Hi. Okay I want to build a simple audio amplifier with minimum components.
Here are two vids on the subject: Diy Heavy Powerful Bass Stereo Amplifier Of 2sc5200 Transistors With Mp3 Bluetooth (100watt Class A) - YouTube
DIY Amplifier simple 2SA1943 and 2SC5200 Transistor Extremely Powerful Using Output Capacitors - YouTube
Any thoughts? Would these be distortion monsters. What changes would you apply. Have you tried anything like this. What would the performance be like. What do you think.
Thanks.
Here are two vids on the subject: Diy Heavy Powerful Bass Stereo Amplifier Of 2sc5200 Transistors With Mp3 Bluetooth (100watt Class A) - YouTube
DIY Amplifier simple 2SA1943 and 2SC5200 Transistor Extremely Powerful Using Output Capacitors - YouTube
Any thoughts? Would these be distortion monsters. What changes would you apply. Have you tried anything like this. What would the performance be like. What do you think.
Thanks.
I didn't bother to watch the 2nd video but the first one is just an output stage, no input differential pair, no VAS, no global NFB, so yeah, its not the best thing out there...
Unless you have experience in building high power amplifiers I would suggest building the fig 2 amplifier you cant get more simple than single rail amplifiers
Project 178 and progress from there to more powerful ones on Rod's site
Project 178 and progress from there to more powerful ones on Rod's site
These Youtube videos are bit too simple. Their "high power" means maybe 10 Watts vs 0.2W. This is fiddling with parts for amusement and not about making a music system that you want to listen to.
If you want "simple", I suggest you buy a module or maybe a chip-amp. There are plenty on Amazon etc but you should read the reviews because some of them are trash.
DIY audio readers would not call "high power" anything that runs on batteries or an external power supply (<100W).
If you want "simple", I suggest you buy a module or maybe a chip-amp. There are plenty on Amazon etc but you should read the reviews because some of them are trash.
DIY audio readers would not call "high power" anything that runs on batteries or an external power supply (<100W).
It takes 3 to 5 watts to drive a class AB output stage to maximum potential. If your signal source has that kind of drive current & voltage, why build a power amp at all? Most listening in houses is 1 -2 watts.
AX6 has about 70 wires, 6 transistors, no center tap required of the power transformer. Can be driven by a 250 kohm source (12AX7 in PAS2) with my modded input stage with a high gain mps8099 input transistor. **** simple, <.1% hd. 70 W for 5 seconds out of my build with mj15003 equivalent output transistor. Retro Amp 50W Single Supply - Page 22 - diyAudio
I had 70 v rail voltage.
djoffe designed a 3 transistor amp but it doesn't have 1/6 the wattage of the ax6. TIP31/32 outputs, 2n3904 input, and 12 v single rail voltage.
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There is always compromise between the demands of simplicity and performance. If you are just fooling around for fun, any example of a proposed and functional design from an electronics teaching text could be used. Looking at your examples though, I guess your real requirements are medium power, quick, easy assembly and likely cheap.
These aren't the best specifications for a project that requires almost as much effort to prepare for, supply power to and fit in a protective case as any other amp. but I guess we have to comply with whatever the user wants.
Sound quality is probably what determines whether yours or anyone's amp remains useful or winds up gathering dust in storage. I draw the line there and the simplest amplifier that sounds satisfying enough to me for extended personal use, is the evergreen 4-transistor JLH'69 amplifier. 10-15W, class A.
There are plenty of imitators, alleged upgrades, kits, threads and interminable arguments running in several threads about it as well as experimental variations and even class AB variations but the basic design does all that's needed for personal use. If you really want to shake the walls, blast your neighbours etc. in relative safety and comfort, you need to go up-market and build something typically big, more complex and expensive.
These aren't the best specifications for a project that requires almost as much effort to prepare for, supply power to and fit in a protective case as any other amp. but I guess we have to comply with whatever the user wants.
Sound quality is probably what determines whether yours or anyone's amp remains useful or winds up gathering dust in storage. I draw the line there and the simplest amplifier that sounds satisfying enough to me for extended personal use, is the evergreen 4-transistor JLH'69 amplifier. 10-15W, class A.
There are plenty of imitators, alleged upgrades, kits, threads and interminable arguments running in several threads about it as well as experimental variations and even class AB variations but the basic design does all that's needed for personal use. If you really want to shake the walls, blast your neighbours etc. in relative safety and comfort, you need to go up-market and build something typically big, more complex and expensive.
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If you want to build a really, really minimal amp - check out some of Nelson Pass' designs.
For an extreme example, the De-Lite consists of a single (depletion) MOSFET and a handful of passive components and achieves pretty decent performance, if a tad, err, inefficient.
http://www.firstwatt.com/pdf/art_delite.pdf.
For an extreme example, the De-Lite consists of a single (depletion) MOSFET and a handful of passive components and achieves pretty decent performance, if a tad, err, inefficient.
http://www.firstwatt.com/pdf/art_delite.pdf.
