I love your none BS videos, always refreshing, to the point, solid testing, gives me much better confidence to buy an item after watching your vids! Thanks!
Great video! I prefer amps that can use simple power supplies or batteries though (also already assembled, lol). You are much more handy with a soldering iron than me 😁. Keep up the cool vids and get your hands on one of the TPA3116D2 2.1 amps...they are impressive!
@@JohnAudioTech Hey there is a prebuilt version of this amp that costs about half the price from aliexpress,you should check that out.some claim that ic used in that is actually 7294 but falsely advertised as 7293 so we need to change boot strap capacitor pin ( 12 /14 pins).that will be fun to test and check what actually is in it!
I also prefer amplifiers with simple power supply (of course, does it simple to have got in praxis for ex. car acumulator or other batteries) but you have to count with one important thing - you never can reach most low frequencies with simple power supply amplifier's like by dual (symetrical) power supply amplifiers. Maybe till 100 Wats audio power is possible to use single power supply. For higher audio power is recomembed use dual power supply amplifiers.
On your brief testing that must be one of the best chips around at present. Leaves the class D stuff well behind. Almost tempted to get a couple and do some full tests on distortion, frequency response power bandwidth to see how close it gets to a full Hi end amplifier. Interesting if nothing else. PS We would say IT'S THE DOGS BOLLOCKS!! Just a thought, I see many suppliers put 2 or even 3 of these in parallel to produce amazing power output for very little money. Forgetting about the extra power, the current delivery must be amazing. I think I will investigate this arrangement, should! sound better even at normal listening levels.
I'm interested in your thoughts regarding 'Leaves the class D stuff well behind'. How so? A disadvantage with this chip (TD7293( is that it must run via a dual-rail supply and the class-D chips don't. Also from what I see, both this chip and the TPA3116 seem fine in relation to sound quality.
Hello Michael! I know this is an old thread, but i must respond: I originally built this kit, using the supplied components, as well as a kit using the LM3886 ics. They both promptly blew up!! I suspect the chips were poor counterfeits.! I'm glad John had no issues. I subsequently built the same kit, using chips purchased fron Mouser., and they worked fine...no issues. So be warned. BTW, I recently came into possession of a 1980 Sansui G5700 receiver, which was touted as sounding wonderful. I can honestly say I am much more satisfied with the sound of the LM3886 boards. Go figure! Best regards...
Hi, Thanks for this video, I bought 2 of these, but the version that you can use AC directly on them and they work very well.I use 2x30V AC 300VA transformer (measured is actually 32. something so it goes to the max 40V DC after rectifiing).I cool them with 2 AMD coolers (they are cold enough up to 30 percent power to not run the fans) and the fans are powered by a 5V USB adapter once I need more power.Most impressive is that they are dead silent when there is no input.I added a volume control and it started picking up some noise, but you can barely hear it and also is the same noise regardless of the potentiometer position.Anyway nice product and very cheap.
There's another version of this amp with a bridge rectifier on it to accept a 50 - 60 volt center tapped AC input and the issue with the amp is you get small but annoying AC hum in the amp. I've removed the bridge rectifier and I plan on setting it up with a decent filtered DC source and I think this will clean it up like what you have with this amp in this video. I am going to use this in a small bass guitar amp but I don't plan on pushing anymore than 50 or 60 watts RMS into an 8 ohm load with the option to run a second external 8 ohm speaker but still not push it past 60 or 70 watts RMS. I may reply back to this video and let you know if removing the bridge rectifier and setting it up for a split DC voltage cleans up the hum. I did add a steel plate to the bottom of the amp to deal with any grounding issues and it helped some so with a little bit of luck going to a DC input will remove any AC hum.
Finally. A great video of the all mighty TDA7293 chip. Had been looking around for this kinda video from months. Thank you so much for this great video. (Coul you please suggest a good power supply for this amp. Can't use the toroidal Transformer)
That's a lot of power for such a small chip! I wouldn't have thought that could do any more than about 20 before clipping. Be a good subwoofer amp for a home theater sound system.
That's a fantastic rundown of that board, I've got a similar one (hope it's as accurate in spec as yours was). But I've been having a heck of a time finding resources online that explain clearly enough for us newbies on how to properly power up a Center Tapped device like this in real world scenario (as in, not connected to a special bench-top power supply). Could you possibly do a video where you explain where to get, and what kinds of supplies are needed, and how to figure out best transformers for your needs (and things like, what's the minimum size you can use for your project board, how to safely wire it up to mains, any additional parts needed (like what's this stuff about additional power bridge rectifier boards I've seen a bit of) ...etc) Thank you so much.
