Continue to Site

Welcome to

Welcome to our site! is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Looking for +-48V 3A Power Supply

Not open for further replies.


Full Member level 6
Nov 18, 2001
Reaction score
Trophy points
Activity points
Dear all,
I want to build an amplifier that uses +-48V 3A power supply(As you see dual voltage +-48V) Can somebody light my way or better a schematic?

You should be use toroidal transformer, good rectifier diods (fast enough) and big high quality caps. All this things are necessary for good amplifier. Also I thing that 3A is to small for your need. It shoud be at least 5Amps transfomer. In most amplisfier designs there is no need for stabile supply voltage for output stage( it only must be filtered enough). For input stage you can easily make power suply with some LM317HV. Check this datasheet you will find out more.
Amp will be working without this, but not well.

Thank you very much.I decided to build my amplifier application with TDA7294.But you are right, i think 3A is small for my app.Do you have any schematic?

take a look maybe here:

**broken link removed**

of course You need use about 250W dual toroidal transformer. Output must be about 34 Volts, use 5 Amps diods and good caps 2x15.000uF/60V or better more... block 50Hz with 100nF caps and You will get good +/- 48Volts/3A

Prices here in Poland (local shop) is about:

trans: TST250/022 2x35V 20 Euro
bridge: 1-1,5 Euro
caps: 5-10 Euro

Hmm Thanks admin.Then my biggest problem is to find a good dual toroidal transformer.I dont know if i can find it here.Anyway, i want to use a shock inductor to filter 50hz noise.I hope i can find them.Thanks again.

35v from the transformer became after been rectified around 48 volts ; (35x1,41)-1,2 = 48
at this voltage the tda will blow up

for 4ohm drivers use a 2x25v transformer and for 8 ohm use a 2x28v trasformer
the tda need around 2 amps so for a stereo version a 150w toroid is enaught

Not open for further replies.

Part and Inventory Search

Welcome to