Tech Support Biasing the CA-306

Disclaimer of Liability

Under no circumstances does Canary Audio assume liability or responsibility for injury or damages sustained in biasing this equipment or for damages to any other equipment connected to it.

Even though we provided the procedures, we suggest that these adjustments to be performed only by an authorized Canary Audio dealer or repair center as an incorrect bias setting can cause damages to the tube and to the amplifier.
Tools Required

Digital multimeter
Long-handled slotted screwdriver

To check and adjust the bias voltage of the 300B tubes, simply follow the following procedures:
  1. Making sure that the power switch is in the OFF position.

  2. Install all the tubes to the corresponding sockets using a gentle rocking motion.

  3. Connect your speaker leads, input cable and power cord to the amplifier.

  4. Turn ON the amplifier.

  5. Turn on the multimeter. Select the section for measuring up to 20V DC. Attach and secure the negative test lead to the chassis or to the binding post.

  6. Insert the positive test lead into the bias test point marked as "300B - V1".

  7. Carefully insert a long-handled slotted screwdriver into the bias adjustment pot marked as "V1". Slowly rotate the screwdriver to adjust the bias voltage until it reaches 0.55V.

  8. Repeat steps 6 and 7 to adjust the bias voltage for the three remaining 300B tubes in the same fashion as biasing 300B - V1. Using bias test points marked as "300B - V2, 300B - V3 and 300B - V4" for measuring, and bias adjustment pot marked as "V2, V3 and V4" for adjusting. You will need to go back and forth a few times until all four 300B tubes are properly biased.

  9. Once you have finished biasing all four 300B tubes, wait a few minutes and recheck the settings again.

  10. The CA-306 mono blocks power amplifier is now ready to use.

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