M2 Power Supply
Support Information

Resistor Positions

The following picture shows the positions of the resistors for the M2 Power Supply Board. This may be a useful reference while you are building it so you can make sure you have the right values in the correct positions.

NOTE: The DAC Kit 2.1 (Levels A and B) uses a slightly different resistor/zener arrangement for a lower HT value. In this case, R2 is 68K instead of 33K. The 33K version is shown below.

Procedure for installing resistors in HT ADJUST position

On the M2 Power supply board we used to use a small Blue 10mm square Trim pot for the 50K Volt position these are no longer available in the quality and power ratings that we would like so we have switched to installing resistors in place. This is what Audio Note UK is also doing in their finished products now.

The picture opposite shows the HT ADJUST position with 3 holes where the trim pot used to go.

Start by taking out the 2x 22K resistors that we have provided in your M2 Power Supply Kit Bag.

These are the two resistors with RED RED Black Brown color codes.
Start by positioning the resistors in the two holes at the bottom of the 3 hole triangle as shown opposite.
Next, bend one of the resistors over into position as shown and solder into place.
Finally bend the other resistor lead such that it curls around the first resistor and then solder together.

* I have just shown the resistors bent around each other you need to solder them together

This procedure sets the correct HT or High DC voltage for the B+ of the M2 Power Supply. The recommended output voltage is 260V Dc for the L3 Line, L3 Phono and L2 pre-amp. This might be 263v approx. with this new resistor method which is fine anything between 255 and 265 is ideal.

For the DAC Kit 2.1 (Level A and B) we require about 230V DC and again the voltage may be slightly higher by a few volts with this new resistor method the beyshlag resistors are high quality and ideal for this power supply application.

If you have any questions feel free to contact us.

Schematic with test voltages

NOTE: The DAC Kit 2.1 (Levels A and B) uses a slightly different resistor/zener arrangement for a lower HT value. In this case, R2 is 68K instead of 33K. The 33K version is shown below.