Sound Skulptor MP573 User manual

www.soundskulptor.com
Document revision 1.1 – Last modification : 14/08/10
MP 73 Setup guide
Follow the testing procedure in the shown order. If one test fails, find out the problem, correct it then resume.
Always unplug power between steps because it is very easy to create a shortcut when moving a DMM probe. And most
of the time, shortcuts are fatal to the circuits.
Step Description
1. Short circuit check Do a basic short circuit check with
your digital multimeter (DMM) set
to Ohms between V- and 0V and
between 0V and V+.
You should get a value greater than
one kilo-Ohm. If it is not the case,
find out and fix the short before
applying power.
2. Test setup Remove the Di01 board if present and make a connection on CN3
between [RL] and [V-] with a bit of wire (a cut resistor leg will do
nicely).
Unplug the output transformer connector.
Remove all other modules from you 00 rack or lunchbox and insert
the MP 73 in the leftmost slot.
3. General power check Set your DMM to volts on a 30V scale. Connect the (-) lead to TP3 and the (+) lead to
V+ on CN3 (third socket up).
Plug in power. You should read about 24. Volts.
Plug off power.
Insert the output transformer connector and make the same check. The voltage should be
around 24.2 Volts.
Copyright ©2010 SoundSkulptor

www.soundskulptor.com
Document revision 1.1 – Last modification : 14/08/10
Step Description
4. Bias adjust With P2, we are going to adjust the bias of Q6 in order to flow about 6 mA of direct
current in the output transformer primary. To do this, we are going to measure the
voltage across resistor R39, between TP2 and TP3.
Set your DMM to DC volts.
Place the (+) probe of your DMM on the test pin TP2. Place the (-) probe of your DMM
on the test pin TP3.
Adjust P2 until you read 3.0 Volts on the DMM. P2 is a multi-turn so it may take several
turns to see a change.
Warning : If you do not see any voltage change when turning P2, stop adjusting and check
your board. You probably have a wiring error.
Warning : Turning P2 clockwise increases the current in Q6. If you turn it too far, the
current will reach a value that might smoke R39 !
. Sound check Plug in a dynamic microphone to the input XLR.
Connect the output to your monitoring system. It can be a headphone amplifier or it can
go through one of your ADC inputs if you run a software studio.
Set Gain switch to 10dB, “Trim” knob to center, 48V to Off.
Plug in power.
Turn the gain switch until you hear that your mic pre is working. Check all the positions of
the gain switch, the “Trim” pot and the Phase switch.
Verify that the green LED lights up when a sound is playing and that it turns red when it
come near saturation.
Make the same test with a condenser microphone, with the 48V switch set to On.
Plug off power.
Set the 48V switch to Off.
6. DI check Remove the wire jumper we made in step 2 and install the Di01 board.
Insert an instrument jack into the front panel jack socket.
Plug in power.
You should hear your instrument when playing.
Plug off power.
7. Congratulations Done !
Copyright ©2010 SoundSkulptor