I bough this same board awhile ago. But the 2 chip version w/ paralleled outputs for 160 watts max power. At the time I think it was about 8 or 9 bucks. shipped.
Hi guys if anyone interested this was a project in the Elektor Electronics Magazine November 1996 page 44 . search American Radio history should find it there . It uses a TDA7294 same chip configuration as there are 94s 95s 96 all different power levels 50 W 80W 120W same pub board. .as for power you need a Toroidal and 10000uf capacitors keep supply leads short . also recommended is the choke, ten turns on a pencil 18 G with Parallel 10R0 resistor and 100nF and 4R7 in series to ground, A Barkhausen circuit to prevent oscillation with certain loads, as they are not just resistive as in the test! inductance and capacitive play a part as well. would like to see some 1Khz testing otherwise good video
I got about 130w into 4,7 ohms with TDA7294 at 72V before clipping. And about 80 or 90w into 9.4 ohms. (only had 4.7 ohm resistors, so with 4 ohms and 8 ohms there would be even more power). At this power i don't think chip will last long.
I bought 2 of these preassembled from aliexpress. I opened the first one and connected it to a 12v-0-12v AC transformer. as soon as I turned the power on the tda7293 chip fried. smoked the thing. I believe the chip was bad from the start. I took a few pictures of the amp before I tried to hook it up, and the TDA7293 had several of the legs that looked burnt.. they were darker than all the others. and guess what, that is the side the fried. I'll try the other one later.. it looks ok,, but who knows with these Chinese sellers. there is a few differences, the board I got, has a rectifier built in.
Greetings from Xenia, I just found your channel and love it. I have a question, is there an American supplier for some of these OP Amp bare pcb's? Looks like everything from China is taking 4-6 weeks. Thanks in advance.
@@JohnAudioTech I bought several preassembled boards, and all of the chips I could find on Mouser/Digikey. I plan to build my own from scratch using some of the chips, I'll most likely copy one of yours. We just moved to the Xenia/Yellow Springs area, it's nice to know there is someone in the area that shares my interest in audio and electronics. Thanks for the great videos.
Hi, i was planning on reusing my transformer, its rated at 29-0-29 vac. Can this board handle that power after rectification and filter caps? Thanks a lot i hope you can reply on this
Hi John. Great video. Just wondering if you have any thoughts on higher voiltage rails. I can get my hands on a couple of transformers (for free) with 34VAC secondary. After rectification, with no load, I should have +/- rails around 46V to 47V. Should be within spec in theory. If I trim the gain back a touch to limit the power output, I figure I'll just have a little more headroom, less chance of clipping/distortion right? Any other disadvantages I need to consider? Look forward to your reply. Love your channel by the way!
Hi there john, i just recieve a couple of this audio amps, a good ebay offer, $3 - 4 dollars each, the board or pcb version is "yx-1536", with a couple of big 50Volts - 2200uF capacitors in it. (maybe a "nichicon" copy but functionals caps), i'm planning to feed this with a 40 Vac or 48 Vac central tap transformer, max 50 Vac. (possibly from a microwave, i built one lately at 36 Vac central tap and it kicks good!) i have a couple of projects with this amps, power a couple of sub woofers; one sony 8" at 6 Ohms (SS-WG490) that i carefully reconstructed, and rescued from a very nasty hands and other handcrafted that i have around ages with no spk in it, but ready for action. it will recieve a 10" s.woofer probably. seeing your video, i'm possibly changing my mind, because of the distorsion factor wich is minimum in this amp... im just thinking... well, what do you think about this amps for power a s.woofer? (max 10" s.woofer at 150-250 Watts) it is efficient or is too much for (i mean quality vs power) ? or is a better option for a full range amp with a decent preamp? i hope to read a perspective from some else who make a similar project and can tell how was the experience too, it will be helpfull, and thanks in advance. thanks for your videos john and sharing your work with all of us, greetings from Colombia.
Could you give more detail regarding the low pass filter input? Specifically, one that would allow speaker level/high level signal input into this little jewel! Thank you for your hard work, time and attention.
