On Nov 7, 4:54 pm, Andre Jute wrote:
A STAX 252A amp, same as the 2050 sold in anglo markets, has parallel-
connected input ports, called "through ports". With both sets of
inputs connected, one to a CD player, one to a computer output, the
sound is muted, dulled. With the computer leads pulled, the sound is
louder and brighter.

Is this report what we would expect? What is the key mechanism at work
here? Suggest some ballpark values.

Newbies especially welcome.

Andre Jute
Invigilator

So, you tried this by accident, got results that are utterly
predictable as no competent design would permit this to happen. That
second "port" is to drive a speaker amp as the amp you describe is for
headphones.

What are you, some kind of idiot that would attempt to look "smart" by
posing a stupid question?

Peter Wieck
Wyncote, PA

Peter Wieck wrote:
On Nov 7, 4:54 pm, Andre Jute wrote:
A STAX 252A amp, same as the 2050 sold in anglo markets, has parallel-
connected input ports, called "through ports". With both sets of
inputs connected, one to a CD player, one to a computer output, the
sound is muted, dulled. With the computer leads pulled, the sound is
louder and brighter.

Is this report what we would expect? What is the key mechanism at work
here? Suggest some ballpark values.

Newbies especially welcome.

Andre Jute
Invigilator

So, you tried this by accident, got results that are utterly
predictable as no competent design would permit this to happen. That
second "port" is to drive a speaker amp as the amp you describe is for
headphones.

What are you, some kind of idiot that would attempt to look "smart" by
posing a stupid question?

He usually asks these questions through West so as not to appear stupid
himself.
His next question will be how to put the magic smoke back in after doing
the same with power amps.

The best answer is a switch box.
Another method would be to put a 10k resistor in each cable; then if both
sources are powered up, they would see a 20k load and the amp would see
aproximately a 5k source resistance. With only one source powered,
results are unpredictable.

--
Eiron.

Another method would be to put a 10k resistor in each cable; then if both
sources are powered up, they would see a 20k load and the amp would see
aproximately a 5k source resistance. With only one source powered,
results are unpredictable.


I've done that back in my distant past...

Works fine if both sources are powered up, and one outputting silence,
but if one source is not powered up, the ESD diodes in its output op-amp
will start to conduct at above and below 0.7V (as the supplies are at
zero volts), and that will make for horrid non-linear clipping or sorts.