The weather is amazing

But I did manage to do some DIY, I drilled and tapped holes for the TDA7293, 2SC5200 & 2SA1943.

So, the heatsinks are done. Waiting for another fan, fan-grilles and some mounting hardware. 

Short post today, the sun is calling 🙂

/Mayday

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LM317 compatible TPS7A4700 regulator

I got the boards from oshpark today.

They look quite nice, I only have bad cellphone pics…but here they are.



/Mayday

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LM337 alternative using TPS7A3301

I threw this layout together quickly, maybe too quickly, as it needs to be mounted with the back of the PCB facing “forward” to match the pinout of the LM337.

No big deal though, not for me anyway.




GND pin is adjust pin on the LM337.

I’ve got 3 of these and 3 of the positive version on the way from Oshpark.

/Mayday

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TPS7A4700 regulator with LM317 pinout

I sent files for these some time ago, but I think I forgot to post about them on here.

Anyway, here are some renderings from KiCad.




As you can see by the size, it won’t fit in all spots that an LM317 can be used. I opted for heat dissipation over absolute compability. If needed, a heatsink can be used as long as non-conductive TIM (thermal Interface material) is used.

I have used Arctic Silver Lumina thermal epoxy with good results in the past when I needed to attach a heatsink/alu-piece to add cooling. This stuff does bond PERMANENTLY though, so keep that in mind. The 0402 Resistors are 0R and used as Jumpers to GND to set the regulators V-out.

/Mayday

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TDA7293 “base PCB” populating

I’ve been going over the single TDA7293 PCB’s with the DMM to find how to out how to implement the schematic for the enhanced chipamp with output transistors (2SC5200/2SA1943).



The heatsinks I will use, with 90*90mm 24Vdc brushless fans (speed will be controlled using a simple lm317 circuit with adjustable Vout).


The heatsinks are 150*100mm. I use these and the fans to get a somewhat compact amp.

More to come…

/Mayday

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NPN/PNP + TDA7293

I found a thread on diyaudio about adding BJT’s to the TDA7294(originally) chipamp. I found it interesting and it looks like an easy build and from what I read, a solid/stable amp design. I figured it may be good for driving the Dayton 15″ IB woofers in H-baffles that provides the low end of my dipole speakers. I had two heatsinks in my stash, I wasn’t sure they’d handle the dissipation though. I ordered some 24Vdc 90*90mm brushless fans of ebay and used thermal epoxy to fasten some brass standoffs to the heatsinks.

As a base, so to speak, for the amp I got two mono PCB’s for the TDA7293’s. I have not yet gone over them completely with the DMM. Some parts will be omitted, some added outside the boards (on perf boards). I have populated parts that I, by comparing the schematic to DMM testing, know are to be populated.

I’ll use a 500VA 2*24Vac toroidal transformer and 4*10000uF/63V (and rectifiers of course) for the PS.

More to come later.

/Mayday

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Audio-widget

First board nearly done. Finally recieved all but the USB-connector today. All that is left to do is the dual color LED and the USB-connector. And uploading the firmware of course.




/Mayday

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