Halo A52 Class A watts..

[Micke.H]

I read somwhere thath A52 did like 5watt class A :B anyone Who knows?
It gets real hot so it seams like i could be so and the sound Sounds like it :T
//Micke

[Peter Nielsen]

FWIW, the A51 idles at 2 watts/channel in 8 ohms, and you know it has 5 huge heat sinks.

An educated guess is that the A52 idles at something like 1 watt/channel in 8 ohms.

Peter

[psychdoc]

Here is a question for ya Peter (since you seem to know a lot about the inner workings of the Parasound amps): why do the Halo amps run so hot and have all the "huge" heat sinks that you have talked about, especially compared to the NewClassic amps? My NewClassic amps, even when run hard, get as warm as a battery powered alarm clock, which is to say- not very! Is there some new process or inner workings with the newer amps????? I must admit I do love that they remain cold- it is hot enough already out here in Hawaii.

[Peter Nielsen]

All current Parasound amplifiers are Class AB amplifiers. The idle bias current in the amplifier determines when the amplifier switches from running in Class A to running in Class B. The Halo amps run with a higher idle bias current than the New Classic line, which gives the Halo amps more power in Class A before it switches over to Class B, but this also means that the amplifier runs hotter...

Peter

[Micke.H]

FWIW, the A51 idles at 2 watts/channel in 8 ohms, and you know it has 5 huge heat sinks.

An educated guess is that the A52 idles at something like 1 watt/channel in 8 ohms.

Peter

Oki lets say it`s so ...My speakers sensivity 90db 1watt 4ohm then A52 idles 2watts :P lets say 1 watt classA with my 90db Usher is quite high.. 8O i used a soundpreasure meter "RadioShack" and can tell that 90db is higher than i usualy play at evenings.....
I normaly play like 75-85db so 1 watt is more than most people think :T
I used it 1meter from the speaker and from my seat..
//micke

[Peter Nielsen]

Oki lets say it`s so ...My speakers sensivity 90db 1watt 4ohm then A52 idles 2watts :P lets say 1 watt classA with my 90db Usher is quite high.. 8O i used a soundpreasure meter "RadioShack" and can tell that 90db is higher than i usualy play at evenings.....
I normaly play like 75-85db so 1 watt is more than most people think :T
I used it 1meter from the speaker and from my seat..
//micke

No, that is incorrect. At 4 ohms, the Class A power is only half of what it is at 8 ohms. So if it is 1 watt @ 8 ohms, it will be 0.5 watt @ 4 ohms.

The idle current I is constant. Ohms laws say that the power P=(I^2)*R. Since the current is constant, the power will decrease as you decrease the resistance. Or, to put it in other words:

P=(I^2)*R == (P/2)=(I^2)*(R/2)

But you're absolutely right in that the effective sound level is directly affected by the speaker sensitivity. Efficient speakers do not need much power to play loud...

Peter