Can I run 4 speakers off of this Amplifier?

mc_bob · 1 Sep 2006 at 19:54

Hi,

Im looking at buying an amp as my last one died in a nice way.

It will need to run four speakers.
Two Goodman Speakers and two Kef Speakers.

The Goodmans need about 40w and the Kef speakers say 50-100W (they ran fine on 50W) on the back.

I found the Cambridge Audio 5 for £90 (im going to try and get this down) which I think is reasonable.

Website : http://www.cambridgeaudio.com/summary.php?PID=32&Title=Summary

PDF of Specs : http://www.cambridgeaudio.com/assets/documents/AP105134CAAmplifiersUsersManual.pdf

It says only 1 pair of speakers can be used but the guy says 2 pairs will be Ok?

He says putting two on each channel will still work as they arent power hungry speakers.

Is this true and will it work?

Reading now the amp gives out 60W per channel. Now Ive confused myself

So the Q is, Will my four speakers work on this amp?

Thank you

MC_Bob

squiffy · 1 Sep 2006 at 20:03

What are the speaker specs? It's best not to run two pairs of speakers from the same amplifier, especially if it's a budget amp. When you do so, impedance is halved between the two (ie if two pairs of 8ohm speakers are used, the load will be 4 ohm) 4Ohm load is too much for a budget amplifier.

Why do you need to run four speakers? (impedance and sensitivity) Why not buy a amplifier with speaker switching (A/B)

mc_bob · 1 Sep 2006 at 20:12

Keg Coda III - 50W 8Ohms
Panasonic - 30W 8Ohms

Those are the correct names now I looked

If the amp won't run this, how much am I really looking at spending on a decent amp which will support the 4 speakers?

The Goodmans 40+40 wasn't very powerful but made a nice sound.

Thanks

MC_Bob

Clarkey · 1 Sep 2006 at 20:32

Wouldn't recommend it on any stereo amp tbh, its probably what killed your last one.
I'd get a seperate power amp to run the second pair.

mc_bob · 1 Sep 2006 at 20:45

Clarkey said:
Wouldn't recommend it on any stereo amp tbh, its probably what killed your last one.
I'd get a seperate power amp to run the second pair.

The last one was designed for four

So I take it that it wont work?

Thanks

squiffy · 1 Sep 2006 at 21:01

mc_bob said:
The last one was designed for four

So I take it that it wont work?

Thanks

What make/model was it?

mc_bob · 1 Sep 2006 at 21:04

Goodmans 40+40

james.miller · 1 Sep 2006 at 21:05

4 ohm should be fine im sure as long as your not pushing it to the limits 24/7. Having said that, i ran 2 4ohm subs off a cheap creek 4140s2 for years and that never missed a beat. infact its still going to this day, powering somebody elses main speakers.

squiffy · 1 Sep 2006 at 23:32

james.miller said:
4 ohm should be fine im sure as long as your not pushing it to the limits 24/7. Having said that, i ran 2 4ohm subs off a cheap creek 4140s2 for years and that never missed a beat. infact its still going to this day, powering somebody elses main speakers.

Your setup with subs is different to loudspeakers.

Distortion at 4ohm is increased considerbly. This will likely damage the voice coils on a treble driver. Distortion isn't so audible on a subwoofer, and unlikely damage it. Will on a treble driver though.

I've used amps which have overheated and cut-off with 4 ohm speakers. So not a good idea.

Best thing would be to get stereo amplifier with A & B speaker switches, and only use one pair at a time. Later on could add a 2 channel poweramp to drive the other pair.

OP- take it you're doing multi-room audio? And not quad-surround or four front speakers which generally makes a mess of the sound.

mc_bob · 1 Sep 2006 at 23:50

Hmm,
Its actually all four in one room. Thought they sounded Ok lol!

I won't get that Amp then.
Should I invest in some nice speakers then and just have two instead?

MC_Bob

mc_bob · 2 Sep 2006 at 00:18

Ive been offered a Sony str-de475 for 55 inc.

Some specs here http://www.gooshing.co.uk/home_cinema_receivers/sony_str_de475/

Is that good and should I take it up?

Thanks

james.miller · 2 Sep 2006 at 02:23

squiffy said:
Your setup with subs is different to loudspeakers.

Distortion at 4ohm is increased considerbly. This will likely damage the voice coils on a treble driver. Distortion isn't so audible on a subwoofer, and unlikely damage it. Will on a treble driver though. I've used amps which have overheated and cut-off with 4 ohm speakers. So not a good idea

and i never said ive only done it with subwoofers so whos right now? Ive run numerous amps with 6 and 4ohm nominal loads. out of the 7 or 8 amps ive mess around with, only one of them failed. That one has the power supply fail, but that was a n old amp which wasnt very good any how. See i can afford to experiment because i get them for virtually nothing. my findings? well, nothing really. they all still work bar that one.

Just an observation squiffy but you always have an 'answer' for everything i say, no matter if you jump the gun or not, as you just did. Just an observation, as i said.i only mentioned the creek running subs because that was the amp that got the most sustained abuse.

mc_bob said:
Ive been offered a Sony str-de475 for 55 inc.

Some specs here http://www.gooshing.co.uk/home_cinema_receivers/sony_str_de475/

Is that good and should I take it up?

