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KEF 104/2 Speakers - tips

bus2stcloud

bus2stcloud

New Member
Some useful tips to Kef 104/2 Ref Series speaker owners. Use as much power as you can. I have two systems running the rosewood finish bi-amp version of these speakers. One has large heavy mono blocks (can't recall specs) and the other has Parasound A21 (400 watts RMS x 2, 20 Hz - 20 kHz, 4 Ω) and a Parasound Halo Preamp (270 watts x 2 @ 4 Ω). In the past I've run the speakers with various vintage pieces but nothing has bettered this combination.

Use the highest quality power cords (i'm using hurricanes from audioquest) and speaker wire (again high end audioquest).

I'm still using vintage turntables so I'll leave them out of my "tips".

Use a high end CD player. My current CD player is an Esoteric K-03X - well worth the investment (at a used price). This is an upgrade from an older player (same brand) and before that Oppo and others. The K-03X when added was the largest jump in sound quality. The soundstage opened up even bigger than it normally is with the 104/2s. All of the sound, bass, mid and high took on a new life. Discs I hadn't paid much attention to suddenly came to life. I've read similar comments by other owners of this machine so I know I'm not alone in this opinion. What is notable is that the KEF 104/2 really takes advantage of these capabilities.

Falcon Acoustics (UK) will shortly have restocked the caps for this speaker. Since I have two pairs I'm finally taking that plunge and fix the fluid in the tweeter at the same time.

Warm regards
 
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I understand that people always- usually for good reason- recommend high-power amps for the 104/2s;

That said- some of the best I've EVER heard them sound, in a moderate size living room, was on a NAD 310 (20w/ch) and a Harman-Kardon Award A300 tube amp (15w/ch). They just did EVERYTHING right on those amps. No KUBE needed, either.

They will definitely tell you, in no uncertain terms, if your upstream equipment (source and amp) are not of the best quality. Get that right, and get them placed in the room well, and they will just sing, though.

Regards,
Gordon.
 
The double cavity (4th order bandpass) enclosure design of these speakers inherently reduces excursion in drivers and they can take an awful lot of power in transients. They also are capable (with a KUBE) to reproduce extremely low frequencies at realistic levels. To the point that they can exhaust the current reserves of modest amplifiers.

I have never listened to 104/2 but have a pair of 107. Same enclosure design for the low frequencies. I thought they sounded great with a 100WRMS amplifier. They really came to life with a 400+ WRMS dbx BX-3MkII making music sound like I never heard before.

If you don't care (or can) listen to music at high SPL transients, then a lower power amplifier can do a good job. But for realistic sound levels, a high power amplifier able to drive 4Ohm and 2Ohm speakers takes them to a different level.

And to avoid misunderstanding. I'm not talking about listening to heavy metal or hard rock at concert levels, although you can. I enjoy Jazz and classical music that have a high dynamic range. Even though the average level may be in the 90-95dB level, there are transients that need to exceed 100dB or more if compression is not introduced. These doesn't sound loud or cause distress. They just sound normal and relaxed. With a lower power amplifier, compression occurs and you just don't hear these and don't know they existed...
 
I run mine with a Marantz 2270 which seems to provide enough power. Especially once the amp warms up and i open it up a little. I have a pretty early set of walnut veneer non bi-amp models in a moderately sized living area. The kube absolutely opens up the lower end, unfortunately the power supply for mine seems to have died.....
 
Very interesting to learn what people are using to drive the 104/2 - Since posting the message that started this thread I've upgraded my amp from a Parasound A21 to Parasound JC1 Mono Blocks (800w 4ohms) - Here's a review:

http://www.enjoythemusic.com/superioraudio/equipment/1103/parasoundjc1.htm

What changed in my sound? Well it was a pretty substantial jump in feeling that the music was being performed in my listening room. The bass is much faster - making all of my classical piano recordings much more realistic. The attack on the piano strings (wires) as they are hit by the hammer - the decay of the sound coming from the hit string. Same is true of pizzicato passages on the violin. That "pluck" just resonates better. Hearing this detail, I am able to listen for a much longer time. I liked the speakers before. Now I just drink in the sound. Likewise recordings in other music genres hasve taken on a more intimate sound.

Here are some specifics on what I'm listening to... Itzhak Perlman/Daniel Barenboim - Brahms Sonata for Piano and Violin 1/2/3 (red book CD) and Janine Jansen - Vivaldi Four Seasons (SACD) and Jacqueline Dupre (various recordings) (LPs). The LPs have the great warmth but the CDs via the Esoteric K-03x sound great as well. On the non-classical side I'm enjoying a Bobby Gentry CD box set as well as The Band - Music form Big Pink (LP 45 rpm).

