Need Amp Help - KEF R700

[mdenny101]

Hello all.

I am purchasing a used pair of KEF R700 for a great price and will need something to power them.
I want to stay under $1,000 and am open to purchasing refurbished or used.
I also have a sub, SVS SB12-NSD, that I will most likely want to use with the KEFs.
I have been focusing on Integrated Amps as I will never need to do surround with this configuration.

I would love the Parasound Halo Integrated but way out of my price range.
I've been trying to find a Rotel RA-1570 in my price range but have not yet.

The 2 I'm most interested in are:
Outlaw RR2150
Yamaha A-S801 (most interested in this)

My questions are:
Do you have any amp recommendations other than the ones I'm looking at?
Of the amps i'm looking at will they power the KEFs properly?
How well can I integrate my sub with the KEFs using the Yamaha A-S801 since it doesn't have base management? What settings would I use?

Thanks in advance!

 

[PENG]

I have been using my R900 with a Denon avr-3805 and previously a Parasound A21 without any issues. Unless you listen at reference level in a medium large to large room, I think any 100W rated receivers or integrated amps can drive the R700 easily.

 

[j_garcia]

RR2150 sounds like an excellent choice to me, but wouldn't complain about the Yammy.

No bass management means you run the mains full range and manually dial the sub in to blend with a meter.

 

[RichB]

From Stereophile:

http://www.stereophile.com/content/kef-r700-loudspeaker-measurements#eB3ZSeVZTpmDD7MP.97

My estimate of the KEF R700's B-weighted voltage sensitivity was 87dB(B)/2.83V/m, which is 2dB lower than the specified 89dB/2.83V/m. KEF specifies the R700's impedance as 8 ohms with a minimum magnitude of 3.2 ohms. My own measurement (fig.1) shows that the minimum impedance, which includes the impedance of 10' of speaker cable, was 3.3 ohms at 145Hz. The impedance magnitude (solid trace) remains between 4 and 6 ohms for almost all of the audioband, but the electrical phase angle (dashed trace) is generally benign.
Read more at http://www.stereophile.com/content/kef-r700-loudspeaker-measurements#kfsmCBHBgxZ4gbMk.99

So, they are another example of an "8 ohm" speaker that dips to 3.2. So, at 145Hz the amp will have to supply 2.5 time to power to maintain the voltage.

Of the above choices, I like the Yammy since it has nice DACs and a USB input.

- Rich

 

[lovinthehd]

Hard to determine amp needs without spl needs. I'd rather have bass management than not and doubt a receiver won't be better than some feature-short 2ch integrated amp. 2ch stuff is often priced higher than an avr that can do more for less.

 

[mdenny101]

From Stereophile:

http://www.stereophile.com/content/kef-r700-loudspeaker-measurements#eB3ZSeVZTpmDD7MP.97



So, they are another example of an "8 ohm" speaker that dips to 3.2. So, at 145Hz the amp will have to supply 2.5 time to power to maintain the voltage.

Of the above choices, I like the Yammy since it has nice DACs and a USB input.

- Rich

Thanks for the replies everyone...

Rich, I'll admit that this is a little above my head.
2.5 times what exactly? Does the Yammy have the power for this?

Also I'm a newb when it comes to setting up the sub to blend well with the speakers anyone can explain this or link me too a good reference to learn.

Thanks!

 

[lovinthehd]

Thanks for the replies everyone...

Rich, I'll admit that this is a little above my head.
2.5 times what exactly? Does the Yammy have the power for this?

Also I'm a newb when it comes to setting up the sub to blend well with the speakers anyone can explain this or link me too a good reference to learn.

Thanks!

Bass management gives you the ability to cross the subs/speakers at various points ideally, not just a fixed value, or where you aren't duplicating signal to both sub and speakers due to lack of control. You can get separate units to manage this depending on your gear but an avr is usually a better route than a limited-feature 2-ch integrated amp that often omits bass management. Seems to appeal to some of the 2ch crowd due to nostalgia or something

ps Try this https://www.audioholics.com/subwoofer-setup/bass-management-basics-2013-settings-made-simple

 

[PENG]

Thanks for the replies everyone...

Rich, I'll admit that this is a little above my head.
2.5 times what exactly? Does the Yammy have the power for this?

Also I'm a newb when it comes to setting up the sub to blend well with the speakers anyone can explain this or link me too a good reference to learn.

Thanks!

He meant 2.5X the power needed if the impedance was 8 ohms instead of 3.2 ohms. That's not an issue if you don't need a lot of power but if you do listen loud in a medium large to large room, then a 100W amp could be marginal. That is not in terms of average power needs but high "peak" power needs. Using a good sub with bass management can help a little but for the R700 it wouldn't help much because base on the graphs Rich posted it looks more like a 4 to 6 ohm speaker to me. Still, I think bass management is an important feature to have regardless.

 

[mdenny101]

Ok thanks for the additional info.

Hypothetically, lets say I do go with something that does not have bass management and want to use a sub and do not want to use a meter.

