Ad1994

[AudioGeek]

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!

[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.

[Neil Davis]

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).

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

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.

[theAnonymous1]

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.

[Neil Davis]

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

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

Here's a picture:


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

[FUCHSAUDIO]

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.