Op amp rolling: I had a BEL 1001 Mk IIIa for many years. Before this I used to own a Mk I. I finally got the urge to do some op amp rolling for the Mk IIIa. The BEL uses two dual op amps. I found the following combinations sound the best: first stage OPA627 (dual), second stage OPA2604.

Here is a distorton measurement using my Pentium III 450 and Sound Blaster Live! sound card. At 1W with 4 ohms load, harmonic distortion is less than 0.003%. This is very low. Most solid state amplifiers have 0.02% at 1W with 8 ohms load. (Note: 8 ohms load distortion would normally be half the distortion of 4 ohms load)

When I first heard this amp I loved it but before I bought it , I used it as my reference to compare to the other amps I will be auditioning up to $6K. I compared to Krell 300 and Levinsons' 100 watter(both in the 6k range), the Plinius SA-100 ($4K), and the Ayre V-3($3750). While all of these amps are very good indeed, the BEL just did everything that much better. The highs and mids are as good as it gets as far as solid state is concerned but what SURPRISED ME THE MOST WAS THE BASS CONTROL IT HAD. If this amp was ($6k) it would be a bargain but for ($3k) it's just plain silly to pass this amp up. Listen and Compare for yourselves!!!!!

I own the BEL 1001 MK 1. I have not listened to the MKIII. ButI did listen to the MK II in a store. Here is my opinion:
1) The BEL is not a class A amplifier as advertised. I talked to
Mr Brown himself several years ago. He said it is commercial
necessity to advertise it as class A. He also said "why it
has to be class-A?" I agree with him 100%. Class A does not
guarantee good sound. There are a lot of class A amplifiers
on the market. They do not sound that good. They sound close in.
They are lacking in liveliness.

2) The BEL MK 1's circuit topology: input signal goes through
2 stages of OP-AMP for a total gain of approx. (-5). The power
amplifier itself is an inverting amplifier of gain approx.(-4).
The OP-AMP is TL072 which is not exotic. I don't believe "better"
OP-AMP will sound better in this case. Some kind of distortion
cancellation is at work here.

3) The BEL MK 1's parts are not audiophile grade. I am not
a believer of exotic parts neither. The BEL sounds fine, thank you.

4) The BEL MK 1 dc offset is hand tuned while the MK II is dc servo.
I believe that the MK1 has tighter bass than the MK II because of
this difference. The dc servo is for ease of production, not for
good sound!

5) The MK 1 sounds sweeter than the MK II but has less detail.


I would like to receive e-mail about more knowledge of the MK III
circuit design features.

The BEL is able to clearly separate instruments in large orchesteral works without being bright or harsh. Excellent bottom end extension and control.

I can't think of any.

The BEL 1001 MkIV has been the perfect match for my KEF107/2 speakers. The bottom end is extended and controlled, and each instrument is clearluy portrayed without any harshness. Densely orchestrated classical music (Brahms, Schumann,Mahler,etc.) is much more enjoyable when you can hear each instument through the BEL. Jazz combps swing. Voices have considerable presence and body. Sometimes I think Tito Gobbi and Maria Callas have come to my living room! The BEL seems to favor no single portion of the orchestra --- it is excetionally well balanced. While it offers a hih degree of resolution, I have not experienced listening fatigue. The BEL speaker cables really make a synergistic match with this amplifier.

Similar Products Used:

Levinson 331, Bryston 4B, Conrad Johnson Premier 11, Quicksilver V4, Mesa Baron, Krell KSA-50

I started with one BEL 1001 and liked it so well I upgraded it and bought another for a dual mono set up. Superb amps! Voices are extremely clear and lifelike. To the extent they are not transparent, they lend a slightly tubey quality. The base is extremely well controlled. They play a wonderful symphany, a warm piano solo, a personal jazz trio and kick-ass rock. If you are looking for an amp that doesn't get in the way of the music, you can't beat Bel for the price.