High frequency noise - diyAudio
Go Back   Home > Forums > General Interest > Everything Else
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 7th November 2008, 06:40 PM   #1
fraserh is offline fraserh  United Kingdom
diyAudio Member
Join Date: Oct 2008
Default High frequency noise

I've asked a few friends and none of them can hear this, but it's driving me nuts!!! I have a new DAC from Derek Shek but the psu he sent me omits a HF noise (at the socket, not at the dac) It has a a switch on the plug to switch between various voltages- is it safe to try them all and see if it goes away?? Outputs is 800mA

  Reply With Quote
Old 7th November 2008, 08:12 PM   #2
Dr_EM is offline Dr_EM  United Kingdom
diyAudio Member
Dr_EM's Avatar
Join Date: Oct 2006
Location: Swindon
Must be a SMPS, try and swap it for a linear, this wil sort this problem
  Reply With Quote
Old 7th November 2008, 11:59 PM   #3
fraserh is offline fraserh  United Kingdom
diyAudio Member
Join Date: Oct 2008
I thought that would be the problem, i've heard of that before with that kind of supply... I have a linear one kicking about but it's slightly different:

3V DC, 1000mA

the original one is set to 12V 800mA- but i've heard that the 1000mA might result in an improvement anyway, it's the lower DC output i'm concerned about
  Reply With Quote
Old 8th November 2008, 02:49 AM   #4
diyAudio Member
Join Date: Dec 2007
Location: Phoenix, AZ
Hello fraserh, without knowing the DAC requirements, it's hard to say what will happen with using a lower voltage. I would suspect that the DAC circuit would not be happy with the lower voltage, but it's hard to say without specs. Having extra current available from a PS is not going to cause any problems. If the circuit doesn't need the current, it won't draw that much. But if there is a little extra there, that can be a good thing at times.
So, if you can post some specs on the DAC, we could probably answer better what supply to use. I can agree that it's possible that an SMPS will create some HF noise. Bloody things are a double edged sword. They are much more efficient, and if designed well they can work great. But like anything else, if it's cheap, it probably isn't very good.


  Reply With Quote
Old 8th November 2008, 03:40 AM   #5
fraserh is offline fraserh  United Kingdom
diyAudio Member
Join Date: Oct 2008
I can't find a schematic for the DAC but if it's any use here's the photo i could take of the guts if that helps? The inputs from L to R are: DC, optic, input switch and coax

Click the image to open in full size.
  Reply With Quote
Old 8th November 2008, 04:28 AM   #6
diyAudio Member
eclectic2k's Avatar
Join Date: Nov 2005
Location: Silicon Valley
definitely an SMPS. I checked the sigtone website. - Nice little DAC, btw.

Since he states it is 100-240v 50/60Hz it is certainly SMPS (autoranging) Sounds like a cell phone charger I have. Whenever I plug in to charge the phone, the supply emits a little high frequeny "whine". He should swap this out for you. I don't care for my phone, but it's unacceptable for a piece of audio equipment. The supply shouldn't do that, so it's a bit of a lemon though it probably meets all it's functional requirements.

Not uncommon in very cheap switch mode supplies. Something not well damped resonating with the switching frequency. A slightly "off" inductor most likely.

oh, and 3v isn't going to cut it. Most likely the circuit will need at least 9v to operate. Depends on the power regulator scheme and the voltage specs of the active parts.

As Dave said, higher current capacity from the supply won't hurt, and can only help most likely. I think you'll need to get within a volt or two of the 12v it requires. Be careful about going over hard to know how it would like that. (really, a 12v supply shouldn't be too hard to find)

  Reply With Quote
Old 8th November 2008, 04:35 AM   #7
fraserh is offline fraserh  United Kingdom
diyAudio Member
Join Date: Oct 2008
Thanks so much, everyones helpful round here! I'll get a hold of a decent linear 12V 1000mA supply then. I think i might email him as well just to let him know: it's definitely very noticable- at least to my ears.
  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Wanted - High Power, High Voltage, Audio Frequency Transformer Manual. kimbal Tubes / Valves 4 11th May 2009 08:05 PM
Deluxe Reverb Re-Issue High Frequency Noise. jordankersten Instruments and Amps 1 22nd December 2008 09:20 AM
high frequency high voltage power supply... moray james Planars & Exotics 6 23rd July 2008 07:57 PM
High-Frequency Noise in CD Recordings PrecisionAudio Digital Source 44 16th December 2007 08:27 AM

New To Site? Need Help?

All times are GMT. The time now is 10:55 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2