QA403 left output problem

QA40x
1

Hello!
I noticed that the left output of my QA403 (+ and -) is very low. When connect outputs to the inputs of the device and send a 1kHz sine wave, I’ve got this:

qa403
qa403800×816 27.9 KB

I of course swapped channels, change cables, and the issue comes from the left output.
Has anybody an idea of what would the problem?

Antoine

2

You should be seeing this:

image
image1087×859 36.6 KB

What happens if you send the left output to right input- is the -67.57dB the same? You don’t have shorting plugs on your outputs do you?

If you are connecting via differential, are your hots and colds all wired correctly? It could almost be a cancellation at -68dB.

3

When feed the right input with the left output, the -68dB is on the right in:

qa403_LRswapped
qa403_LRswapped800×816 27.2 KB

I dont have shorting plugs on the outputs, I use small BNC cables to connect outs to ins, and the problem is the same either with hot or cold output.
In balanced mode, I’ve only got the usual +6dB:

4

qa403_balanced
qa403_balanced800×816 27 KB

5

I would suggest contacting @matt and asking for his advice/suggestions. It looks like you may have a left channel gen output issue than may need investigation. Cheers.

6

ok thank you! I will contact him.