Connecting speakers to a PA amplifier

Justin_k

Hi

I need to find out if it's safe to connect a pair of Bose 701 loudspeakers to a PA amplifier.

The amp is not from a home stereo system, rather it has been used in a classroom to power perhaps 8 loudpeakers.

The speakers are rated at 100W max per channel while the amp is rated at I think 40W per channel.

The speakers are 8ohm, as is the speaker output.

The main concern I see is at the back of the amp at the speaker terminals I noted it says on the amp 8ohm, 10V.

I've never seen a home hi-fi amp ever state that there was 10V across the speaker terminals.

So - I suspect that it's not safe to connect these speakers to this kind of amp. I think the amp is this type

Can anyone confirm?

Thanks
Justin.

bushy...

Could it be 100v ? http://www.ukslc.org/Technical_Articles/Sound/Guide_to_100v_line_PA_systems.html

Justin_k

Hi

I don't have the amp in front of me today.. it's in work but it's possible.

I guess the question is whether there is a risk of destroying these home hi-fi speakers by connecting them to a PA amplifier like this.

Or are all speakers in cabinets in roughly the same range much of a muchness when it comes to hooking them up to amplifiers in roughly the same power range

Justin

cornbb

Moved from Recording/Mixing/Pro Audio. You'll probably get good advice from whoever hangs out in this forum.

Justin_k

I checked the Amp and it seems to allow 2 kinds of speaker connections. It seems that I can connect to the 100V speaker output if I want to cascade other large PA speaker systems together

Instead there is both a 4ohm and 8ohm connection facility with a common terminal - but this means that the amp only supports mono output which is really no good.

I asked around and one of the guys in work reckons he has an unwanted Marantz hi-fi amplifier at home in his attic and that would be perfect - as long as it belts out a decent amount of power and has 8ohm compatible speaker connections.

So - I guess that makes this thread closed.

highlydebased

No- It would be 100w. Thats the power rating of the amplifier.

Provided you have the right impedence (8ohm) Selected I should see no problems

Red Alert

That most certainly is a mono 100V public address amplifier. The eight and four ohm terminals will drive the amps entire output into a speaker of the correct impedance.

100V line is used in places like supermarkets, shopping centres, churches etc. Basically the amplifier (whatever its size) has a transformer that sets the max output RMS voltage to 100V. Each speaker has a transformer that steps the voltage down, and it will usually have multiple 'taps' so that speakers can be set at different levels to compensate for things like ceiling height. There's little losses in the distribution wiring, speaker levels are easily balanced and also the system is expandable - because of the voltage matching you could in theory connect a 1kW 100V power amp to a 100V speaker tapped at 6 watts and you'd have no problem other than wasting your money! The catch with these systems is the slight reduction in low-end response from them. Great for places like shopping centres, but not very useful for home.

Don't be fooled - it may have stereo input terminals so that a stereo CD player or radio can be connected to it. Internally they'll be summed to mono.

Not sure this amp is what you want!