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.
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:
- Single PCB to include all blocks except input and output connectors
- Encapsulated toroidal transformer for PCB mounting
- Double the capacitors in the regulator (2x2200uF for each polarity)
- All electrolytic capacitors are now Panasonic FR series (newer and better than FC)
- 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
- ALPS Blue Velvet potentiometer
- New heatsinks for the voltage regulators
- All possible components switched to SMD
- Rectifier diodes changed to 2A model
- Delay On circuit has now its own voltage regulator
- 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)
- Delay setting trim potentiometer is replaced with Bourns precise model for easier setting of desired delay
- Power LED will now turn on and off together with the headphone relay
- The new PCB has option for 115V in addition to 230V (supported by the new transformer)
- 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”
Somehow I forgot to translate this second part of the Headphone Amplifier project from Bulgarian to English. Better late then never 🙂 The project has been finished in March 2010 and all relative time references should be linked to that date. That was quite a while ago. It seems I have lost track of time or I’m just getting older. I am building an updated version at the moment and I will post an article about it soon. Now let’s go back to the finishing of the first version.
Time has come to finish the project, started long ago, headphone amplifier with TPA6120A. After I finished the assembly of the PCB for the amplifier and performed some tests in August 2009, I just didn’t have an opportunity to finish what I have started. Now everything came in its place and one PCB became a finished product. The final version combines the amplifier together with toroidal transformer, voltage regulator and circuit for delayed output enabling in a nice aluminum enclosure. Continue reading “Headphone Amplifier With TPA6120A Part II – Finished Product”
Дойде време да се довърши отдавна започнатият проект за слушалков усилвател с TPA6120A. След като в средата на август 2009-та приключих с изработката на платка за усилвателя и направих някои тестове, просто нямах възможност да приключа започнатото. Сега всичко си дойде на мястото и от една платка се стигна до завършено изделие. Финалният вариант помещава усилвателя заедно с тороидален трансформатор, стабилизатор и верига за забавено включване на изхода в приятна алуминиева кутия.
The following article is devoted to a HiFi headphone amplifier project of mine based on BurrBrown’s (Texas Instruments company now) integrated circuit TPA6120A . This IC consists of two high power operational amplifiers in one package. Both amplifiers have separate power supply pins, placed symmetrically on both sides of the package so developing a high density PCB will be easy. TPA6120 has impressive parameters, which make it fit the usage mentioned in its datasheet. The main parameters as follows:
- 80 mW into 600 Ω From a ±12V Supply at 0.00014% THD + N
- Current-Feedback Architecture
- Greater than 120 dB of Dynamic Range
- SNR of 120 dB
- Output Voltage Noise of 5 μVrms at Gain = 2 V/V
- Power Supply Range: ±5 V to ±15 V
- 1300 V/μs Slew Rate
- Differential Inputs
- Independent Power Supplies for Low Crosstalk
- Short Circuit and Thermal Protection