Running 4 speakers from a 2-channel amp


I love the sound of 4 speakers playing at once around me. I've got a simple old SS amp, Luxman L507 (mid-1970's) that runs 4 speakers at once. I'm running a pair of Yamaha NS-1000x (6 Ohm) as mains, and a tweaked set of B&W 805Ns (8 Ohm) as B's.

I'm talking here about 2-channel sound, 4 speakers, not 4-channel surround sound.

I've been looking for a higher-end amp, but find almost all are two-channels only, with ports for only two speakers.

Some great old Luxman tube amps offer 4 channels, but only one pair at a time is available on the selector ("A or B," not "A and B"). One shop told me they could have one modified for me to be able to play 4 speakers, at only a small cost.

Another shop told me that playing 4 speakers at once, even on my current old Luxman, which has the "A and B" option, overburdens the amp and shortens it's life.

I wonder - can't we wire-up 4 speakers, say two on each side in parallel, like in so many car stereo setups?

Am I really limited to only 2 speakers with a 2-channel amp?
jimthewebguy
A much better solution would be to get a second power-amp or a high-end home-theater power amp (i.e. McIntosh MC7205), and run each speaker of its own amplifier channel. Simply split the preamp signal with Y-cables on the amplifier inputs.

Also, if the second/new power amp has input gain controls, you can adjust the front/rear loudspeaker balance to your liking, with no performance side-effects.
Hifitime - Yes, in parallel that looks bad.

I suppose that amps with an A+B selector option have a different wiring than parallel. I do not notice any change in volume in set A or B when I switch from A or B to A+B, so I suppose there is some degree of separation of the output stages. Mine is an old Japanese amp for which I have no specs.

Would you, or anyone out there, know whether it is true that driving 4 speakers from an amp designed with that option actually causes excess wear on and eventual damage to the amp, as some sales guys (in an amp department - maybe not without motive) told me?
Heat does shorten transistors life.Running two 8 ohm speakers is about the limits of most amps(4 ohms total).All the amps I've owned do parallel the speakers through the speaker switches.Some budget receivers run them in series,but that ruins the sound because both speakers would be using the others crossover along with its own.The 8+6 ohm speaker combo is over doing it in my opinion.The other peoples ideas sound better if you like the amp and want it keep on going.
Thank you all for the facts n ideas. It sure cut out a lot of time for me. I'm still thinking about my next move.
I am running 18 separate speakers, that are "passive",
with 3 Amplifiers driving them ALL.

Respect "Ohms Law!" and you can safely run in "series",

several speakers without presenting a low impedance that

is hard on the amplifier.

In addition, I implement 2 Velodyne subwoofers.

An 18" and a 15" one in front, one in the rear.

I implement front speakers, and side speakers, along

with rear center speakers.

Stereo ONLY, simply put, just 2 separate systems working

together to fill the room EVENLY with sound.

I have done speakers in both parallel and series, for over

30 years without ANY incidents at ALL.

PS Audio GCA 500, and a GCA-250 do the lions share,

while a Pro Hafler 300 wpc. @8ohms and 500wpc. @4ohms

for the side speakers.

NO sound processors are used, just PURE 2 channel sound

that is IMHO, the finest "Surround" Sound I have heard

so far.

Every speaker adds +3db. so you can see that this is an

easy way to squash the -10db. that most people have,

from their listening spot.

My idea was simple, 1 speaker must play very Loud to try

and fill a given room.

Placing speakers, in key locations where the hearing, is

able to pick up sound literally "ALL Around".

So I have plenty of "Headroom", and there is NO need to

ever increase the Volume, since the moment the "play"

button is engaged, it is as if a metamorphosis of the

Audio kind takes place.

Never be afraid to think outside the box.

Some of my Best ideas, have spawned out of the box.

Love Your Music!