More power for KEF reference 5?

[soerenssen]

Yep.

Most of the Reference speakers have their lowest impedance around 40ish Hz plus minus (at least mine Ref 3 has). Offloading this area to active subs is a very good strategy, even more for reasons of room mode minimization. I use 2 subs (KEF 92s) crossed at 80Hz

(I also have “strong” power amps (380W into 4ohm), but it is debatable if I would really need them, if the SPL requirements are not too high).

Especially if you have 2 subs for the lower frequencies.
May I ask what power amps do you use and how do you like the sound (subjectively)? I'm just wondering what could cause the OP's KEFs sounding harsh with the Purifi. Can it be the DAC or the LM opamps in the Audiphonics amp or the room itself? @SvanTeK, did you do any measurements?

 

[Willem]

Such subjective impressions about amplifer sound are just what they are, and meaningless.

 

[JayGilb]

Hi,
I recently jumped on the opportunity to buy a pair of KEF reference 5 second hand at a good discount. Specs recommend an amplifier between 50W and 400W (cf specs). I already had a Mark Levinson 5805, rated at 125W under 8 ohms and almost double under 4 ohms (cf meas). The system is setup in a room measuring (WxDxH) 20x21x22, open at the back and cathedral ceiling. Often with classical music records, I turn the volume knob higher, let's say up to 50 or even 60 over 80 which is the max. I was wondering if I was under exploiting the potential of the KEF and needed a more powerful amplifier. KEF is also recommending using an amplifier providing 60% to 110% of the speakers max amp rating (cf kef blog). So I was thinking about using the Mark Levinson as a pre-amp and adding a class D power amplifier like the NCx500. But given your experience and your expertise, will it make such a big difference in terms of sound quality? Is my amplifier sometime clipping without me noticing and slowly but ultimately, it's destroying my speakers? I don't have access to a class D amp "just to try", so what's why I'm looking for your opinion.

Since your KEFs are 4 ohms, the Mark Levinson is putting out 250 watts per channel. Your speakers are rated for 400 watts max and doubling your power would exceed the speaker's max power rating and add less then 3 db spl increase.

What are you driving the Levinson with ? Is the source output too low and you're not really pushing your amp to the maximum output ?
Maybe some subs as others have recommended ?

 

[HarmonicTHD]

Especially if you have 2 subs for the lower frequencies.
May I ask what power amps do you use and how do you like the sound (subjectively)? I'm just wondering what could cause the OP's KEFs sounding harsh with the Purifi. Can it be the DAC or the LM opamps in the Audiphonics amp or the room itself? @SvanTeK, did you do any measurements?

I have Neurochrome Module 686 monoblocks (380W RMS 4ohms, >110dB SINAD).

The reason the OP perceives them as harsh is not explainable and most likely influenced by his room, his preference and sighted listening. I would not base your decisions on the subjective description of others. That’s why I also refrain from them. It is generally worthless data, as everyone has different preferences, everyone has a different room, sighted listening and no statistical relevance. You need to listen in your room to make the final decision.

 

[soerenssen]

I have Neurochrome Module 686 monoblocks (380W RMS 4ohms, >110dB SINAD).

The reason the OP perceives them as harsh is not explainable and most likely influenced by his room, his preference and sighted listening. I would not base your decisions on the subjective description of others. That’s why I also refrain from them. It is generally worthless data, as everyone has different preferences, everyone has a different room, sighted listening and no statistical relevance. You need to listen in your room to make the final decision.

Got it. So...if the KEFs sound harsh with a specific amp or DAC or whatever, and asumming that you like how your speaker sounds (or sounded in the shop when you auditioned), it's better to focus on the room and measure with REW, before blaming / replacing any of these components, because it won't change anything audibly as long a the room, speaker position, listening position, our ears, etc. remain the same.
It would be interesting to know then, how the same speakers sounded in the same room arrangement with the previous amp.

 

[HarmonicTHD]

Got it. So...if the KEFs sound harsh with a specific amp or DAC or whatever, and asumming that you like how your speaker sounds (or sounded in the shop when you auditioned), it's better to focus on the room and measure with REW, before blaming / replacing any of these components, because it won't change anything audibly as long a the room, speaker position, listening position, our ears, etc. remain the same.
It would be interesting to know then, how the same speakers sounded in the same room arrangement with the previous amp.

Correct.

Comparing with the previous amp, would have to be conducted as double blind test (or also called ABX) test, which is intended to reduce chance (guessing) and bias (expectation bias, especially here where the OP has made up his mind) and with accurately matched levels (as louder is always perceived as better).

