MBL 101 (~1990) - amp suggestions.


Does anybody have experience with those speakers:
Designation was MBL 101, or MBL 101a/b/c (letters may designate colour).
They have _no_ cone drivers, only three 'Radialstrahler' units, the same size units as in later/current MBL 101 range, but lower crossover points. Subwoofers (MBL 201) were optional, I do not have them.
So far I have tried the following amps:
Pass Aleph 4: almost there, but feels like lacking authority. Also, female vocals seem to suffer (males fare better).
300B SET (glasshouse/hificollective): they make sound, even loud if pushed (circuit allows 300B to go A2), yet the match is poor, orchestra becomes a mess.
Moderate power SS AB amp ("INnovative Audio Ultrapath"): pointless. Sounds flat and gutless, worse than Aleph 4 or SET.
Mark Levinson 23: the best match so far. Controlled and effortless; merciless at times (poorer recordings are exposed for what they are).
-- Do you think I can [substantially] improve over ML 23?

inefficient
  • On MF AMS50:
interesting in general, but I don’t see it working from a technical pont:
76w in 4 Ohm do not seem to do the trick @ 80 dB/W (or even 80 dB/2.83V).

To R.:
in ‘cost no object’ situation I’d start with a pair of ML 33 and see if they are any good.
In real life I tred ML 23, I could get a Krell ksa 250s, probably a ML 333, a Pass X350...
or —and that is quite realistic right now — another Pass Aleph 4 and run them paralelled one per channel.
= I look for ideas and _experience_
Experience with old MBL 101 seems a scarce commodity though...

MBL makes amps that are on the warm side and I would think would be a very good match for these speakers. These can be had used at reasonable prices. You need lots of power!
Dear @inefficient: My first ML amp was the 23 followed by the 23.5 ( that I choosed over that Krell you mentioned. ) and 20.5's and 20.6's.

From those times were excelent designs and between them Threshold S500 II and S5000e, believe it or not are a challenge for any today Pass ones.

You need to take a look to the Parasound monobloks JC1. I listened paired with different big speakers: top of the line Soundlabs, the big Dynaudio and  Magico. Very good with either.

The ML33's has very good engeneering but its performance has not the design levels.

I never heard these Electrocompanient but I owned its electronics and are very good designs:

https://www.audiogon.com/listings/lis9d7a3-2-each-electrocompaniet-nemo-aw600-monoblocks-amplifiers

I forgot another very good choice could be the Gryphon Antileon where I have too first hand experiences.

Have fun in your hunt.

R.
This speaker is not that hard to drive; its efficiency appears low because most of the sound does not get to the microphone that is placed only one meter away.
You can drive it quite successfully with tubes. But a lot depends on the size and liveliness of your room. How big is it?
Currently I use MBLs in open living area, 6 x 7.5  x 2.5 m (or 20' x 25' x 8'4), Room has large windows, at  it's other end it opens to upper floor ( ~2 x 3 m / 7' x 10' "hole") + extends into a hall (1.2 x 4.5 m / 4 x 15 feet), not empty space (open kitchen, some furniture and clutter).
MBL 101 ability to fill the room is quite surprising (not nearly as much volume 'gradient' as when I used Lowther Fidelios).
And there is bass, -- my neighbour from two floors down informed me so.