8 Ohm speakers with amp in 4 Ohm mode ?

[bleeding ears]

Hi all, I am considering purchasing some dali surround speakers which are 4 Ohm.

The problem is my centre and mains are 8 Ohms.

I can set the switch on my Sony Ta-n9000es 5 channel amp to 4 ohm mode to cater for the 4 ohm rears, however what effect if any will there be with the other speakers being 8 ohms ?

Will it cause damage to the amp or speakers ?

Obviously it is not the optimal situation, but can I do it without any problems ?

Anyone know ?

[Karma]

HI bleeding,
It's hard to say without actually seeing the schematic diagram to determine the circuit changes that are made with the 4/8 ohm switch. I suspect Sony limits the power supply current draw in the 4 ohm mode because the components are not designed to operate with twice the current that 4 ohm loads potentially demand. Thus, no harm will come but you may notice your 8 ohm speakers will not perform as well.

This is especially true if the amp is somewhat underpowered the begin with. Amps that have these switches are usually mid fi types that are not power monsters to begin with. It is not the best situation.

Sparky

[whoaru99]

No, there will not be damage to the 8 Ohm speakers or the amp running in the 4 Ohm position. But, as Karma says, current will be limited so the amp will not deliver as much power to the 8 Ohm speakers. If you play at lower levels, you may not notice, but when you turn it up, the bass probably will not have as much punch.

I can speak from some experience here because I used to have a Sony STR-G3 (Vision Touch) receiver that had a 4/8 Ohm switch. I had it connected to 4 Ohm speakers and tried the switch in both positions. It definitely had more oomph with the switch set to 8 Ohms. Against Sony's recommendations, I left the switch set to 8 Ohms for a couple years with this receiver and had absolutely no problems - although it did tend to run fairly hot. Never did shut down though.

If it was my gear, I'd leave the amp on the 8 Ohm position given only the surrounds are going to be 4 Ohm speakers. However, it's ultimately up to you to decide.

[bleeding ears]

Yes, the sony amp does limit the output in 4 ohm mode,according to the manual, but it limits it to about the same output of the 8 ohm switch position. It obviously is not designed to handle double the output with 4 ohm speakers

8 Ohm position 140 watts (DIN)
4 Ohm position 130 watts (DIN)

Judging by the above I am hopeful there will be no noticeable difference in sound quality or volume level.

My main concern is not to damage anything

Perhaps I should give the amp a trial run in 4 ohm mode using only 8 ohm speakers and see what i get. Hmmmm

[whoaru99]

Yes, I would try that.

Be sure you try a listening level at least as loud as you normally do, and something that demands power.

The ratings are close with the switch in either position, but in the 4 Ohm position I assume the power rating is with 4 Ohm speakers connected. So, when you connect 8 Ohm speakers and have the switch in the 4 Ohm position, I believe the output would be approximately 65 watts to the 8 Ohm speakers.

[comeup]

Bleeding Ears I'm no expert, but since it's only surrounds why not go with 8 Ohm speakers? Are your mains Dali's? I know some of those Dali's sound darn good I like them alot.

[Azeke]

Bleeding Ears,

Whatever your ohms per channel, use that ohm or higher, just don't go lower, (i.e. don't use a 3 ohm speaker with a 4 ohm amp). As long as your 8 ohm speakers can handle the additional wattage you should be fine, IMHO. Just my pennies worth.

Peace and blessings,

Azeke

[bleeding ears]

comeup, yes it may be better to just get 8 ohm rear speakers but I am very impressed with the dali sound and unfortunately nearly all their speakers are 4 ohms nominal.

Currently my mains are Energy C3 and centre is an orpheus .5 both of which are 8 ohms.

I am sort of in between a change in speaker brands.

As for the testing of 8 ohm speakers with the amp in 4 ohm mode, yes there is a difference.

The speakers seem to lack a little of oomph or slam or dynamics when the amp is in 4 ohm mode compared to when the amp is in 8 ohm mode.

This is a problem that I was not expecting, so the info you guys have given me has been great.

Looks like I may have to go to a full 4 ohm speaker setup or get another amp ?

I am assuming the amp will not lack in 4 ohm mode with 4 ohm speakers, the way it did using 8 ohm speakers?

Pete

[whoaru99]

Just leave the switch in the 8 Ohm position - unless of course, you are looking for an excuse to buy a different amp. ;

Remember, these are surrounds you're talking about - usually not as demanding as mains or center, typically closer to the seating position, and they are 4 Ohms. These factors come together and result in less apparent demand from the amp. Given the likelyhood of closer distance and the 4 Ohm speaker impedance, the trim levels for the surrounds probably will be in the order of -6dB (give or take) from what ever the mains are. This means the amp won't have to work nearly as hard on those surround channels to keep pace with the mains/center.

Oh, and the "sound" of the amp probably has not changed much, if at all, but the performance has. It's putting out only about 1/2 power when you have the switch in 4 Ohm position and connect 8 Ohm speakers.

I believe leaving the switch in the 8 Ohm position will not cause you any problems at all.

[bleeding ears]

who, yes sounds like a reasonable option to me.

I am actually using a seperate 2 channel amp for the fronts so it would only be the centre speaker and rears that are being powered by the sony multichannel amp so it should not be working too hard.

Hopefully I can get away with it until I get a 4 ohm centre or a different amp.

Thanks for the info.

[comeup]

Pete, I understand why you love the Dali's so much I heard them for the first time in San Francisco a few months ago and loved them the helicons to be exact. I didn't know you had all different speakers I don't know your financial situation, but I would go with Dali's all around. I listened to the Dali Ikons too a step down from the helicons and the sound is almost as good with a lower price with great reviews. What ever you do get the same speakers all around the sound is so much sweeter i'm pretty sure you already know that. Anyways good luck.