If i'm not wrong this is the only chip that you've reviewed that puts out this kind of power (Class AB) with close to no distortion. I had these boards for a while now and I was waiting since a long time for you to review them. The only down side to this chip I can think of is the dual rail supply apart from that I am gonna use it in a Subwoofer. You should really check out NCS (No Copyright Sounds) on TH-cam, That might help you with the Sound test of these amplifier tests you do. Thank you for the Quality Content.
thanks for your videos. would love to see a test on ljm l15d pro. I built 2 amps with them and liked them a lot. but I don't have any instruments for testing.
@ibles bosuok , lho.. njenengan disini juga to Mbah? 👍👍😄😄 Kebetulan saya baru beli kit tda7293,, di spesifikasinya tertulis input AC Dual 12-32 V.. emangnya aman Mbah disuplai CT 32VAC?
I'm so late to the show but DANG! been decades since electronics classes, but you could "probably almost" use a huge bridge rectifier into 110-115v AC ( x .707?) to get 75-80vdc? couple big power caps to help suppress 60hz sliding past the rectifier.. and rock ON! (?)
John, I'm wondering if they sent you authentic chips for the test. I built these boards, and they promptly blew up! I also built a LM3886 kit from AliExpress...same thing. I subsequently built another 3886 amp, using chips from Mouser and they are working great.
John, i would really like if you could provide the link where to buy this amp and all others that you review. I am trying to find this TDA 7293 kit and can't find it... I am a new sub, love your work.
I have a question- 1. What should be the power supply capacity for this amplifier ( Volts and amperage) if powered by unregulated supply like a transformer ? 2. While calculating a power supply for an audio amplifier (voltage and amperage) whether a person should take the maximum Wattage of an audio chip as given on datasheet in consideration or the actual maximum power before Clipping ?
Actual maximum power is the better metric to use, this just makes sense as noise is completely unwanted. I usually use +-25-35VDC for a 50WRMS design accompanied by proper gauge wiring at least 18 in my opinion. Keep in mind transformer secondaries are always 1/sqrt2 V less than VDC rail voltage. I would use at least 10000uF per rail for proper supply filtration.
Hi John, I am interested in buying this kit, but does it come with proper build instructions? I am a complete novice where it comes to electronics, for example I will have no idea where to install the resistors on the board if they have different values. If there are no proper instructions ,do you know where I may purchase a completed unit.
These kits rarely have detailed instructions or anything included at all. The nice thing is the part value is clearly silk screened on the board. You just have to be careful and read the part value carefully before soldering. Also be sure polarized components like capacitors and diodes are in the right way around.
hello friend: very interesting review of that integrated circuit and very well explained, I congratulate you for that good explanation, I also wanted to ask a question, would it be possible to build an amplifier for guitar with that kit? Thank you in advance for your response.
Hey John, just so I'm clear, the total voltage of the chip is the total between the rails and not the voltage per rail? So 50 volts total means 25 volts per rail and NOT 50 volts per rail?
Question John...I thought these amplifiers were AC input thats what the eBay listings say only reason I ask is because you're powering it with your DC power supply. And another question around the 5 minute mark you have 25v by 25v is that considered 50v or 25v together? I'm looking for a transformer.
There might be a version of this for AC supply but would have a bridge rectifier and large capacitor on the board. If it looks exactly like the one I have in the video, it is split DC supply only (could be mislabeled in the listing). A transformer with a 28-0-28 volt, 4 or 5 amp secondary is what you want for 60w @ 8 ohms stereo (two amps used).
JohnAudioTech Thank you for the reply, I knew it was most likely a typo but needed some clarity as the board I ordered is practically the same as yours. I will be using two boards to get stereo. So I'm looking for a 28v multi tap transformer at 4 or 5. and it is at 8 ohms that i'm going with. does that sound right to you? I'd usually ring my dad or grandfather because they're in this field of work but I can't do that right now. thanks again.
Unfortunately, a decent power supply isn't cheap. You could use a switch mode power supply, much cheaper, but they're unreliable, and apparently produce noise. Ideally, you'd want a centre tapped transformer that gives about 24-0-24 vac, and a linear power supply board, available on ebay, with at least 2 capacitors of 10000uf. This would give you about 35vdc at the output, which would be ideal. A little less is ok, just less power as a result. As a suggestion: look for a transformer salvaged fron an old receiver or amplifier. You should be able to find one easily if you look around, as a new one would cost you 60-100 dollars.
