linuxslate
Well-Known Member
Background:
This thread is actually a continuation of a thread posted in the Solid State Forums.
As you will see, I thought it better to continue the thread in this forum.
In that other thread, I reviewed a "2000W" Sunbuck amplifier -- which in actuality wouldn't do anything more than ~11W TRMS, and wouldn't do that without significant distortion.
What am I Trying to Do?:
I am basically trying to make a set of remote speakers for informal outdoor DJ events.
Yes, I could buy some "party speakers", or even professional battery powered speakers, but in addition to the cost, it would mean storing more speakers. I figured that by using a small 12V powered amp, a gell-cell, and speakers I already have, I could make something for far less, and it wouldn't take up additional space.
The Sunbuck amp seemed to fit the bill. It was small, nice looking, cheap, ran on 12 VDC, 110 VAC, or 220 VAC, and included Bluetooth.
Don't get me wrong here - I never thought for even a second that it was 2000W (even peak), but I figured that with modern IC's it should be easy to make a 20 to maybe as much as 40 WPC amp in a chassis that size, and that it would be adequate quality for fill-in sound for an outdoor event.
No such luck.
Perhaps in this case, being deterred would have been a sign of intelligence, but --- well --- I wasn't.
What did I Buy Next?:
My next try is a "Dual 100W Class D Amplifier Module" from Marlin P Jones. MPJA.com
... and before the mods get me... Yes, this post is a bit of a plug for MPJA. I have been ordering from them (very sporadically) for decades, and I credit them with helping me to learn electronics. That's the only relationship I have with them, and I will also admit that the same amp module is available from many other vendors and sites. However, MPJA actually had them in US stock, and the amp module was here in a couple days.
...But I still had a problem... That TDA7498 based class D module won't do anywhere near 100 WPC on 12VDC. Yes, I could stack up several 12VDC gell-cells, or use a 6S Lithium Polymer pack like I use for my Electric Ducted Fan (EDF) model airplanes, but I really wanted just 1 simple, safe gell-cell.
So I used a step-up boost converter.
Results:
Here is the basic setup as it stands now, an I must say that I am impressed.
With the Boost Module set to 28VDC output, it will happily light the 22.8W level on the pictured Realistic APM-500 TRMS watt meter.
In fact, the limit is actually the bench supply I am running from. It's limited to 6 A, and it will actually dim the lights in the room on the bass beats.
With an adequate power supply set to 36 VDC, I think it really could hit the 100 W Led on that meter (each channel). For now, I'm going to leave my boost supply set to 28V, and use the volume know to stay away from the point of distortion.
With the power limited by the input voltage, it provides the hard bass one would expect from a class D amp. Of course it doesn't have the "accuracy" or "presence" of a high end system, but if you judge by either horsepower per dollar, or horsepower for input power, I don't think it can be beat.
What's Next?:
For use as a remote DJ speaker, I am going to put the amp module, the boost module and a Bluetooth audio adapter in some sort of chassis. It will include a coaxial power jack, better speaker terminals, and an input switch (RCA line in or BT). The BT module also contains an MP3 player and an FM radio, so it will be quite a versatile unit.
In fact, I may just scrape the insides of the Sunbuck amp into the trash, and use that chassis. That's how to "fix" it.
This thread is actually a continuation of a thread posted in the Solid State Forums.
As you will see, I thought it better to continue the thread in this forum.
In that other thread, I reviewed a "2000W" Sunbuck amplifier -- which in actuality wouldn't do anything more than ~11W TRMS, and wouldn't do that without significant distortion.
What am I Trying to Do?:
I am basically trying to make a set of remote speakers for informal outdoor DJ events.
Yes, I could buy some "party speakers", or even professional battery powered speakers, but in addition to the cost, it would mean storing more speakers. I figured that by using a small 12V powered amp, a gell-cell, and speakers I already have, I could make something for far less, and it wouldn't take up additional space.
The Sunbuck amp seemed to fit the bill. It was small, nice looking, cheap, ran on 12 VDC, 110 VAC, or 220 VAC, and included Bluetooth.
Don't get me wrong here - I never thought for even a second that it was 2000W (even peak), but I figured that with modern IC's it should be easy to make a 20 to maybe as much as 40 WPC amp in a chassis that size, and that it would be adequate quality for fill-in sound for an outdoor event.
No such luck.
Perhaps in this case, being deterred would have been a sign of intelligence, but --- well --- I wasn't.
What did I Buy Next?:
My next try is a "Dual 100W Class D Amplifier Module" from Marlin P Jones. MPJA.com
... and before the mods get me... Yes, this post is a bit of a plug for MPJA. I have been ordering from them (very sporadically) for decades, and I credit them with helping me to learn electronics. That's the only relationship I have with them, and I will also admit that the same amp module is available from many other vendors and sites. However, MPJA actually had them in US stock, and the amp module was here in a couple days.
...But I still had a problem... That TDA7498 based class D module won't do anywhere near 100 WPC on 12VDC. Yes, I could stack up several 12VDC gell-cells, or use a 6S Lithium Polymer pack like I use for my Electric Ducted Fan (EDF) model airplanes, but I really wanted just 1 simple, safe gell-cell.
So I used a step-up boost converter.
Results:
Here is the basic setup as it stands now, an I must say that I am impressed.
With the Boost Module set to 28VDC output, it will happily light the 22.8W level on the pictured Realistic APM-500 TRMS watt meter.
In fact, the limit is actually the bench supply I am running from. It's limited to 6 A, and it will actually dim the lights in the room on the bass beats.
With an adequate power supply set to 36 VDC, I think it really could hit the 100 W Led on that meter (each channel). For now, I'm going to leave my boost supply set to 28V, and use the volume know to stay away from the point of distortion.
With the power limited by the input voltage, it provides the hard bass one would expect from a class D amp. Of course it doesn't have the "accuracy" or "presence" of a high end system, but if you judge by either horsepower per dollar, or horsepower for input power, I don't think it can be beat.
What's Next?:
For use as a remote DJ speaker, I am going to put the amp module, the boost module and a Bluetooth audio adapter in some sort of chassis. It will include a coaxial power jack, better speaker terminals, and an input switch (RCA line in or BT). The BT module also contains an MP3 player and an FM radio, so it will be quite a versatile unit.
In fact, I may just scrape the insides of the Sunbuck amp into the trash, and use that chassis. That's how to "fix" it.
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