Electronics > Beginners
2 power supplies for a amp
vol.2:
Thanks for your input. :)
--- Quote from: mariush on September 26, 2019, 08:40:40 pm ---It's also in the standard configuration of 50w + 50w max, so chances are you're not gonna damage your speakers if you accidentally set the volume to maximum ...
With two of the other (same chip but configured in BTL mode, mono) you may accidentally damage your speakers and you'll also have to do extra DIY (case, add volume control etc etc)
--- End quote ---
I have a passive volume control with four inputs that goes into the power amp. This will be replacing the power amp in a system I've been using for awhile. Yeah, I guess I'd need a case eventually.
--- Quote from: dazz on September 26, 2019, 08:35:43 pm ---having a 100W+100W amp makes no sense, unless you want to blow your speakers.
--- End quote ---
According to the review anyway, this actually maxes out at 50W at 4ohms. Maybe they are only using one channel?If the 141's are 6ohm, then at 19VDC, it should be more like 27W or so? Or is my logic flawed here? Am I crazy?
dazz:
Those figures are pretty close to the spreadsheet graphs at 4 ohms, probably at 0.1% THD or something like that.
At 19V and 4 ohms he's getting about 32W so at 19V and 6 ohms you would get up to 21W if we extrapolate those figures. That's for a single channel.
The way that chip works, you can have it configured in BTL stereo mode so that it's a two channel amp that you can drive at 2 x 4 ohms for a maximum output of 50W + 50W, or PBTL mono that combines both channels in a single one that you can drive at 2 ohms, 100W. But again, I don't see the point in getting PBTL mono boards if you're going to be using 6 ohm speakers since the whole point of PBTL is to lower the load impedance to increase the output power. There are also dual PBTL boards like this one: https://www.ebay.com/itm/TPA3116D2-2x120W-Digital-Power-Amplifier-Board-DIY-Kit-Class-D-Dual-Stereo-Audio/202786866259. That's two TPA3116's in a single board for a maximum of 100W + 100W.
That might be a good option if you want to take advantage of PBTL in the future with 2 ohm speakers, but be careful not to blow your current ones.
vol.2:
I ended up purchasing the stereo version of the TPA3116 board. I'll use a 19VDC laptop supply and it looks like the max I can push with my 6 ohm speakers will be around 25W a side. I am thinking it will be just about right.
I'll post once I get it in the mail and set it up in case anyone who read this thread wants to know what happened.
vol.2:
I got the little stereo version of the TPA3116 board installed and working in my setup.
https://www.ebay.com/itm/TPA3116-TPA3116D2-120W-120W-Dual-Channel-Stereo-Digital-Audio-Amplifier-12V-24V/392072658051?hash=item5b4959fc83:g:5mgAAOSw3ChbMrPQ:sc:USPSFirstClass!20905!US!-1
It was pretty easy to get going; I used a 19V 4.8A laptop supply and I jumped the little gain pots on the board because they looked really cheap and I'll never use them. (I also tied the wiper back to the left side of the pot with a resistor the value of the pot in order to keep the impedance identical)
It sounds good and clean, but it seems to me that my sound now lacks the energy in the mid range that my setup had with the previous power amp. I'll be repairing the old amp and put it back, but for now this will work.
One last question here, in case someone can help me! When I turn the stereo on or off (I use a power strip) there is a pop. Is there some way I can remove this pop by adding some components?
This is the board in question:
Thanks,
fourfathom:
--- Quote from: dazz on September 26, 2019, 08:35:43 pm ---1. Those are 40W speakers, so having a 100W+100W amp makes no sense, unless you want to blow your speakers.
--- End quote ---
It's not uncommon to use an amplifier capable of delivering more power than the speakers can handle. When running a lower-power amp near its limits you can get clipping of any transients which can produce tweeter-destroying amounts of high-frequency power. Obviously trying to run 100W into a 10W speaker will also cause problems, but it's not a bad idea to give yourself some head-room when choosing an amplifier.
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