As this is very difficult to do and an elaborate process, most people don’t know how to do it and therefore the majority of the subjective online description are not useful.

 

[SvanTeK]

Did you try with other amps?

Yes I have. I borrowed from a local dealer a few NAD power amplifiers. The expensive C298 sounds best and the C268 sounds good too, a lot better then my Audiophonics. I have also tried some old Denon POA-4400 and Sony TA-N77 ES they too sounds much better. And that is strange.
Last night I desoldered the ceramic capacitors closest to the op amps on the buffer boards and changed them for some NPO ceramic capacitors with the same value 0.1µF. And I also added some 0.01µF NPO capacitors. It sounds better but still not good. I don't know what type the original capacitors are, I'm guessing it's X7R.
However, It seams that the bad sound is caused by either poor psu filtering or bad buffer board design.

 

[Willem]

As for sound, I think this sounds like subjective snake oil.

 

[SvanTeK]

As for sound, I think this sounds like subjective snake oil.

The easy way out is to simply call it Humbug or Snake oil.
I'm not the only one here at my place that thinks it's a bad and tiring sound coming from the Audiophonics.
My Rigol DHO924s is showing me the sound is nearly perfect. I don't agree.

 

[soerenssen]

The expensive C298 sounds best and the C268 sounds good too, a lot better then my Audiophonics. I have also tried some old Denon POA-4400 and Sony TA-N77 ES they too sounds much better.

Do you have a measurement microphone? While you still have the different NAD amps, along with the Denon, the Sony and the Audiphonics, it would be interesting to see how they measure in your room on the KEF (with all kinds of DSP and EQ turned off). Maybe REW could highlight the difference in the higher frequencies. Just an idea, I would also ask the experts once I have the measurements myself to help me analyze them because I don't have experience with it.

 

[soerenssen]

I won't call it snake oil, I am also trying to decide what power amp to buy for my KEF Reference 3 Metas and any useful input/feedback would be useful. So thank you in advance for doing any kind of measurement, I'm sure others (myself included) can benefit from those too.

 

[soerenssen]

My Rigol DHO924s is showing me the sound is nearly perfect. I don't agree.

Can you share the output/results? (We were posting in parallel and I didn't catch your previous update, sorry.)

 

[frmir]

Since your KEFs are 4 ohms, the Mark Levinson is putting out 250 watts per channel. Your speakers are rated for 400 watts max and doubling your power would exceed the speaker's max power rating and add less then 3 db spl increase.

What are you driving the Levinson with ? Is the source output too low and you're not really pushing your amp to the maximum output ?
Maybe some subs as others have recommended ?

Thank you for your answer. It’s true that considering the KEFs as 4ohms, the amp produces power around the recommended range. I’m playing music from tidal and my own digital library. Some music play louder than some other, depending on how it was recorded I guess so I don’t need to push the volume all the time. I don’t like to have many components in my setup, so even if speaker+subwoofer is certainly technically and sonically interesting, in the end, I just stayed with what I have.

 

[exm]

Thank you for your answer. It’s true that considering the KEFs as 4ohms, the amp produces power around the recommended range. I’m playing music from tidal and my own digital library. Some music play louder than some other, depending on how it was recorded I guess so I don’t need to push the volume all the time. I don’t like to have many components in my setup, so even if speaker+subwoofer is certainly technically and sonically interesting, in the end, I just stayed with what I have.

I ended up getting the ATI AT3305 amp, powering my Reference 5, Reference 2 Meta and R3 Meta. With 5 channels you get 2 toroidal power transformers.

ATI Pure Balance Series - AT3300 - Amplifier Technologies Inc.

The AT3300 Pure Balance Series amplifiers deliver 330 watts per channel at 8 ohms and are available from 2 to 8 channel models.

www.ati-amp.com

 

[steve59]

I had the h590 driving my Blades and life was good at moderate and loud volumes, bass was a bit tight, but image placement was suburb. I treasure those low volume listening sessions also though and my Blades were lacking...dynamics? contrast, energy? I'm not great on the terms, suffice to say the Blades were boring at low volume until I tried a pair of Mac Mc611's on them. The Blade and Ref5 driver compliment are similar and if you could borrow the Mc611's you might be startled as I was at the transformation at less than a single watt output these speakers now are detailed, dynamic, and alive. Who knew that (besides Paul Klipsch) that the first watt could make such a huge difference?

I initially bought the H590 when I went to Axpona and so many 10x10 rooms had Kef ref 3's and the only rooms that didn't sound hard in the mids were being driven by the H590. I still have it, bought it new and there's some warranty left if you want to try it pm me.