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Cary rocket 88 vs dynaco st70

I currently have a completely rebuilt and upgraded dynaco st70 that sounds very nice in my system.

Classe dr6 pre
Quad 11L monitors
Denon dvd/sacd

I am having some low level hum from my dynaco, and am considering a used Cary rocket 88.
If you have a rocket 88,how quiet are they,and would this be an overall sound quality upgrade over the dynaco?
Speakers are 6ohm, 86db and have plenty of volume with the dynaco.

I had a pair of 96db klipsch kg4 in the system and the hum was unbearable.

There are no groundloop issues since my bryston 3b at has no hum in the system.
????
dave
dav65mus
calbrs03
184 posts
 
I had a problem similar to yours. Turned out to be weak output capacitors.
rodman99999
5,984 posts
 
Output capacitors? What are those? I've owned both amps. Had no noise from either, at all. Over the years I had upgraded the coupling caps, multi-section cap(which could be your issue), and added some capacitance to the B+ supply(plus a few other mods). The Rocket 88 was still an improvement, especially in triode mode. If you move to the Cary; you won't regret it. BTW- Try flipping the Dynaco's plug over in your wall outlet. If it's still stock; the prongs should be the same size.
calbrs03
184 posts
 
Rodman: Dunno what they are. You'll have to call Cary and ask. This was a while back, too, so I'm probably a bit loose in the jargon. Anyway, it was a capacitor that made the same hum that Dav65mus is experiencing. When fixed, things were dead quiet.
rodman99999
5,984 posts
 
A bad power supply filter cap(in any electronic component) can cause a variety of noises. Could that be what you're thinking of?
hifitime
715 posts
 
Might be a problem with the upgrade/rebuild job? A friend with the big 104db Klipschorns swaps amps for variety,and no hum on his stock Stereo 70.
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