SpeakerTalk

audiolabtower · VIP Contributor 500+ Joined: 06 Jan 2009 Posts: 686

that's interesting, I asked the question of Kef years ago and they sent me both data sheets showing the printed specs were identical and told me the only difference was the mounting plate. The magnet specs are identical 10000gauss density and 50000maxwell total flux. How is a pcb used inside the drive unit, is it the coil former?

T.O. Chef · Posted: Thu Oct 22, 2009 6:49 pm Post subject:

Hmmmm. Admittedly, I'm a bit confused now too. I seem to recall it being said that the extra iron around the SP1072 results in only a very small decrease in its sensitivity.
Does the construction of the SP1072 contribute other sonic variations over its predecessor too?
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speakerguru · Posted: Fri Oct 23, 2009 8:17 am Post subject:

ColinR · Posted: Fri Oct 23, 2009 11:16 am Post subject:

audiolabtower · VIP Contributor 500+ Joined: 06 Jan 2009 Posts: 686

thanks for the clarification guys Smile

, so the tweeters are interchangable as far as performance was concerned but obviously needed different flush mounting arrangements. So the early 105.2s had 1049s? and later ones 1072s without the series small inductor in the crossover (or maybe this was a select on printout depending on the measured drive unit)?

One more clarification of the diagram please - I assume the later crossover was 450uF total series caps, or was it 2x450 which would be quite a jump from the earlier total 480uF?

cheers Very Happy

ColinR · Posted: Fri Oct 23, 2009 8:33 pm Post subject:

speakerguru · Posted: Sat Oct 24, 2009 8:46 am Post subject:

ColinR · Posted: Sat Oct 24, 2009 9:51 am Post subject:

The lined holes on the SP1072s are 57 mm apart.

Now the soldered joints on the SP1049 dome are side-to-side (in ths same plane as the faceplate), so the hole isn't big enough to locate them.

The SP1072 has metal lugs/rivets to which the lead out wires are soldered in an up-to-down (perpendicular to the faceplate) which fit into the lined holes.

The "bodgit" option of desoldering a SP1072 dome, filing down the metal stub and doing a new parallel joint for repairing a SP1049 OR making a new vertical soldered joint on a SP1049 dome to fix a SP1072 has never been investigated by me.
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audiolabtower · VIP Contributor 500+ Joined: 06 Jan 2009 Posts: 686

pfby · Posted: Sun Feb 28, 2010 12:08 am Post subject: Shy bass with Kef 105/II

Hi,
This is not a real reply - a little bit late I suppose - but rather a reflexion about what our friend named "a lack of bass" ... I have a pair of 105 from the beginning of the 80's (not 105 /II). I don't think there is an noticeable difference between these models.
I first used these speakers with a Sony pre+power amplifier (I can't remember the reference but it was at least rated 2x150 W). When this amp died, (no possibility to have it repaired) I wasn't able to buy another very good amplifier at hte moment. So I bought a Yamaha integrated AX 892 (rated 110 W per chanel). The result was sadly "standard" neither good nor bad...
Some years after, I bought a McIntosh power amp (2x270 W) used together with the Yamaha AX 892 preamp (this very model factory came with a strap between preamp out and power amp in).
It was "night and day" (more exactly, day and night...) A larger and deeper stereo image and more strong low frequencies.
Later, I bought a Mc preamplifier, and again, quality increased... more softness, more detail and very solid bass.
As a sound engineer, I have recorded many pipe organs, among them, in Paris, St-Eustache's, which has within its 100 stops - three 32' (one "reed" at the Pedal "Contretrombone", and another one in the Swell (rather unusual !) "Contrebasson"... At the Pedal as well at the Great Organ there is a mouth stop (real 32') 'called "Contrebasse" and "Flute".
I edit my recordings monitoring them with my 105 and I can assure you there is no loss in any part of the spectrum.
On the other hand, 105 "ne font pas de cadeau" this means they don't magnify the sound at all : if the recording is well-balanced, they sound good, but if there is something wrong, they sound quite "poor".
May be your problem only came from an amplifier not powerful enough to drive them correctly ? It might be easier to try a stronger amplifier rather than modifying filters...
Let me know...
Best regards
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Pierre-François Bourgey

proffski · Posted: Sun Feb 28, 2010 1:51 am Post subject: Re: Shy bass with Kef 105/II

Agreed!

Forget paper specs and 'average' listening power / volume go for an amplifier with grip & authority.

In order of my preference in the earlier days with KEF loudspeakers...

Krell, Amcron, Adcom. The differences are incredible yet on paper almost zero!

Oh, I once heard a monitoring session on early 105s being driven by professional Yamaha amplifiers at the Cheltenham Music Festival, amazing!
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Lee in Montreal · Senior Contributor 200+ Joined: 22 Aug 2009 Posts: 231

One thing I noticed about the 105/2 is that it doesn't lack bass at very low frequencies, but the rolling bass (80-90Hz) is indeed sometimes missing. And I think it has to do with the crossover filtering it out. I came to this conclusion from when I had the other "foreign" filters in my FrankenKefs. The bass was way "rounder" while on a "real" 105/2, some of the bass you don't hear, you just feel.
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Current line up
2 sets basic Kef 104/2
2 sets bi-wire Kef 104/2
Plenty of KEF components for a few fun builds