Lyngdorf Audio Room Perfect TDAI 2200 - Manual (Page 13)

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Finally, the PWM output signal is shaped into the audible analog signal via a passive low-pass
filter.
For the output filter coils we have elected to use
ferrite cores. Simply because, thanks to their
linearity, they give the best sonic performance . . .
Normally, amplifiers use a feedback loop from the
output signal to the input to compensate for non-
linearities. However, in a fully-digital amplifier it is,
for obvious reasons, very complicated to feedback
a signal from the analog domain (speaker output)
to the digital domain. Therefore linearity must be
controlled throughout the amplifier without feedback loops.
This is why the Equibit TM modulator can accurately be described as the heart of the system
since this technology facilitates linear conversion from PCM to PWM in a pure non-feedback
design like the TDAI-2200.
As mentioned earlier the power supply works as a volume control.
From +/-3V, corresponding to a 62dB reading on the display, until
maximum voltage is supplied to the output stage the digital signal
operates with full-scale resolution, giving maximum dynamic range and
sound quality, even at very low sound pressure levels. At 62dB the
signal on the speaker terminals is actually lower than the line-out signal
from a CD player!
This means that only at below 3V is it necessary to further attenuate
the digital signal, in order to further turn down the volume.
The volume setting on Lyngdorf Audio products works a little different than on most amplifiers
on the market. We do not use a logarithmic scale… instead the reading on the display is
relative to dB, as is common on ‘Pro’ products.
And whereas most amplifiers run full output with a full scale recorded CD at the 12 o'clock
position of the volume control, Lyngdorf Audio amplifiers aren’t delivering full output until
around 88dB. And if you are not playing a full-scale recorded CD (most CDs are not) you can
go 12dB higher, to 99.9dB, in order to reach full output.
So, there is no reason to worry that you are running the TDAI-2200 too hard even if the
volume setting shows a relatively high number – an 88dB setting equates to running a
conventional amplifier with the volume control around 10–12 o’clock position.