John I enjoy learning from your videos. Would it be possible for you to add Frequency Response/Range test to these AMP? The RMS Output and THD is good, but would love to the what range they will play.
Well, who wants to "sit and listen" to music at 100 watts anyway? ST isn't the only manufacturer that rates them that way, and honestly, I don't blame them. A lot of people do just want it as loud as they can get it for a party or their car or PA, and often they don't even notice the distortion. People will even deal with distortion from their laptop speakers just to get it loud enough to hear sometimes.
They are probably up and dancing at those power levels :^) Back when there was National Semiconductor, you'd not see the 10% figure on most of their "hifi" chips. ST always used it to "balloon" the wattage figures on comparable chips.
Looks good. I bought 3 ready made kits for £3.50 each so maybe they're lower spec. Components don't look as fancy and mine is rectified. I am guessing I don't need to Insulate them from the heat sink?? Looked at the data sheet and it said only power transistors needed insulating in one of the schematics. Did you just use paste?
Hi John, People selling these boards are also selling the chips for $2.89. Digikey or Mouser sells the chips for $6.26, or $4.69 if you buy 100. Do you think those are real chips for $2.89? I know the boards tested well with the provided chips, but that's quite a discount!
I can't be 100% sure but they seem authentic based on their performance. The TDA2050 chips I bought from China were always counterfeit because they didn't perform as well as the authentic ones. When I opened the IC package they had much smaller silicon die inside.
John, I received one of these assembled. I have a Hammond 56V CT transformer. I see some kind of monolitic IC on it which I presume is the rectifier bridge. Is there any other external components beside fusing and the transformer that is required to use this amp? I have a large heatsink for it and it is also mounted to the inside of a aluminum chassis with thermal grease with the heatsink mounted on the outside of the chassis. What kind output power does this amp produce into 8 ohm load?
Hi John, greetings from Brazil. How we can specify the transformer current to feed this IC, let's say, on your examples for 32V+32V both 4 and 8Ohms loads?
Hi John, great video as always. Would it be possible for you to upload that test tone of yours with the 1% distortion harmonic to somewhere like filedropper? I know you can make them in audacity but I'm not very confident in using it. Thanks.
I put them up a while ago. You should be able to download them. There are tones with other % levels of reference signal as well. drive.google.com/open?id=0BwoY8sWBPT5odTl3MlFIcmJUSXM Just don't click to play the signal because it is recorded at the highest digital level and might give you a bit of a headache! Let me know if you were successful in downloading them.
Yes you can, all you need is some kind of switch be it rotary or slide or whatever, such that you switch signal in from each source. Or you could manually change wires yourself. Just make sure the device has an output of something above 500mV rms. Lower and you won't get proper gain
The 3886 has lower distortion at high frequencies (probably not a real issue in normal use) and it has a slightly lower power rating although I think National was conservative in rating it.
out of all the DIY kits out there which would you recommend preferably one I can wire right to a AC120V wall outlet and stereo that can also use one of those cheap Bluetooth mp3 decoder boards ?
Hello secret viewer here😅 can i ask is it possible to load 4ohms speaker even i use 32vac? Because i use 8ohms load at this little amp but sometimes i testing 4ohms connection like u said 4ohms load is for 29vac only. What if i don't change the transformer still 32vac then i load 4ohms speaker will it burn ic or explode? Hope you answer me thank u😊 btw i watch your other vidoes😊
You can run it above +/- 29v with a 4 ohm load temporarily but it may activate the current limiting circuitry inside the IC which will result in distortion. I would not do this long term.
hi john, i hope you can point me to the right direction, i am planning to build a six channel amp using these kit/ module and i am wondering how can i wire it to a single output bridge rectifier, can i just parallel the supplies or should i have multiple rails?
You can supply all six from one supply provided there is enough current for all six amplifiers. I'd have a supply per two amplifiers. You could have 1 supply for every amplifier, but that could be expensive.
I have tried the same amplifier and I hear a quite unpleasant hum/white noise passing to the speakers. Do you have any explanation/solution to this? I tried it with 18 volts. Could this be the problem? Thanks.
