How many amps of power does a 3875 with 400VAC need?

[Destroyer OS.]

I have a power isolator and filter thing I can use but it only puts out 2 amps..... Would that be enough?

[Nisbeth]

400VAC kills the chip....


/U.

[Destroyer OS.]

400VAC transformer with 2x23-26v secondaries in the amplifiers? Hmm Peter uses 400VAC's.....

[lineup]

Maybe you mean the MAINS Filter only puts out 2 Ampere.
That it is rated 2 A

If you have 240 VAC mains this filter can deliver like this power:
Power = Volt x Ampere
P = V x A

volt=240 ampere=2 A
P= 240 x 2

Max Power = 480 VA
That mains filter is okay to put before a 480 VA transformer (max).

With such big trafo, you can easy drive 2-4 LM3875.

A trafo 400VA, 2x25 Volt, will output
400 / (2x25) Ampere
400/50 = 8 Ampere

50 Volt x 8 Ampere = 400 Watt

===================

you know a transformer has two sides
Primary = input side
Secondary = output side

Both sides use formula:
power = volt x ampere

Power what comes in = Power what goes out
240 volt x 1.667 ampere = 50 volt x 8 ampere

Your filter can take 2 A ( at 400 volt max, safety margin )
So it is okay for 1.667 A ( at 240 volt )

[Destroyer OS.]

Uhh this filter is a 115v to 115v at 2 amps from the wall, a socket.... This is just to plug things into.

I was going to put a 300-400VAC transformer into the amplifier. There is no filter in the amplifier.

[Russ White]

I think you are confusing VA with VAC(Volts Alternating Current).

[Tweeker]

VA= Volt-Ampere. 1 VA= an amount of reactive power such that the product of volts and amps is 1.

Watts refers strictly to real power, but if you have 100% power factor, a purely resistive load, 1 VA would give 1 watt. This is not normally the case, except with toasters. Generally you want ~twice the VA of your load in DC watts to be comfortable, as rectifiers are an ugly load.

[Destroyer OS.]

None of this is really helping. I am not confused about any thing.

I want to know is 2 amps from the wall, that normally has 15-20 amps is enough to power a 3875 amplifier with a 400VAC Toroidal transformer.

The wall, as in a "plug in" as commonly refered to, puts out 15-20 amps at 115v right (60hz). Well if I have a power filter that also is a isolation transformer that only puts out 2 amp at 115v, I need to know if it can power my amplifier and say a small pre-amp, that uses a PS10 from marchand.

[Tweeker]

Your isolation transformer is about 230VA (115V*2A=230VA) and will be the limiting factor, but is likely big enough. Going to assume you mean the LM3875 toroid is 400VA (Volt Amps) and not 400VAC (Volts Alternating Current).

If your LM 3875 has a good psu you might not want to use the isolation transformer on it, unless you have DC offset issues or something. Using the isolation transformer will increase the source impedance of your power supply by almost 3 times.

[Byrd]

If you are not confused and you actually intend to power your 3875 with a 400 Volt Alternating Current Transformer then it will certainly be enough as the chip will be blown in a matter of nano seconds and you will need no current past that point.