Hi everyone,
I'm trying to searching for an amplifier than can work well with low power supply like 15V dual rail or single rail and expected to able to output about 10~15W to 4ohm speaker with signal from my laptop.
Since i dont have any audio mosfet (which is hard to obtain in VietNam) so i hope it will use common BJT.
Thank you very muchh.
I'm trying to searching for an amplifier than can work well with low power supply like 15V dual rail or single rail and expected to able to output about 10~15W to 4ohm speaker with signal from my laptop.
Since i dont have any audio mosfet (which is hard to obtain in VietNam) so i hope it will use common BJT.
Thank you very muchh.
Are you wanting to go Class-D, or linear? Tons of Class-D amps will fit that bill and offer much higher power levels but you won't be able to build one yourself easily, so I assume you want to go linear. For that high power level you will have to look for a Bridge Tied Load (BTL) type amplifier. A standard single class-AB amp will be limited about half of that power or less (if you are limited to single rail supply of 15V).
A BTL amplifier uses two amplifier channels, of opposite phase, and the speaker is "bridge tied" between the two outputs, so it doubles your output voltage and quadruples your output power. You can find many different inexpensive BTL amplifier chips, or design your own using standard amplifiers, and use op-amp circuits to provide opposite phase signal to drive them with.
If you can use +/- 15V, achieving 10-15W is no problem. You just need to decide which parts you can get and what style of amplifier circuit you want to build.
A BTL amplifier uses two amplifier channels, of opposite phase, and the speaker is "bridge tied" between the two outputs, so it doubles your output voltage and quadruples your output power. You can find many different inexpensive BTL amplifier chips, or design your own using standard amplifiers, and use op-amp circuits to provide opposite phase signal to drive them with.
If you can use +/- 15V, achieving 10-15W is no problem. You just need to decide which parts you can get and what style of amplifier circuit you want to build.
For such low voltage I wouldn’t even bother with discrete amps but,
You have many chip amplifier options, lm1875, tda2040/50, lm3886, tda7293/4 etc
You have many chip amplifier options, lm1875, tda2040/50, lm3886, tda7293/4 etc
If you are not going to build this amp for learning purposes using discrete transistors then the best advice is to go with the chip amp route. Both LM1875 and TDA2050 are gives around 15 watts to 4 ohm load at +/- 15V or single 30V supply. Choose whichever is available to you easily at your local market.
TDA2030 is good enough and parts from STMicro are still sold to this day, TDA2040 is also good for the usage but it was obsoleted
before the 2030, so dunno if there s still available parts from STMicro, max supply voltage is +-18V (36V single rail) for the TDA2030 and +-22V for the TDA2040 (44V single rail).
before the 2030, so dunno if there s still available parts from STMicro, max supply voltage is +-18V (36V single rail) for the TDA2030 and +-22V for the TDA2040 (44V single rail).
If you’re looking for a chip amp, look at all the great suggestions you’re getting above.
If want to build something discrete from scratch that’s good enough to amplify computer audio, just build one of the countless blameless-style designs. I have one that’s powering my office speakers if you’re interested. Nothing fancy, but more than good enough for computer audio.
If want to build something discrete from scratch that’s good enough to amplify computer audio, just build one of the countless blameless-style designs. I have one that’s powering my office speakers if you’re interested. Nothing fancy, but more than good enough for computer audio.
You have LCSC in Hongkong.
They have a good sortiment and are cheap-
I would not use the old TDA 20xx types because their distortion is clear to hear.
Personally i have an amplifier with 2x17v and expensive desktop speakers at my computer.
It is the place where the music goes 6 hours a day.
Tell us a little more of you and your plans.
Are you an experienced builder or is it your first project?
Do you have multimeter, tone generator or oscilloscope?
Do you want something like 0,0000001% distortion or the simpliest build?
Can you plan a PCB or do you want a tested amplifier kit?
They have a good sortiment and are cheap-
I would not use the old TDA 20xx types because their distortion is clear to hear.
Personally i have an amplifier with 2x17v and expensive desktop speakers at my computer.
It is the place where the music goes 6 hours a day.
Tell us a little more of you and your plans.
Are you an experienced builder or is it your first project?
Do you have multimeter, tone generator or oscilloscope?
Do you want something like 0,0000001% distortion or the simpliest build?
Can you plan a PCB or do you want a tested amplifier kit?
Here is the one, built in many pieces. 14W/4ohm from 2x15V PSU.
