Did my new KEF Q150s blow my amp - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 9 Old 12-02-2019, 08:09 PM - Thread Starter
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Did my new KEF Q150s blow my amp

So I decided to give my wife a nice present for her birthday.
She is disabled and listens to music about 4 hours a day. She has been listening to a pair of vintage Ultralinear speakers through my also vintage Sansui 5000x.
I wanted to give her something nice so I bought a pair of KEF Q150s and a SVS SB-12-nsd sub. She likes her bass.

Hooked everything up and the first day every thing went well. Playing at very moderate listening levels.

Second day the right channel with (what I will call KEF-1) stopped working. A power cycle of the amp fixed it.
Ok, simple glitch I said.

Third day have the same problem only multiple times.

Fourth day I decide to put KEF-1 on the left side and KEF-2 on the right. Is it the speaker or the amp.
I also plugged the amp in to a Kill A Watt meter. It is reading about 15 watts while we are playing music.
Well the right channel goes out again. I am thinking that maybe by some strange coincidence the right channel decided to go bad when I hooked up new speakers.
The amp supports 3 sets of speakers, A, B, and C. I hook both KEFs to C. At least we will have more than one channel sound. Nothing. OK, I don't think I have ever hooked anything to C before so maybe it has always been bad and I didn't know it.


I had previously been using the B channel with another set of speakers so I unhook the wires from those and hook up the wires from the KEFs. I have not swapped speakers back so KEF-1 is still on the left side.
So now the left side on B goes out and won't come back.
I hook the KEFs back to A. Now the right side is working and the left side is dead.
I hook the Ultralinears back up to A and the right side is working and the left side is dead.


I am thinking that the KEFs are killing my amp. They say 8 ohms, min 3.8 ohms on the back.
With a meter I measure 3.4 ohms on both.
The Sansui is rated 85w per channel with a 4 ohm load and 60w per channel in to an 8 ohm load.

I guess I will be calling KEF tomorrow. I am very disappointed. The amp has run flawlessly on and off for years until I hooked up the KEFs. I opened it up about three months ago to inspect it and put a little deoxit on the pots and it looks almost new inside. No evidence of leaking caps. A slight film of dust on the top which I blew out and on the bottom it looks like it just came off the assembly line.

Any thoughts on what might be going on?


I just ordered a new amp for her but I don't think I want to connect the KEFs to it.


Is it OK to do a double post and post this over in the speakers thread also?

Last edited by aveatch; 12-02-2019 at 08:23 PM.
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post #2 of 9 Old 12-02-2019, 09:14 PM
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Sounds like you are shorting it somewhere and is why it keeps needing a cycle. If it was blowing your amp, it would release the magic ghost inside and smell terrible.

Leave it at 8 ohms and call it a day :)
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post #3 of 9 Old 12-03-2019, 02:08 AM - Thread Starter
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Quote:
Originally Posted by Russdawg1 View Post
Sounds like you are shorting it somewhere and is why it keeps needing a cycle. If it was blowing your amp, it would release the magic ghost inside and smell terrible.
Well, it turns out it really was just a very weird coincidence. The speakers apparently had nothing to do with it. The output stage is fine. I can push mono and I get sound out of both speakers. Didn't think to try that before. So it is something before the output stage. I couldn't really mess with it until my wife went to bed. She gets really testy when I am messing with stuff like that.
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post #4 of 9 Old 12-03-2019, 02:16 AM
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KEF speakers are kinda crappy, when buying british speakers, the best choice is ATC or Meridian followed by B&W and Monitor Audio. I always stay away from stuff like KEF, elac, wharfedale.
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post #5 of 9 Old 12-03-2019, 06:35 AM - Thread Starter
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Quote:
Originally Posted by Rysa_105 View Post
KEF speakers are kinda crappy, when buying british speakers, the best choice is ATC or Meridian followed by B&W and Monitor Audio. I always stay away from stuff like KEF, elac, wharfedale.
Yes Thank you.
I'll be buying these next time.

https://www.soundandvision.com/content/meridian-dsp3200
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post #6 of 9 Old 12-03-2019, 01:27 PM
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Quote:
Originally Posted by Rysa_105 View Post
KEF speakers are kinda crappy, when buying british speakers, the best choice is ATC or Meridian followed by B&W and Monitor Audio. I always stay away from stuff like KEF, elac, wharfedale.
Really!
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post #7 of 9 Old 12-03-2019, 02:43 PM
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I enjoy that no matter what someone asks on this forum someone always suggests buying new equipment, usually at additional orders of magnitude to the price of whatever the thread poster has.
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post #8 of 9 Old 12-03-2019, 05:25 PM
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Let’s get one thing straight. KEF speakers are not crappy.

Jolida Fusion Preamp, Jolida JD1000P Amp, VPI Scout turntable with Dynavector 10X5 cartridge, Paradigm Studio 100 v.5 speakers, Sonica DAC streaming lossless files. Furman Elite 15 Power Conditioner.
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post #9 of 9 Old 12-03-2019, 07:14 PM
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Quote:
Originally Posted by Rysa_105 View Post
KEF speakers are kinda crappy, when buying british speakers, the best choice is ATC or Meridian followed by B&W and Monitor Audio. I always stay away from stuff like KEF, elac, wharfedale.

There are a lot of happy Q150 owners on the forum. I rather enjoyed the R-line I auditioned a few years back. I don't think I'd call them crappy? I was also extremely impressed by a KEF (L/C/R) theater belonging to a forum member here that I had the pleasure of experiencing.

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