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Old 3rd October 2007, 04:24 PM   #1
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Default Ad1994

I have decided to try a mono AD1994 Class D amp with a battery power supply.

I guess i need some help pointed in the right direction for designing layout software and the PCB.

Are there any companies out there that will manufacture and/or solder the IC's on the pcb's?

I narrowed the search on Class D chips out of:

AD1994
MP7782
MAX9709
TPA3123D2

I am looking for something around 20-30W mono, similar to the Tripath stuff, and can run of off 24V DC. Low THD+N too.

AD1994 looks like it will work for me... just never done a PCB, SMD or layout.

sooo..... where do i begin?

Thanks!
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Old 3rd October 2008, 06:31 PM   #2
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Default TPA3123D2

Anyone else playing with this chip too / I like it 25-25-W small, sounds very good too. 50-W mono. I'm experiencing some heat issues (the chip and output inductors getting warm), but working through it.

Just wondering if anyone else has had success with them.

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Old 3rd October 2008, 09:52 PM   #3
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Default Re: TPA3123D2

Quote:
Originally posted by AudioGeek
I guess i need some help pointed in the right direction for designing layout software and the PCB.
You are welcome to have the ExpressPCB files that I used for the AD1994 amp shown on page 6 of this slide show:
http://www.audiodevelopers.com/plate..._family_files/

However, if you could transfer this layout to Eagle for me I would be most appreciative. I would like to have an AD1953/AD1994 board, but I need to stop using ExpressPCB, because it locks me into using their fab services. Transferring over the amp part of the circuit would get me "jump-started" on the AD1953/AD1994 design (right now my AD1994 board is using the TAS3004, which is OK but not as versatile or as high quality as the AD1953).

Quote:

Are there any companies out there that will manufacture and/or solder the IC's on the pcb's?
Soldering this stuff yourself is tedious but not impossible. I've made a number of them without going blind or insane
However, if I can get this design converted to Eagle it would be possible to send it out for assembly by a service house

Quote:
Originally posted by FUCHSAUDIO
Anyone else playing with this chip too / I like it 25-25-W small, sounds very good too. 50-W mono. I'm experiencing some heat issues (the chip and output inductors getting warm), but working through it.
Just wondering if anyone else has had success with them.
The inductors I am using run cool. The chip is designed to be soldered on the back to a good ground plane. If you do that the chips gets a little warm, but nothing to be concerned about. You can use a small heatsink designed for video RAM chips on the top of the chip to help out.
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Old 4th October 2008, 12:05 AM   #4
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Default Re: TPA3123D2

Quote:
Originally posted by FUCHSAUDIO
Anyone else playing with this chip too / I like it 25-25-W small, sounds very good too. 50-W mono. I'm experiencing some heat issues (the chip and output inductors getting warm), but working through it.

Just wondering if anyone else has had success with them.

I was going to build a board for these at one time but decided to try the TPA3106D1 instead. I've also tried the TPA3122D2N. They both sound excellent.

My TPA3122D2N BTL proto

I had some heat issues with the TPA3106D1 at first, but after redoing the layout the problem went away. The chip and inductors stay cool unless driven into hard clipping.
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Old 4th October 2008, 02:04 AM   #5
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Default Re: AD1994

Whoops--link is incorrect. See the BCPA-2 slides

http://www.audiodevelopers.com/plate...amp_family.htm

Here's a picture:
Click the image to open in full size.

The AD1994 is near the blue caps and toroids. I added a few IC pins to the back of the board to act as a small heatsink, but they aren't needed
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Old 8th October 2008, 08:59 PM   #6
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Default FYI SMD Prototypes

Guys, I use a shop in Michigan called Nelson Specialties, who does PC board assembly work, and will do SMD prototypes as well .

I've soldered a few myself, but it's tedious, and worth paying someone who's got the right setup to do it. I paid a pretty reasonable rate for some SMD amp sample boards recently.
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