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

Not that this is helpful for the OP, but...

I own MBL 121 monitors, which have essentially the same tough-to-drive specs as the big models.

And yet my CJ premier 12 140w tube amps seem to drive them great and even more wild, probably my favorite pairing has been my old Eico HF-81, 14W tube integrated.   They sound glorious driven by that Eico!

(I don't listen very loud, but even when I do crank it up, it still sounds great).
Also explains why Aleph 4 was not happy, it can live with 4 Ohm, but not with 2 Ohm.
So ML 23 is a decent match, and an amp doubling output down to 1 Ohm could be worth a try.
What is important is that the amp be able to act as a voltage source. It does not need to double power at 1 or even 2 ohms to do that.
A friend owned the 101's for a while, and the smaller model with the brass pyramid up top ( as rear channels), I forget the model. These speakers need POWER. Dont attempt to run them on an integrated or small amp. I personally tried running the little pair with outlaw audio monoblocks (300w into 4ohm), and it was no where near enough. You can just tell they sound... flat. He was using Crown Studio Reference 2's which were fine on the 101, but I heard them with the MBL amps at CES and in a home and they were definitely better. Like one other said, if you power them correctly, they will bring you to tears. BTW a fellow from MBL flew from germany to the states to come set up the speakers. He tried to up-sell my friend on their high end speaker cables. We spent some time A-B'ing between the mbl wires and (dont laugh) some terminated welding cable. Yes, welding. I dont recall the gauge, but I think it was fine stranded and maybe 4 gauge?! There was definitely a difference in the sound, but it was not better or worse, just different. If you weren't A-B'ing it, it would be very hard to tell. My point is, put your money into the amp, not the cable. :) BTW my friend still has that smaller set of mbl's around and chatted about selling them recently. They've just been sitting in the back of his room for years.
@doug1234 .
I would love to hear those MBL's. Any chance your friend is in the NYC area?
Bob
I would think that an Atmosphere MA-3 mk. 3.3 would be able to drive that speaker by looking at specs.Just another option,Tish