MODEL 1001 MK V POWER AMPLIFIER
In defiance of conventional wisdom, the performance goals set for the 1001 dramatically reduce the physical proportions expected of the very best amplifiers. A special design transformer provides exceptional performance in a compact package. Instead of great numbers of power devices on rows of heat sinks, sound quality is optimized by using a concentrated physical layout. The apparent simplicity reflects a philosophy of design elegance.
The heart of an amplifier is its power supply and the most vital component is the transformer. A power amplifier's current drive (by way of its power supply) is provided by the transformer. As the audio load frequency (the power at the speaker) drops below the line frequency (50-60hz power into the transformer) the necessarey current to maintain power increases dramatically. Conventional transformers provide only a fraction of the required current under these conditions. Symptoms include a lack of control (bass bloom), reduced drive in the lowest octave and modulation of instruments throughout the spectrum. BEL addressed this need with a new transformer design that provides ample current for load frequencies as low as 10hz. The controlled relaxed character of the amplifier speaks for itself.
Performance is enhanced by using a well-ordered, compact circuit topology and a minimal number of output devices. The notion of total quiescent current for Class A operation is rejected for a design that addresses the specific needs of the power output devices (high lq and elevated chip temperature). Fewer devices with modest heat-sinking allow high current densities and an ideal operating temperature for the most linear operation. Each output circuit uses two sets of high current devices with eight power transistors in a parallel multi-mode configuration to address distortions specific to both Class A and AB operation and provide the drive necessary for the most difficult loads. Temperature stabilizing circuitry maintains a stable operating point while lower thermal inertia and special start-up circuitry eliminate long wait times for warm-up. Compact dimensions provide short signal paths for good transient performance and stability. This, along with many circuit refinements, provides a purity of resolution that goes beyond previous experience with high performance amplifiers.
The Model 1001 takes full advantage of these performance enhancing measures and maintains reliable operation with an elaborate fault sensing system. It allows unrestricted operation of the amplifier while protecting against load faults and improper inputs including rf, ultrasonic and subsonic.
The Model 1001 is uniquely able to achieve measurably higher loudness levels than other amplifiers without audible stress. BEL's long-standing reputation for ease of presentation is legendary. Perceived loudness is related to distortion and loudness related distortion creates a false sense of dynamics. Enhanced resolution at the lowest levels with greater comfort at the highest levels expand the usable (actual dynamic) range beyond previous limits. This is equally apparent in the mono mode and with the added performance of its balanced output configuration, the 1001 monoblock has no equal. Review Review Review Review
Prices start at $3895
BEL cables are intended for use in installations requiring a maximum transfer of information. Systems often use the filtering effect of their cables to accomodate some particular distortions but the better systems will be able to use the superior performance of BEL wire.
In our cable measurements, other cables show aberrations starting in the low mid-range and increasing with frequency. Such cables are linearized only with significant amounts of compensation. Since BEL cable provides ten times the bandwidth capabilities of other cables, it needs no compensation and information is not lost in the process.
Magnetic Field Compensation is responsible for the unique performance characteristics of BEL cable. The virtual elimination of series reactance creates a transparent coupling with a resistive impedance. By eliminating a wire's non-linear component (series reactance), we have created a low impedance, broadband cable of unmatched linearity.
The low impedance created by this technique provides superior noise immunity and reduced sensitivity to placement. It is also the reason that BEL speaker cable is the first to provide full control of the speaker over the entire audio band. Cables place a damping factor in series with the amplifier. A high impedance cable is the same as an amplifier with poor damping and the result is the same - ringing.
With the elimination of series reactance leaving only a benign linear resistance to consider, cable thickness needs are dramatically reduced. Cables need not be gargantuan rigid devices that are difficult to use.
Series reactance isolates an amplifier from its load, reducing the amplifier's control over it. Magnetic field compensation increases capacitance while eliminating series reactance. Capacitance is easily controlled by the amplifier and, without series reactance, control is achieved over the full length of the cable.
Cable capacitance is far less than that of some speakers; any drive difficulty suggests an inadequate amplifier design or a defective unit.
*SPECIFICATIONS The Wire:
Type S12 speaker cables - 2 nf, 15.0 milliohms (total circuit) /meter
Type S24 speaker cables - 4nf, 7.5 milliohms (total circuit) /meter
Type P1 interconnect cable - 400pf/meter
1 Meter pair Interconnects $295
3 Meter pair Speaker wire $595