My tda7294 Amp

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This is my attempt at building an amp using the tda7294 ic.
 

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the smoothing capacitor + rectifier + transformer loop MUST be kept small for least interference.

The smoothed DC can be any length since cable impedance does NOT affect DC.

The on board local decoupling does the job of supplying current demand at HF and VHF.

Makes sense to me, I have 1500uf local decoupling on the boards and 24700uf per rail on the smoothing capacitors. The amp is absolutely silent when powered on no hum at all and the sound is pretty dynamic too.
 
Pretty neat asymmetrical heatsinks!

Could you also post a pic of it when closed?

I still have about 50 caps of 12,000uF. Maybe I should put them all in one TDA7294 amp just to boast... :D
(originally bought for a TDA7294 dual supply-rail project, the testversion had 2x24,000@+/-20V and 2x54,000uF@+/-40V with 1000uF on the PCB for each voltage :p).
 
Did you hear any difference using the different voltages?

It switched between the voltages by itself, it is a function discussed in the datasheet.
I never got it to work properly and one blew up, so I left the project for years until I found cheap boards in China for the regular use and shortly after, this thread. (And still have not finished one :whip:)

One thing that always puzzled me is that my version clipped the signal at 25V (oscilloscope, not a voltmeter showing rhe RMS or average voltage). Why it clipped at 25V with a 20 and a 40V supply, I never found out.:confused:
 
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Main reason for doing it is being able to wring the most power out of it. I wanted to use it on a 4ohm speaker, and back then, it was the cheapest/simplest solution I could see (mid 90's) to make a subwoofer-plate amp of about 150Wrms@4ohm on a 12" sub with active filtering down to 24Hz within 3dB.

If I had seen this thread back then, I wouldn't have had design a PCB, to have custom transformers wound, to order everything in 5 fold with the plans to sell 4 of them, etc... :D

I should also have left it to the more experienced members...

It did work for a while though, just not putting out the numbers I had hoped, but enough for some decent rumble in the livingroom of my student dorm. (But the reference was my 15"sub on a car cross-over + caramp + battery + 12V 5A supply, so we were spoiled already).
 
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At the moment the setup I am using has a 300va transformer with 22 volt secondaries and 26200uf pf capacitance on each rail, initially I used some high speed diodes in the rectifiers u860 actually but these seemed to get rather hot when playing louder I have since changed to generic 35amp bridge rectifiers.
I had a look at that thread a while ago and am sorely tempted to try out that circuit with the booster transistors maybe one day... At the moment i am quite pleased with the sound so far.
 
since cable impedance does NOT affect DC.
Cablr resistance does though!............
impedance is an AC effect not a DC effect.

The quality of the DC is completely unaffected by impedance effects.

Resistance adds to the voltage drop that can be calculated or modelled or simulated to see that when non varying current (DC) is drawn that there are no other effects.
 
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