KEF 104/2 Speakers. What sort of amplifier?

MadcapLaughs

MadcapLaughs

Active Member
Hi all,

I know this has been covered in depth in the past, but I would like opinions on just how hard of a load these speakers are to drive? So far I have the following amps in my inventory:

Pilot SA 232 (12 wpc).
Sony TA-N55ES (110wpc into 8ohm
HK 730 (40 wpc into 8)

Are any of these amps up to the task of handling this sort of impedance? I would think the Sony would, but other discussions say its not so great at handling 4 ohms. These KEFs were recently serviced and sound really good running through the HK 730... but im pretty nervous about turning the volume up as it stands. I also had heard the 104/2s didnt dip any lower than 4ohm and were an easy efficient speaker to drive....thoughts? Thanks, these are my first pair of 4 ohm loads so Im a bit nervous, Im so use to Tannoy, vintage altecs and that stuff.
 
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My experience with the 104/2s is a a high current 100 wpc amp is the minimum required to make them sound their best. They sounded good with my Onix A120 integrated (120 wpc) but they really opened up with my Belles 150A Reference amp (150 wpc) and my Acurus A200 amp (200 wpc).
 
They like some power, I used a Hafler DH 200 for years, was fine, just fine and could play loud (I was younger then). Currently running mine with a DH 500 I scored a few years back, its also sweet, though you gotta keep the fan clean to keep the noise down. The 110 wpc Sony should due fine, maybe even the HK if room isn't too large and you aren't looking for rock concert volume.
 
I've seen some crazy amp combinations, just EXCEL driving 104/2s.

The one that shocked us the most, was the Harman-Kardon Award A300 tube amp. 14w/ch. We were just gobsmacked. No, it wasn't "stadium loud", but it did EVERYTHING well. Huge soundstage, nice dynamics, great bass.

The other one that was almost as impressive, was the NAD 310 integrated amp. A TWENTY WATT per channel amp. Again, it did EVERYTHING well.

So, don't assume that small amps can't cope...

Regards,
Gordon.
 
GordonW said:
I've seen some crazy amp combinations, just EXCEL driving 104/2s.

The one that shocked us the most, was the Harman-Kardon Award A300 tube amp. 14w/ch. We were just gobsmacked. No, it wasn't "stadium loud", but it did EVERYTHING well. Huge soundstage, nice dynamics, great bass.

The other one that was almost as impressive, was the NAD 310 integrated amp. A TWENTY WATT per channel amp. Again, it did EVERYTHING well.

So, don't assume that small amps can't cope...

Regards,
Gordon.
Click to expand...

Ya I had my suspicions these speakers could be driven by tube amps. My pilot SA 232 doesn’t have 4ohm taps but I’ll give it a shot. Currently I’ve been using the Sony TA 55ES run through the HK 730 preamp out, and it’s a great combination. The cabinets are in ok shape but have some minor water damage at the base.
 

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They are "4 ohm resistive" according to KEF. What the means is the designers tried to keep the impedance of the speakers as flat across the frequency range. If you've seen an impedance curve of a "regular" speaker, you will see it goes all over the place. 8 ohm speakers may dip to 4 ohms or below, 4 ohm speakers might drop to 2 ohms or less.

I would recommend something known to have higher current capabilties. How much power you need depends on how loud you plan on listening to them.

Lee.
 
All good recommendations.

I personally like a high wattage Mosfet amp powering 104/2's. But it all depends on your listening level. I can't recollect if I have heard tubes with these, but I don't see any reason that wouldn't sound great. 104/2's are really interesting speakers, and for some are the end of the journey, hope you enjoy them.
 
leesonic said:
They are "4 ohm resistive" according to KEF. What the means is the designers tried to keep the impedance of the speakers as flat across the frequency range. If you've seen an impedance curve of a "regular" speaker, you will see it goes all over the place. 8 ohm speakers may dip to 4 ohms or below, 4 ohm speakers might drop to 2 ohms or less.

I would recommend something known to have higher current capabilties. How much power you need depends on how loud you plan on listening to them.

Lee.
Click to expand...

They really don't need the sort of "arc welder" amps that thing like Infinity or Apogee speakers need- there are no one ohm craters in the impedance.

Most any good quality amp, that can handle a 4 ohm resistive load (without overheating or such) will usually work fine.

