Internal power supply and PSU mod

Discuss Yocto construction and related issues

Re: Internal power supply and PSU mod

Postby rv0 » Feb 16th, '16, 09:30

See "Slide Switch Grounding?" => viewtopic.php?f=16&t=720

This reduces (conga) noise a lot.
Get the latest unofficial Yocto V1 firmware here.
Be sure to check the revised manual.
Leave your comments in this thread.
User avatar
rv0
 
Posts: 184
Joined: Feb 11th, '14, 09:09

Re: Internal power supply and PSU mod

Postby bmaximus » Feb 19th, '16, 07:11

deejayraoul wrote:
EchoBoy wrote:@deejayraoul: Did you keep the external supply option to make a SNR comparison between external and internal supply?

I did not have time to investigate on my hum issue yet. Sorry Jeroenbvo for not having replied earlier.
In my case the hum is present on all outputs, whether instruments are played or not. This hum also exists with the external supply but >10dB quieter which makes it acceptable.
For now I suspect radiation from the toroidal transformer.

I kept my external power supply, didn;t do any scientific comparison, but it was obvious.
I gues i need to
find a shieldedtransformer (wich would be quie hard as the transformer hardly fits in the metal case at the moment)
ór
find a way to shield this transformer (does anyone know of a safe way/material to do this?)
ór
deal with the noise
ór
go back to the external power supply.




About the noise (the hum at 50/60 Hz) the true "Achilles heel" in my case were once again the flat cables that carry the audio signal to the two printed circuits. It can happen that some wires may become broken, while maintaining an unstable connection that causes a strong hum. After mounting the yocto in the container sold by Kacper, I had to replace it again these cables for the fourth time. About the transformer, i think that the resin toroidal are the best. You can be further shielded with a Faraday cage, stealing the idea for this CD players I have at home.
Image
User avatar
bmaximus
 
Posts: 57
Joined: Sep 28th, '15, 05:50
Location: Roma

Re: Internal power supply and PSU mod

Postby m303 » Feb 19th, '16, 08:44

bmaximus wrote:About the noise (the hum at 50/60 Hz) the true "Achilles heel" in my case were once again the flat cables that carry the audio signal to the two printed circuits. It can happen that some wires may become broken, while maintaining an unstable connection that causes a strong hum.


About the flat cables: I'm using PSK multi-pin connectors for the connection between the IO board and the main board. It's a bit more work (even more if you do not have the fitting crimping tool like me), but I think it pays off, because of the looks and being able to disconnect the two boards at any time. For the power cable I used a molex connector.

Image
m303
 
Posts: 9
Joined: Feb 14th, '16, 16:13

Re: Internal power supply and PSU mod

Postby bmaximus » Feb 19th, '16, 10:30

This picture is very reassuring. Well made!
User avatar
bmaximus
 
Posts: 57
Joined: Sep 28th, '15, 05:50
Location: Roma

Re: Internal power supply and PSU mod

Postby gihaume » Feb 19th, '16, 13:28

Nice !
gihaume
 
Posts: 285
Joined: May 12th, '14, 14:48

Re: Internal power supply and PSU mod

Postby ALFREDO » May 27th, '16, 19:23

What about to put the toroid trans inside one of this?

Image
ALFREDO
 
Posts: 30
Joined: Apr 11th, '16, 18:01

Re: Internal power supply and PSU mod

Postby Kazper » Jun 12th, '16, 16:24

Something like this may also work: https://www.don-audio.com/trafo-shield or you can get MU Metal in sheets from http://www.lessemf.com/mag-shld.html.

The enclosure would work, but make sure any toroid mounting don't touch the box.
Kazper
 
Posts: 61
Joined: Feb 20th, '16, 20:06

Re: Internal power supply and PSU mod

Postby hofmann25 » Oct 14th, '16, 03:38

jeroenbvo wrote:
I have also connected the chassis ground to the PSU using a loop breaker intended to prevent earth/ ground loops to prevent hum when systems are interconnected.




What 2 diodes did you use for the ground loop breaker jeroenbvo? :)

1N4004's or 1n5818 or other schottky diodes?

The reason I ask is because at the top you mention 1N4004's and on your blog you say the 1N5***'s http://imgur.com/a/IeBch#3

Will this mod work for the Nava?
User avatar
hofmann25
 
Posts: 272
Joined: Jan 26th, '16, 21:30

Re: Internal power supply and PSU mod

Postby hofmann25 » Oct 14th, '16, 08:52

Also what is the benefit of changing the PSU into a full wave bridge/Full wave Rectifier (removing D1&2)?

Does this turn the PSU into DC?
User avatar
hofmann25
 
Posts: 272
Joined: Jan 26th, '16, 21:30

Re: Internal power supply and PSU mod

Postby Altitude » Oct 14th, '16, 15:09

hofmann25 wrote:Also what is the benefit of changing the PSU into a full wave bridge/Full wave Rectifier (removing D1&2)?

Does this turn the PSU into DC?


Both set ups take an low voltage AC and convert it to DC. The difference between half and full wave rectified supplies is that the full wave has better ripple characteristics but requires a transformer secondary with a center tap. Those are generally only seen in internal transformers, external AC-AC bricks dont have a center tap. In this case, I am not convinced that an internal transformer is somehow better. Sticking a big ass magnet inside a tight case which leaks magnetic flux everywhere is probably going to cause more noise problems than it solves
User avatar
Altitude
 
Posts: 147
Joined: May 28th, '15, 13:01

PreviousNext

Return to Yocto v1.0 Hardware

Who is online

Users browsing this forum: No registered users and 6 guests