What settings on the back of the sub(SVS SB12-NSD) would be best to start with for the KEF R700?
Doesn't it depend on how low the speakers will go where you cross the sub over?
There's a Phase dial and a Low Pass dial to configure along with the Gain dial of course.

Back of sub:
http://4.bp.blogspot.com/-b7N1-FMXQ9w/T6L-xP69t2I/AAAAAAAAAGE/8qes1tc3xYg/s1600/SVS+xB12-NSB+Amp.jpg

Or am I going down the wrong path here?

 

[PENG]

Ok thanks for the additional info.

Hypothetically, lets say I do go with something that does not have bass management and want to use a sub and do not want to use a meter.

What settings on the back of the sub(SVS SB12-NSD) would be best to start with for the KEF R700?
Doesn't it depend on how low the speakers will go where you cross the sub over?
There's a Phase dial and a Low Pass dial to configure along with the Gain dial of course.

Back of sub:
http://4.bp.blogspot.com/-b7N1-FMXQ9w/T6L-xP69t2I/AAAAAAAAAGE/8qes1tc3xYg/s1600/SVS+xB12-NSB+Amp.jpg

Or am I going down the wrong path here?

That depends on what that "something" is. For the two devices you listed, the RR2150 will allow you to take advantage of separate power amp input provision (the main ins), so that you can connect it's "preout" to the SVS sub's L/R line in and then connect the sub's L/R high pass out to the RR2150's "main in" so that the RR2150 power amp will amplify the signals above 80 Hz (not a brick wall though). The SVS sub will take care of the low frequencies based on the low pass filter setting. If you don't want to use any meters and software then you will have to adjust the phase, low pass filter and gain knobs by ear.

The RR2150 does have some bass management features so you will actually have at least two options. If you choose the option described above the XO will be 80 Hz. If you use the subout of the RR2150 then you can select 60, 80, 100 Hz or BP but the internal power amp of the RR2150 will have to amplify the full range signal. For that reason, my choice would be the first options, though any difference may be too minute to be audible. Other integrated amps may or may not have the separate preout and main in that the RR2150 has.

The A-S801 does not offer separate preout and main in but you can use the subwoofer out for the SVS sub. In that case you should set the NSD sub's low pass filter to maximum and the adjust the phase and gain knobs by ears to your liking.

 

[j_garcia]

Between USB and bass management, I'll gladly take bass management. Either will be plenty of power.

There is no way to tell what settings will work properly for your room for the sub. It shows -6dB for the R700 as 37Hz, so I'd expect somewhere around 60hz would be a good place to start for the SVS x-over. Without bass management, you'll need test tones and a SPL meter to dial it in properly.

 

[lovinthehd]

Even if your R700s do go down to 37Hz, at what spl can they do that? Especially compared to a sub? If you only listen at low/moderate volume levels you might be able to blend it in suitably....but when it comes to bass I like more capability than those speakers possess.

 

[j_garcia]

-6dB at 37 means not a whole lot of output at that level. -3dB must be somewhere in the 50s-60s.

 

[KenM10759]

I have the lesser R500 and can play a LOT of music in direct mode without my sub running, still sounds really surprising with how low it goes. The R700 would be even better.

When I bought my speakers I read all the reviews and pored over the measurements. Those measurements don't tell the whole story of how good they actually sound in my space, with my placement...and my ears.

 

[mdenny101]

Thanks again everyone for all the info. I really wish Outlaw would update the RR2150 with optical or digital coax inputs. The limited base management it offers would be nice but I honestly can't see myself pulling the trigger on that one. So I'm still leaning towards the Yamaha A-S801.

This 2.1 system (or possibly 2.0 if the R700 low end blows me away) will be 75% music, 25% tv/movies in a room approx 19' x 15' and again I'll never go with more than 2.1

What are your thoughts about going with separates? I looked at Emotiva and could go with this combo:
BASX A-300 ($400) - https://emotiva.com/products/amplifiers/300
BASX PT-100 ($300) - https://emotiva.com/products/pres-and-pros/pt-100

For $700 I'd be getting very solid 2 channel amplification:
150 watts RMS per channel; 20 Hz - 20 kHz; THD < 0.1%; into 8 Ohms
300 watts RMS per channel; 1 kHz; THD < 1%; into 4 Ohms

But I'm not sure about the PT-100. Would I be missing out on anything over the Yamaha A-S801?

 

[PENG]

You can supplement the RR2150 with a low cost DAC to take care of the digital inputs.

 

[j_garcia]

The Emotiva BAS-X line is literally brand new. I might wait a bit to see some real world data on them. I am however waiting for the new 7ch Pre-pro to come out from them.

The RR2150 was not aimed at a digital market and it has been around basically unchanged for years for that reason. Most integrated amps lack digital.

 

[mdenny101]

What are your guys thoughts on the Peachtree Audio nova220se?
http://www.peachtreeaudio.com/nova220se-amplifier-with-dac.html

I may have an opportunity to buy one at a great price. Wonder how it would pair with the KEF R700?

 

[RichB]

^
It looks nice. If the deal is good enough, why not, you can always sell it on eBay if you don't like it.

- Rich