ohms.....HELP!!!

[78finn]

Hi there...
Have a quick question regarding ohm ratings. I’m sure this is a very basic question to answer, but I haven’t really looked at Hi Fi equipment for a long time and am just in need of a quick refresher...
I have a really old Sony TA-FB940R, which I absolutely adore....it was What Hi-Fi’s budget amp of the year back in 2000. The amp is built like a tank and sounds like a valve amp...very warm sound. So I have no reason to really change this component – or at least, I don’t really want to. However my youngest son (3 years) put his hand though my KEF Coda 9 speaker the other day..........obviously I’m devastated, but I did have a good excuse to by some new speakers ; )
I managed to pick up a brand new pair of Wharfedale Diamond 9.2 (cherry) speakers on eBay for a really silly price.....however the speakers have a power rating of: 20-100W, Nominal Impedance 6 ohm.
My amplifiers power is rated: 2 x 70 watts/channel, 8 ohms, RMS.
Am I going to have a problem running the Wharfedale’s? Being that technically ohm’s required to run the speakers is greater than my amp supplies. I have always thought that my Sony was relatively powerful budget amp....at least enough to run most budget speakers...like the Diamond 9.2’s.
Well any advice would be very much appreciated.

 

[professorhat]

I'm not particularly technical when it comes to this stuff, but looking at what you have, I don't think you've got much to worry about unless you're driving the speakers really hard. The fact your amplifier is rated less than the speakers suggests you could do some damage if you start turning the amp up close to full power, but you should hear some tell tale signs from the speakers when this is happening (e.g. distortion, clipping etc.) so just be careful, increase the volume slowly and watch out for this. Once you know if you're reaching your limits and don't go beyond this, you'll be fine I would say.

 

[Anonymous]

The speaker rating defines the resistance the amplifier will 'see' when it's driving the speaker. If you take 'normal' as 8 ohms, 6 or 4 ohm ratings are usually OK with any amp. When you get higher ratings - like the old LS3/5a 15ohms - things get more difficult.

The amplifier rating - 100 watts into 8 ohms for example - defines what the amp can deliver into a typical 8 ohm speaker - it's just a handy formula for making amps look powerful! A 6 ohm speaker won't cause it much of a problem, and you won't be counting the watts while you listen to the music.

 

[Anonymous]

Speaker impedence is not a constant....it varies with frequency. The values quoted are nominal values. Speaker impedence on an 8 Ohm speaker could vary anything between a low of 2 Ohms up to way way over the 8. I would say not to worry about it and that any reasonably designed amplifier, which I am sure the Sony is, would not have any problem connecting and driving your chosen speakers.

Have a look here....

http://en.wikipedia.org/wiki/Electrical_characteristics_of_dynamic_loudspeakers

 

[SteveR750]

so long as you don't listen at ear plsitting levels or drive the amp close to its maximim then you will have no problems. You'll know when an amp is being overdriven...think marshall stack

 

[manicm]

If the speaker is rated at '6 ohms nominal' then there's nothing to really worry about. Let's assume the maker's being honest, then that means that's the lowest resistance it would sink to - your amp will won't raise a brow.

Take the 685s as an example - B&W rate them at '8 ohms, 3.7 ohms nominal'. That means that it could demand more power at said nominal resistance, and by rights should have been fried by my 25w Solo Mini amp - or the latter should have been fried.

Thankfully after 3 months neither has happened. One just needs to use common sense.

 

[78finn]

Ok, so as I am now understanding it...the lower the speakers Ohm rating the harder they will be to drive...

There for as long as I'm not cranking up the volume on my amp (which has a higher ohm rating), I really dont have to much to worry about.

Think I have got that right....??

To be honest I dont think I have ever pushed the amp to much past half way.....showing my age...

Thanks for everyones input on this...

Another thing I would like to ask everyone now is. Bi-Wiring... My new speakers facilitate this and my old speakers didn't. Alot of people tell me that it really makes sod all difference on budget setups and not to bother. Is this correct? I spoke to a guy in a hi end hifi place and he pretty much said the same thing.....he told me that Bi-wiring makes nowhere near as much of a difference as either Bi-Amping or simply upgrading a component (funds prohibiting).

The reason being.....well I guess if I dont have to shell out on another line of cable or Bi-Wire cable (always soooo expensive)...I wont.

Sorry to change the topic slightly, but I think Ohm ratings have been well covered....

 

[Anonymous]

Biwiring.......its a split camp........half will say it makes a difference, the other half not.

The only way to find out if t works for you is to try it. No hard and fast decision here Im afraid.

 

[margetti]

Re bi-wiring.... agree with raym87. I have had my speakers bi-wired for years (it really was THE thing to do) but if I were to change my speaker cables I'd probably go with the thinking that you're better off with a single run of good quality cable than two runs of cable that are half the price.

 

[Anonymous]

Biwiring seems to be going out of fashion. Many of the top-end speaker manufacturers no longer make provision for it, if they ever did before. ÿSave your money and buy some CDs

 

[manicm]

I have to say Chord have been extremely helpful. If one has single-wire to a biwire speaker and single-wire amp they suggested to me I connect the + to the High Frequency portion and the - to the Low Frequency portion.

I tried it out and it did make some sort of difference. Bass seemed more defined, imaging slightly better but midrange slightly recessed.

Can't say if it's better but I'm sticking with it for now - still enjoying the music.

 

[78finn]

I had heard it was a split camp. All in all I think I'm going to save my money and go with a standard setup - spend the money left over on a better phono cartridge.....think that will yield better results for my system overall. Cheers for the advice though...