What's the typical transformer VA rating used in relation to amplifier power rating for Class B solid state amps?
I suppose manufacturers may have different engineering ratings but what's typical. eg for a 100 WPC AMP, is it typically 300VA, 500VA, other?
I'm guessing with class B amps running at around 60% efficiency, that must come into play....
I suppose manufacturers may have different engineering ratings but what's typical. eg for a 100 WPC AMP, is it typically 300VA, 500VA, other?
I'm guessing with class B amps running at around 60% efficiency, that must come into play....
It depends on use.
Typical is around 50% more, Audiophiles don´t have to resell in the open market so, 100% extra gives pride and peace of mind, generic competitive $$$ home use amps can sometimes get by with very tight 100% (so 100 VA for 100W amps) simply because they assume they will NOT be constantly run at high power , but at, say, 10% to 20% max.
Typical is around 50% more, Audiophiles don´t have to resell in the open market so, 100% extra gives pride and peace of mind, generic competitive $$$ home use amps can sometimes get by with very tight 100% (so 100 VA for 100W amps) simply because they assume they will NOT be constantly run at high power , but at, say, 10% to 20% max.
You have to figure what load the amp is driving, if it is expected to drive lower z speakers ( or even two sets) such as 4 ohms, you’ll have to double maybe quadruple the VA rating
I am working on the Bob cordell Bc-1 amp, we are in the 150w/8 ohm range, I bought a 500va/90vct triad toroidal for this project from Arrow which imo is a pretty good price
I am working on the Bob cordell Bc-1 amp, we are in the 150w/8 ohm range, I bought a 500va/90vct triad toroidal for this project from Arrow which imo is a pretty good price
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A class AB amplifier producing 100 watts continuously at clipping draws 250 VA off the transformer. Real-world use with music (even highly distorted) draws about half that.
125 and 250 VA transformers, at the same voltage, will NOT produce the same amount of power. The penalty is the voltage dropping like a stone. Apparent “loudness” is more directly correlated to the voltage you get when the amplifier is driven to full sine wave output continuously than it is to any other factor. If you use a 125 VA or 250 VA, you will get the same peak level when you start to see a bit of clipping on your scope. But if you turn it up until you HEAR distortion, the 250VA will go noticeably louder. It will also measure a higher power - about 1.5 to 2 dB more. Barely “audible” but the increased energy in the room is certainly perceived.
125 and 250 VA transformers, at the same voltage, will NOT produce the same amount of power. The penalty is the voltage dropping like a stone. Apparent “loudness” is more directly correlated to the voltage you get when the amplifier is driven to full sine wave output continuously than it is to any other factor. If you use a 125 VA or 250 VA, you will get the same peak level when you start to see a bit of clipping on your scope. But if you turn it up until you HEAR distortion, the 250VA will go noticeably louder. It will also measure a higher power - about 1.5 to 2 dB more. Barely “audible” but the increased energy in the room is certainly perceived.