Topping PA3s Review (Desktop Amplifier)

[legrandmeaulnes]

The 15 uV are A-weighted. Looking at the noise floor of the PA3 (higher noise below 1 kHz) it's possible that the 56 uV unweighted could be similarly low when A-weighted (noise below 1 kHz counts less as it is not as audible as noise above).

Maybe @amirm has a way to calculate SNR with A-weighting for the PA-3.

I think so. You won't need the attenuators as the noise from the DAC hasn't been a problem so far.

Thanks a lot

 

[JakeK]

This seems like what the B100 was built for - low output power with very low noise.

The B100 does seem like it should be well suited to these speakers. Super low noise.

 

[dan_remaincalm]

i ended up ditching my PA3S. i was using it to drive an old set of B&W 601S2 from a focusrite audio interface via a balanced connection.

there were two problems:

* the power supply had an audible acoustic whine.
* turning on the PA3S added low-level noise to my focusrite mic inputs. i've not seen this before.

the actual audio output from the device was clean and loud though.

i could try and diagnose it but meh whatever. not worth it.

 

[LTig]

i ended up ditching my PA3S. i was using it to drive an old set of B&W 601S2 from a focusrite audio interface via a balanced connection.

there were two problems:

* the power supply had an audible acoustic whine.
* turning on the PA3S added low-level noise to my focusrite mic inputs. i've not seen this before.

Look at the last graph in the review in posting #1. There is a lot of high frequency noise. It could emit from the loudspeaker cables and find its way into the microphone cables.

 

[dan_remaincalm]

Look at the last graph in the review in posting #1. There is a lot of high frequency noise. It could emit from the loudspeaker cables and find its way into the microphone cables.

it was actually also coming through with no input plugged into the mic inputs, presumably something was going on either on the power supply ground or (less likely) something related to the balanced audio connection. or maybe just radiating EM out of the box - they were a little close together on the equipment rack. either way, i switched to an older class D amp based on an Anaview AMS0100 and my problems went away.

 

[antcollinet]

it was actually also coming through with no input plugged into the mic inputs, presumably something was going on either on the power supply ground or (less likely) something related to the balanced audio connection. or maybe just radiating EM out of the box - they were a little close together on the equipment rack. either way, i switched to an older class D amp based on an Anaview AMS0100 and my problems went away.

Almost certainly a ground loop/common mode ground difference between devices. This is a system problem rather than an individual component problem.

 

[dan_remaincalm]

Possibly ... although almost everything in here except power is isolated one way or another (DIs, balanced connections via transformer isolation, USB isolators...).

It was probably diagnosable with some work, but the audible transformer whine was a problem by itself, and my other amp doesn't do it, so it's a moot point.