using multiple amplifiers on one speaker

[saltmiser]

I was stumbling around the internet, and I found this page -
http://www.recess.co.uk/html/tech.html

From the page

Buy three 100W amps (and sets of speakers), and run each of them at two-thirds of their power. This way, you don't really have to worry about your units collapsing due to the vigours of running at full whack the whole time. Plus, if one of the amps in the 2x100w option blows, you've lost half of your power - if one of your amps in the 3x100w option blows, you've only lost a third, and there's still the option of turning up the remaining two a little (all though, you have to think why the first one blew - it might still happen to the remaining two.)

Now, some googling for "using two amplifiers on one speaker " gave me some results saying that doing this will actually just blow your amps apart, and others saying that you can do it.

So, between all the mixed results, I wanted to ask this forum, is it possible? Why or why not?

[Dag]

You should NOT connect more than one amp to the same speaker input!!! The amp could blow.

"Buy three 100W amps (and sets of speakers)" = "Buy three 100W amps and three speakers"

(However, it is possible to use multiple amps to one speaker. This is called bi(tri) amping or active speakers)

[Cal Weldon]

Originally posted by Dag

(However, it is possible to use multiple amps to one speaker. This is called bi(tri) amping or active speakers)

Which requires an active XO or the ability to split your passive XO. Not the same as wiring your amps together on one speaker. As mentioned, do not do this unless your evil twin likes the smell of smoke.

Active speakers have the amps built in.

[dangus]

Well, there is bridging, which runs one speaker off two amps, and doubles the voltage output compared to a single amp. Parallel amps can be used too, if the amps are correctly matched; see the LM3886 app notes. And, I think it was OK to do that with a Dynaco ST-70 tube amp. This would just double the current capability.

There's some weird configurations where the common of one amp is connected to the output of the other. This is like bridging, I guess, but allows one side of the speaker to remain at ground potential. IIRC there's some examples in Ben Duncan's book on power amps.

As to the original suggestion to use multiple speakers and amps... I doubt that multiple amps are cost-effective, unless you've already got them lying around. Multiple speakers do offer the advantage of sharing power, improving room coverage, and increasing bass efficiency if they're close enough together.

[saltmiser]

I found some articles here => http://sound.westhost.com/index2.html. There's a few on there about bridging and what not, it all looks pretty interesting.

[picopos]

yes there's systems like those....the amps have to be identical and there's limits......in tthe past that was the way to have power in outdoors(someone says)anyway i losted the link but there's a company and i know they service the vintage crown stuff,they do amps on demand for industrial level costumers and they produce systems were u can stack several amps ,of course i'm talking about massive power,no 120v 15amp aplication....tri phase 480v....but this as an example....at lower power i believe is easier....
beetwen series pwr sources u only want one ground...carefull with that axe eugene



much respect

[picopos]

i believe so...but i might be very wrong............
in class d u have to syncro the several amps(pwr source)but with bjt's they have to be sinch in all specs (as in class d also)or else i believe efficiency will drop has a result of the current produced beetwen different potencials of different dynamics of the amps....it's really just like bridging(or paralleling,deppending on the need),and not really a good ideia(in my honest don't know what i'm saying oppinion),u'll loose sonic quality for sure,in parallel the amps will be slower and in bridge u'll have distortion,noise,on the lowest fastest dynamics,much more perceptable in my oppinnion then in parallel....if u'r going to buy a match for ur amp,sell it and buy something with X times more pwr then what u have now,or have more current avaialable on pwr supply,maybe doubling output devices(go easy on that )(i believe some good designs drop the voltage also as a prevention)...

if u have a decent,let's say 200 w in a pnp/npn bjt ended amp,u'll beat u those 3 of 100 at those leves and whatever level because the first one will sound better,allways,if i'm wrong please someone hit me....all this assuming u want to connect 3 amps to one coil,or several coils either parallel or series to one source,something that the quote of ur 1st post dont mention,it mentions that it's 3 amps and 3 sets of speakers.....
peace

....what am i doing here....

also the more focused sound source(less speakers) the better imaging and everything else (my ears tell me)(some like orange some like grape)