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Dev Junior Contributor 20+
Joined: 17 Aug 2012 Posts: 24 Location: India
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Posted: Thu Oct 17, 2013 5:43 pm Post subject: Amp for 105.2 |
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Hi, I have my 105.2 recapped and refurbished and pairing them with a Sansui AU-9500.
The Soundstage is fantastic but high frequencies are not reproduced as good.
Which is the ideal match for them?
I understand they were designed for solid states only.
So which amp to go for?
And originally back in late 70's & early 80's, which amp were they matched with, originally, any insight?
Gurus please guide.
Dev |
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speakerguru Über Contributor 1000+
Joined: 18 Nov 2005 Posts: 1192 Location: Green Hut, Tovil
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Posted: Fri Oct 18, 2013 9:05 am Post subject: Re: Amp for 105.2 |
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Dev wrote: | I understand they were designed for solid states(sic) only. |
Your understanding is erroneous. I am at a loss to understand how you could have come to make such a statement. |
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SaSi Senior Contributor 200+
Joined: 24 Aug 2008 Posts: 256
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Posted: Sat Oct 19, 2013 1:36 pm Post subject: |
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These are not super efficient speakers of the 96dBW/1m to be effectively driven by a 10W amp.
They do need a lot of power (in the 200WRMS range) but if you have any amplifier and don't overdrive it it will do fine.
I listen to my 105.1 at moderate levels using about 1-2W of power. |
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audiolabtower VIP Contributor 500+
Joined: 06 Jan 2009 Posts: 686
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Posted: Sat Oct 19, 2013 10:25 pm Post subject: |
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They are not as efficient as modern speakers, but are a relatively easy load, so should not be difficult to drive. A solid state amp with good bass grip (damping factor) might be useful to control the B300 but this is not like saying they are totally unusable with a wide range of (or valve) amps. |
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proffski Über Contributor 1000+
Joined: 22 Aug 2003 Posts: 1297 Location: Tewkesbury UK
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Posted: Sun Oct 20, 2013 1:37 pm Post subject: |
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Back in 1974 / 1975 we happily monitored on LS35As using Leak and Lowther valve amplifiers. Even two unknown BBC made mono amplifiers.
As long as you are sensible with the volume control and know the systems limitations there should be little if any problems
Later we went onto Amcron DC150 and DC300 transistor amplifiers which did help somewhat. I still found it amazing that coming back after the weekends I quite often found that somebody had reconnected the Leak amplifiers in preference to the Amcrons... _________________ I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill |
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Thierry Intermediate Contributor 75+
Joined: 02 Sep 2010 Posts: 81 Location: France - Outskirts of Paris
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Posted: Sun Oct 20, 2013 4:08 pm Post subject: |
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In my humble opinion the Quad 606 (MkI or MkII) is a very good choice.
I also used a Quad 405 and an two home made Quad hybrids using the Quad 405 boards and a swicthing mode power supply.
All of the above amps give excellent results and 140 watts per channel with the 105.2 is well enough to get a comfortable listening level on any musical program without any audible stress on the most demanding music peaks.
Thierry |
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rx7rotary Intermediate Contributor 50+
Joined: 20 Feb 2012 Posts: 59
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Posted: Tue Oct 22, 2013 12:49 am Post subject: 60w |
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I have been running mine with 60w Audio Research Classic 60, without any sweat. Control of bass is fantastic, midrange and highs a brilliant.
cheers |
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proffski Über Contributor 1000+
Joined: 22 Aug 2003 Posts: 1297 Location: Tewkesbury UK
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Posted: Tue Oct 22, 2013 9:09 am Post subject: |
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Thierry wrote: | In my humble opinion the Quad 606 (MkI or MkII) is a very good choice.
I also used a Quad 405 and an two home made Quad hybrids using the Quad 405 boards and a swicthing mode power supply.
All of the above amps give excellent results and 140 watts per channel with the 105.2 is well enough to get a comfortable listening level on any musical program without any audible stress on the most demanding music peaks. Thierry |
Is that a Quad 405 or 405 MKII? _________________ I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill |
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Thierry Intermediate Contributor 75+
Joined: 02 Sep 2010 Posts: 81 Location: France - Outskirts of Paris
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Posted: Tue Oct 22, 2013 9:18 am Post subject: |
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proffski wrote: | Thierry wrote: | In my humble opinion the Quad 606 (MkI or MkII) is a very good choice.
I also used a Quad 405 and an two home made Quad hybrids using the Quad 405 boards and a swicthing mode power supply.
All of the above amps give excellent results and 140 watts per channel with the 105.2 is well enough to get a comfortable listening level on any musical program without any audible stress on the most demanding music peaks. Thierry |
Is that a Quad 405 or 405 MKII? |
It is the first Quad 405, not the MkII.
Thierry |
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audiolabtower VIP Contributor 500+
Joined: 06 Jan 2009 Posts: 686
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Posted: Tue Oct 22, 2013 11:32 am Post subject: |
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Years ago I used a 405.1 I built to the exact circuit when they first came out (bridge components matched to 0.5% with youthful enthusiasm!). The 105 is an easy load, 6 ohm minimum and not too reactive so it was a good match.
