RE: You may be

RE: You may be

Posted by beppe61 (A) on June 11, 2016 at 13:38:24

In Reply to: RE: You may be posted by Ugly on June 11, 2016 at 11:40:22:

Hi ! thanks a lot for the very kind and valuable reply.

" The biggest peak, around 37kHz could be emi from some switching power supply in your environment.
Though, often times it is the audio systems immunity to these types of interference which is more the blame than the switcher when quality switching power supplies are being utilized. "

Exactly ! Other interfaces I tried with the same exact set-up (only the interface changed) have lower noise and almost no spikes to speak of ... or at least not evident like the one in the picture.
However, and just for comparison purposes, i am attaching the noise powering the interface with a linear psu ... same spikes more or less than with the cheap smps.
So it is noise generated inside the interface, maybe for not enough filtering. Usually these interface take the 12VDC supply and generate the different voltages needed with dc to dc switching converters.
There must be a significant difference in the quality of this power generation between cheap units and more expensive ones.
Even if some exceptions could exist.

" Note that a low level, high Q spike at ~37kHz is not likely to be related to MHz band instabilities in the power supply output of your usb cable wart.
When doing loopback testing such as you seem to be doing, especially in a noisy pc environment where single ended audio gear is being utilized, the ground loop problem is a huge concern.
In order to believe what you see in these types of setups is you have to beak that loop in the D/A to A/D chain since it may even be the culprit you are now chasing!
Do you have some type of loop breaking isolation inserted into your loopback chain if you are using single ended signalling? Or, are you using all truly balanced audio hardware?
If the answer to both those questions is no then the loopback connection itself can be a major contributor if not the sole contributor to these types of noise entering the audio signal.
This is the technical difficulty of doing believable loopback. "

Actually what i am doing is just measuring the noise floor with open input. There is no analog connection between the DA and AD section.
So i guess it is not a complete loop-back. Both ins and outs are left open, not connected.

My conclusion is that changing PSU has no significant impact on the noise floor of the interface, as long as the PSUs used are of decent quality.

The best interfaces have a very low and flat noise floor, evidence of a superior design and construction.
Of course there is also the distortion ... but this is more difficult to measure.
I hope to be able to carry out distortion measurements soon.
Thanks a lot again.
Kind regards,
bg

This post is made possible by the generous support of people like you and our sponsors:

Follow Ups Full Thread

Topic - Here is a review that says the $1400 Power Supply for the MicroRendu is the 'Biggest Sonic Improvement'..... - Cut-Throat 15:42:32 06/07/16 (23)

RE: Here is a review that says the $1400 Power Supply for the MicroRendu is the 'Biggest Sonic Improvement'..... - datman 10:22:58 06/09/16 (0)

RE: Here is a review that says the $1400 Power Supply for the MicroRendu is the 'Biggest Sonic Improvement'..... - Windows X 16:42:15 06/08/16 (0)

You may be - fmak 06:32:55 06/08/16 (18)

RE: You may be - beppe61 10:57:38 06/08/16 (17)

RE: You may be - Tony Lauck 12:14:51 06/08/16 (16)

RE: You may be - beppe61 00:23:23 06/09/16 (15)

RE: You may be - Ugly 07:22:54 06/09/16 (4)

RE: You may be - beppe61 10:31:16 06/11/16 (2)

RE: You may be - Ugly 11:40:22 06/11/16 (1)

RE: You may be - beppe61 13:38:24 06/11/16 (0)

RE: You may be - beppe61 22:25:11 06/09/16 (0)

RE: You may be - fmak 06:30:51 06/09/16 (7)

RE: You may be - Ugly 07:16:22 06/09/16 (3)

RE: You may be - fmak 08:19:18 06/09/16 (2)

RE: You may be - Ugly 08:30:04 06/10/16 (1)

RE: You may be - AbeCollins 10:19:30 06/10/16 (0)

RE: You may be - beppe61 06:46:43 06/09/16 (2)

RE: You may be - fmak 07:07:16 06/09/16 (1)

RE: You may be - beppe61 22:31:56 06/09/16 (0)

RE: You may be - Windows X 00:37:51 06/09/16 (1)

RE: You may be - beppe61 02:58:56 06/09/16 (0)

Are noise spectra of the device available ? - beppe61 03:54:19 06/08/16 (0)

RE: Here is a review that says the $1400 Power Supply for the MicroRendu is the 'Biggest Sonic Improvement'..... - Isaak J. Garvey 15:55:11 06/07/16 (0)

Follow Ups

RE: You may be - beppe61 13:38:24 06/11/16 (0)

Post a Message!