Thanks

thats a different ball game lol. av amps arent nearly as robust as a little 2 channel amplifier. that sony probably has an inpedance switch to limit current delivery to enable it to drive a 4 home load, like my yamaha. They dont do this to protect the speakers, its to protect the amp lol. budget av amps really dont cope well with low resistance loads. Although it may well be 'suitable' for a 4hom load, i wouldnt push an av amp in such a configuration

find a cheap set of power amps of the bay or in a 2nd hand shop. £15-20 each and your sorted, you dont need to spend much. lower end denons go for petty cash, they would more than do the job

mc_bob · 2 Sep 2006 at 03:10

james.miller said:
thats a different ball game lol. av amps arent nearly as robust as a little 2 channel amplifier. that sony probably has an inpedance switch to limit current delivery to enable it to drive a 4 home load, like my yamaha. They dont do this to protect the speakers, its to protect the amp lol. budget av amps really dont cope well with low resistance loads. Although it may well be 'suitable' for a 4hom load, i wouldnt push an av amp in such a configuration

find a cheap set of power amps of the bay or in a 2nd hand shop. £15-20 each and your sorted, you dont need to spend much. lower end denons go for petty cash, they would more than do the job

Ah, You sound like you actually know what I need lol!

Is it OK for me to add you on MSN and ask you a few Q's?

Thanks

MC_Bob

daz · 2 Sep 2006 at 03:26

squiffy said:
Your setup with subs is different to loudspeakers.

Distortion at 4ohm is increased considerbly. This will likely damage the voice coils on a treble driver. Distortion isn't so audible on a subwoofer, and unlikely damage it. Will on a treble driver though.

Bull tbh. A small increase in distortion from showing the amplifers an easier load isn't going to kill the voice coils.

I've used amps which have overheated and cut-off with 4 ohm speakers. So not a good idea.

Poor quality amps with poor power supplies can't handle low impedance loads particularly well...
Most amps are actually fine though if you listen at a normal level (i.e. aren't having a party)

squiffy · 2 Sep 2006 at 10:15

daz said:
Bull tbh. A small increase in distortion from showing the amplifers an easier load isn't going to kill the voice coils.

4Ohm is a "easier load?" :rolleyes:

Rergardless what you two might think, it's still not a good idea to use 4ohm speakers on budget amplifiers. When you give out bad advice I'm not going to sit here and do nothing to disagree with your expert "advice"

How do you know the pressure levels he's liistening to? Who's jumping the gun now?) Perhaps he's using four because he wants it louder?

My advice would be to get a stereo integrated amplifier, only use one pair, and ditch the lower quality speakers.

ps regarding your sig, have you ever owned any THX Ultra gear? I have, a THX is a nice feature to have (have used few of THX's options/processing)

mcmad · 2 Sep 2006 at 10:20

squiffy said:
4Ohm is a "easier load?"

Rergardless what you two might think, it's still not a good idea to use 4ohm speakers on budget amplifiers. When you give out bad advice I'm not going to sit here and do nothing to disagree with your expert "advice"

totally agree, 4ohm loads are not a good match for low end amps.

mc_bob · 2 Sep 2006 at 10:39

Ok so now I'm just confused...

I saw a couple of Denon's on the bay, should I just get one of them and see how it goes?
Judging by the price, won't it sound crap?

MC_Bob

IamMed · 2 Sep 2006 at 11:13

bleh, get yourself an old Class AA Technics amp, will run the 4 speakers fine.

SU-V40 upwards will do, ran 2 sets of 6ohm speakers on one of them for 3 years, now my sister has had it for 2 years running 2 sets and it was 12 years old or so when I bought it!

You could have course sell what you have currently and invest in a semi decent set of speakers and a 2nd hand amp which is preferable to just adding sets of speakers to make it louder

mc_bob · 2 Sep 2006 at 11:23

IamMed said:
bleh, get yourself an old Class AA Technics amp, will run the 4 speakers fine.

SU-V40 upwards will do, ran 2 sets of 6ohm speakers on one of them for 3 years, now my sister has had it for 2 years running 2 sets and it was 12 years old or so when I bought it!

You could have course sell what you have currently and invest in a semi decent set of speakers and a 2nd hand amp which is preferable to just adding sets of speakers to make it louder

Lmao, yeah I should really get a decent set. They are actually quite good and I just bought the Kefs because... I'm not sure now but I did.

Looking on the bay there is a Technics RMS SA-EX310
Can't seem to find a manual on the net but the seller says it has a 60watts RMS x 5

They live in Hemel so I can pick it up. It's at 1 quid at the moment

Should I bid on it?
Yay or nay?

#Thanks for your help

squiffy · 2 Sep 2006 at 11:26

mc_bob said:
Lmao, yeah I should really get a decent set. They are actually quite good and I just bought the Kefs because... I'm not sure now but I did.

Looking on the bay there is a Technics RMS SA-EX310
Can't seem to find a manual on the net but the seller says it has a 60watts RMS x 5

They live in Hemel so I can pick it up. It's at 1 quid at the moment
Should I bid on it?
Yay or nay?

#Thanks for your help

That's a AV amplifer.
Get just a budget Rotel stereo integrated amplifer, and at least have quality. Denon and Technics don't sound great imo (yes I have owned both)