KEF Q55 speakers bi-amp - AVS Forum
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post #1 of 20 Old 09-02-2013, 05:46 PM - Thread Starter
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Could anyone tell me the best solution to amplify a pair of KEF Q55 using bi-amp ? I have a receiver Yamaha RX-A1000, connected to these speakers without bi-wire, but I am afraid the receiver is not strong enough to power these speakers. So I was thinking of connecting the receiver to the 2 amplifiers and then them to the speakers. Is it a good solution or it is not necessary? Which amplifier do you suggest? I am thinking of two Niles SI2100 …
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post #2 of 20 Old 09-02-2013, 06:15 PM
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Bi-amping and/or bi-wiring are not necessary at all. Don't sweat it.

If you don't think the Yammie's amp and power supply sections are up to the task (sometimes receiver specs. are, shall we say, "exaggerated"), then take a look at some Emotiva, Parasound, Outlaw Audio, etc. power amps that are more robust. You have pre-amp outputs.
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post #3 of 20 Old 09-02-2013, 06:29 PM - Thread Starter
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Tks for the answer. And how much power should these amplifiers output to feed the KEFs Q55? I have read it is necessaty the 2X, so in this case 300w, since KEF has 150W...it is right ?
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post #4 of 20 Old 09-02-2013, 06:33 PM
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Quote:
Originally Posted by jluizaf View Post

And how much power should these amplifiers output to feed the KEFs Q55?

See this... http://www.allegrosound.com/Power_AllegroSound.html
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post #5 of 20 Old 09-02-2013, 07:25 PM
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Originally Posted by jluizaf View Post

Tks for the answer. And how much power should these amplifiers output to feed the KEFs Q55? I have read it is necessaty the 2X, so in this case 300w, since KEF has 150W...it is right ?

Maybe something in the 250 to 300 watt/channel range. Remember, you'll only hit those numbers if playing something LOUDLY. At normal volumes, you'd rarely hit the amp's full capacity. The biggest problem can be too little power with high distortion levels leading to clipping.

Again, many receiver amp specs. are more than generous on the part of the manufacturer (usually hard to believe), especially once the maximum number of speakers are hooked up. Their power supplies are tiny in comparison to a quality power amp.
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post #6 of 20 Old 09-02-2013, 08:22 PM
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Well, I run Q65s (10-15 years old now) from a Rotel 100 wpc receiver. If the Yammy can't drive them, then the Yammy is pretty weak. You don't need anything like 300 wpc for these. 100 CLEAN wpc will be fine.
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post #7 of 20 Old 09-02-2013, 08:29 PM
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Originally Posted by lespurgeon View Post

Well, I run Q65s (10-15 years old now) from a Rotel 100 wpc receiver. If the Yammy can't drive them, then the Yammy is pretty weak. You don't need anything like 300 wpc for these. 100 CLEAN wpc will be fine.

What if the OP decides to upgrade their speakers at some point? The higher watts/channel range and a more robust power supply will serve them well in the future. Why just spend for the now? The higher watts won't hurt the KEF's.
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post #8 of 20 Old 09-03-2013, 02:02 PM - Thread Starter
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OK Guys. Thank all of you for the answers. The receiver Yamaha RX-A1000 has 105 w (RMS) per channel. So it seems it does the job. I don´t know but I feel like it doesn´t.... To feed the spekers with a more powerful amplifier around 150/200 wpc thru bi-amp, which one would you guys use ? TKS
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post #9 of 20 Old 09-03-2013, 04:46 PM
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Not necessary to bi-amp. For a good budget amp, try an Emotiva XPA unit. They're having a summer sale with a coupon code. emotiva.com
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post #10 of 20 Old 09-14-2013, 08:11 AM - Thread Starter
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What do you think about Emotiva UPA-200 ?

Topology: Fully discrete, dual differential, high current, short signal path Class A/B.
Number of Channels: 2
Power Output (rated power; THD < 0.05%):
125 watts / channel (8 ohms; all channels driven).
200 watts / channel (4 ohms; all channels driven).
Rated Power Bandwidth (at rated power; 8 Ohm load): 10 Hz to 20 kHz + / - 0.1 dB.

Remember my KEF spekers have 6 Ohm each one. I think with 6 Ohm the UPA-200 would deliver around 160W each channel, right ? If the speakers can receive unitl 150 W (max.), I think it is ok, no ?

