Tannoy vs. ATC

I should add for posterity, if I chose the actives I would still have to buy a new preamp with balanced outputs to connect to the speakers.  Vintage McIntosh have RCA only.  Also, active speakers have power chords, so you have to consider additional power chords and available wall outlets (or extensions) with regard to speaker placement.  Still they are a great option.

" The amps also have sentimental value and I would like to use them." as far as I am concerned this is your answer...

A wonderful aspect of ATC is how faithfully they reproduce what has been recorded on the media.  This can be amazing with excellent recordings but horrible on poorly recorded ones.  They are very clear, resolving and tonally neutral.  I've owned the 20-2's and the SCM-11's.  I currently own the SCM-19's.  The bass for the size has slam and is very detailed. They do require powerful amplification.  Many don't like ATC because they are too revealing.
On the other hand Tannoy are not as "fast" are more mellow sounding and less detailed.  With good tubes they produce a warm blanket of sound which many people like.  I own the Glenair 15's and once owned the Turnberry's.  

Based on your listening preferences I would recommend the Tannoy's.

                                                                      Jim

Here is a reply that you will love Jimmy2615.
I went from a ATC SCM40 to Tannoy Turnberry SE. It was not an upgrade effort. I just had relocate to a different city so I sold my ATC (with a heavy heart) and bought a Turnberry SE (just took a chance after some auditions). Contrary to what many will tell you, they are more alike than different:

1. They are both very very neutral. Yes, Tannoys are very neutral when driven by good high current amps. But people normally drive Tannoys with more colourful (soulful) tube amps and in the process lose some neutrality and transparency. Drive the Tannoys and ATC with a quality class A amplifier or say something like the ATC SIA-150 and you will hear both of them doing terrific in terms of speed, transparency and tone.

2. The ATC is a bit more neutral to tone but is also drier than the Tannoy. With the Tannoy the timbre is more wet and audible. You can hear a more breathing guitar with the Tannoy whereas ATC will sound more straightforward. To me, Tannoys sound more realistic whereas ATC sounds more accurate (slightly academic in comparison).

3. In terms of dynamics the ATC is amazing. It is more dynamic and effortless than 95% of conventional speakers out there. But Tannoys are partially horn guided and that shows! The Tannoys are even more effortless! Those big drivers do scale and dynamics in a more natural fashion. Those horn guided tweeters bring the bells and triangles more into the room and closer to the listeners, more live I would say.

4. The bass of ATC and Tannoys are different. ATC is drier and punchier, more pistonic. Tannoy is juicier, more wholesome. Kick drums sound more exciting via ATC due to that outright punch, double bass sound more engaging through Tannoy because of the texture and tone which makes it feel more like a real instrument in the room. Just that one needs to understand, while Tannoys sound wonderful with a 30 watt tube amp, if you want it to rock and groove, give it more power like you give the ATC.

5. In terms of outright transparency the ATC is better. The Tannoys on the other hand is more coherent and sounds like a point source more readily because of the concentric drivers. When I moved from ATC to Tannoy I knew the ATC could sound more transparent but the Tannoy was also very transparent so I did not miss the ATC. By the way when I listen to a well setup active ATC I do not miss the Tannoy either. 

6. The Tannoys are more forgiving but they are not coloured. They are just a bit more natural sounding while ATC is a bit more surgical in its approach. But it is really not something to be worried about. ATC is not clinical or surgical in absolute sense. It is only a bit more surgical compared to a Tannoy Prestige. 

Big drivers by law of physics do some things that small drivers cannot do and vice versa. But when well implemented big drivers and small drivers come very close to achieve the same sonic goals of the more realistic music reproduction. Tannoy and ATC are an example of similar convergence.
 
All said and done I would one day like to own a ATC SCM100 active and a Tannoy GRF MK4. They both remain my favourite conventional speakers till date. There are other amazing speakers that I really like  e.g Pioneer Exclusive 2402, Avant Garde Trio Omega, TAD CR1. I may get into these big horn speakers if I leave Tannoy and ATC.

I would suggest you look at the Turnberry GR Limited edition instead of Kensington. Kensington sounds more transparent but it also sounds a bit too bright. Turnberry GR is very balanced. Or you could directly go ahead with Canterburry which is the best of the lot.

On the ATC side, get the 40 active or if it has to be passive then get ATC amplifers to match. Dont try to match amplifiers from other brands which is a pain. I have done that and ultimately found ATC own amplifiers to be an amazing match.

Hoggshead and Pani,  thanks for the all the info !  It is very helpful, indeed.  I was afraid I would not be able to find people with experience with both manufacturers, so is this great.  Pani, what do you think about the Turnberry's ability to fill a room my size compared to the SCM40?  I was concerned it might be on the smallish side; also, I like the height of the Kensington - the Turnberry seems like a must for stands.