Miss-matching Channel Impedance with the Amp

[PhilPC]

OK, so I've got a Z-5500 here, the satelite speakers are 8 ohms, and I'd presume the amp is also at that. I also have the speakers of an old Sony S.A.W stereo system, the speakers are also 8 ohms and are much better. According to WikiHow, if I connect them in series, the impedance of the circuit would be 16 ohms; and if I connect them parallel, the result would be 4 ohms.

Is impedance matching a valid concern with the z-5500? I hear with most modern amps it's not, however Logitech don't want me using anything but their speakers with it let alone multiple per channel.

[Guest]

Basically the ohm rating or impedance is the resistance. Amplifiers will produce different output wattages at different impedances. The higher the impedance the lower the power output from the amp.

I'm on my phone right now but do you know the wattage output for the amplifier channels and the wattage of each speaker?

[Guest]

Just got home and had a look at those speakers - there is no way in hell you'll be able to power the S.A.W's off the Z-5500 amp - Those Logitechs probably take somewhere in the order of 5-20w each whereas the S.A.W's are somewhere around the 100w mark and even if that was peak power stated, you're still a long way from 25w. (Peak = 2 x Program = 2x Continuous) (continuous = Peak/4)

What was the aim? Swapping out the Logitech LR fronts with the Sony ones?

[ccx90]

Windspeed36 your just off the speakers are rated up to 100watts and 20watts is enough to run them however just quieter than say running off a 50watt amplifier. Long as you match up left and right with the same impedance your fine cause that balances with the amplifer any less than 8ohms and it may overheat and may cause damage as too much current will be flowing though it :) and more imdeance will drain more voltage causing a drop in volume for the other speakers.

[Guest]

Windspeed36 your just off the speakers are rated up to 100watts and 20watts is enough to run them however just quieter than say running off a 50watt amplifier. Long as you match up left and right with the same impedance your fine cause that balances with the amplifer any less than 8ohms and it may overheat and may cause damage as too much current will be flowing though it :) and more imdeance will drain more voltage causing a drop in volume for the other speakers.

For any speaker you want to amplify you want 1.8 to 2.0 times the continuous power rating - so in all realism he would want about 45 watts per speaker @8ohm.

[ccx90]

Windspeed36 your just off the speakers are rated up to 100watts and 20watts is enough to run them however just quieter than say running off a 50watt amplifier. Long as you match up left and right with the same impedance your fine cause that balances with the amplifer any less than 8ohms and it may overheat and may cause damage as too much current will be flowing though it :) and more imdeance will drain more voltage causing a drop in volume for the other speakers.

Hmmm ok well i am sorry for my half i am still learning alot and want to learn more as it intresting to me while I study electronics but Unfortunatly my lectures don't have a great deal of knowledge in audio systems. Out of curiosity what sort of amplifier would you recommend for a pair of 4ohm speaker as the amplifier i am running it from is only their because that is all i could afford at the time. I am using cabasse Doris m1 speakers? And thank you for your input.

[PhilPC]

Thankyou for your quick response.

My aim is to have the front L,R, and C, S.A.Ws next to my tv pointing at my couch, the Logitech Satellites on my desk pointing at my chair, and have the rear Logitech Satellites mounted on the wall.

I have already tested the front S.A.Ws on their own with this amp and they're great, even if they're not much louder, they sound much wider than sats.

Here's the specs I found for the z-5500 http://forums.logitech.com/t5/Speake...ce/td-p/153833

and I'm yet to find a single spec on the S.A.Ws aside from the rated impedance sticker on the back.

[Guest]

Thankyou for your quick response. My aim is to have the front L' date='R, and C, S.A.Ws next to my pointing at my couch, the Logitech Satellites on my desk pointing at my chair, and have the rear Logitech Satellites mounted on the wall. I have already tested the front S.A.Ws on their own with this amp and they're great, even if they're not much louder, they sound much wider than sats. Here's the specs I found for the z-5500 [url']http://forums.logitech.com/t5/Speaker-General-Discussion/Logitech-Z5500-speaker-impedance/td-p/153833 and I'm yet to find a single spec on the S.A.Ws aside from the rated impedance sticker on the back.

From what I've seen most of the SAW's are about a 100w peak. If I were you I'd have a look around my local pawn stores and the like for an amp that can put out something like 50-80w per channel at 8ohm.

[Guest]

Windspeed36 your just off the speakers are rated up to 100watts and 20watts is enough to run them however just quieter than say running off a 50watt amplifier. Long as you match up left and right with the same impedance your fine cause that balances with the amplifer any less than 8ohms and it may overheat and may cause damage as too much current will be flowing though it :) and more imdeance will drain more voltage causing a drop in volume for the other speakers.

You'll probably want about 70w per channel at whatever the impedance is. As I said in the other post; have a look around eBay, pawn stores ect for a cheap Kenwood or something

[PhilPC]

The S.A.Ws normally live on my Kenwood 6.1 receiver (I've forgotten the model number) and they worked beautifully; The only thing is, that I'd like to have my home theater speakers outputting the same as my desk speakers. Is there anyway I can make the digital output of my Xonar DX soundcard the same as the analogue out?

I really should of thought of doing it this way in the first place. -_-

Edit: Using the Digital-out of the Kenwood, is not an option, because the z-5500 has an incredibly mediocre DAC

[Guest]

Thankyou for your quick response.

My aim is to have the front L,R, and C, S.A.Ws next to my tv pointing at my couch, the Logitech Satellites on my desk pointing at my chair, and have the rear Logitech Satellites mounted on the wall.

I have already tested the front S.A.Ws on their own with this amp and they're great, even if they're not much louder, they sound much wider than sats.

Here's the specs I found for the z-5500 http://forums.logitech.com/t5/Speake...ce/td-p/153833

and I'm yet to find a single spec on the S.A.Ws aside from the rated impedance sticker on the back.

Just noticed those numbers supplied by logitech are most likely fakes or inflated - amplifier fuses are normally set above the max output total; for example there's a pair of speakers i've got that have amplifiers rated at 550w and their fuse is stated for 600w - The logitech system has a 4amp fuse for 120v use meaning a total of 480w.