Pass Aleph 30
Board size: 340 * 42MM
thickness: 2. 0MM, plate FR-4 epoxy glass
power supply: AC 18-20V
Double side plate through holes
Output 25-30W single-ended
Harga: Rp 250.000,-
contact : 08161371018
SPECIFICATIONS
Gain 20 dB balanced, 26 dB single ended
Freq. Response - 0.5 dB @ 2 Hz, -1.5 dB @ 100 KHz
Power Output 30 watts/ch @ 8 ohms, 40 watts @ 4 ohms
Maximum Output 25 volts, 5 amps
Distortion (1KHz) 0.2% @ 30 watts, 8 ohms
Input Impedance 47 Kohm single-ended, 52 Kohm differential
Damping factor 100
Crosstalk > -80 dB 20-20 KHz
Balanced Input Rejection -50 dB typical CMRR
Output Noise < 500 uV unweighted
Random noise floor 5 uV typical
DC offset < 100 mv
Power Consumption 200 watts
Temperature 25 degrees C. above ambient
The Pass Aleph 30 is the first of the second generation of Aleph single-ended Class A power
amplifiers. This design results from my commitment to create the best sounding product, a
simple circuit having the most natural characteristic. The Pass Aleph 30 integrates power
Mosfet devices and pure single ended Class A operation in a simple two-gain-stage topology
with the sole purpose of recreating subjectively natural sound.
The Pass Aleph 30 is unique in a number of ways:
Most amplifiers on the market have between five and seven gain stages in series between the
input and the output. The Aleph 30 has but two, and enjoys a very direct path from input to
output, further enhancing the purity of the circuit and the resulting sound.
The output stage of the Aleph 30 is a unique blend of traditional design and innovation
addressing the unique requirements of loudspeakers. Previous methods of loading the output
stage have used networks consisting of resistors, coils, transformers, and active current
sources, all of which offer an optimal load line based on a resistive load.
The Aleph 30 has a current source topology which optimizes performance for a wide range of impedance and reactance in the load, improving all aspects of performance into real loudspeakers. Pass
Labs has US patent No. 5710522 on this output stage topology.
The Aleph 30 is unique in that there are no adjustments of any kind in the circuitry. There are
no potentiometers to adjust. The operating parameters of bias currents and DC offset and so
on are defined by physical constants, and will not go out of adjustment.
Most important, the Aleph 30 brings improvement to the recreation of subjective sonic reality.
The amplifier delivers detail and subjective space rarely found in semiconductor circuits,
coupled with the authority and clarity rarely found in tube amplifiers.
The Pass Aleph 30’s ancestry lies in the highly praised Aleph 3. We have kept virtually all of
the circuit design and choice of parts intact.
The amplifier uses exactly the same circuit topology except that a balanced XLR input has
been provided in addition to the single-ended RCA input of the Aleph 3. The balanced input
circuitry is the same topology as the rest of the original Aleph series, accomplishing true high
performance balanced input without additional active components. It has been improved,
however, to offer a higher input impedance on the single-ended input, 47 Kohms. The original
Aleph 3 had a 23 Kohm input impedance, and the other Aleph amplifiers had a 10 Kohm
single-ended input impedance.
The input devices are slightly better than the originals, but significant improvement is to be
found in the manner of matching the input devices. Previously the input differential transistors
were merely matched to each other, but beginning with the Aleph 30 they are now matched
both to each other and to the rest of the amplifier circuit. We select the input devices as part
of the complete amplifier, swapping them in and out until the best performance is achieved.
Tweaking the input stage in this manner and with other adjustment techniques we have been
able to significantly lower the noise floor and improve the power supply noise rejection of the
amplifier. Typically the Aleph 30 has about 6 dB greater dynamic range compared to the
Aleph 3.
We have increased the number of output power Mosfet devices from four per channel to six.
These are the same devices as the original Aleph 3, and are matched in the same manner,
taken from the same lot codes and matched to about 2% Vgs. The greater number of devices
lowers the distortion and improves the damping factor by about 50%, and also allows us to run
the bias up a bit, giving higher heat sink temperatures but with the same on-chip
temperatures.
The power supply has been improved with half-again more power supply capacitors with twice
the voltage ratings, giving lower ESR figures. Also the power supply incorporates much
improved line noise filtering in both differential and common mode, which filters out incoming
noise and reduces noise emission by the amplifier.
One of the biggest differences in the Pass Aleph 30 is the type of chassis and heat sink used.
The Aleph 3 was machined entirely from aluminum extrusions stock. While this resulted in a
unique and very functional appearance, it had several drawbacks. First it was very expensive.
Also, it allowed very limited space for access to input and output terminals on the rear of the
amplifier, and required the on/off power switch to sit in the rear underneath the wiring. It has
been said that ownership of the original Alephs was proof of the owner’s dedication to sound
at the cost of convenience.
The Aleph 30 has a new, more conventional, chassis with heat sinks on the side, a faceplate
with a power switch, and a regular sheet metal type chassis. In addition to being more
convenient, this approach costs less, and we have passed the difference on to the customer.
The final result is that the Aleph 30 performs better than the original Aleph 3 in all areas, has
the additional feature of balanced inputs, and costs a lot less.
Enjoy.!
