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4 ohm speakers connected to 8 ohm amp.

Hi, I have just purchased a pair of KEF C35 bookshelf speakers, but their impedance is only 4 ohm. How will this affect my amp which is 8 ohm output?



Re: 4 ohm speakers connected to 8 ohm amp.

Many thanks for your reply. I have now discovered that most of my amplifiers can cope with anything between 4 and 16 ohms, so I do at least have that choice.

karodimitrov's picture

Re: 4 ohm speakers connected to 8 ohm amp.

If you have another pair 4 or 8 Ohm speakers you can connect it with your KEF in pair-one KEF+one from others in series in a left channel and do the same for another channel. Thus you'll have 8 or 12 Ohm at channel and 4 speakers. Only remains the sound to your liking.

karodimitrov's picture

Re: 4 ohm speakers connected to 8 ohm amp.

What brand is your amp?

Re: 4 ohm speakers connected to 8 ohm amp.

I am currently using three amps in my 'Audio Sanctum' set-up: JVC AX-A662; NAD 3150, and Arcam Alpha 5 plus.
One day I am going to devise a system where I can wire all of my amps up to a kind of switchboard, and make full use of them. I have two other NAD's, two Yamahas, a Teac and a Marantz, but I find it difficult to tell which is the best for my ears, although I think that the NAD suits heavy rock music better; the Arcam is best for guitar and classical, whereas the JVC can do anything except make toast or coffee. My best speakers for 'oomph' are Vintage KEF Concertos; JBL L40's, and Monitor Audio MA 1's.

Re: 4 ohm speakers connected to 8 ohm amp.

for a given level of amplifier output a 4 ohm speaker will draw 2 times the current for a given position on your volume control. poorly designed or underrated amps this can be a problem. a speaker is a complex load to start with so with a great powerful amp listening to music at somewhat less than earsplitting volume 4ohm, 8ohm, 16 ohm who cares, they can handle it. if you're fussy you can put a nice 4 ohm power resistor in series with the speaker, problem solved, don't let them dangle next to the drapes for those extended heavy metal sessions ! now 2 ohm or less, don't go there unless your amp is spec'ed for it.

Re: 4 ohm speakers connected to 8 ohm amp.

Not very good advice. Putting too much of a load on an amplifier is like hauling too much load with a truck or car; sure you can say 'I towed a 4 ton trailer with a 3/4 ton pickup, and it worked just fine!' You aren't taking into account the damage that can happen; a 50 watt amplifier won't explode when it delivers 52 watts, at any load, but your are taking a big chance with twice the loading (4 ohms instead of 8). NOT recommended.

Just get the right speakers.

Re: 4 ohm speakers connected to 8 ohm amp.

Many thanks for your quick response. I have no less than nine amps, so I am bound to find one that has a rating of between 4 and 8 ohms. James.

Re: 4 ohm speakers connected to 8 ohm amp.

I recommend NOT using 4 ohm speakers with an amp made for 8 ohm impedance. It is too much of a load.