Problems driving kef 203/1's

R

Roderick1st

Audiophyte
#1
Hello Audioholics,

I've inherited a pair of kef reference 203/1's. I've managed to blow up a musical fidelity a300 amp and am now trying to get them running on a cyrus system.

I have got 2 x-powers driving just the subs (bottom speaker terminal) with each x-power in mono mode on one speaker. Another x-power is driving the rest of the speakers in stereo mode.

I would have thought this was more than enough power but the mono mode amps still get very hot with the volume not turned up very far and if I push them they cut out.

I have now noticed that one speaker has the 2nd from bottom driver not working. Could this requirement for power be caused by damaged crossovers?

Both bass amps get a hot as each other but the amp driving the mid and tweeter is as cold as ice.

My monitor audio rs8's can go twice as loud without any amplifier breaking sweat.

Any ideas?
 
ryanosaur

ryanosaur

Audioholic General
Ratings
674
#2
They claim those only need 50w minimum power to run. Are you bi-amping them???
And you damaged an amp doing it?

If you think there's a damaged driver you should probably stop trying to use them. I can't speak to whether that would have caused your a300 to blow, but looking at the specs you should be able to power them pretty straightaway and quite respectably with 1 of your x-powers for both speakers. That they are each getting hot as you are using them now should be a serious warning that something isn't right.
Edit to remove suggestion of bridged Mono. I agree with the following posts!
 
Last edited:
ski2xblack

ski2xblack

Audioholic General
Ratings
763 6 4
#4
Hmm. Something you should keep in mind is that the KEFs have a 3.2 ohm minimum, and if you're running the amps in bridged/mono mode they're seeing half that. I doubt the amps are rated for such abusively low loads, and it would certainly explain the heat and cut outs. You're probably triggering some sort of thermal protection circuitry in the amps. Hard to say about the driver. It could be the driver itself or a break in the circuit somewhere else (although the driver's voice coil is probably the weakest link).
 
TLS Guy

TLS Guy

Audioholic Slumlord
Ratings
7,372 17 25
#5
Did you remove the jumpers between the terminals on the back of the speaker? If not that blew the amps up.

Do not use bridged mode, the impedance of the speakers is too low.

I also suspect the speakers are damaged which may be a big part of your problem.
 
R

Roderick1st

Audiophyte
#6
Thanks all,

Not overly versed in the science of HiFi!

I did remove all the terminal links from the rear of each speaker.

I'll put a single amp in stereo mode and see what happens, then pack them away and revert back to MA rs8's ;-)

Thanks for all your suggestions.
 

newsletter
  • RBHsound.com
  • BlueJeansCable.com
  • SVS Sound Subwoofers
  • Experience the Martin Logan Montis