While I wait for the second round of PCBs for the breadboard adaptors, I started working on the next adaptor design. The first pass adaptors came in very handy while prototyping the Audio Amp Breadboard design. Here you see 3 of the new adaptor boards and my IPhone working together to test a TDA7052A.
The TDA7052A is a 1-Watt audio amp that drives the speaker in a push-pull fashion so no large AC coupling cap is needed as with the older LM386 part. I will write more about this new adaptor board when its closer to done.
In the picture here you see the TDA7052A in the upper left. Along the top you see four breadboard adaptors. From left to right, a mini-prototype, screw terminal, mini-headphone jack and breadboard power supply adaptors.
Oh and the music I test with… Ugress!
Better picture and more information after the jump to the full article.
This is a better picture of the breadboard with the adaptors in use. The breadboard I used does have its own power supply but I wanted to make sure everything worked well with the breadboard supply sold by Curious Inventor. I hope to see all my adaptor boards there in the near future.
The first adaptor on the far left is just one of the mini proto boards with a pot installed. This was better then trying to stick it into the breadboard directly and servers as a sort of prototype itself as one of the planned adaptor boards will have this pot on it. Including the audio amp board. The pot works well but unfortunately does not control the volume in this circuit. The wrong version of the TDA7052 I have is not the "A" version so it does not have the volume control input. One of the TDA7052A features is a volume control input. This is better then just attenuating the input signal as you would normally do with an LM386 for several reasons I will cover in the future article. Unfortunately I ordered the wrong part which is another good reason for prototyping. Be sure and use your planned parts list when you buy parts for a new design. That way you can insure that your list is correct.
The second adaptor board provides two sets of screw terminals. I use it here to connect the speaker. The old Design Acoustics speaker had some 16aug wires attached. I could have found some smaller wire to use but with the screw terminal adaptors it was easy to adapt them to the breadboard.
The third adaptor is from Curious Inventor. Scott beat me to an adaptor for the stereo mini-headphone jack. This is where the IPhone output is coming into the audio amp. You can see the small AC coupling cap next to the black jumper lead. Ground is the center pin which is jumpered under the adaptor to the ground rail of the breadboard.
The amp has been playing my Ugress collection for a good while at near clip limits on the 5V power supply. Its luke-warm and running strong. I admit that 1-Watt is not nearly loud enough for Ugress. Maybe I will jump the supply up to max for the TDA7052 and see if I can push the thermal limits to shut down. Sounds like fun to me.