4-8 ohm Speakers same receiver/amp

[Ricardo]

I made a search on the subject and the closest I got is this:

http://www.polkaudio.com/forums/show...hlight=mix+ohm

which talks about a receiver with an impedance switch.

How about receivers/amps that do not have this switch? Specifically, is there any risk to the speakers or amp in doing this for:

1.-HK 3480
2.-Adcom 535

Both have two speakers outputs; thinking in connecting 4 ohm in one and 8 ohm in the other. Only one output would be used. (There is always a possibility though of mistakenly keeping both..)

Thanks.

[AsSiMiLaTeD]

So you have two sets of speakers, one 4 and one 8 ohm, and you want to put them on the A and B channels of your receiver?

Well I definitely wouldn't run them at the same time given that scenario, but I don't see any reason why you couldn't do what you're saying and just listen to one set of speakers at a time. I suppose if you had A and B both accidentally selected you wouldn't blow anything up - but I wouldn't try listening like that for any real amount of time.

P.S. - I don't know why you can't run both simultaneously, just doesn't sound right to me and it's not something I'd want to do.

[Ricardo]

Thanks; one of the speakers set would be in the deck; the other one inside. I plan to use the adcom, though might experiment with the HK..have heard good things about that receiver.

[heiney9]

Thanks; one of the speakers set would be in the deck; the other one inside. I plan to use the adcom, though might experiment with the HK..have heard good things about that receiver.

The Adcom would have no trouble running both at once at moderate levels. I not 100% sure but almost all units with speaker switching capabilities have the swtich wired in series so it doesn't halve the impedence like running them in parallel would. So I wouldn't worry.

Not sure about the impedence switch...never owned any equipment with that function. Adcom's have no trouble running 4 or even 2 ohm loads. I'm sure the HK would work well also.

Fwiw

H9

[labrat]

While H9 is right:

almost all units with speaker switching capabilities have the swtich wired in series

I have a Denon that runs them in parallel. While it is great for running the mains bi-wired (sorry about opening that can of worms) it would probably cause problems running a 4 ohm load with anything else. IMHO it sounds like it may be time for a check or the receiver's manual just to make sure it doesn't get more than toasty warm.

Labrat

[Mike682]

Not sure about the impedance switch...never owned any equipment with that function. Adcom's have no trouble running 4 or even 2 ohm loads. I'm sure the HK would work well also.

I was told to never use the impedance switch on a receiver. It's a requirement from UL that enables manufacturers to say a lower line (lower cost) amp can handle 4ohm speaks. Basically it cuts down the amp so it doesn't overheat...

Most HKs can handle 4ohm speaks but they can't advertise it because of the above mentioned electric standards set by UL for home use. (this is what an HK rep told me).