The second video is a typical three-transistor circuit with errors. Power supply 12 v. Power 2W.
DIY Amplifier simple 2SA1943 and 2SC5200 Transistor Extremely Powerful Using Output Capacitors - YouTube
DIY Amplifier simple 2SA1943 and 2SC5200 Transistor Extremely Powerful Using Output Capacitors - YouTube
Thanks.
I am going to try out the second amplifier video. Can you make any recommendations as to the componenets stated. Should i use those or are there any changes you think i should make, different transistors or diodes, different cap sizes or psu voltages.
I am going to try out the second amplifier video. Can you make any recommendations as to the componenets stated. Should i use those or are there any changes you think i should make, different transistors or diodes, different cap sizes or psu voltages.
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"With errors" indeed. Like, how many mistakes can one make in a schematic involving less than 10 components?
D1 & D2 are the wrong way round.
Q1 collector connects at the wrong end of D2.
Only local feedback is provided, but simulation reckons connecting the feedback resistor at the output would make distortion slightly worse - go figure.
None of the transistor types are still made by their original manufacturers, so what you get may vary.
Here's something like this in slightly fancified. As shown, simulation indicates that it manages almost 1 W / 8 ohm at a 1% THD limit (about 2 W or so max). Output transistors require heatsinking, and silpads or mica washers if mounted on a common heatsink. For stereo, a power supply capable of at least 1 A @ 12 V is required.
An amp like this is better than nothing... but even a single transistor more would give a disproportionate upgrade in performance, as demonstrated by the JLH. We live in a time where silicon is cheap but heatsinking and power supplies are expensive.
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My lm1875 amp motorboated inexorably. Both channels. Buy a PC board from the worlds biggest jail etched to the pattern in the datasheet, or throw it away. PointToPoint can't get parts close enough.
PTP AX6 works great.
PTP AX6 works great.
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Don't Build That, it's a waste of time and money
I could write 10 pages about all the failes, it should forbidden to place such misleading VDO on the internet.. this is just CRAP.
Don't build that, it's a waste of time and money
I could write 10 pages about all the failes, it should forbidden to place such misleading VDO on the internet.. this is just CRAP.
There is simple, there is cheap, and there is something approaching a design some of us would call hifi. Unfortunately the three do not often go together, as circuits evolve to eliminate distortion.
There was a very simple Class A amplifier design in Electronics World (might have been Wireless World, actually, at the time) using three NPN transistors- a small signal input device in classic common emitter mode with RC emitter bias; a bootstrapped collector load and a Darlington connected driver/output pair using a high power resistor load similar to the intended load impedance (i.e. about 10 ohms for an 8 ohm speaker). That is about the simplest I have built and sounded reasonable, but not hifi. It had an efficiency of 10% so for3W output you needed a big heatsink and at least a 25W resistor. But it is a neat little amp.
For higher powers, the best option would be the original four-transistor John Linsley Hood 10W. It's pretty bomb proof using 2N3055/TIP3055 or as you would see from the JLH 10 W thread a number of other devices like MJ15003. That I would say is perhaps the optimum between simplicity and quality.
After that there could be some 30-50W classic Class AB circuits using single ended input transistor, a medium power VAS transistor and a complementary output stage. An often overlooked amplifier from the late 60's is Bailey's 30W design. It had, I think, the best sound of all of the traditional circuits at the time. You can probably find it on the web somewhere. Also in Wireless World, 1968 to be precise. Original transistors no longer available, but works well with BD139/BD140 2N3055/MJ2955 output set at up to 50W (with protection circuit mods).
These all use coupling capacitors and are relatively safe for simple designs.
Most of the simplest circuits you find on the web are actually not good at all.
There was a very simple Class A amplifier design in Electronics World (might have been Wireless World, actually, at the time) using three NPN transistors- a small signal input device in classic common emitter mode with RC emitter bias; a bootstrapped collector load and a Darlington connected driver/output pair using a high power resistor load similar to the intended load impedance (i.e. about 10 ohms for an 8 ohm speaker). That is about the simplest I have built and sounded reasonable, but not hifi. It had an efficiency of 10% so for3W output you needed a big heatsink and at least a 25W resistor. But it is a neat little amp.
For higher powers, the best option would be the original four-transistor John Linsley Hood 10W. It's pretty bomb proof using 2N3055/TIP3055 or as you would see from the JLH 10 W thread a number of other devices like MJ15003. That I would say is perhaps the optimum between simplicity and quality.
After that there could be some 30-50W classic Class AB circuits using single ended input transistor, a medium power VAS transistor and a complementary output stage. An often overlooked amplifier from the late 60's is Bailey's 30W design. It had, I think, the best sound of all of the traditional circuits at the time. You can probably find it on the web somewhere. Also in Wireless World, 1968 to be precise. Original transistors no longer available, but works well with BD139/BD140 2N3055/MJ2955 output set at up to 50W (with protection circuit mods).
These all use coupling capacitors and are relatively safe for simple designs.
Most of the simplest circuits you find on the web are actually not good at all.