Single PSU for 5 or more Amps ?

[veeds16]

Hi

Please share.

BR
Ved

 

[googlyone]

Veeds,
There is really not a lot of magic to this. Provided you are not looking for something regulated or containing magical circuitry.

If you are building chip amplifiers, then you really shouldn't need anything too fancy. Refer example 1.

If you are making an audio driven arc welder, then you need something very larger indeed. Refer example 2.

Examples from my past include:
- 4 off LM3886 plus a bridged amplifier for subwoofer. The application here was for PA for a local petanque club (i.e. occasionally moderate volume, but not seeking to be a nightclub). For this I used a 625VA transformer, bridge rectifier and as many big caps as would fit in without going silly. If I recall, there was about 80,000uF total. Probably more than needed, but worked fine. On music type signals the rail slump was insignificant.

- A six channel monster driving 250W each into four 4 Ohm subs, and two 250W channels into main speakers. This used a massive, and by massive I mean 30+ kg EI transformer with windings made of what can barely be called wire, it was square bus. It is probably 2kVA. The capacitors comprise pair of banks, one with 120,000uf a rail and the second bank which I added later more or less doubles this. This "works" but given the very very low overall impedance of the "paralleled" speakers, the voltage does drop noticably at high signal levels. This power supply fills a 2 foot by 18" by 12" volume, and has enough wire in it to jump start a nuclear submarine.

Both of the above require soft start circuits.

So the question is, where does your application sit?

 

[veeds16]

Hi googlyone,

My planning is in between both examples.

I am new to this i completed successfully 2.1 channel amp with online available kit help so i dont have much tech. knldg about this.
2 LM3886 for main speakers. (24-0-24 5A)
1 Lumin Mosfet 250 watt for sub. (25-0-25 12 A)

I used two PSU and two transfo.

Now planning is to built 7.1 Channel.
7/120 watt par channel @4ohm (2 LM3886 par channel mono.)

1/500 watt par channel @4ohm


I have one question which always round in my mind about VA.
for example normally 1 LM3886 which require 68VA to 136VA with input -/+ 28 - 30VDC to produce 68watt at 4ohm.

If i use same input -/+ 28 - 30VDC but VA is much more like 500VA or 600VA for 1 LM3886 will it damage my single Chip.

If you can visit please and check if this PSU is able to handle my 7 channel amp.
https://www.eightaudio.in/collectio...dual-psu-10-000uf-100v-x-4-200v-20a-rectifier

 

[KMossman]

The specification sheet should be clear as to the voltage/current limits.

I'd suggest 3 PSU; one for sub, one for the front speakers, and another for the satellite speakers.

 

[AndrewT]

I suggest separate amplifiers. Each amplifier located close to it's speaker.

 

[veeds16]

Veeds,
There is really not a lot of magic to this. Provided you are not looking for something regulated or containing magical circuitry.

If you are building chip amplifiers, then you really shouldn't need anything too fancy. Refer example 1.

If you are making an audio driven arc welder, then you need something very larger indeed. Refer example 2.

Examples from my past include:
- 4 off LM3886 plus a bridged amplifier for subwoofer. The application here was for PA for a local petanque club (i.e. occasionally moderate volume, but not seeking to be a nightclub). For this I used a 625VA transformer, bridge rectifier and as many big caps as would fit in without going silly. If I recall, there was about 80,000uF total. Probably more than needed, but worked fine. On music type signals the rail slump was insignificant.

- A six channel monster driving 250W each into four 4 Ohm subs, and two 250W channels into main speakers. This used a massive, and by massive I mean 30+ kg EI transformer with windings made of what can barely be called wire, it was square bus. It is probably 2kVA. The capacitors comprise pair of banks, one with 120,000uf a rail and the second bank which I added later more or less doubles this. This "works" but given the very very low overall impedance of the "paralleled" speakers, the voltage does drop noticably at high signal levels. This power supply fills a 2 foot by 18" by 12" volume, and has enough wire in it to jump start a nuclear submarine.

Both of the above require soft start circuits.

So the question is, where does your application sit?

Hi did you managed PSU in your both the projects ?

BR
Ved