High Fidelity Cables MA-1 Amplifier, 55% off

Excellent condition, demo unit.

 MA-1 Amplifier from High Fidelity Cables. Best of sound in three shows. 
150 watts into 8 ohm, 200 watts into 4 ohm. A/B Current injection construction: a purely current driven amplifier. 

Single stage equivalent amplifier. 

Specifications: Gain: 60db in current mode Frequency response: 1Hz - 1MHz Slew rate: 450v/µs Damping factor: 1000 Chanel separation: stereo 90db Input impedance: 20k ohm Signal to noise ration: 100db  Musical Fast Fourier Transform distortion: 0.08% under load  Intermodulation distortion IMD: measured with 19 & 20Khz intermixed equally 0.007% Total Harmonic distortion THD: less than 0.01% at full power, less than 0.002% at 1 watt  Total square wave distortion: 0.02% Under load 

With the creation of this new circuit came a demand for new testing parameters. In the world of audio, amplifiers are most often tested without music signal or load and therefore the testing is not in a real world environment. It means little to an end user. 

Therefore two brand new tests have been added to the specifications of the amplifier: Total Square Wave Distortion and Musical Fast Fourier Transform distortion. 

These new specifications teach us what the amplifier does in the real world with music and under load. Operating under load in a real signal flow environment is the most difficult part for any amplifier. The challenge for any amp is to actually reproduce music accurately. 

So, these new tests are critical in understanding the potential of this circuit to deliver reproduced music like never before. These tests are preformed to allow the user to know what will happen to the music signal when the amplifier is actually in use playing music. This is a surprisingly new concept we have not seen before, and something we hope eventually becomes commonplace. 

These are measurements that make an amplifier truly unique and truly in a class by itself. 

Here's a brief description of both of these new tests: 

Musical Fast Fourier transform distortion: Real world test using a music sample of 1/10 of a second intervals each bit. By breaking down the music sample into 1/10 of a second or keeping the bits small they are reasonable enough in size to fully analyze the data. This measurement measures the "input to output data" of the amplifiers performance allowing listeners to know the total sum of all distortion that will actually be added to the music. 

Total Square wave distortion: Although it's not uncommon to see square wave distortion testing on an amp, it is quite uncommon to see it as important. It is also uncommon to see square waves accurately reproduced by audio amplifier. A square wave is the most demanding of signals. We feel it is critical for an amplifier to be able to reproduce square waves without distortion. The amp, if required, could reproduce any signal virtually without distortion. 

This new amplifier design only amplifies current. It is a current amplifier only, as transistors can only amplify current and are only linear when operated in a current mode. 

Current injection is unique. All the transistors inject current into one common line that then drives the speaker. Each transistor is connected to the input instead of to the stage before it, effectively creating a one-stage amplifier. 

Audiophile-grade quality hand picked parts go into each and every amplifier, but innovation doesn't stop there. High Fidelity Cables uses new technology brought forth to filter the power supply. Our unique patented dampening technology filters unwanted noise from the transformer. Magnetic conduction technology waveguides help deliver signal accurately and cleanly. 

Overall, this new amp design is a revelation in thinking. It is truly a new concept and it comes from one of the great designers Steve Keiser. Steve is been an analog circuit designer dating all the way back to early B&K. His circuits have been a revelation in the past and are certainly proving to be once again in our more modern era.