When we began to tackle the idea of a world-class, budget-priced integrated amp, the first ugly reality we faced was that you can't build an excellent-sounding active line stage on the cheap. Our answer was to build a passive line stage using the same level of parts you'll find in very high end preamps.

Although passive preamps are theoretically the most pure, many good free-standing designs just don't sound that good when connected to solid state amps. Most of them sound lifeless and lacking in dynamics. Reality is that the very high output impedance of the passive unit is being asked to drive the (generally) low input impedance of a solid state amp. Making the situation worse, is that the signal has to travel from preamp to amp over a length of reactive interconnect cable.

BUT...

What if you connected the output of this preamp directly to the input of a high-gain solid state amp designed expressly to receive that specific signal? That's the guiding design principle of the Portal Panache.

We're not claiming that the preamp section of this unit is perfect. It's just more perfect functionally than anything remotely in its price class. The input selector, balance control, and attenuator are Alps controls, each hand-selected for neutrality, lack of noise, and reliability. All point-to-point wiring - 14 gauge OFC with PE dielectric - is the shortest possible path. In other words, the signal only goes through the Alps controls and scant inches of pure copper before being delivered intact to the input of the amp.

Dual Mono Amplifier Section

The amplifier section is a dual mono design. The toroidal transformer, custom built for us in California, has separate windings and separate rectifier bridges for each channel. After the transformer, the two channels are completely separate, each with its own bank (40,000 MFD/ch) of filter capacitors, and each channel physically isolated to prevent interaction with its twin.

The transformer itself is rated at 425 va and is capable of producing twice its rated power for extended periods. With a potential 400 watts of power dissipation per channel - 4 pairs of high-speed bipolar output devices rated at 100 watts/12 amps per device - the rated 100 watts per channel into 8 ohms is very conservative. Operation is A/AB, with all stages before the output transistors operating in single-ended Class A mode.

MADE IN THE USA

To order call 1-888-737- HIFI

Description and Specifications

The amp design is a classic complimentary symmetry A/AB design with a current source differential pair followed by a common emitter going to a Darlington configuration output stage.



Specifications:


Rated output: 100 watts/ch at 8 ohms;
200 watts/ch at 4 ohms
Distortion: 20 Hz-20kHz both ch driven
@ no more than 0.1% THD
Bandwidth:5 Hz to 100 kHz
Gain: 20 dB
Input impedance: 22 k Ohm
Slew rate: >20 v per microsecond