Rockbox.org home
release
dev builds
extras
themes manual
wiki
device status forums
mailing lists
IRC bugs
patches
dev guide



Rockbox mail archive

Subject: Re: Getting rid of that damn noise.
From: Rob Ward (wards_at_paradise.net.nz)
Date: 2001-12-28


If you can hear the whistle with the vol right down, then it is probably a
switching regulator. Ofter the chokes (inductors) on these whistle at maybe
5-10kHz, but as you say, the whistling disappears as the load increases -
this is because the duty cycle (or sometimes frequency) changes as the load
varies. What voltage do you need to drive the HDD? Is it 12V?

Rob

----- Original Message -----
From: "Tjerk Schuringa" <regenpak_at_yahoo.com>
To: <jukebox_at_cool.haxx.se>
Sent: Friday, December 28, 2001 2:52 AM
Subject: Re: Getting rid of that damn noise.

> I observed two things about the whistle: it is also present with the
volume all
> the way down and it does cease when the HD spins up in my newish (used to
be
> heehee) unit. I haven't looked at the schematics yet but it could be that
one
> of the voltage inverters (there must be several!) that feeds the HD goes
into a
> sort of "burst" mode which is about 1 kHz (that irritating whistle) and
goes to
> an ultrasonic frequency when the HD draws current. It's likely to be a
messy
> mod in any case!
>
> T.J.
>
> .
> .
> .
> .
> .
>
>
> __________________________________________________
> Do You Yahoo!?
> Send your FREE holiday greetings online!
> http://greetings.yahoo.com
>

---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.298 / Virus Database: 161 - Release Date: 13/11/01



Page was last modified "Jan 10 2012" The Rockbox Crew
aaa