help to make a simple psu for my LM3886

[arunpanchami]

hai all,
i want to make a psu for myLM3886 amplifier. some components are already at my hand,
1,4 x MUR860
2,2 x 15000mfd 63V caps
trafo 22 -0-22 4 amp
can anyone help me to complete this psu .

 

[quad]

hai all,
i want to make a psu for myLM3886 amplifier. some components are already at my hand,
1,4 x MUR860
2,2 x 15000mfd 63V caps
trafo 22 -0-22 4 amp
can anyone help me to complete this psu .

A couple -

LM3886 Schematics + PCB - diyAudio

?????????? PCB ?????? ?????????????

 

[arunpanchami]

:sad:my old setup is here. my plan is replace this amp board with mew LM3886. also plan change psu with mur860

 

[Aniket]

:sad:my old setup is here. my plan is replace this amp board with mew LM3886. also plan change psu with mur860

Ohh, that looks like a mess. BTW which is that amplifier you are going to replace with LM3886.
You won't gain anything with MUR860, those are ultrafast diodes and are suited to switching supplies. standard transformers operate at 50~60Hz, our mains supply freq. If you still want to use these anyway, then use 0.01uF250V film capacitors across the anode and cathode of each diode.
Better use a standard 15~25A bridge rectifier.
Also, have a thorough reading on this: Power Supply for Power Amplifiers

Regards,
Aniket

 

[arunpanchami]

finally connect with a 27-0-27 trafo psu.not satisfied in sound quality considering old setup. that was TIP 142, 147 combination

 

[Aniket]

You need to tidy up your wiring a lot. and I can't understanding your wiring scheme.
It should be connected like Transformer-> Rectifier board-> Main filter capacitors-> Amplifier modules.
it looks like you have taken the supply rails from the rectifier board, correct that. take the supply rails and the ground from the main filter caps.
Also shorten the length of the supply rail wires as much as possible. use shielded wires for inputs, and the speaker returns should be connected to the common ground at the filter caps. also your audio input connectors are placed right adjacent to the transformer. keep these two things as far as possible.

 

[arunpanchami]

first Ac to rectifier board. main filter caps are connected parallel to blue Samsung 4700uf. i take supply rails from rectifier board out.ground is also from there. ..i think that was a wrong wiring

 

[pranavkumar]

A 27-0-27 trafo would give out 27*1.414 V = 38V .. Which is more than required. The recommended voltage is 30 V DC if I am not wrong.

I built this amp recently using the same PCBs. Used a 21-0-21 5A transformer. Works brilliantly.

I suggest you lower down your DC voltage to 29-30V.

 

[arunpanchami]

i bought that board from sudheer @ Bangalore. 27-0-27 trafo give 25 V out

 

[pranavkumar]

looks like you have a poorly made transformer there.