Vivaldi: Four Seasons/Quattro Stagioni - Janine Jansen - Internationaal Kamermuziek Festival

Itzhak Perlman & Martha Argerich record Brahms: Scherzo, F-A-E Sonata (different recording but better video)

Bobby Gentry - Ode To Billy Joe

This greater detail is one that others have commented on when upgrading to amp's with more power, The person I got the JC1's from went to Bryston amps and had the same comment - more power is more "realism" when then speaker can handle it.

What's interesting to me is that the 104/2's appear to just soak up power (at least any power I've given them). The result is that in my opinion - the KEF 104/2 is a speaker which remains current. Maybe it lacks the highs of a ribbon tweeter - that said I really prefer the laid back delivery of the KEF product. I find myself having a difficult time listening to new products at local stores. I'm certain that many folks like the newer sound. Me - I'm wondering if Mr Cooke knew his speakers would support a discussion like this one - nearly twenty years later. My guess is that he would not be surprised.

Finally I should comment that I have every intention of looking into a TUBE pre-amp - as Gordon suggested. Would be very interested in learning what Tube pre-amps others are using with the KEF 104/2.
 
S Peterkin said:
Maybe it lacks the highs of a ribbon tweeter
Click to expand...
I replaced the tired T33s with something more modern on my 104/2s. The ferrofluid doesn't age well in the KEF tweeters, and they become more and more dull after a couple of decades.
The fluid becomes sticky and gummy, resulting in high frequencies roll-off. I did measurements of the 104/2 with the new tweeters and it confirms the reinstated frequency response.
Lovely sound, diamonds on a velvet cushion are the words coming to mind.
 
Thierry said:
I replaced the tired T33s with something more modern on my 104/2s. The ferrofluid doesn't age well in the KEF tweeters, and they become more and more dull after a couple of decades.
The fluid becomes sticky and gummy, resulting in high frequencies roll-off. I did measurements of the 104/2 with the new tweeters and it confirms the reinstated frequency response.
Lovely sound, diamonds on a velvet cushion are the words coming to mind.
Click to expand...
Specifically what did you replace the T33 with?
 
S Peterkin said:
Specifically what did you replace the T33 with?
Click to expand...

Oh sorry, forgot to mention it : https://www.parts-express.com/pedocs/specs/264-1040--tymphany-bc25tg15-04-spec-sheet.pdf
Bonuses :
- they are incredibly cheap (but they really sound like high-end models)
- mechanically, they're a real drop-in replacement which, given the specificity of the Kef pods, is very important.
I have studied many 4 ohms tweeters alternatives with similar Fs and sensitivity to the T33s in all prices ranges, but they needed either to modify the pod or the tweeter itself, or even both. Exactly what I didn't want. Above all, the neutral and balanced character of the 104/2 is preserved.
Don't trust the price tag for those, they are a real challenge to products costing A LOT more.

Here's the frequency response of the system with the new tweeters. Not bad uh ?

104-2with Peerless.jpg
 
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Run mine (RW skin, non-biamped) on a McIntosh MA-6200 or a McIntosh MAC-4100. Works flawlessly & sounds great through either of these, both essentially the 6200 IA.
 
Interesting - I have a pair of those I ordered years ago but thought replace the fluid would finally be a better choice. Did you compare them to T33 with replaced fluid?
 
Thierry said:
Oh sorry, forgot to mention it : https://www.parts-express.com/pedocs/specs/264-1040--tymphany-bc25tg15-04-spec-sheet.pdf
Bonuses :
- they are incredibly cheap (but they really sound like high-end models)
- mechanically, they're a real drop-in replacement which, given the specificity of the Kef pods, is very important.
I have studied many 4 ohms tweeters alternatives with similar Fs to the T33s in all prices ranges, but they needed either to modify the pod or the tweeter itself, or even both. Exactly what I didn't want. Above all, the neutral and balanced character of the 104/2 is preserved.

Here's the frequency response of the system with the new tweeters. Not bad uh ?

View attachment 2026252
Click to expand...
should have also asked - have you recapped the crossover? -thanks
 
S Peterkin said:
should have also asked - have you recapped the crossover?
Click to expand...
No, and no one should !
Have you noticed that your speakers have the same serial number followed by letters A and B ? This is because every single part in them is matched to the drivers to obtain an exact copy of the other speaker. KEF did match them very carefully by selecting among hundreds of capacitors, inductors and resistors. That why you shall never rely on the markings on the caps, they did select them by measuring actual value. That has been reported by an ex-Kef employee I discussed with. This ain't marketing bullsh1t, I have measured my own 104/2s and their frequency response is actually matched by 0.5 dB on all the range from bass to up to 12Khz :eek:
That is why you get that 3D imaging when they're properly installed (i.e. according to the user manual).
 
