Transformer VA Rating vs. Current Rating

[Easyamp]

You want's some opa541?? I've got em, I have 2 for whoever wants them. They were samples from awhile ago.

first 2 reply get's them.

[JhonDoe]

Originally posted by Easyamp
You want's some opa541?? I've got em, I have 2 for whoever wants them. They were samples from awhile ago.

first 2 reply get's them.

If u can send it here in the philippines,, why not...

Ti's doen't have a stock for opa541 and 549...I'm still waiting for my order(sample) since last month....

[Easyamp]

I'll send them But I ask that you pay for the shipping. If interested email me your address to support@easyamp.com and I'll give you a shipping cost.

Cheers,

[Steven]

Originally posted by Jocko Homo
But larger transformers sound better..........as they operate further from saturation.

Jocko

Do they? I mean, maybe they sound better but do they operate further from saturation? As far as I know saturation and maximum flux is determined by the primary voltage (higher voltage, more flux) and frequency (lower frequency, more flux) and not by secondary current. Even a small transformer can supply a lot of power, but only for a short moment because of overheating, not because of supposed saturation.

Steven

[Christer]

Originally posted by Steven



Do they? I mean, maybe they sound better but do they operate further from saturation? As far as I know saturation and maximum flux is determined by the primary voltage (higher voltage, more flux) and frequency (lower frequency, more flux) and not by secondary current. Even a small transformer can supply a lot of power, but only for a short moment because of overheating, not because of supposed saturation.

Steven

I don't know the magnetics well enough to judge, but Kuei
has suggested an alternative solution which is in line with
your reasoning. Use two transformers instead of one and
connect their primaries in series, thus underrating them.
You also need to connect the secondaries in series two and
two, or choose transformer with a different rated secondary
voltage.

[Matttcattt]

Originally posted by joan2
if you mean you tested your woofer with a sine wave, then this is no surprise, energy content of sine waves is much more than music signals...

even if your woofer was rated at 350w it could still be damaged with a 2watt sine wave input...

I understand this, and thats why I said that it didnt mean much.

Originally posted by Easyamp
I’m curious how you are measuring the current load of your amp this could be the misleading point.

You said before you are running a mixed bridge parallel configuration, are you measuring in front of one of the chips or right after the bridge and filter caps, or the ac going into the bridge/caps? If you are using a dmm check that it will measure other then 60hz ac current if measuring after trnsfo I've had this problem before.

I stick a low value power resistor in line with one of the rails (.22 ohm or something) and measure the voltage drop and use ohms law to find current if I'm curious about the current load.

I am currently powering the amp with my bench power supply (2x 0-30v 1A) and it has ameters on each output. they both read about 500mA.

I havent tried the resistor/ohms law method yet.

[Tony]

these are traffos handmade by me, smallest at 15va, biggest is 3000va...

[JhonDoe]

Originally posted by joan2
these are traffos handmade by me, smallest at 15va, biggest is 3000va...

Hey Bro.. nice trafo! can u send me the big one? hehehe...
How much the maximum current rating for that trafo(the big one)?
Are you going to sell that? if yes, for how much?

[Tony]

hi,
the BIG one is intended for a leach amp that can do 1000watt per channel at 2ohms...it weighs in at around 25kilos...
specs are:
1. primary 220volts
2. secondaries: main= > 120volts center tapped, auxilliary windings, 140volts center tapped at 1amp, 12 volts at 2 amps


the one beside it with a copper banding is suitable for a bridged gain clone and can power up to 6 chips....i can sell that to you if you need it.....

or i can make one custum wound to your specs...

all my traffos have secondary windings that are bifilliar wound, i know of no other winder in manila doing biffiliar secondary windings besides me....

[JojoD818]

Tony,

Good luck with those trafos, you'll need a gorilla to move your gear around the house with that size.

Johndoe,

You can use wahtever resistors you have, just match them with a good DMM and your off. This is audio electronics, not rocket science.

JojoD