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?

5d97e9e2 7638 45a0 a207 9625d2b9cf98inefficient
yes Musical Fidelity AMS50
I have heard them w subs with AMS100....incredible

a big Threshold also more than up to task...
Dear @inefficient: Which your $$$ floor level for it.

Regards and enjoy the MUSIC NOT DISTORTIONS,

  • 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:


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

Have fun in your hunt.

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.
Dear @inefficient : I forgo, I heard twice those MBL speakers one time in ahome audio system paired with Music Reference tube amps and the other at a distributor paired with SS electronics.

The system with the MR sounds good but nothing more in change the ones with SS electronics really makes the speakers shines.

The MBL's performs better at over average listening SPL and even the manufacturer ask for amps over 200 watts.

From my point of view of MUSIC home reproduction tubes never can honor MUSIC. Can " sounds " but that's all.

Of course that each music lover/audiophile has its own priorities and choices according to.

IF you look closely at the refrigerator sized AMS-100 you might get faith in the AMS-50

but agree the Threshold are quite good as would be anything Nelson builds today

I have been dying to hear MBL for years.
And, from what Tomic told me: A Great choice.
( And this is from a Vandy guy).
Dear @georgehifi  : The non-Evo Antileon even today is a good choice. I never herad the Evo but certainly is way $$$$$$ higher than the " old " Antileon.

My buddy who loaned me his Sonus Faber Extremas for a year, went to the MBL 101 right after. We tried my Crown Studio Reference, which did well, but he had the Jadis JA 500 monoblocks, which were so incredible with the MBL 101s, I cried, listening to my vinyl of Santana’s " Europa ", from the Amigos album, on his mega buck phono playback rig. No drugs, no alcohol, just listening bliss.
The non-Evo Antileon even today is a good choice.
Yes all model Gryphon's are good.
These MBL's are only "tested" at 81db!!!, so amp around 150w or more is needed.
But also they have epdr resistance of around 2ohms in the low bass, and need an amp with BIG current to deal with this, if the owner of the speakers wants to get the very best out of the bass.

Cheers George    
Looked up 'EPDR resistance' -- thanks for the tip!
Stereophile has a good article in their archive, that clarifies a lot, among other things sets in perspective use of tubes (300B with a 6 Ohm tap really did not work too well, in 2 Ohm 'epdr' resistance they should not).
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.
Thinking of 'eprd', McIntosh with their autoformers are on to something.
Gryphons seem rather costly.
Dear @inneficient :  The 20.6's double its power ( 100 watts at 8ohms. ) from 8ohms to 1 ohm, goes from 100 to 800w and 400 at 2ohms.

Do it a favor and don't put in the signal " road " transformers7autoformers and the like: can't improve that music signal.

This is other great alternative:



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?
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
Thank you all for input!
I will live with ML 23 for now, possibly sell Aleph 4 and look out for MORE POWER https://tenor.com/view/toolman-taylor-tim-allen-homeimprovement-gif-5701538

@gdnrbob  sorry I missed your message. I am not on here a lot. He still has the mbls.. He is located upstate a few hours away.
I’d lean towards matched mbl amps for large mbl speakers if cost not an issue. That’s what dealers use. But otherwise in general you want a beefy amp with lots of power and current. I have very efficient BEl Canto ref 1000m Class D amps that might be had for reasonable cost if found used that would surely do the job well. They can pretty much drive anything to their max.   I use them with a pair of similarly large Ohm Walsh speakers.

Congrats on those mbls. Set up well they are in a class of their own.
I heard one of these models with a pair of CAT monoblocks and it sucked them dry. Even at low volumes you could tell that these amps werent nearly powerful enough. Perhaps atma-sphere is correct, although I have my doubts, that it is the type of the tube amp. 
I will go active in bass and relieve MBLs from 100 Hz downwards: my 101s are super old and have no bassreflex box, which current 101s have; MBL themselves suggested pairing with their active MBL 201, but I will try home-made dipoles instead (I find room modes and booming ported box bass rather dilsturbing, reproducing bass that way does not recreate classical concert or opera experience too well).
I might be jumping to an obvious but wrong conclusion, But I think open baffle subs would be quite compatible with the MBLs.