Hi fi problem (ie 'Stuff' rather than 'Computers'!)

[cirks]

only just got my hi-fi separates system connected up again after a long break of having building work done but now got a problem. The speakers are transmitting a horrible noise even when volume turned down BUT only when the amp (Arcam Alpha 5) is not in 'direct' mode. So, can't see the problem can be mains cable interference (speaker cables under floor) as this would happen whatever mode the amp was in. Can only think it's an internal amp problem? The speakers are Mission 700s (?) and are bi-wired with 79 strand.
Any thoughts? Advice appreciated.

[FunkyGibbon]

IIRC direct mode cuts out any setting you have made with bass, treble and balance on the Arcam 5.

So, if it works ok in direct mode, then it suggest summat up with the pre-amp bit of the gubbins inside.

I used to leave mine in direct mode anyway.

Not much use to you, but I'm sure someone who know's what they are on about will be along shortly.

[Plotloss]

Yeah I'd agree with that, direct just bypasses most of the pre-amp circuitry leaving it just as volume controllable power amp.

[mr_yogi]

just a thought (not knowing the Alpha 5), but some amps have a processor loop which when no processor is present use shorting pins to connect processor out to processor in. If it has these are they dirty/ connected properly?

[zumbruk]

Dirty contacts on the "Direct" switch?

(I've got problems with the input select switch on my Alpha 9. The damn thing's so difficult to get out that ICBA to mend it,)

[cirks]

Thanks for the thoughts so far. I'm happy to leave it in Direct as the sound is good anyway. However, it would be nice to find out what's causing it. I'll check the contacts etc.

[NiceCupOfTea]

I'd go with dirty contacts too - I have an Arcam Alpha 9 and the switches get very dirty, the source select is especially bad on mine. Try moving them about a bit, spray them with contact cleaner and compressed air and then see what's what.

[robdickinson]

cpc will ship you contact cleaner for a few quid, open her up & clean all the pots/switches, clean the contacts etc. Should fix it.

[steviebee]

Assume you've checked that the speakers are wired to the correct terminals.