Full – Hafler P7000 User Manual
Page 20
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BUILDING CUSTOM XCARDS
The XCard crossover control modules used in the P7000 are a versatile and inexpensive method for configuring the
amplifier for a wide range of system applications. The XCard eliminates the need for an external crossover or expensive
plug-in accessories for multiple amp applications. By having the crossover built into the amplifier input circuit and with
the XCard containing all the components controlling the operating frequency, it is very simple to customize to meet
system specific requirements. Each amplifier, as supplied, has two 100Hz Butterworth aligned XCards each of which
contains two resistors and two capacitors to control the crossover frequency. The XCard will operate as either a high-
pass or low-pass filter, depending upon its orientation. The following tools are needed to build the XCards:
Soldering Iron (appropriate for PC board work)
Solder (suitable for electronics)
Desoldering Braid
Our tests have shown that for operating frequencies at 100Hz and lower using 0.047
µ
F capacitors results in more linear
crossover control. For frequencies above 100Hz use 0.022
µ
F, the voltage rating should be a minimum of 10V.
Use 1/8 or 1/4 watt 1% metal film resistors. Solder the components to the card according to the following diagram.
Crossover Card
High Pass
Low Pass
Full Range
R1
R2
R1
R2
FULL
C1
C2
C1
C2