DCAudioDIY.com

DC Area Audio DIYer's Community
It is currently March 28th, 2024, 5:05 pm

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 52 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6  Next
Author Message
PostPosted: December 15th, 2017, 1:32 pm 
Offline
User avatar

Joined: February 19th, 2017, 9:43 am
Posts: 530
SoundMods wrote:
Cogito wrote:
ratbagp wrote:
For various reasons I have needed to change to an old HP laptop. It uses a 120 watt, 18.5 v 6.5 amp charger. It runs Windows 10 and I use Jriver.

Everything is fine except that I get noise coming thru my usb ODAC when the charger is connected. There is no noise when I disconnect the charger and use the internal laptop battery.

I could buy a replacement charger but I suspect that the problem may be internal to the laptop and not in the power supply. Any ideas?

On a separate note, I seem to remember a website that listed Windows services that could be turned off but I cannot remember what it was. Does anyone have recommendations?

ray


Plug in the laptop charger into the power conditioner.


If the laptop is driving a DAC it is more likely that the noise is on the AC line and affecting the DAC, not the laptop.

That won't work. The power conditioning has to be between the laptop and the switch-mode power supply.

_________________
I have too much stuff - https://www.pleasebuymystuff.com


Top
 Profile  
 
PostPosted: December 15th, 2017, 1:43 pm 
Offline

Joined: July 17th, 2016, 6:24 am
Posts: 1099
DaveR wrote:
SoundMods wrote:
Cogito wrote:

Plug in the laptop charger into the power conditioner.


If the laptop is driving a DAC it is more likely that the noise is on the AC line and affecting the DAC, not the laptop.

That won't work. The power conditioning has to be between the laptop and the switch-mode power supply.


DACs usually have LPS. Most likely the AC noise effecting the laptop which is cascading to USB power.


Top
 Profile  
 
PostPosted: December 15th, 2017, 1:55 pm 
Offline
User avatar

Joined: February 19th, 2017, 9:43 am
Posts: 530
I'd be surprised if this is the case. The noise would be common mode by the time it got to the USB port.

_________________
I have too much stuff - https://www.pleasebuymystuff.com


Top
 Profile  
 
PostPosted: December 15th, 2017, 3:46 pm 
Offline

Joined: March 12th, 2013, 11:12 am
Posts: 738
My suggestion is to listen to it with battery power and charge when not listening. My MacBook Pro sound better in battery mode compared to charging mode even though I hear no noise in either mode.

Some DAC receivers do not need the 5v+ USB leg, if your DAC is one of these you could run a data only USB cable.


Top
 Profile  
 
PostPosted: December 15th, 2017, 4:07 pm 
Offline
Site Admin
User avatar

Joined: February 28th, 2013, 10:38 am
Posts: 1682
TubeDriver wrote:
Some DAC receivers do not need the 5v+ USB leg, if your DAC is one of these you could run a data only USB cable.


Even of it does need the +5V line, build a 5V linear supply and splice it in instead of getting the +5V from the laptop....

Roscoe

_________________
I can explain it to you, but I can’t understand it for you.


Top
 Profile  
 
PostPosted: December 15th, 2017, 4:13 pm 
Offline

Joined: January 14th, 2015, 11:15 pm
Posts: 499
For the moment, I am doing as you suggest and just use battery power. The ODAC gets its power from the USB connection.

In the meantime I will try to come up with something using one of my LT1083 regulators.

ray


Top
 Profile  
 
PostPosted: December 15th, 2017, 4:16 pm 
Offline

Joined: January 14th, 2015, 11:15 pm
Posts: 499
Roscoe Primrose wrote:
TubeDriver wrote:
Some DAC receivers do not need the 5v+ USB leg, if your DAC is one of these you could run a data only USB cable.


Even of it does need the +5V line, build a 5V linear supply and splice it in instead of getting the +5V from the laptop....

Roscoe


I will look into it. Probably a better all round solution.

ray


Top
 Profile  
 
PostPosted: December 15th, 2017, 5:12 pm 
Offline
User avatar

Joined: January 13th, 2016, 9:14 pm
Posts: 787
You can find LT1083 based variable output regulator kits on EBay, good to 7amps. Very low noise and 18.5VDC is in the adjustment range. Already have bridge rectifiers. They are LDO regulators, so a 15vac 120va power transformer should be within the heat dissipation range.

Just a thought.


Last edited by HAL on December 15th, 2017, 5:40 pm, edited 1 time in total.

Top
 Profile  
 
PostPosted: December 15th, 2017, 5:21 pm 
Offline

Joined: January 14th, 2015, 11:15 pm
Posts: 499
HAL wrote:
You can find LT1083 based variable output regulator kits on EBay, good to 7amps. Very low noise and 18.5VDC is in the adjustment range. Already have bridge rectifiers. They are LDO regulators, so a 18vac 120va power transformer should be within the heat dissipation range.

Just a thought.


At under $12, it probably is a good simple solution. I'll make my mind up tomorrow. With a glass of single malt in hand watching the snow, decisions are best left postponed for a day.

ray


Top
 Profile  
 
PostPosted: December 15th, 2017, 5:37 pm 
Offline
User avatar

Joined: January 13th, 2016, 9:14 pm
Posts: 787
If you can find an E-I core power transformer, the will limit bandwidth both directions.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 52 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6  Next

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: Bing [Bot] and 42 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group