QSC Audio UF-3 owner manual Programming the High-Pass Filter and CD Horn Equalization, Channel

Programming the High-Pass Filter and CD Horn Equalization

To use either the high-pass filter or the constant-directivity horn equalization, or both, set the jumper on Jx02 across pins 2 and 3, which are the lower two pins on their header. If, however, you do not wish to use either one and want to bypass them instead, set the jumper across pins 1 and 2.

To set the corner frequency (at which the output is 6 dB down) of the high-pass filter, choose the appropriate value for RNx04; use the table at right.

If there is a resistor network already installed in the socket, carefully pull it straight out. Insert the pins of the new resistor network into the socket holes and carefully press the network into the socket. Be careful to avoid bending the pins of the resistor network. Orientation of the resistor network is unimportant, as long as all eight pins are well seated in the socket.

In addition to enabling the high-pass filter at Jx02, if you opt for CD horn equalization you must place a jumper at Jx03 as well. The UF-3 offers two equalization curves for CD horn correction: one with +6 dB of boost at 20 kHz (place the jumper across pins 1 and 2 of Jx03), and one with +10 dB of boost at 20 kHz (place the jumper across pins 2 and 3). If you do not place a jumper in one position or the other, the CD horn equalization circuit will be inactive.

The table below is a summary of jumper settings for the UF-3; similar information is printed on the breakaway section of the UF-3’s circuit board. Figure 4 shows how to identify the SIP resistor values.

Pins 1 & 2 Pins 2 & 3 None

	Function	Header
	Bypass low-pass	J101	X
	Enable low-pass	J101		X
	Bypass high-pass	J102	X
Channel 1:
	Enable high-pass	J102		X
	Disable CD horn boost	J103			X
	CD horn boost, +6 dB @ 20 kHz	J103	X
	CD horn boost, +10 dB @ 20 kHz	J103		X
	Bypass low-pass	J201	X
	Enable low-pass	J201		X
	Bypass high-pass	J202	X
Channel 2:
	Enable high-pass	J202		X
	Disable CD horn boost	J203			X
	CD horn boost, +6 dB @ 20 kHz	J203	X
	CD horn boost, +10 dB @ 20 kHz	J203		X

Frequency	SIP resistor
(Hz)	network value
20	120K
30	82K
40	56K
50	47K
80	27K
100	22K
120	20K
150	15K
200	12K
300	8.2K
400	5.6K
500	4.7K
800	2.7K
1000	2.2K
1200	2.0K
1500	1.5K
2000	1.2K
4000	560
5000	470
8000	270

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