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JKA · Features
JKA - Acoustic DI BOX - Line Driver
The JKA is a dedicated DI for acoustic instruments. The JKA features a high-
impedance 1/4" jack input capable of receiving signal from all types of pick-ups.
A +10dB gain boost is available for low-level instruments. The JKA also features
a tuneable notch filter for eliminating the resonant frequency in an acoustic
instrument, reducing feedback issues.
1. Phantom Power Supply
For ease of use, maximum headroom and low noise the, JK1 is powered by phantom
power from the mixing console. A green LED indicates the presence of phantom
power. Simply switch on phantom power on your console and you are good to go.
2. High Impedance Input
The JKA includes one 1/4" high impedance jack input. It is adapted to connect
the pick-up of acoustic instruments that require high load impedance (e.g. Piezo
electric pick-ups). By using the GAIN selector switch, the amplification of the JKA
can be increased by +10dB.
3. Line Out XLR Output
The main symmetrical LINE OUT output works with an impedance of 50Ω and it is intended for connection to
a mixing desk. The output is not separated galvanically from the input.
4. Monitor Out 1/4" Jack Output
The adjacent symmetrical MONITOR OUT 1/4" jack output has an impedance of
100Ω, the same level as LINE OUT and it is separated from the main output using
a transformer. When using a mono jack the relevant input is switched automatically
to the asymmetrical mode. It can be used for monitoring on the stage.
5. Tunable NOTCH Filter
To eliminate the dominant self-resonance, (feedback) of any acoustic instrument,
the JKA is equipped with a phase switch selector and a tunable NOTCH filter
with a switchable attenuation level of - 6dB and -12dB. Recommended method
of adjustment for the NOTCH filter:
a) Increase the amplification until the acoustic instrument feeds back
b) Suppress the acoustic feedback at low frequencies using the PHASE switch
c) Increase the amplification until the acoustic instrument feeds back again, put
the NOTCH switch selector to the - 6dB position and eliminate the feedback by
use of the potentiometer. If the acoustic feedback continues to happen at the
same frequency put the NOTCH switch selector in the -12dB position.
6. PHASE Switch Selector
Selects between 0° and 180° for LINE OUT output. This switches the XLR pin-2 and pin-3 to interface with older
equipment. Also can be used when the instrument is being reproduced by the DI and microphone to avoid
cancellation.
JKA - part number KVV 987 204