GamuT Di150 - Manual (Page 13)

13
The protection circuitry - a second of silence
The idea for the protection circuit come from our professional amplifi ers, where it has worked well
since 1982.
The protection circuit can detect:
DC errors •
high level subsonic signals •
long-term ultrasonic signals •
high temperature •
low impedance loads or short circuits •
If needed, the protection circuit will simply mute the input signal, and if necessary open the out-
put relay. The relay will normally open only after muting the input signal to avoid relay switching of
strong currents that could damage the relay contacts.
In case of e.g. a short circuit, the input is muted for a second. Then a 1 millisecond long pulse is sent
out to test again. If the short circuit still is present, it waits a second and tries again, and so on. Less
than a second after the user has removed the faulty cable, the system will remove the muting.
The protection also detects too low impedance loads, and alerts the user by muting for a second. This
way, the user can be sure of hearing only clean non-distorted audio. The normal current limiting and
momentary distortions of the music are completely avoided in the GamuT DI150 power amplifi er.
You may experience a second of silence while the music is playing loudly. This is the protection acting
to protect your audio system. Any amplifi er will start to clip the top of the music if you exceed the
maximum power level. Technically, clipping generates a lot of high-frequency energy, which can burn
out the tweeters in your loudspeakers. The protection also constantly checks the energy above 20
kHz, which humans do not hear.
This means that the protection circuit can interfere even though you cannot hear any reason for this.
If you experience these seconds of silence, simply turn the output level down until the music plays
without interruption.
You can also provoke the subsonic protection by playing warped records without using a subsonic
fi lter. Please check your tone-arm/cartridge resonance frequency, which should be about 8-12 Hz to
reduce the effect of warped records.