Codifus wrote:
Chung wrote:
Codifus wrote:

DOA wrote:

When I don't have anything playing and just a bit of volume I can hear
a hiss from my speakers. But thats only if i put my ear up to it(2
inches away). But its more evident if I have the volume up to max. Then
I can hear it. Its not extrememly loud but its there. Is that normal on
all speakers? Or do I need to get better connectors for the speaker
wire? Now to reiterate I don't have anything playing. just turining the
volume knob. What do you think? Is there a problem? thanks for your
time.

It's not the speakers that are causing that, it's the amplifier.
You're hearing the switiching distortion associated with Class A-B
amplifiers. The switiching distortion is usually very small when
compared to the audio signal. If you had a Class A amplifier connected
to your speakers you would here nothing at all, even at full volume.
Class A design virtually eliminates switching distortion. The
drawback to class A is that amps of that design consume alot of power
and generate alot of heat.

Nothing to worry about. It's normal.

CD


No, it is not switching distortion that you are hearing! It is
definitely not an issue of whether it is a class A or class AB amp.

If the hiss level changes with the volume control, then the majority of
the noise is coming from electronics prior to the volume control: the
preamp buffers, and sources such as CD players, phono preamps, etc. If
the hiss goes away when the volume control is at low settings, then the
noise is most likely not coming from the power amp. The OP can find out
more about the noise origin by selecting different sources, or by
shorting inputs to ground. Or by disconnecting the preamp from the power
amp. If he can provide information on the power amp and the preamp, it
might help. By the way, the hiss is louder if the speakers have higher
sensitivity. But if the noise cannot be heard at the listening position,
at normal listening levels, then it should not be a problem.
I'm not an engineer but my experiecnce has been that Class A amps are
*dead* silent no matter what the volume. Class AB amps have a bit of
noise, noise that is still much much lower than any muscial signal, but
there nonetheless. And it's most noticeable by hearing it in the
tweeters when very close to them, as the OP was.

CD

No, there are Class A amps with noticeable hum and hiss, and there are
Class A-B amps that are close to dead quiet. It depends on things like
how much gain there is, how efficient the speakers are, and most
importantly, how well designed the amplifier is. This is something that
is easily measurable on the bench, and there is simply no evidence, or
reason, why Class-A amps are quieter. Of course, a particular amplifer,
whether Class-A or AB, may be noisier than another, but that is not due
to the class of operation, but implementation.

The hiss is mostly coming from electronic stages *prior* to the power
amp anyway, if the volume control setting affects the amount of hiss.