Vintage DD turntables. Are we living dangerously?

Agree. Not all panels are created equal. I agree with you on the Magnepan.
I heard Martin Logan, King-Sound, Quad ESL and various models of Acoustat including 2+2, 3, 33, 4, 66.
The best of best of the lot was 3 located between two rooms (so it had almost the same distance to the back wall as to the front wall) with very high ceiling in the listening room. Dipole powered sub (two woofers back to back) included.
Driven by push pull tube amps and by OTL's.
Sound stage is huge, clarity is unparalleled, background is pitch black and it's quite dynamic too, unlike Quad ESL 57.
Probably the best implementation of ESL I hand ever heard.
Again, depending on source material, to my ears, mid bass was missing and bass to midrange connection was not to my liking.
Its a very impressive big orchestral pieces material. Just not one that I can personally live with. I am missing the wood:-)
Its interesting that in speaker choices there are camps:
Horn guys can never settle for anything else, ESL ditto (they are very sensitive to "box colorations" and to what they describe as separate drivers rather than one coherent sound wave, at least in the mid to upper frequency) and box speakers guys are also pretty stubborn in their choice.
In the end speaker choices are like "choosing" your wife:
She is not perfect but she is perfect for you, if you know what I mean:-)
I never changed my main "lowly" Sonus Faber Grand Piano Home speakers after hearing countless other speakers, including, comparing them, in the same room to "higher end" Sonus Faber speakers. Just to show there is a reason why I chose them in the first place,
The main thing is to chose a pair of speakers that work in your room (can't over emphasize that because speakers are never one size fits all) and to work with them rather than becoming a "speaker womanizer" who swaps speakers left right and centre to never assume each spraker's potential rather than picking a pair and find out how to make them sing.
Just my opinion based on my experience.

I have noticed that some of the members here had experience witn Lenco and other idler wheels as well and was wondering what was your impression of the results compared to a DD in a heavy plinth.
My experience is limited to a friend's JN Reference with Analogue Instruments, 12" Cocobolo, Uni-pivot tonearm and various cartridges (SAE 1000 LT, Koetsu Black, low output Elac).
On the plus side:This combo had very good flow and sounded very smooth.
On the negative side: noise floor was high, which made dynamic contrasts lacking. Air, 3D and detail were missing.
A while ago, 3 audiophiles from Canada conducted a "Lenco Challenge": building a CNC machined, heavy birch plywood plinth for a donated Lenco drive, greasing the bearing and following The Lenco Heaven instructions.
Results were not super positive when compared to modern tt's like DD Brinkmann Bardo for instance:
http://www.canuckaudiomart.com/forum/viewtopic.php?f=32&t=28246&hilit=lenco+project+brinkmann&start=285

I was wondering what was your experience?

I personally use other peoples' opinions only in the grossest way, as a guide to what I might NOT like. Which is why I usually don't even ask. This is because my brain already knows what it wants, and I've already spent decades taking my brain to where it wants to be. I own a Lenco in a slate plinth with a "PTP" top plate (see Lenco Heaven). The OEM bearing is completely replaced by a "Jeremy" Superbearing (see also Lenco Heaven). The platter is stock, but it has been dampened. The idler wheel and idler arm are stock, but I have replaced a spring that loads the idler assembly with a lead weight on a string. This was the idea of Jean Nantais, possibly one of the Canadians to whom you refer. I have a Dynavector DV505 mounted on the slate. The AC comes from a Walker Precision Motor Controller. This combo gives me great pleasure, plenty of "air", dynamics, 3D-ness, whatever. It may be a hair less super accurate on timing, compared to my Technics SP10 Mk3 and Kenwood L07D, but if you don't compare it to those two every day, you don't worry about it or notice a problem. It definitely crushes the prior turntable, a Notts Hyperspace, in terms of timing, but I thought the Notts crushed the SOTA I owned before that, especially on piano music. You mentioned noise; I hear zero issues with noise, but again the Mk3 and the Kenwood (especially) may be a hair quieter. No idler noise that I can hear whilst sitting in my listening chair at normal (loud-ish) sound pressure levels. I think (very tentatively) that the slate plinth is superior to the Nantais plinth Lenco I owned prior to embarking on the slate project, less noise by a tad.

Sorry to all. I think I wrote much the same post only a few days ago up the page.

Lewn,
Glad to hear again that the Kenwood L07D is the protagonist on your stage. Proves the superiority of the maglev spindle over other designs. Without having not heard your system I do believe your evaluation 100 % and would agree because I have experienced the benefits of my maglev.
In my system I will never even think of trying a non-magnetic spindles. In my system I have managed to get rid of all the direct rim noise just recently, the adjustment is really a hair less.
Thanks for confirming this essential info about the Kenwood L07D, again.

Hi and thanks for the thorough response!
What I meant by noise is not audible noise as much as high noise floor or lack of pitch black background which hurts the 3D and the dynamic contrast and gives you a sense of flatness to the sound.
It is still amazing that with 4 pole (!) motor, 50-60 dB S/N and wow and flutter at 0.6% one gets results that are not far off DD's with 75 dB S/N, core-less motor and 0.02% wow and flutter.
A lot of isolation, superior bearing and better platter, somewhat reminiscent of the EMT 927 and 930 idlers, I assume.
The one thing that these idlers have in spades is torque (which translates to drive, a sense of flow and PRAT) but my question is:
How much torque do you really need?
If you manage to overcome cartridge drag on transients with ease do you need the extra torque?
Does a Technics with 16kg cm sound more convincing than a TT-101 with 1.3 kg cm?
Lewm, I agree with you that opinions are just that, opinions.
At the end each of us have different reference points and preferences and what appeals to one person might not appeal to other.
I remember having a discussion with a guy who was very opinionated about things audio. He talked about turntables, about building his own record cleaning machine, about soundstage and audio preferences.
When he visited me and heard my system he said that the midrange intimacy and concentrated sound was too much to bear.
When I visited him I saw two Kef mini-monitors the size of Bose AM-5 located on the sides of a plasma TV with 1,600 watts SVS sub.
Basically a Bose sound - bloated bass and two tweeters with no midrange to be found. This is just to show you how amazingly subjective this hobby is. Who am I to judge? To each his own.
Many audiophiles will look at my gear and will say to themselves that its mediocre and that's fine with me. In the end its about pleasing our heart and not about convincing others that our sound is great.
I believe that with this understanding, when it comes to opinions, one can judge a differential (one item compared to another when all other parameters are the same).
Based on what I read between the lines, it seems that to make an idler wheel work one needs a heroic effort: see EMT 927 with its industrial washing machine sized motor and steam train flywheel sized platter and EMT themselves moved to DD once they could (once torque was sufficient to start a song in less than half a second when broadcasting).