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AndrewT, I believe the first link was just to reference Mr Ibre as a recognized writer in France... The speaker return should be made directly to the centre-tap of the power supply filter capacitors, despite the fact that the PCB has a ground padfor the speaker. The pad on thePCBis a 'convenience' that allows PCB connectorsto be used (as shown in the photo above). These should only be used if the connection to the power supplyis very short (less than 100mm).
I used an old computer power supply as case. It is compact, has good shielding and main power input connector and power switch are already present. qualified if this is a requirement where you live. Death or serious injury may result from incorrect wiring. Symmetrical source, mount 2.1. Printed circuit board PCB suggestion for 2.1 amplifier assembly with tda7294 2.1 tda7293 2.1 Tda7294 2.1 Tda7293 2.1 Power Amplifier Pcb Component View Tda7294 2.1 Tda7293 2.1 Power Amplifier Pcb Top Tda7294 2.1 Tda7293 2.1 Power Amplifier Pcb Bottom Tda7294 2.1 Tda7293 2.1 Power Amplifier Pcb Top Overlay BOM for mounting or amplifier 2.1The diagram above shows the pinouts for the TDA7293V (the "V" means vertical mounting). Soldering the ICs must be left until last. Mount the ICs on your heatsink temporarily, and slide the PCB over the pins. Make sure that all pins go through their holes, and that there is no strain on the ICs that may try to left the edge off the heatsink. When ICs and PCB are straight and aligned, carefully solder at least 4 pins on each IC to hold them in place. The remaining pins can then be soldered. Remember, if you mess up the alignment at this point in construction, it can be extremely difficult to fix, so take your time to ensure there are no mistakes. The TDA7293 has a bewildering number of options, even allowing you to add a second power stage (in another IC) in parallel with the main one. This improves power into low impedance loads, but is a rather expensive way to get a relatively small power increase. It also features muting and standby functions, although I've elected not to use these. I have shown a 2A slow-blow fuse, but this depends on the size and type of transformer and your mains supply voltage. Some manufacturers give a recommended fuse rating, others don't. The fuse shown is suitable for a 150VA transformer at 230V AC, and is deliberately oversized to ensure that it will not be subject to nuisance blowing due to transformer inrush current. A 2A fuse will fail almost instantly if there is a major fault. They have similar sound character. The mini-crescendo has more "full sound". The Hitachi K135/J50 has unique good character but the 7293 that I tried was at least as listenable as the mini-crescendo. But the same thing happened again, instantly after powering on, a flame shoots out the bottom of the IC and that's it...
Note: Output power up to 10 Watt RMS per loudspeaker is more than sufficient for a practice bass/guitar amplifier! Your neighbors can confirm this. :-) On the first try I had both TDA7293 chips soldered to the board. I have shorted the audio input signal to ground.
The TDA7293 IC uses a MOSFET power stage, where the others featured use bipolar transistors. The main benefit of the MOSFET stage is that it doesn’t need such radical protection circuitry as a bipolar stage, so unpleasant protection circuit artefacts are eliminated. There are no apparent downsides to the TDA7293, although it was found that one batch required a much higher voltage on the Standby and Mute pins than specified, or the amps would not work. This is not a limitation, since both are tied to the positive supply rail and are therefore disabled. As readers will know, there are already several power amplifier projects, two using IC power amps (aka power opamps). Both have been popular, and this project is not designed to replace either of them. However, it is significantly smaller than the others, so it makes building a multiple amp unit somewhat easier because the space demand is much lower. It’s quite simple to include 4 amps (two boards) into a small space, but be aware that good heatsinking is essential if you expect to run these amps at significant power levels. about 2 months ago I decided to take on the project of designing my own amplifier which is supposed to be driving my subwoofer in the future. I use small 1N4007 diodes, but some equipment uses heavy rectifier bridges to absorb high currents. In my setup I did not measure any current as everything is connected to the same main earth. A nother application of TDA7293 is the Bridge Tied Load configuration, where two TDA7293 are used. In this application, the load must not be lower than 8 Ω for dissipation and current-capability reasons. With a power supply of ±25VDC the maximum output power is about 150Watts at 8Ω. With a power supply of ±40VDC the maximum power output is 200Watts at 16Ω.
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