TDA8924 filter inductor

ghabrius · 22nd April 2011, 10:45 AM

Hello, Recently I've been hanging around those all-in-one package chips that philips offer and I gotta tell you they sound pretty good but my problem is that the inductors that I use run at 40-50C degrees or so no matter on the load conditions.. I was told by many people that I needed the iron powder cored ones but this stuff always gets on my nerves what inductors should I use for this?

switching frequency is around 310kHz
currently I have setup on the LC a 15uH 6A iron powder core inductor (link below) and a 1uF cap.

VISHAY DALE|IHLP4040DZER150M11|INDUCTOR, 15UH, 20%, 6A | Farnell United Kingdom

nightanole · 22nd April 2011, 11:38 AM

Roll your own?
41Hz Audio:Sounds Good to Me!

nigelwright7557 · 22nd April 2011, 08:43 PM

Get a t106-2 core and wind your own with a couple of meters of 18 SWG enamel coated copper wire.
Amidon do the cores but you can pick them up on ebay too.

ghabrius · 22nd April 2011, 08:54 PM

The toroid color tells the material right?

Is it OK to go with blue/green one cause I've got one at hand?

BTW is it normal that the amp runs alot hotter at idle than in operational use?

ghabrius · 22nd April 2011, 08:55 PM

thanks btw

nigelwright7557 · 23rd April 2011, 11:41 PM

Quote:

Originally Posted by ghabrius

The toroid color tells the material right?

The t106-2 is red.
Colour denotes material.
-2 is the material and 106 is the diamter.

nigelwright7557 · 23rd April 2011, 11:43 PM

Quote:

Originally Posted by ghabrius

BTW is it normal that the amp runs alot hotter at idle than in operational use?

Do you mean the toroid of the amplifier ?

I run my class d amps at 200KHz and they dont get hot at idle.
The toroid shouldnt get warm either.

theAnonymous1 · 23rd April 2011, 11:50 PM

These are the ones you want....

2 Two Toroid T106-2 Micrometals T-106-2 Torroid | eBay

~33 turns will get you close to 15uH.

ghabrius · 24th April 2011, 09:04 PM

Quote:

Originally Posted by nigelwright7557

Do you mean the toroid of the amplifier ?

I run my class d amps at 200KHz and they dont get hot at idle.
The toroid shouldnt get warm either.

No, I meant the the chip itself. Could be because it's giving 50% duty cycle with a little shout-through. I guess if I turn the frequency down to 200 I won't get that quality and it not that big of a deal..

Also if I wind my own toroid is it better to use a couple thinner wires or a single thick one?

22nd April 2011, 08:43 PM	#3
nigelwright7557 diyAudio Member Join Date: Apr 2008 Location: Carlisle, England	Get a t106-2 core and wind your own with a couple of meters of 18 SWG enamel coated copper wire. Amidon do the cores but you can pick them up on ebay too. __________________ http://www.murtonpikesystems.co.uk PCBCAD40 pcb design software.

23rd April 2011, 11:50 PM	#8
theAnonymous1 diyAudio Member Join Date: Feb 2004 Location: Anonymityville	These are the ones you want.... 2 Two Toroid T106-2 Micrometals T-106-2 Torroid \| eBay ~33 turns will get you close to 15uH. __________________ "If you don't like funerals don't kick sand in Ninja's face." - Ninja

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22nd April 2011, 11:38 AM	#2
nightanole diyAudio Member Join Date: Feb 2009	Roll your own? 41Hz Audio:Sounds Good to Me!

22nd April 2011, 08:54 PM	#4
ghabrius diyAudio Member Join Date: Feb 2007 Location: Boston	The toroid color tells the material right? Is it OK to go with blue/green one cause I've got one at hand? BTW is it normal that the amp runs alot hotter at idle than in operational use?

22nd April 2011, 08:55 PM	#5
ghabrius diyAudio Member Join Date: Feb 2007 Location: Boston	thanks btw

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