So, pins 27 and 22? Offset compared to what?
i'm running off-the-shelf BTL module (with BTL-marked chip, in mono BTL mode). Maybe different than your setup.
If you have a chance, can you try running both power-rails at 15v?
thx!
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The offset is a negative deviation from half-rail, on both sides.
Your setup is bound to be different from mine as I made my own PCB for mine.
What can be learned by running at 15V? I'm not interested in lowering my power output thank you 🙂
Your setup is bound to be different from mine as I made my own PCB for mine.
What can be learned by running at 15V? I'm not interested in lowering my power output thank you 🙂
In my BTL, I can't detect any reduction in volume or SQ at 15v.
Just less heat.
That seems a major benefit, without any discernible drawback.
There won't be a reduction in volume, unless you're playing to within 6dB of the rails already. In which case reducing the supply will induce clipping.
Great! I'm not getting any clipping, running at very high volume.
So, no drawback that I can hear. Just less heat.
I am getting dropouts at 30 v, but no dropouts at 15v. That's another major benefit. (Again, this is BTL)
Why wouldn't you want that?
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Um, let me see..... because I don't much care about my heat and I'm fulfilling my design goals (SQ, output flexibility) by having an OPT. Which also gives me zero dropouts at 35V.
Here by flexibility I mean ability to cope with a range of speaker impedances (at the very least 4-8ohms) with constant power output and no dropouts.
OPT is shorthand for output transformer.
OPT is shorthand for output transformer.
Somebody plz prove that this tiny OEP50WX2 chip isn't as good as the TDA8932, if not better.
OEP50WX2 50W+50W Dual Stereo Digital Amplifier DC4.5-24V 50-100W D Class | eBay
the only difference i can hear is that the TDA has dropouts at high volume. The OEP doesn't.
OEP50WX2 50W+50W Dual Stereo Digital Amplifier DC4.5-24V 50-100W D Class | eBay
the only difference i can hear is that the TDA has dropouts at high volume. The OEP doesn't.
The secret: The amount of power available to the speaker depends on NOT sending power to heat the amplifier's thermal interface instead.
High efficiency (almost no waste-heat):
32ohms, bridged amplifier
16ohms, unbridged amplifier
Medium efficiency (low waste-heat):
16 ohms, bridged amplifier
8 ohms, unbridged amplifier
Low efficiency (medium waste-heat):
8 ohms, bridged amplifier
4 ohms, unbridged amplifier
Worst efficiency (High Heat may cause dropouts):
4 ohms, bridged amplifier
2 ohms, unbridged amplifier
Problem: More power wasted for heat = less power for the speaker
So, you could make a more efficient setup, Or apply heatsink (to the bottom), Or choose an amplifier with at least double the capacity, such as:
And, there's more to it than just power.
If you have hard-to-drive speakers, but you want to hear a difference, of better linearity, then shop for a Parallel amplifier (not BTL).
A parallel amplifier (not BTL) will have your speakers sounding just like the speaker designers knew something about audio amplifiers, even if they didn't.
Many thx for efficiency notes! Where in your table would we put "parallel"? (you only have bridged)
i'm actually not overheating the TDA8932. I run it at 15v, BTL into 4 ohms. It stays only slightly warm to touch. There are no dropouts. SQ sounds same to me as 24v.
But if i push it to 35v, i get rhythmic dropouts on every audio peak. It's very precise. The same thing happens if i push the OEP50WX2 to it's max power supply. Precise dropouts on peaks.
So, it sounds to me like an over-voltage situation (not dropouts due to overheating).
ah, ok, so that will run cooler eh? Great!
"hard to drive"?
thx
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volts times amps equal watts. Watts make heat somewhere, and it readily observable where that heat goes.
Yes. Speaker designers hardly ever pay attention to audio amplifiers. 4 ohm speakers are hard to drive. 4 ohm speakers are twice as hard to drive for bridged amplifiers. Straining outputs compromise amplifier quality. Doubly strained outputs further compromise amplifier quality. Thus, comparing two bridged amplifiers driving 4 ohm speakers is incredibly uninformative. That's because they're both in pain.
Let's proceed forth to the goal of good audio, which overrides any concern over what parts we need to accomplish that. What is the square footage to fill (metric fine too)? Is the usage mostly TV/Movie or is the usage longer duration music listening? Those two parameters are necessary to determine the path forth. Maybe the 8932 or its bigger brothers can do it. Maybe it will be something different. But, we should do it on purpose.
are there any tips for wiring these for stereo.
i wired mine up split power and ground, split left/right audio and ground to the 2 amps, but get a high pitched wine. it still noticable through the music when close to the speakers.
if i power the 2 amps from 2 power supplies they are silent, and sound great.
i wired mine up split power and ground, split left/right audio and ground to the 2 amps, but get a high pitched wine. it still noticable through the music when close to the speakers.
if i power the 2 amps from 2 power supplies they are silent, and sound great.
They sound great.
Mine are mounted next to one another on a common board with some 6800uF power line decoupling. A single well sized ground wire, a single well sized supply wire and no whining.
Mine are mounted next to one another on a common board with some 6800uF power line decoupling. A single well sized ground wire, a single well sized supply wire and no whining.
You'll most likely want to disconnect the -ve input from the 0V power on one of the modules and connect it to the ground point of the -ve input on the other module. Then use that common 0V ground point as the shield connection to your input RCAs.
I am here assuming you're using one of the el-cheapo TDA8932 modules from Taobao/Aliexpress as you don't say which particular one you're having problems with.
I am here assuming you're using one of the el-cheapo TDA8932 modules from Taobao/Aliexpress as you don't say which particular one you're having problems with.
tried all those. it was y split, then i wired it to like you have said. all the same.
and yes they are the cheap little ebay boards.
and yes they are the cheap little ebay boards.
Problematically, I'm absolutely certain that you're even more clever than that. Not a downvote at all, but merely a suggestion not to throw too many transformers because they do weigh a bit. There is just a slight chance of fix at wrong locale which installs a shortfall that impedes further progress most inconveniently. I would always like to skip Plan B. Yet, I'm really curious what would be Plan C? The thing is that even though transformers are glorious devices, I'm so curious as to what you would use for an alternative.