TI TPA3255EVM

I got a Meanwell SE-600-48 PSU for this EVB. I didn't realize the fan runs all the time. I unplugged the fan and ran it hard for two hours, the internal heatsink reached about 45°C.

I bought some thermal switches and put one inline with the fan. I then tucked it in next to the stock over temp cut off switch. This particular switch isn't isolated from the case, it comes with a silicone tube that goes over it, otherwise I would have slid it into the same channel the existing switch is in. On other Meanwell supplies, the fan kicks in at 50°C and off at 40°C, so 45 seemed right, no clue what the hysteresis might be.

Now the fan doesn't run unless you're listening very loud, in which case the fan can't be heard. :D
 

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diyAudio Editor
Joined 2001
Paid Member
Hi N Brock.

That’s just what
I need for my PSU’s
That’s probably an advantage of getting the 600w PSU. Most of the time it’s just loafing, and it probably has a bigger heatsink too.

I suspect the fan will never turn on, but it gives lots of peace of mind having that switch just in case!
 
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All of the above, and then some :) <snip>

From the tpa3250 datasheet's output power vs THD graph, it seems this chip in BTL mode, provides least noise for output of around 7w to 40w for 8 ohm load.

Now how do we run the EVM board in BTL mode, to output in the range of " 7w - 40w " per channel of stereo ? Do we need to limit the supply voltage from 15v to 24v? or is there any other way for maintaining low noise output power?
 
Member
Joined 2008
Paid Member
I got a Meanwell SE-600-48 PSU for this EVB. I didn't realize the fan runs all the time. I unplugged the fan and ran it hard for two hours, the internal heatsink reached about 45°C. <snip>

I also got a MW 600 series to try out. It is frickin' LOUD. I bought a Noctua 60mm fan off amazon to swap in but haven't done it yet. Perfectly happy with my Connexelectronic PSU. Yes, the Connex cost more than the MeanWell but they are so convenient and compact and well made, that it's worth every penny.
 
From the tpa3250 datasheet's output power vs THD graph, it seems this chip in BTL mode, provides least noise for output of around 7w to 40w for 8 ohm load.

Now how do we run the EVM board in BTL mode, to output in the range of " 7w - 40w " per channel of stereo ? Do we need to limit the supply voltage from 15v to 24v? or is there any other way for maintaining low noise output power?

I think the " 7w - 40w " sweet spot you see is the result of using the highest recommended power supply voltage. If you used a 24 volt power supply, the maximum power would be 36 watts into an 8 ohm load. Remember, 1/2 the voltage equals 1/4 power. Your sweet spot would probably be 2w - 10w(?).
Now, if your listening level is low and/or your speakers are very sensitive, this may be fine.
 
Member
Joined 2008
Paid Member
Meanwell SE-600-12 Fan Control - Page 1

This guy has done a nice job by connecting Zalman Fanmate 2 controller in the fan so he can reduce the speed. The issue he says is that the voltage from the fan header is 14.7V but the fan is only rated at 12v, thats why the fan runs loud.

I saw that vid. Even with resistors dropping voltage it is still loud. It's just a crappy fan. I swapped in the noctua and it is close to silent. Well worth the $15, just a few dollars more than the fan controller.
 
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I installed the Noctua 60mm in the MW SE-600-48. The fan was not as loud as the stock fan but it was little louder than I thought. So I installed the noise adapter along with the fan. That has reduced the speed of the fan and also silenced the fan a bit. The noise is more from the airflow than the fan itself. The stock fan itself was louddddd.