Question IMPEDENCE.

[ianrjones]

Hello everybody.
It's something I know next to nothing about. I have the opportunity to purchase; NEAT ACOUSTIC ULTIMATUM XLS used speakers.
My problem is this; they are 6 ohms average, minimum 4 ohms. The amp I am currently suffering with is the YAMAHA as701.
Which is 8 ohms. the amp I will replace it with will also be 8 ohms. So here is my question (at last), are they compatible ?
or is it a no-no?
P.S. apologies to NOPIANO, whom I insulted some time ago, no excuses.
Thanks in advance,
IAN.

 

[Al ears]

Shouldn't be any problem. Just about any amp you can buy is nominally 8 ohm, some valve amps have 4 ohm speaker taps but it merely depends on how well an amp can drive low impedance speakers.
What are you considering to replace the Yamaha?

 

[ianrjones]

Thanks AL, The amps I am considering for next year, (JAN-SALES) are the LUXMAN Z series. 505Z, 507Z or the 509Z. To be realistic, waiting for one used or ex display will be highly competitive, with hundreds of bidders. So I believe I will have to buy new.
THANKS,
IAN.

 

[good_enough]

This is about the power reserves of the amp. At 4 ohms the speakers will take more current as there is lower impedance to the voltage the amp creates. Similar relationship to the familiar formula V=IR between resistance voltage and current for DC.

Amps SHOULD have indicated power into 8 ohms and 4 ohms. Hence my amp the Roksan K3 is rated at 140 watts per channel into 8, and 220 into 4 - the higher figure into 4 reflecting the fact that the current is going to be higher.

And behold - looking at the Luxman specs, the 505Z says "100W+100W (8Ω) and 150W+150W (4Ω)" which implies that they have anticipated different loads and given it a power supply adequate to the task.