Raleigh Audio RAKK dac Mark III Extreme Preamplifier, Assembly Manual

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Final Adjustments
Adjust the Constant Current Sources
The adjustments that you are about to make on the Active Output board interact. Therefore, the
first time you may have to alternate adjustments to get them in range.
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1. Install a 6N6P tube in locations V1 and V2.
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2.
Power on the Extreme RAKK dac and allow it to warm up for about one minute.
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3.
Adjust the Left B+: Measure the voltage across the 20K Ω resistor, R27 and adjust
potentiometer R34 for 200V across R27.
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4.
Adjust the Right B+: Measure the voltage across the 20K Ω resistor, R26 and adjust
potentiometer R30 for 200V across R26.
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5.
Measure the voltage across each of the four CCS current sense resistors and adjust the
associated potentiometers for 240mV across its resistor.
Measure Adjust Voltage
R39 R38 0.240V
R44 R43 0.240V
R49 R48 0.240V
R54 R53 0.240V
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6.
Allow the unit to warm up for about 15 minutes and then check and re-adjust the above six
adjustments.
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