I remember the Spendor BC3 could drive it into very nasty overload (banging between the rails) before Spencer Hughes put the resistor mod in the crossover to tame the very reactive 3 ohms or so in the midrange, and Angus McKenzie's first paperback Hi-Fi Choice led Peter Walker to start the road to the surface mount pcb (no room left on main pcb) time averaged protection circuit of the 405.2. |
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iso Senior Contributor 200+
Joined: 29 Aug 2011 Posts: 215 Location: Finland
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Posted: Sun Nov 24, 2013 2:16 pm Post subject: Re: Amp for 105.2 |
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Dev wrote: | The Soundstage is fantastic but high frequencies are not reproduced as good.Dev |
The problem can also be aged T52`s. After Cantata rebuild, HF reproduction of Cantatas was congested compared to modern tweeters. Kef folks explained in Kef 105 HiFi News vintage review that T52 used plastic damping ring that will harden due age... I tried 4 different T52´s and did not note too much difference.
SG may know if there is something that can be done for this.
Best Regards
Kimmo |
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speakerguru Über Contributor 1000+
Joined: 18 Nov 2005 Posts: 1192 Location: Green Hut, Tovil
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Posted: Sun Nov 24, 2013 11:28 pm Post subject: |
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I worked on T52s quite a bit when developing the KM1 version. The damping ring was an over-plasticised PVC like you get on car tax disc holders (UK). It sticks to glass OK in summer and stays on, if you're lucky, for the year.
In the case of the T52 it was stuck to the diaphragm surround using a flexible hot melt adhesive. The diaphragm surround had to be sand blasted first to get a matt adhesive friendly finish and even then it was difficult to prevent or get air bubbles out. With time things tend to recover and the air bubbles may come back and the damping action could be lost. |
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Thierry Intermediate Contributor 75+
Joined: 02 Sep 2010 Posts: 81 Location: France - Outskirts of Paris
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Posted: Mon Nov 25, 2013 1:46 pm Post subject: |
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speakerguru wrote: | I worked on T52s quite a bit when developing the KM1 version. |
The KM1 is one of the best loudspeaker system (if not the best) I have ever listened to in my life and the closest thing to real life music performance. Shame I couldn't afford the KM1 by then. Today I wonder how many of them are still in use, I wish I were one of their lucky owners. Congratulation for having worked on this incredible system, definitely a credit to KEF engineers, probably still unequaled today.
speakerguru wrote: | The damping ring was an over-plasticised PVC like you get on car tax disc holders (UK). It sticks to glass OK in summer and stays on, if you're lucky, for the year.
In the case of the T52 it was stuck to the diaphragm surround using a flexible hot melt adhesive. The diaphragm surround had to be sand blasted first to get a matt adhesive friendly finish and even then it was difficult to prevent or get air bubbles out. With time things tend to recover and the air bubbles may come back and the damping action could be lost. |
Very interesting reading, this is exactly what makes this place unique, as far as I know there is no other forum where "the ones who really know" give us such light with an insider perspective on our beloved gear genesis. Thanks for this.
Back to the T52 : unless I am completely wrong, what you describe would rather result in an excess of brilliance than a dull sound, wouldn't it ?
Thierry |
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iso Senior Contributor 200+
Joined: 29 Aug 2011 Posts: 215 Location: Finland
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Posted: Mon Nov 25, 2013 6:07 pm Post subject: |
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Thierry wrote: | Very interesting reading, this is exactly what makes this place unique, as far as I know there is no other forum where "the ones who really know" give us such light with an insider perspective on our beloved gear genesis.Thierry |
Designer or someone in the design team will most likely know shortcommings of product most toroughly.
Schematics and pictures are good starting point if our aim is 100% concours restoration... even if we like to make things work as well as possible, without being 100% original.
I refurbished H/K Citation 11 from mid 70´s earlier this year. There were 5 or 6 incorrectly made groundings in wiring loom, muting relay was in series to signal. Performance of preamplifier improved considerably, when I sorted incorrect groundings and wired muting relay between ground and output. Citation 11 is most likely performing better now than when it was new... I do not feel quilty for this, even some wires in the loom are now connected slightly differently.
But anyway... it took 3-4 weeks sort this all out, even I had correct service manual. But as there was no information about physical lay out of preamp. I had to draw grounding idea from amp by using DVM. Even then some wires needed to be disconncted, before I coud be shure where the other end of wire was.
With some inside information this could have been easier. It is great to have SG here...
Best Regards
Kimmo |
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proffski Über Contributor 1000+
Joined: 22 Aug 2003 Posts: 1297 Location: Tewkesbury UK
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Posted: Mon Nov 25, 2013 6:27 pm Post subject: |
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[quote="iso"] Thierry wrote: |
With some inside information this could have been easier. It is great to have SG here... |
Seconded without a moments hesitation! _________________ I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill |
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