Tks
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post #11 of 20 Old 09-14-2013, 12:44 PM
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Should be fine as long as you don't have a large room necessitating louder volumes to compensate.

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post #12 of 20 Old 09-15-2013, 07:16 AM - Thread Starter
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I found another one: OSD Audio AMP300 2-Channel Dual-Source 300-Watt Stereo Power Amplifier. Do you think this one would be a better choice then Emotiva UPA-200 ?
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post #13 of 20 Old 09-15-2013, 11:29 AM
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Originally Posted by jluizaf View Post

I found another one: OSD Audio AMP300 2-Channel Dual-Source 300-Watt Stereo Power Amplifier. Do you think this one would be a better choice then Emotiva UPA-200 ?

I've never heard of OSD Audio. Doesn't mean they're not any good. Somebody with experience with their products should chime in.

If you're thinking of adding speakers for a full surround system, then I'd suggest looking at multi-channel amps like the Emotiva XPA-5, Outlaw Audio's Model 7500 (Made in the U.S.A.), or Parasound New Classic's 5250 v.2.

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post #14 of 20 Old 09-15-2013, 11:50 AM - Thread Starter
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I am looking for a power amplifier only for my main speakers. Since you have mentioned Parasound, what do you think about this:

Parasound 2125

or this:

Niles SI 2100

Tks
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post #15 of 20 Old 09-15-2013, 11:56 AM
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I'd probably go with the Emotiva XPA-2, if that's the case. However, if you have a center channel, you'd probably want to have the front three speakers have fairly equal power. If you do, then go with the XPA-3.

Now large is your listening room? What's your budget range? Is it fairly flexible?

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post #16 of 20 Old 09-15-2013, 04:27 PM - Thread Starter
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My room is 4 x 3 m. My budget is no more than $500.00. To the center I've already had the receiver Yamaha RX-A1000. I just want something more powerful the the Yamaha to the KEF-Q55 main speakers. I consider bi-amp as well.

Tks
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post #17 of 20 Old 09-15-2013, 07:16 PM
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Quote:
Originally Posted by jluizaf View Post

My room is 4 x 3 m. My budget is no more than $500.00. To the center I've already had the receiver Yamaha RX-A1000. I just want something more powerful the the Yamaha to the KEF-Q55 main speakers. I consider bi-amp as well.

Tks

I would save up and get the XPA-3 from Emotiva as it's only a little bit more expensive than your budget. As I mentioned above, you do want to power your front three speakers with the same amp power... just like timbre matching the sound of the front three (since they're KEF's, you want the matching KEF center). These are the most important speakers in the system (with the bulk going to the center during movies or multi-channel music). Don't sell yourself short. I can't stress that enough.

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post #18 of 20 Old 09-28-2013, 08:46 AM - Thread Starter
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There are some power ampliers like Parasound 2125 to which you can connect two pair of speakers: A + B. According to its specification it delivers 200 watts rms per channel into 4Ω. If I use the two pair speakers A + B connected, and all of them have 4Ω, the amplifier will feed all the 4 speakers with 200 watts rms, or just if I use one pair if speakers ( A or B) ?

Tks
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post #19 of 20 Old 09-28-2013, 09:16 AM
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Quote:
Originally Posted by jluizaf View Post

The receiver Yamaha RX-A1000 has 105 w (RMS) per channel. So it seems it does the job. I don´t know but I feel like it doesn´t.... To feed the spekers with a more powerful amplifier around 150/200 wpc thru bi-amp, which one would you guys use ?
Unless you quadruple the power the difference will be barely audible, and not worth the cost. And if you don't have a pre with a built in electronic crossover, so that the amps separately handle the highs and lows, and you remove the crossover from your speakers, you aren't bi-amping anyway. So-called 'passive bi-amping' accomplishes nothing.

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post #20 of 20 Old 09-28-2013, 12:43 PM - Thread Starter
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There are some power ampliers like Parasound 2125 to which you can connect two pair of speakers: A + B. According to its specification it delivers 200 watts rms per channel into 4Ω. If I use the two pair speakers A + B connected, and all of them have 4Ω, the amplifier will feed all the 4 speakers with 200 watts rms, or just if I use one pair if speakers ( A or B) ?

Tks
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