S Peterkin said:
Interesting - I have a pair of those I ordered years ago but thought replace the fluid would finally be a better choice. Did you compare them to T33 with replaced fluid?
Click to expand...

At first I had the T33s repaired by a shop in Germany. Very good job indeed. But still, the T33s did show their age, I was expecting more fineness and subtelty, which they lacked. I tried alternatives and ended with the Peerless. Before deciding which would stay I made a comparative measurement. Red trace is the KEF, blue trace is the Peerless.
Do not mind about the small amplitude differences, they are absolutely inaudible.
Oh, and the dip @ 200Hz has nothing to do with the tweeter of course :)

KEF vs Peerless.jpg
 
Thierry said:
No, and no one should !
Have you noticed that your speakers have the same serial number followed by letters A and B ? This is because every single part in them is matched to the drivers to obtain an exact copy of the other speaker. KEF did match them very carefully by selecting among hundreds of capacitors, inductors and resistors. That why you shall never rely on the markings on the caps, they did select them by measuring actual value. That has been reported by an ex-Kef employee I discussed with. This ain't marketing bullsh1t, I have measured my own 104/2s and their frequency response is actually matched by 0.5 dB on all the range from bass to up to 12Khz :eek:
That is why you get that 3D imaging when they're properly installed (i.e. according to the user manual).
Click to expand...

Understand your point on the testing KEF did when build took place. Yet CAPs do not last forever. I count myself as a fan of these speakers as I have two sets (have them in two different rooms in the house and enjoy them tremendously). SO I am carefully looking at options for keeping them in good repair. Falcon Acoustics tests their replacement caps to insure the quality...discussed in what I'm certain you've read (old thread follows)...

https://audiokarma.org/forums/index.php?threads/kef-104-2-restoration-and-crossover-recap.613028/

Again - I'm just looking at alternatives. I was talking with someone who worked at KEF when these speakers were made and he encouraged me to face up to replacing the fluid. As I already own the PARTS EXPRESS tweeters I may install those while fluid is being replaced and from your description and measurements may never go back to T33's.

Any thoughts on upgrading the wiring to high silver content wires?
 
bus2stcloud said:
Some useful tips to Kef 104/2 Ref Series speaker owners. Use as much power as you can. I have two systems running the rosewood finish bi-amp version of these speakers. One has large heavy mono blocks (can't recall specs) and the other has Parasound A21 (400 watts RMS x 2, 20 Hz - 20 kHz, 4 Ω) and a Parasound Halo Preamp (270 watts x 2 @ 4 Ω). In the past I've run the speakers with various vintage pieces but nothing has bettered this combination.

Use the highest quality power cords (i'm using hurricanes from audioquest) and speaker wire (again high end audioquest).

I'm still using vintage turntables so I'll leave them out of my "tips".

Use a high end CD player. My current CD player is an Esoteric K-03X - well worth the investment (at a used price). This is an upgrade from an older player (same brand) and before that Oppo and others. The K-03X when added was the largest jump in sound quality. The soundstage opened up even bigger than it normally is with the 104/2s. All of the sound, bass, mid and high took on a new life. Discs I hadn't paid much attention to suddenly came to life. I've read similar comments by other owners of this machine so I know I'm not alone in this opinion. What is notable is that the KEF 104/2 really takes advantage of these capabilities.

Falcon Acoustics (UK) will shortly have restocked the caps for this speaker. Since I have two pairs I'm finally taking that plunge and fix the fluid in the tweeter at the same time.

Warm regards
Click to expand...
I stopped reading the moment I read 'highest quality power cords' and 'Audioquest' ; good god.
 
huskyfox said:
I stopped reading the moment I read 'highest quality power cords' and 'Audioquest' ; good god.
Click to expand...
High quality does not need to be expensive, and yes, it can make a difference. I made mine using 'high quality' cord and ends. How much difference depends on the quality of the rest of the equipment, and of course your ears. Unfortunately, some (many?) are not able to hear subtle differences in equipment/cables, etc.
 
I just finished the restoration of a beautiful pair
In teak. I purchased one extra falcon recap kit by mistake. You should hear them in my 70 wpc Accuphase P20. It’s not all about pure wattage. He found an EQ without power. I built a power adapter for him.

Any one want to buy my Falcon kit, give me a shout.
 

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