Thanks Sachin. I read the description and it mentions input from a 500 mA transformer. My amp would require something like 4A to 5A. Do you think this circuit would scale up to that level? I would probably need higher watt diodes, etc.
Also do you know if there's a single place from where I can source all these parts? I am not sure if I can get everything from the local market here.
That PS, regulator chip can deliver 1.5A Max, those MUR8X0 didoes are X00V, 8A didoes. Our use case was B1 preamp hence we recommended optimum 500mA. You amp will required 2A max when it reaches 1%THD.
Looks like SMPS is the simplest way to go. I don't have any preference for linear PS except that it is simple to build. I don't think I can build a SMPS
Yes, that has a reason. Tripath chips are variable switching amps. They are also called digital amps because they amplify square wave of variable width, dependent upon input. When you give analogue audio input it is modulated with triangular carrier which converts to output of fixed voltage (generally 5V) but variable width square wave. This is switched to max PS rail voltage by internal MOSFETs. Only width is maintained, voltage is increased to PS rail. So output LC filter converts back this variable switched square wave pattern into analogue signal (of new amplified amplitude) . So PS noise is also smoothed. Same time nowhere amplification is analogue, Hence no noise pickup from PS rail. Although these switching in amp creates noise for others
. take AM/FM radio near speaker wire you will come to know, in case of weak station.
So no problem with SMPS and switching amp. Only criteria is good build quality and robust.
I was actually thinking of using a 12V-0-12V 4A transformer with a 4 diode bridge rectifier, a 10000 uF cap and regulated by a 7812 voltage regulator. Would that be good for powering an amp?
This is bad idea in this case and insufficient for your requirements as 7812 max current is 1.0A only (with sufficient heat sink).
I saw the circuit that you and Sachin used for the PASS B1 and it is much more complex. What would you recommend?
Its more filtered but avoided if you get good SMPS.
Also, for SMPS would you recommend I buy a computer SMPS and modify it? Or are there general purpose SMPS power supplies available? Also, would I need to add a few caps at the output of these PS to reduce noise? Is that recommended for SMPS when used to power audio equipment?
Rather than computer SMPS, (where you get 12V, >5A and okay but overkill for this amp), look for good SMPS in old market used for routers etc. They are robust and good quality. Buy new one if you can get.
I think this PS cab be used for your purpose.All power supply parts,(except coils) are available in local market(Pune),contact Omishra for more detail info.
We shipped 25 kits all over India from Pune. So its not a problem.
