I use Tor to get around the china firewall to access there website, which has up-to date ebay links to available product. For ebay links that don’t work, on new product webpages. i think is because they are not available yet 
Tor Browser is very easy to use and is libre software . It’s a web browser with tor built in. a portable app. so unzip and all its stuff is inside its folder, no files spread around your system.
Tor Project | Privacy Online
Tor is free of charge but donations wanted. They deserve the money more than a typical vpn, i would say, easier than a vpn to use. slower than fiber but workable for web browsing (hence donations wanted to fund more network capacity).
Tor Browser is very easy to use
and is libre software . It’s a web browser with tor built in. a portable app. so unzip and all its stuff is inside its folder, no files spread around your system.Tor Project | Privacy Online
Tor is free of charge but donations wanted.
They deserve the money more than a typical vpn, i would say, easier than a vpn to use. slower than fiber but workable for web browsing (hence donations wanted to fund more network capacity).
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i assumed it was china firewall... idk. Looking at the link xlisec posted Website Availability Test - Uptrends
i see its unavailable in the uk which is where my home internet comes from. Hence i needed a proxy like tor.
i see its unavailable in the uk which is where my home internet comes from. Hence i needed a proxy like tor.
Anyone with the 3e-audio tpa3251 board using 24v supply by chance?
I got this board about a month ago as a gift. I finally got around to testing it out tonight. I want to use a 24 volt supply, in particular a Meanwell epp-200-24. When I connect this supply, the amp board's red power-on LED lights up, and none of the fault LEDs light up, but there is no sound.
I also have a 36v supply (Meanwell lrs-350-36). The amp works as expected with this supply.
Unfortunately, the EPP series 24v doesn't seem to have an adjustment pot, as I was thinking maybe if I could bump up the voltage a bit the amp would work. My cheap DMM says it's output is 24.1v.
Anyone have any thoughts?
Thanks!
I got this board about a month ago as a gift. I finally got around to testing it out tonight. I want to use a 24 volt supply, in particular a Meanwell epp-200-24. When I connect this supply, the amp board's red power-on LED lights up, and none of the fault LEDs light up, but there is no sound.
I also have a 36v supply (Meanwell lrs-350-36). The amp works as expected with this supply.
Unfortunately, the EPP series 24v doesn't seem to have an adjustment pot, as I was thinking maybe if I could bump up the voltage a bit the amp would work. My cheap DMM says it's output is 24.1v.
Anyone have any thoughts?
Thanks!
According to the datasheet there is an adjustment, but only +/- 5% so not quite enough according to the comment from 3e.
/U.
Where are you seeing that? I combed the datasheet several times, but am not finding that. Even if it's not enough it's a trivial quick and easy thing to test.
Nice find. Although the 200-27 comes with a lower max current relative to the 200-24, the 300-27 might be better suited (though physically bigger and more expensive).
I have some options I suppose. I also have the TI TPA3251 EVM board. I could use the 24v supply with that. Although I wanted to make a 24v amp that was physically small, and the TI board is pretty big (relative to the 3e board anyway).
Thanks all!
Using 300-27 is unnecessary, because TPA3251 can not handle that much power with that low voltage. See TPA3251 datasheet to graph with label "Output Power vs Supply Voltage".
Ahh, yes, I see that... but I can't find how to actually adjust it!
I looked at that, I guess my question is: when looking at output power in BTL mode, is the reported output power per channel, or total output power coming out of the chip? I assumed it's per channel, meaning I'd have to double what the graph says for running two channels. E.g., page 10, figure 5 says about 100 watts power with 3R load at 27v supply. Would that be 200 watts if running two channels?
See the blue trimpot just to the right of the mounting hole?
/U.
An externally hosted image should be here but it was not working when we last tested it.
/U.
See the blue trimpot just to the right of the mounting hole?
Oh my.
I physically looked that supply over so many times looking for a trimpot like that! And that trimmer isn't too far from the DC output connector, which I closely looked at numerous times---and labeled with a marker---to ensure I had the polarity right. It's even illuminated by the power-on LED! Sigh.
Now, how to fix my dignity?
FWIW, now that I've found the trimpot on the epp-200-24, I was able to get your tpa3251 to turn on at 25.5v. I wanted to see where the actual cutoff was. If I barely adjusted the voltage down, to where my DMM kept jumping back and forth between 25.5 and 25.4, it turned off. So at least mine will technically turn on at 25.5v, but I doubt it's wise to run it so close to the edge like that.
Interestingly enough, the lrs-350-36 can be adjusted down all the way to 28.6v. It's just that the dang thing is so big physically!
Also, thank you for the quick email reply, I appreciate it.
You are right
. Output power in graph is per channel. Graphs "Figure 4." and "Figure 5." on page 10 correspond to values in table in section "7.8 Audio Characteristics (PBTL)" on page 9. BTL configuration have 2 channels so total 200W is OK (27V and THD+N 1% and 3R load).EPP-200-27 it is!
I decided I'd rather get a new power supply than hack the 3e-audio tpa3251 board. So I went ahead and grabbed the MeanWell EPP-200-27. (Technically I'm supposed to install a fan for this PSU if I plan to draw over 140 watts, but I'm quite sure I'm nowhere close to that... need to find my Kill-a-Watt so I can measure this.)
The chassis is the "2205" that is sold by many Chinese sellers on ebay. You can see by all the holes in the bottom I've used it for a number of other projects.
Only thing left is to install a power-on LED on the front.
Sounds great!
I decided I'd rather get a new power supply than hack the 3e-audio tpa3251 board. So I went ahead and grabbed the MeanWell EPP-200-27. (Technically I'm supposed to install a fan for this PSU if I plan to draw over 140 watts, but I'm quite sure I'm nowhere close to that... need to find my Kill-a-Watt so I can measure this.)
The chassis is the "2205" that is sold by many Chinese sellers on ebay. You can see by all the holes in the bottom I've used it for a number of other projects.
Only thing left is to install a power-on LED on the front.
Sounds great!
Attachments
Found my Kill-a-Watt. I've heard people say that the Kill-a-Watt isn't particularly accurate at very low power levels. But I tested it on a few items around the house. A 9W CFL lightbulb measured 9W on the Kill-a-Watt. A 25W incandescent bulb read 23W. So it at least seems to be the right ballpark.
With this 3e-audio tpa3251 amp and Meanwell EPP-200-27 power supply, the Kill-a-Watt reads 4 Watts and 21 VA (0.17 amps on 120V mains). That's both at very quiet levels and also at levels nearing what I consider "loud".
For my particular use-case, I'm clearly not getting anywhere near the amp or PSU's maximums. Definitely don't need a fan!
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