Adcom 555 owners
 

I picked up an Adcom 555-2 amp last week and have a few questions.

1. I have heard that it is best to leave the amp 'on' all the time (or most of the time).
The amp gets very hot, even when the preamp is not on. Is this normal? Do you
turn yours on and off with every use?

2. About 45 seconds after powering down, there are audible noises coming from
the speakers when the caps discharge, is this as normal as some say it is?

I leave transistor amps on all the time in the winter (more heat for the house) - during summer, will turn off if not going to use for a few days.

Can't recall how the 555 is biased & dunno re noises.

The electronic's gurus have always told me to leave pre amps on. It takes 2 - 24 hours for them to stabilize for best sound. Power amplifiers take about 15 - 20 minutes.

Ian

I owned one for many years- a very fine amplifier. I never got noises from the speakers after shutdown but I also used an Adcom speaker selector and Adcom power supply (still use 'em BTW) so that insulated them (I shut off the speaker connection then the amp). It would be unusual for any amp to continue to deliver enough power to make noise through the speakers after you shut it off so you may want to check it or put in a switch that decouples the speakers.

I don't think it matters if you leave it on for hours or days but it was never recommended that I know of and I personally wouldn't do it if I were leaving the house because it's a fire hazard.

I have another transistor amp now (an MC602) and I don't leave it on all the time. There's nothing in the McIntosh literature that says you should. I defy anyone to hear a difference between just on and on for a long time.

I turn mine off with every use, but I also keep a cooling fan in the cabinet to extract the heat that it generates. This helps IMMENSELY with keeping it cool. Mine would get too hot to touch before installing the cooling fan. :eek:
Mine has done that since new. I turn off the preamp first and the amp second to cut the signal to the amplifier.

My pre-amp was running very hot once. I took it for some servicing and they found some bad capacitors.

It came back sounding better than ever.

You may want a shop to check it out, or just don't leave it on when you are not in the house.