Newbie quesiton about Pre and Power amp

H

Hungseto

Guest
Dear everyone,

It might sounds very stupid, but I will still ask anyway.

With a pre and power amp system, what is the correct procedure for swtiching them on and off?

at the moment I swtich them on : PRE first then POWER 2nd
and i swtich them off : POWER first , then wait one minute for power discharge then the PRE off.

What if i switch the power amp on without a pre amp connecting to it but with the amp wired to the speaker, will it harm the speakers? I would want to do this to see if the hum i get is from the power amp alone.

my expereince from meomry is that power amp off without a pre amp 'controlling' it will make an instant power discharge hence a pop in the speaker which i guess must not be good thing to do frequently
 

clockworks

Novice Member
With decent quality equipment, it shouldn't make any difference. I've got my Linn, Naim and Denon kit all plugged into an extension lead. I just turn the whole lot on and off at the wall socket.
 
H

Hungseto

Guest
possibly because the quality of my system is not that good then.

its very old. about 20 years old.

Cambridge C75 power amp and A75 pre amp.

but sounded good enough for my ears at this moment.

thank you for your help!
 

clockworks

Novice Member
Are you actually having problems with the equipment making nasty noises?

It's possible that you might have some stray offset voltage somewhere, causing clicks or pops. Maybe a capacitor is breaking down? Some older equipment used relays to isolate the connections until the power supplies had stabilised. These would cause the connections to "float", allowing interference and mains hum until the relay closed.

My Naim power amp does actually give a small pop if I use the power switch (it's about 20 years old). If I turn it off at the wall instead of using the power switch, I don't get any noise.
The Linn power amp is a more modern design (only 10 years old!), and doesn't make any noises at all.
 
H

Hungseto

Guest
No funny noise really, just some ground hum and hisss sound which doesn't affect the normal listening of music, just can be heard of with no source playing and head in front of the speaker within a meter's distance.

I knew that if I swtich off the pre amp first or if i swtich off at the power source on the wall I get one nasty pop, so I don't do this anymore and the system has been working in daily use for some 15 years now and is stilll good.

perhaps there is little problem with my amps but given their age and the quality of sound it still produces today. I will just live with it unitl next upgrade. I have upgraded everthign around it , expect the amps which I always think will cost me at least 1000 quid to beat it. (my guess only, i don't know coz it costed some 400 quid 15 or 20 years ago)
 

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