Sonica 1 – Headphone Amplifier With TPA6120A Part II – PCB Assembly and Rebuild

After some waiting for Sonica 1’s PCB they have arrived. As usual, the quality was very good. I had made a few mistakes, but nothing serious. I will take a few minutes to explain what I had to fix and how the assembly and rebuild of the original amplifier went. The end result was as expected, no change in sound quality.

Continue reading “Sonica 1 – Headphone Amplifier With TPA6120A Part II – PCB Assembly and Rebuild”

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Sonica 1 – Headphone Amplifier With TPA6120A Part I – Schematic And PCB Design

A month ago I started thinking about rebuilding my good old headphone amplifier with TPA6120A. I didn’t realize it was that old until I decided to translate the original article in English. It’s been 7 years and I though it was 3 or 4. Time passes quickly, it seems. I spent some time thinking how to improve it. Now the PCB and components are ordered and once I get them, assembly will take place in the same chassis. What’s new and improved? A number of things in fact.

The list of updates is as follows:

  1. Single PCB to include all blocks except input and output connectors
  2. Encapsulated toroidal transformer for PCB mounting
  3. Double the capacitors in the regulator (2x2200uF for each polarity)
  4. All electrolytic capacitors are now Panasonic FR series (newer and better than FC)
  5. All 100nF decoupling capacitors are now polyester WIMA MKS02 (smaller, allowing them to be closer to TPA6120A). Not as great as the polypropylene Panasonic, but more than sufficient
  6. ALPS Blue Velvet potentiometer
  7. New heatsinks for the voltage regulators
  8. All possible components switched to SMD
  9. Rectifier diodes changed to 2A model
  10. Delay On circuit has now its own voltage regulator
  11. Delay On circuit error fixed – output was switched off when the large capacitors discharged, now this happens when the switch is turned off (well, around 50ms later)
  12. Delay setting trim potentiometer is replaced with Bourns precise model for easier setting of desired delay
  13. Power LED will now turn on and off together with the headphone relay
  14. The new PCB has option for 115V in addition to 230V (supported by the new transformer)
  15. New volume knob

Let’s take a closer look at the design decisions made, updates and why they were needed.
Continue reading “Sonica 1 – Headphone Amplifier With TPA6120A Part I – Schematic And PCB Design”