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2 amplifiers, 1 pair of speakers

Any ideas on the best way to achieve this? My friend has a sony multi-channel amp for HT and a Cary SLI-80 for 2 channel listening. The speaker wires are currently plugged into the Cary. For movies, the Sony runs the surrounds and uses the pre-amp out to the Cary for the main speakers. The sony is off for 2 channel.

He would like to preserve the tubes for 2 channel only but needs a separate amplifier A/B type switch. Online searches have lots of speaker switches but we can't find any quality amplifier switches. One that accepts the spade terminations of quality speaker cables not the spring-loaded type for lamp cord.

Any ideas?

Thanks
stuartbranson
zoya
120 posts
 
I've recently done similar project and had a thread posted here, perhaps you'll find some answers helpfull:
http://forum.audiogon.com/cgi-bin/fr.pl?htech&1079220557&openfrom&1&4#1
If you interested I will send you a picture and a more detailed description of the switch that I had put together.
kr4's avatar
kr4
3,691 posts
 
Do not connect both amps to the speakers at the same time, even if only one is on at a time. First, even when off, the amp will load the other. Second, can you really be certain you will NEVER make the mistake of powering both?

Options:
1) Get a speaker selector switch and wire it backwards as an amp selector.
2) Use the tube amp all the time for the L/R.
newbee
4,768 posts
 
I agree with Kr4's 1st paragraph! Been there, done that, and fortunately I just blew a fuse in one of the amps! :-(

I now run two sets of cables from different amps using banana plugs. Far superior to introducing a switching devise and only a small bit of work to unplug one set of bananas and plug in the other. Personally I can't hear a difference between spades and bananas. If your amps are next to each other and accept bananas you can plug them into and out of the appropriate amp and use spades at the speaker for a more secure connection and have only one set of cables.
hivision
9 posts
 
Hi Kr4,

I am not an electrician or anything close to that. Can you explain -- "... even when off, the amp will load the other." What's the effects to sound quality.

Because that's exactly what I am doing. Marantz 9 amps to my Focus Audio FS-888 (and Arragon amp for late night session so I don't worry about burning up the tubes.)
stuartbranson OP
183 posts
 
Good ideas. Thanks. To answer the first question, No to the 5 way binding posts.
To the second concern, the Sony is only connected to the center ch., rear surrounds and sub. The L/R are connected to the Cary. Thats the issue. It means that the Cary must be powered for movies or the radio etc. and he would prefer to save the tubes for dedicated 2 channel and the Sony running the movies and the background times.
Newbee. This is the obvious answer but he is a man who relishes, nay, demands the convenience of a simple switch. Though I bet in the end the switch will cost him the price of a second set of cables. Likewise, switching at the amp end is a great problem because his system is in a built-in shelf and is VERY difficult to manoeuver. (I helped him install everything and don't want to mess with the cables back there again in this lifetime.)

Thanks Zoya. I will check into your post.

So there are no good quality switches out there?
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