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TDA7293 parallel design DIY [message #81185]

Thu, 05 March 2015 21:30

hydrovac
Messages: 9
Registered: December 2014
Location: Hyderabad

Esquire

Hi all,

As part of my home theater build, have decided to go for 3 way actives for front LCR... so, need to build 9 power amps for fronts and 8 amps for surrounds... to pair up with my Sherbourn PT- 7020A pre/pro. I needed something as easy, but more powerful. This is when I and my friend John found the datasheet of TDA7293. This IC can run up to 100V, low distortion, and can easily be paralleled.

I have been looking for a source of PCBs using parallel TDA7293s... there are not many out there that you can buy. We then decided to do our own PCB. Our schematic is almost the same as in datasheet... the board layouts in the datasheet are flawed and little clumsy... we used them only as guidance with component arrangement on our PCB after few futile attempts to route the board with minimum jumper count.

Pin out on TDA7293 is tricky, so single-sided board is difficult to draw, and in the end contains more jumpers between lines than tracks... so, this one is made as double sided.

I thought it would be good to share my project with the community... maybe someone finds it useful.

Tentative double side PCB layout, top and bottom sides... have to check pitch and spacing with actual components we have before fabricating the PCB.

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Re: TDA7293 parallel design DIY [message #81186 is a reply to message #81185]

Fri, 06 March 2015 09:20

Wayne Parham
Messages: 18787
Registered: January 2001

Illuminati (33rd Degree)

Very cool!

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Re: TDA7293 parallel design DIY [message #81187 is a reply to message #81186]

Sat, 07 March 2015 03:47

hydrovac
Messages: 9
Registered: December 2014
Location: Hyderabad

Esquire

Thanks Wayne,

Between each revision, John will suggest this and suggest that, to improve the schematic and layout. Revised and final layout, film ready... will be sending out for fabrication.

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Re: TDA7293 parallel design DIY [message #81365 is a reply to message #81185]

Sat, 30 May 2015 06:13

hydrovac
Messages: 9
Registered: December 2014
Location: Hyderabad

Esquire

Ok, further on the project:
I found an old enclosure which can accommodate the amp board, heat sink, power transformer rectifier and filter capacitors... the trafo is a 32-0-32 250VA... searches seem to suggest this is the absolute upper limit for TDA7293 setup.

The heat sink I have, also cannibalized from a fried receiver is 11" wide, 3.25" tall, and sports 22 fins, each being 2" long. It weighs about 1.5 kg., give or take. Assuming I can get a decent enough thermal contact for each IC, does this heat sink sound like it will have enough mass to support two TDA7293s? (Yeah, I know there's a lot of thermodynamics data that would be needed to get an accurate reading on whether/how well this 'sink will work, but all I can give are raw measurements.)

For the smoothing circuit, I'm using quad 1200uF capacitors (low-ESR caps designed for power-supply filter applications) per board, in addition to the dual 6,800uF caps in the supply rails. Will this be adequate at least initially, or would it be wise to snag a few 10,000uF monsters to add to the power filtration?
That's all I can think of right now... more as I come up with it.