PDA

View Full Version : Sansui AU-7900 amp help


metalbob
10-17-2007, 07:38 PM
I initially used this amp back in the early 90s as I had "acquired" it from my parents, along with the matching receiver. At some point, I gave it back and purchased another integrated amp (with built in receiver) that I've been using for well over 10 years. I don't recall what speakers I had been using with the amp at that time, but I did buy a pair of Boston Acoustics Sub Sat 7-series speakers I've used ever since. I don't think I ever used them with the Sansui.

A few years ago, I managed to reacquire this amp from my parents as I knew they were never going to use it again. It had been left in the basement and moisture has started to set in a bit, but to my knowledge, it's never been used since I used it in the early 90s. I used it a while back as a pre-amp (there is a switch in the back to use it as such) to do some needledrops and had some issues with one of the channels dropping in volume over time, so I put it in the closet and it sat there until today. I never used it with speakers or even any other components other than a turntable at that point, so I don't know if there was anything wrong with it then.

Today, I took apart the entire unit today, cleaned out all the dust with compressed air, cleaned the dust and muck off of the case and even bought some control cleaner to clean up the pots and blade switches. All seemed fine until I hooked it up. So after spending hours cleaning this thing up, dismantling my entire stereo system and hooking this amp up, I get no sound -- not even hiss. The only noise I got was when I cranked it up to 11, I heard a loud cracking sound which I am sure is not good for the speakers, so I've stopped playing with it trying to figure out what is wrong. I am not sure if there is something wrong with the amp (everything should have been dry at this point, so that's not it) or if it's something more technical like the ohm rating on my speakers is different than what the amp is putting out. I don't know much about those types of things, but it was just a wild guess.

Any guidance on this would be a big help.

Thanks!

BOB

namretsam
10-17-2007, 08:07 PM
Are you using it with speakers this time and do you have the amp/pre-amp switch in the proper position? you probably dont want to hear this but IMO cleaning switches with contact cleaner is NEVER a good idea if you are not having a specific problem.
I have one of these I have used almost daily for 20 years. Currently using it as a pre-amp to drive a pair of Mac 75's...

metalbob
10-17-2007, 08:11 PM
Are you using it with speakers this time and do you have the amp/pre-amp switch in the proper position? you probably dont want to hear this but IMO cleaning switches with contact cleaner is NEVER a good idea if you are not having a specific problem.
I have one of these I have used almost daily for 20 years. Currently using it as a pre-amp to drive a pair of Mac 75's...

I tried it with both and it worked with neither. I know in the past there were a couple of sticky switches, but I didn't hook it up to determine which ones were causing trouble. I wish I knew that beforehand.....I even tried putting the speakers in the A inputs then moved them to the B speaker inputs just to check and got pretty much the same outcome.

I wish I knew back then what I know now about old stereo equipment as I would have hung onto it. I don't recall it being in such rough (honestly, it's not horrible) shape when I used it back in the early 90s.

bluesky
10-17-2007, 10:35 PM
Hi. Over at Audiokarma.org (http://www.audiokarma.org/forums/forumdisplay.php?f=39) there is a Sansui site that deals with Sansui exclusively and every kind of repair you can think of for Sansuis. Those guys know their Sansui stuff inside and out so it may be a good idea to 'cut and paste' what you wrote here and I am sure that the Audiokarma Sansui community will be able to help you out. When it comes to Sansuis they have seen it all. Sansui forever!!