The AMS100 is the most advanced pure Class A amplifier ever made. I know that this is a sweeping and powerful statement, but it is true.
Circuit topology
As far as I know the AMS50 is the first ever 50 watt pure Class A bridged amplifier. There are many advantages to a bridged amplifier; lower distortion and huge power supply noise rejection. These advantages are even more significant in a pure Class A configuration.
The AMS100 has the same basic circuit as the AMS50 but even more of it. In fact the AMS100 has precisely the same circuitry and number of output transistors as our monster Titan.
The AMS100 circuit configuration is unique and delivers excellent technical performance (more about technical matters below) and a beautiful sound.
Power supply configuration
Power supply configuration is usually the “poor relation” in amplifier design. Normally huge effort is put into the circuit and layout but the PSU configuration is taken for granted. Not so for the AMS100!
Pure Class A amplifiers draw enormous current. This exposes any deficiencies in power supply design. The AMS100 has a unique, never done before in the history of hi-fi, power supply design. Below are some circuit illustrations which show the major differences between the AMS100 and any other amplifier.
Click the image above to download a larger version
Looking closely at the AMS100 you can see that it has the following differences to the AMS50:
Separate power supply for each half of the bridge. This allows each half to operate perfectly. It is highly significant for dynamic stability.
Each power supply (for each half of the bridge) has its own separate, dedicated dual bifilar choke regulator. Musical Fidelity’s unique dual bifilar choke regulation system has a power supply noise rejection ratio of 88 to 1. This is the equivalent of multiplying capacitance by more than 88x. It is a huge effect on the technical and sonic performance of the amplifier. Additionally it provides excellent mains noise filtration.
The AMS100 uses a large number of high performance capacitors. This allows it to deliver remarkable dynamic consistency under all load conditions.
N.B. Each half of the bridge has its own separate power supply and dual bifilar choke regulator system. There are a total of 4 dual bifilar chokes in each AMS100.
Below is a picture of the before and after effect of our dual bifilar choke regulation system.
AMS100 Choke regulation
You can easily see the "saw tooth" pattern which is composed of a lot of high harmonics and other unpleasant artefacts. After the choke you can see that it is reduced by 88x. All the HF elements are gone. Quite remarkable!
Technical and sonic overview
The AMS100 has extraordinary technical performance. Ultra low distortion from 20Hz to 20kHz. At normal listening levels the ultra-low distortion is consistent right up to 50kHz.
The AMS100 is the technological tour de force. More important is its sound. The AMS100 has a clean sweet open sound. Huge dynamics are delivered with ease. Bottom end extension seems limitless. And yet the whole sound is tight and cohesive.
The AMS100 realises the full true potential of pure Class A sound. It is expensive, it’s huge, it’s heavy and it sounds like heaven.
The AMS100 has been designed for an elite band of audiophile purists who want the ultimate Class A amplifier ever made. We don’t expect to sell many. Those lucky few who get their hands on one will be fulfilled.
… “Fit and finish on the amplifier are superb” …
… “From the moment it was first heard, there was a clear, open sound to this amplifier. Instantly striking was a sense of clarity in the mid to upper treble region.” …
… “ The lack of grain and the lack of compression were quite amazing. Sound stopped and started with remarkable freedom from any kind of ‘color’ or perceived distortion. My favourite tracks were incredible” …
… “Pink Floyd’s Dark Side Of The Moon could also have been engineered for the AMS100” …
… “Stereo imaging was amazingly precise; and any different reverb and timing clues came across in amazing detail” …
… “One of Water Lily’s audiophile discs, A Meeting By The River, really did transform the acoustic of my listening room to the Santa Barbara church where it was recorded.” …
… “The abundant clarity and cleanliness of sound is truly revelatory. The AMS100 excels in digging out low-level details, in low coloration and in accurate, fast dynamics. It manages to combine absolute control with finesse. Maybe the ultimate Class A transistor amplifier?” …
… “ It’s supremely quiet (the A-wtd S/N ratio is 92dB re.0dBW) while distortion is vanishingly low at low power, just 0.0002%” …
