would tend to be well below the mid-rotation point whilst
being quite loud (in my judgement).

Slainte,

Jim

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