12 channel soundcards

[TomHoward]

Not being familiar with the card I looked it up, and have you seen the last paragraph on this review?

https://www.soundonsound.com/reviews/echo-audiofire-12

 

I was certainly impressed by its sonic performance, and while I found it disconcerting to see the bottom couple of LEDs on my mixer's main meters permanently on due to high ultrasonic noise... Echo told me that their production-line models now have 12dB less ultrasonic noise compared with the review model (at the expense of reducing the bandwidth slightly), which should remove these tell-tale signs of ghostly signals for good.

 

What frequency is the output noise, can it be filtered if it doesn’t cause an audible problem?

[sandall]

Not being familiar with the card I looked it up, and have you seen the last paragraph on this review?

https://www.soundons...ho-audiofire-12

 

 

What frequency is the output noise, can it be filtered if it doesn't cause an audible problem?

Thanks for that Tom - interesting reading. At least one of the cards has been back for repair, so I'm now wondering whether we somehow ended up with a pre-production model. It has a very long serial number, but I didn't think to check whether the PCB had the same S/N as the case. The spare unit is "clean".

 

In my original post I should have said 250mV, rather than 2.5V, of "noise", which sounds similar to what the reviewer reported. No idea of frequency, as I couldn't get my scope to trigger on it. Filtering is a possibility, but that means finding or making 12 channels of (preferably passive) LPF - not quite as simple as a few turns of wire round a ferrite bead.