Help: Impedance, 8 ohms vs 4 ohms

[zurdillo]

Hello,

I have a very basic question. I'm interested in a power amp for my passive monitors Dynaudio BM5 (4 Ohm) and a option is a Yamaha A100 (55+55 w at 8 ohm).

Is possible (or recommended) this combination or the impedance difference will cause problems?

Thank you!

 

[NL5]

Hello,

I have a very basic question. I'm interested in a power amp for my passive monitors Dynaudio BM5 (4 Ohm) and a option is a Yamaha A100 (55+55 w at 8 ohm).

Is possible (or recommended) this combination or the impedance difference will cause problems?

Thank you!

The Yamaha rating isn't the impedance of the amp itself, it's the output at that particular impedance. Check the specs, it's probably OK at 4 Ohms. Most amps will do 4 Ohms just fine, many will do 2 Ohms.

 

[moresound]

Amplifiers are most happy when they are at 4 ohms.

 

[nialldoran]

i thought plugging an 8 ohm power amp into 4 ohm speakers never went, i know you get a maximum volume decrease if the amp is 4 and the speaker is 8, or has everything ive been taught bullshit?

 

[Minion]

Most solid State amps will give the minimum impedance and any impedance lower than the rated impedance would probably blow the amp when cranked up .....

if is says 8 ohms then that would be the lowest impedance I would use it at ..... if it was good at 4 ohms it would tell you so ....

 

[zurdillo]

Thank you very much for your posts.

The Yamaha a100 specs only speak about 8 ohm, I've not seen any reference to 4 ohm... and this is my doubt, if the absence of a clear reference to this impedance mean that don't will work ok.

 

[Minion]

If it only gives you an 8 Ohm impedance spec then that it probably the lowest impedance you can run it at .....

I run a set of Monitors out of an Amp that I built mostly out of spare parts , cost me maybe $50 to build and sounds very good ......


Cheers

 

[stevieb]

Amplifiers are most happy when they are at 4 ohms.

The broadest generalization, and also the most dangerous one, I have heard in months. I know of nothing that supports that statement.

My personal experience with Yamaha is that they are very conservative with this rating. If they don't say it'll do okay at 4 ohms, in the manual, calling them and asking them if it's okay is a waste of time- the answer guys will not countermand the manual. Lower impedance will result in more heat being produced in the amp, which is never good. Too low an impedence will result in the amp burning out- and although some amp makers say their stuff will produce X watts at 2 ohms impedance, "showing" it that low a load is risky business. Consider: the ultimate low load is zero ohms, or a dead short- which burns out amps. Get it?

Short version: that manual says nothing about 4 ohms. Don't use that amp with those speakers.

 

[zurdillo]

The broadest generalization, and also the most dangerous one, I have heard in months. I know of nothing that supports that statement.

My personal experience with Yamaha is that they are very conservative with this rating. If they don't say it'll do okay at 4 ohms, in the manual, calling them and asking them if it's okay is a waste of time- the answer guys will not countermand the manual. Lower impedance will result in more heat being produced in the amp, which is never good. Too low an impedence will result in the amp burning out- and although some amp makers say their stuff will produce X watts at 2 ohms impedance, "showing" it that low a load is risky business. Consider: the ultimate low load is zero ohms, or a dead short- which burns out amps. Get it?

Short version: that manual says nothing about 4 ohms. Don't use that amp with those speakers.

Very clear information. I will do just that!