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How to do Bi-Amping with the TDAI-2170 and SDA-2400 amplifiers
With the introduction of the Lyngdorf SDA-2400 power amplifier, we have received many
questions about the best way to achieve optimal performance by combining it with our
integrated amplifier, the TDAI-2170.
Warning
:
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These setups can only be completed with speakers constructed with separate inputs for mid-
high and low frequencies.
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The inputs must be completely separated both outside and inside the speakers.
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Never connect the speaker outputs of two amplifiers in any way, as this will cause both
amplifiers to defect beyond repair.
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Keep the amplifiers off the mains power when working with speaker cables!
Class-D Amplifiers & Bi-Amping
Using Class D amplifiers in a Bi-Amping setup without enabling any filters is generally not
recommended. In a Class D amplifier an output filter turns the digital output from the amplifier into an
analog signal which powers the speaker. With Bi-Amping, the amplifier powering the bass has no
speaker-load in the high-frequencies, the energy from these frequencies will turn into heat in the
output filter. If the components of the output filter break, the speaker drivers will be damaged.
Lyngdorf amplifiers employ a sophisticated design, and we have not yet experienced a broken output
filter, but in order to protect the amplifier and speakers from potential damage, you should activate
the built-in digital crossover of the TDAI-2170 and remove the high-frequency energy (above 5,000
Hz) from the SDA-2400 driving the bass. This adjustment will have no audible effect.
Use of the Digital Crossover and Delays
Having a digital crossover in the TDAI-2170 leads many to want to use this function in their Bi-
Amping setup. However, you should not apply the digital crossover to substitute for the passive
crossover network in the loudspeakers, because the crossovers inside the loudspeakers are still
active in a Bi-Amping setup.
Applying another set of crossover filters on top the speaker’s own filters is also not recommended.
With a digital connection from the TDAI-2170 to the SDA-2400, the digital signal will be processed in
the SDA-2400, and the resulting signal delay of 0.6 mSec must be compensated for in the TDAI-2170
by delaying the signal to the mid-high section.
Finally, you need to do a RoomPerfect™ calibration, and you will then enjoy the greatest
performance possible from your speakers!
