The Model A1 employs refined digital technology for compact, yet highly efficient sound processing - and more importantly, for amazing sound quality and real-life dynamic range.

The Model A1 main features are:

• True digital amplification
• Unsurpassed dynamic range
• EQUIBIT™ processing modulator
• Pulse Width Modulation (PWM) with fixed switch frequency
• 2 x 400 Watts, 4 Ohm / 2 x 200 Watts, 8 Ohm
• 1 unit rack space
• Passive cooling

True Digital Amplifiers
In the Model A1, signal processing is handled 100% in the digital domain, because only pure digital processing can release the full potential of the Model A1. Featuring the world’s most advanced technology, as well as uncompromised component quality, the Steinway Lyngdorf true digital amplifiers are open-loop amplifiers with zero negative feedback. To achieve this, only the most stable, durable and linear components are used. They are optimized for musical performance with an impressive Signal-to-Noise Ratio of 113 dB – the highest performance of any amplifier on the market today. All this functionality is placed in a compact, 1-unit rack space with passive cooling, for minimum noise pollution to the environment.

The EQUlBlT™ Module
With core technology based on the patented EQUlBlT™ processing and output modules, EQUlBlT™ is a digitally controlled Class D amplifier also known as switching amplifier technology. The unique feature of EQUlBlT™ technology is that the PCM to PWM conversion is made 100% in the digital domain, with advanced algorithms ensuring absolutely linear conversion and the highest possible audio fidelity.

PWM – Pulsating in Time
In a PCM signal, each sample represents a specific amplitude. The output stage of most switching amplifiers is based on Pulse Width Modulation (PWM). The magnitude of each PWM sample is described in terms of the pulse width, as opposed to the pulse height in a PCM signal. The 24-bit PCM digital audio signal is fed to the modulator, where the audio data is up-sampled 4 times – close to 400 kHz for optimal performance in the audio band. The EQUlBlT™ PCM-to-PWM modulator then translates the up-sampled signal to a PWM signal with the same switching frequency.

As a result, the Model P1/A1 system with the Steinway Lyngdorf Digital Link offers an unbroken digital signal path throughout the entire system.
 

No-Compromise Output Demodulation Filter
To re-establish the analog audio signal from the PWM pattern, a reconstruction low-pass filter is used at the output of the switching power amplifier stage. The reconstruction filter - or demodulation filter - of a switched amplifier is often overlooked, partly because optimal components are expensive and take up PCB space, and partly because the filter is regarded as far beyond the audible frequency range.
But even filters placed octaves above audible frequencies affect linearity within the audible band. In the Model A1 system amplifier, uncompromising component quality ensures unsurpassed low distortion and linearity in the filter. Only two components translate the PWM pattern into the pure analog audio signal to which the loudspeaker reacts at the speaker terminals.

Full digital resolution - Power DAC
The output levels are kept at 24-bit resolution when operated at most typical listening levels. Within this range, regulation is carried out purely by the DC/DC-converter by adjusting the supply voltage to the amplifier output stage. Essentially, the Model A1 can be regarded as a high-powered Digital-to-Analog converter.

Thanks to its high-end DC/DC conversion, the Model A1 amplifier features volume adjustment while maintaining full digital resolution at typical listening levels. This unique and technically demanding solution ensures unsurpassed control, noiseless at all sound levels.