BTW: I think that it's the flat impedance curve, that makes them work so well with tube amps. Their response isn't very affected by an amp with a lower damping factor, such as a tube amp (typically have damping factors of 10-20, as opposed to 100 to 200 for SS amps). Enough damping to keep the bass tight, but not excessively high either.

The lower damping of a tube amp, may be why the Award A300 worked so well without the KUBE. The bass is a little "fuller" with less damping, which makes the KUBE less necessary...

Regards,
Gordon.
 
I was running a Marantz 2275 and there was a noticeable improvement when I switched to an Adcom stack (GFA-545II & GTP-500II). I've been very happy with the Adcom. I have a Denon amp sitting around I plan to hook them up to for a listen... eventually.
 
GordonW said:
I've seen some crazy amp combinations, just EXCEL driving 104/2s.

The one that shocked us the most, was the Harman-Kardon Award A300 tube amp. 14w/ch. We were just gobsmacked. No, it wasn't "stadium loud", but it did EVERYTHING well. Huge soundstage, nice dynamics, great bass.

The other one that was almost as impressive, was the NAD 310 integrated amp. A TWENTY WATT per channel amp. Again, it did EVERYTHING well.

So, don't assume that small amps can't cope...

Regards,
Gordon.
Click to expand...
I've never found any correlation between amplifier power and how good it sounds.
 
rothwellaudio said:
I've never found any correlation between amplifier power and how good it sounds.
Click to expand...

Well- I have seen, in older SS amps- somewhat frequently, smaller amps sounded somewhat better than larger amps, everything else as equal as possible, from the same manufacturer.

For a couple of examples- the NAD 3020 integrated amp, did seem to be more "transparent" sounding than its bigger brothers. Also, the Acurus A200 sounded quite a bit better than the larger A250. Again, more open sounding.

The factors at work here, were the complexity needed to create a larger amp, compared to the relative simplicity of a smaller amp. Bigger amps needed more stages of drivers, more parallel output devices (which did not always "share the load" as well as might be desired), and frequently, more feedback to keep the amp under control. These go against the proverbial "straight wire with gain" ideal, to an extent.

As for tube amps- tube output transformers are always a compromise between power output and bandwidth. It's very hard to make a larger output transformer, that performs as well at the ends of the spectrum (ESPECIALLY the highs) as smaller transformers. It can be done- but frequently, it's a lot more expensive and difficult to do well...

Regards,
Gordon.
 
I've run my 104/2 with just about everything that came through the house, from 20 watt SS, 25 watt tube, 50 watt tube, 225 watt SS, and 450 watt SS mono-blocks.

They sounded good with them all, but IMHO, the Adcom GFA-365 at 450 wpc can really get the most out of them.

So I would recommend large-ish SS rated for 4 ohm loads. The bass is better with SS. Tubes were mid-range bliss.

I also prefer to run them without the Kube. I tried the Kube as is, and now re-capped. Not much difference.
 
Agreed on the Kube , running a Sansui Ba / Ca 3000 sounds nice lots of head room , also using a Sansui 9090 Db great with both . Your ears will tell you what fits best for you .
 
I have read of people using Dynaco ST-70s with good results. However, I sadly do not own a pair of Kef 104.2s. They are on my short for the very reason I own an ST-70.
 
My people!

Wanted to give this thread a bump. I recently acquired a nice pair of 104/2s, but haven’t had time to procure an amp for these beasties yet—I’m in the process of furnishing a house and other stuff is taking precedence.

I was hedging towards getting a quality vintage MOSFET amp ($500 range) and preamp (yet to be determined), but as I intend to integrate audio from a projector via HDMI I thought I’d consider modern all-in-one integrated solutions too.

Someone on another thread suggested the Yammie A-S801 as a solid candidate for this. Phono preamp is apparently a weakness, but otherwise it seems to have a great reputation for its price bracket…

Was wondering if anyone might care to opine on the overall loss in ‘sonic niceness’ I might experience going modern integrated instead of vintage separates with these KEFs? They’re reputedly fairly honest and revealing speakers, so I’m slightly leery of cheaping out on upstream components…

Penny for your thoughts and apologies for the mild thread hijacking.
 
I've run them with a number of amps, but the Haflers, to me, have been the best. The 100 wpc DH 200 does fine, if you have more $$ go for the DH 500 or similar.
 
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