Boss BF2 Calibration

Here is a guide I put together to calibrate the BF2. This is based on the BF2 service manual floating around the internet.

Reference points for the measurements:





Step 1:

Set the Manual and Depth to 0%

Connect probe at TP-1

Adjust VR7 so that the period of the measured signal is 25us.

It should look like this.


Now turn the Manual 100%. The period of the measured signal should be 2us plus/minus 20%.



The same plot but expanded in time.


Step 2:

Set Depth and Res to 0% Connect a 220 Hz, 0dBm sine wave.

With a 600 Ohm generator this corresponds to a voltage of 0.775 V.

This is the input signal.



Connect the oscilloscope probe to the emitter of Q3.

Adjust VR6 so that there is no clipping of the measured signal while turning the Manual from 0% to 100%.

The Manual set to 0%


The Manual set to 100%


Negative clipping should look like this.


Positive clipping should look like this.


Step 3:

Set the Manual and Depth to 0% and Res to 100%

Connect a short to the input

Connect the output to the oscilloscope.

Adjust VR5 until it starts oscillating.



Additional info:

if you haven't got a generator you can generate the required signal using audacity and your soundcard:

http://audacity.sourceforge.net/

If you don't use it already, it's a free and very useful waveform editor.

Here are the steps:


    


Before you play back the signal make sure the output of the sound card is adjusted to 0.775V via volume control.

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