Sorry I got confused 70 + 70 CC 50 0 50 ac 800 VA.
I was thinking of making the Apex AX 14 Golosa or NMOS 350 how it would behave with 70V
I was thinking of making the Apex AX 14 Golosa or NMOS 350 how it would behave with 70V
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Maybe in the Hi Fi World 😛
But in the Musical Instrument World, amps are not driven full power sine wave but much worse, straight into squarewave rail to rail clipping for HOURS.
Properly designing PTs is a must.
FWIW I wind my own, they all have low DCR, and rails typically drop 20% under full load.
Specially because voltage drop gets dissipated in the transformer itself, and it´s a "reverse returns" problem: the more it heats up, the more resistive it becomes.
In my amps part of the fan airflow is dedicated to cool the PT off, go figure.
I consider that almost as important as cooling heatsinks 😱
True, but after 6-8 hours in a 12 band night festival , or rehearsal room duty, time is *ample* to heat them up and then some.
Yes, Hi Fi is different, specially because distortion or continuous clipping is unbearable.
Music Instrument amps? they are bought FOR their distortion 😱
Instrument amps may indeed be run at full whomp for hours. But those amplifiers are relatively small. A hundred watts, two hundred is small. Most PA these days is much bigger, and designed to run at less than half power on average - even the good stuff that costs $5000. Take an example of a premium “prosumer” amp - the QSC RMX5050. I’ve blasted those to the point where you can’t even tell what song is playing, and it doesn’t trip the breaker back at the distro. Rated at about 14 amps on the back panel, but the manual states that it will draw 56 AMPS !!! at full sine. And it doesn’t have a 6.7 kVa transformer in it - it has a pair of 1kVa. A 6kVa unit is about a foot and a half in diameter, and eight inches thick, weighing over 150 pounds, costing three times what the amplifier does. I’ve seen them - in systems far bigger than audio amplifiers. A rack full of those amps might be fed off a 100A/240V drop at a festival and if you add up all the maximum possible draw it would probably exceed the 15, 25, or 50kVa unit on the pole. You've got to run the lights and food trucks off that too, and you don’t see breakers tripping all the time when the band takes the stage. The only conclusion is that the real world average power draw is far less than the maximum.
A 100 watt guitar amplifier can get by with a 400 VA transformer, which is less than $100. A 100 watt hi-fi amp might use 100 VA if you’re lucky. A 100 watt PA amp is too small to be useable, except for running the tweeters only.
A 100 watt guitar amplifier can get by with a 400 VA transformer, which is less than $100. A 100 watt hi-fi amp might use 100 VA if you’re lucky. A 100 watt PA amp is too small to be useable, except for running the tweeters only.
