Solid State Logic X-Rack E Series Calibration Information, EQ Alignment, HF EQ Maximum Gain

K.4

Note.

K.4.1

X-Rack E Series EQ Module

Calibration Information

The X-Rack E Series EQ module is factory calibrated and should only need calibration if a potentiometer or other component has been replaced or if it is suspected that there is a problem with calibration.

In each of the following instructions it is assumed that the lid of the X-Rack has been removed and that power has been applied. It is also assumed that unless otherwise specified, all switches are released and all front panel potentiometers are at unity or minimum position as appropriate. The required accuracy for each adjustment will be specified along with the target value. All level and distortion measurements should be made with audio-band 20Hz to 20kHz filters unless otherwise specified.

All presets are accessible from the top of the unit.

The unit should be allowed to warm up with power applied for at least 15 minutes prior to making any adjustments.

EQ Alignment		Calibrated audio oscillator and audio level meter
Equipment Required:
Test Signal:		Sine wave @ 0dBu, frequencies as specified below
Input and Output:	1.	Oscillator to Input, Output to the audio level meter
Unit Setup:		Switch the EQ IN and release all other EQ switches.
	2.	Release the +4dBu/–10dBV switch on the rear panel.
	3.	Set all of the Q and Frequency controls fully anti-clockwise and all Gain
HF EQ – Maximum Gain		controls to their centre indent.
	1.	Ensure that the BLK switch is released.
Adjustment:
	2.	Set HF Gain to maximum and select HF BELL. Set the audio oscillator for
		12kHz and adjust HF Frequency to find the maximum level on the audio
	3.	level meter.
		Adjust VR11 for +15dBu ±0.25dB.
	4.	Switch BLK in and re-adjust HF Frequency for maximum level.
	5.	Adjust VR12 for +18dBu ±0.25dB.
	6.	Reset HF Gain to its centre indent position, de-select HF BELL and release
HMF EQ – Maximum Gain		the BLK switch. Re-check the audio level meter for 0dBu.
	1.	Ensure that the BLK switch is released.
Adjustment:
	2.	Set HMF Gain to maximum and HMF Q fully anti-clockwise. Set the
		audio oscillator for 3kHz and adjust HMF Frequency to find the
	3.	maximum level on the audio level meter.
		Adjust VR13 for +15dBu ±0.25dB.
	4.	Switch BLK in and re-adjust HMF Frequency for maximum level.
	5.	Adjust VR14 for +18dBu ±0.25dB.
	6.	Reset HMF Gain to its centre indent position and release the BLK switch.
LMF EQ – Maximum Gain		Re-check the audio level meter for 0dBu.
	1.	Ensure that the BLK switch is released.
Adjustment:
	2.	Set LMF Gain to maximum and LMF Q fully anti-clockwise. Set the audio
		oscillator for 1kHz and adjust LMF Frequency to find the maximum level
	3.	on the audio level meter.
		Adjust VR15 for +15dBu ±0.25dB.	(continued)

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