Thread:
Sinclair (Project 60) Z-30 amplifier and my DIY mods
It was in 1969 when Sinclair Project 60 kit appeared on the market in UK and it contained Z-30 amplifier modules, advertised as 25W and 50W peak. It also advertised to be “the world's lowest distortion high fidelity amplifier”
and the news and kit description had soon, only few months later, appeared in our local hi-fi magazine Hudba a Zvuk.
Those days I was building my first amplifiers (with Singleton input stage and awkward circuit topology) and I was excited by Sinclair topology! The differential...
It was in 1969 when Sinclair Project 60 kit appeared on the market in UK and it contained Z-30 amplifier modules, advertised as 25W and 50W peak. It also advertised to be “the world's lowest distortion high fidelity amplifier”
and the news and kit description had soon, only few months later, appeared in our local hi-fi magazine Hudba a Zvuk.
Those days I was building my first amplifiers (with Singleton input stage and awkward circuit topology) and I was excited by Sinclair topology! The differential...
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It isn't my first project, i built many before (both discrete and built-in chip amplifier) but they all came to be burnt 😢 (probablyi bought fake ones from china)
I have oscilloscope (4Ch-70Mhz), signal generator (Analog one, 11Mhz bandwidth), fluke 289, agilent E3632A single rail power supply.
I just want a super high frequency response bandwidth (about 200Mhz).
I built and bought tda2030 before, but it's sound isn't quite right to me (i don't know why)
There are a few things i would make different. They wouldn´t make it much but maybe a very little bit better.
I would exchange D1 and D2 for a small npn transistor. That will give you a bit ripple rejaction from negativ rail.
I would exchange D5, D6 and D7 for a yellow or green led. Less to solder and a power on indicator.
But here comes one thing that absolutely matters. I would exchange R12, R15, d8,9,10, 11 to a bias stabilisator with BD 135 or some other TO126 or TO220 transistor mounted on the cooler.
I find the scheme good, following the classic (and good) blameless topology.
I now have a Siglent 1104 and 1032. Much to expensive for me but i closed my eyes and bought them.
It is a dream to make averages to decrease noise or a bode plot in less than a minute.
I would exchange D1 and D2 for a small npn transistor. That will give you a bit ripple rejaction from negativ rail.
I would exchange D5, D6 and D7 for a yellow or green led. Less to solder and a power on indicator.
But here comes one thing that absolutely matters. I would exchange R12, R15, d8,9,10, 11 to a bias stabilisator with BD 135 or some other TO126 or TO220 transistor mounted on the cooler.
I find the scheme good, following the classic (and good) blameless topology.
I now have a Siglent 1104 and 1032. Much to expensive for me but i closed my eyes and bought them.
It is a dream to make averages to decrease noise or a bode plot in less than a minute.
If you are really worried about bandwidth, faster output transistors can be used. At these low voltages, D44H8/D45H8 becomes viable. Although I have built stuff like this with TIP41/42 (from Radio Shack, back in those days), and could find nothing wrong with the sound. I could get the faster pairs to measure better, and those D44’s will give slightly more power. Maybe not with a cascode VAS, though, as that is the limiting factor in output voltage swing here.
Eventually that the gain was too high, STMicro recommend 30dB for low THD, beside your schematic above lack
a resistance in serial with C3/C4, if you omit it the gain, noise and THD will be huge with also a limited bandwith.
Why exactly do you want such high bandwidth? I can appreciate that you want more than 20Khz, because according to Fourier you need several harmonics above the fundamental to reproduce a decent square wave, but at 20Khz your sources will never produce anything but a sinusoid, so maybe 50-60Khz is the highest you ever need to go for a most excellent audible bandwidth. At such high frequencies (and with fast devices) you risk oscillation, and to limit that you will probably have to install bandwidth limitations anyway. I would think low distortion, and flat output vs frequency would be the primary consideration.
Hm... I just hear some humors that the higher the bandwidth, the better the sound will be, so i'm trying to chase for high bandwidth
You should read some good books on basic electronics or on audio amplifier designs (Douglas Self, Philips , etc) or application notes from TI, BB, National Semiconductors. You are trying to achive bandwidth starting from audio band upto VHF band from a +/-15V amp connected to a laptop. Incase you think you have super human capability, visit an ear specialist and get your ears checked, you would be surprised to hear nothing above 20K . Whatever your media source is, no such VHF signal would pass through audio a recording chain
maybe i should buy a pair of D44 and D45 for testing, the pricing seem to be low enough (0.7$ for each piece)