[geoff]

On 5/06/2018 4:02 PM, Matt Faunce wrote:
Why is there no gain control on the Adcom GFA-535?

I've used it in between my computer (iMac) and my speakers, and controlling
the gain from the computer works, but there's always a noticeable hiss.
Wouldn't it be better to have the output of my computer much higher and
attenuate the output of the Adcom?

No. Sounds like the computer output has a much higher output level that
the Adcom's max input level. Set you computer output level on max and
get a passive volume control, adjusting the level down for max Adcom
output. That will be the best background hiss level you can achieve
using the computer's line output. Or get a better computer, or better
audio D-A interface.


Similarly, I've seen many reviews of powered speakers where the reviewers
complain that there's a noticeable hiss that can't be attenuated. Why are
they designed like that?


That sounds like artifacts from a crappy implementation of a Class-D
poweramp section. Or poor power supply, or both.

If a powered speaker has a hiss that can be heard more than 30cm ( a
foot ) away, it is a heap of junk. I have some cheap-and-nasty 30W
powered speakers beside by computer monitor and can't hear hiss unless I
put my ear within a few inches.

geoff