I think that IC is better than using a pair of 5198/1941 I wonder why they are not using this TDA for an ouput of 60-80w at 4ohms load eg powered 10inch car sub
What wattage would you get with your test setup into 8 ohms @ +/-15v and +/-18v please if it's not too much trouble? I figure it's probably about 12w & 17w respectively but I would like to have those values confirmed if at all possible.
dear john can you tell me how much current and a voltage transformer is it needed for normal (not over driving these ics) working of this ics if I needed a sterio set up with two of this
Hi jhon,Can This thing can be powered by a dual 30v DC or 30 0 30 ac transformer ?I just bought this board but don't know what is cheapest power supply I can buy For this one?
That's a bit high. I'd go 25-0-25 for a 6 or 8 ohm speaker. 20-0-20 for a 4 ohm speaker. This is the transformer voltage only. After rectifying and filtering, the voltage will be higher.
tech plus-reviews and gaming! Are you confusing the ‘-‘ sign with a minus sign? The ac transformer voltage is AC so no polarity. The ac voltages are commonly shown with dash’s (-) between them.
@@KissAnalog thanks for reply.I am asking about DC dual supply. luckily jhon made a video on how to convert single rail DC supply to 24 0 -24 supply that helped me.
Yes, after your source, connect a dual gang potentiometer logarithmic of about 50-250Kohm, smaller if possible depending on your output impedance. Google a picture of potentiometer volume control for a pinout of how to do this
I keep hearing about it, but I can't for the life of me find any information about it: What are those input RF low pass filters people keep talking about?
A low pass filter is simply a resistor and capacitor on the input to eliminate unwanted (ie radio frequencies) from infecting the amp. Examples can be found online.
Some 100 Watt amplifiers used this chip, or its 7294 relative anyway. The older Marshall MG100DFX for example. I have an amp based around this chip for which the manufacturer claims 40 watts into 8 Ohms. I measured it to the onset of clipping at 52 Watts, and the claimed 65 Watts into 4 Ohms was just over 80 Watts :-) The built in 'overdrive/gain' sounds are not that nice, but the cleans are fantastic. Loud as all heck too. Real trouser-flapping audio torque The audible difference between 50 Watts into a 100db/W speaker and 100 Watts into a 97db/W speaker is precisely zero, which is nice. Don't skimp on the transformer and smoothing caps and they make great, loud amps. Something like a Boss ME-80 as a front end into one of these amps in a powered cab and you're good to go.
How many volts and amps power supply do you recommend to come up with the maximum potential of this kit? Apologies I don't know much about electronics but I can pretty much wire kits like this. I am actually planning to use digital preamp simulations (either from my laptop or something like AxeFX) in front of this. Basically all I need is a clean and loud (enough to jam with a band) power amp.
A transformer with 2x32V outputs will do the job. Winding 1 start as one rail, winding 1 end joined to winding 2 start is 0V, winding 2 end is the other rail. Meaty ( really, go meaty :-) ) bridge rectifier package capable of 10~15A and at least 4700uF for each rail. That'll give +/- 45V or there about. A meaty ( see earlier comment ) transformer will give a lower voltage drop under load. Look for a transformer capable of delivering ~10A, ~15A would be better. Up to the point of clipping, they make a great sounding amp, which is why they feature in so many guitar amp power stages. When they clip, they do get a bit harsh. If you've got a heatsink from a Pentium 4, that'll do. They do need quite a large heatsink. Take care, don't blow yourself up and use a fuse!
John , can you explain how the power drawn by tge amp is just 3 watts (+-30 volts 50 milli amps) but output power is around 56 watts for 8 ohms resistance. How this is possible? output power can never be greater than input power.
JohnAudioTech thank you for your reply, I have one more doubt, so when the amp is working it can draw more current right? so for a 100 watt stereo amp we need atleast 200 watt power supply for the amp to function without clipping?
Hi can i ask again😂 what if i use 2pcs tda is it suitable with 1 transformer if yes how many vollt AC transfo is needed and ampere or it's okay if i use 2pcs 32-0-32 transfo for 2pcs tda or separate transpo for each tda? Or 1 transfo for 2pcs tda what do you recommend sir thank😊
I have never been a fan of TDA7293 type amplifiers! they break easily and when you connect several in Parallel that you can buy many of on ebay, they do not like 4 ohms. I have seen many active speakers with this type of amplifier and they break fast.
I love your none BS videos, always refreshing, to the point, solid testing, gives me much better confidence to buy an item after watching your vids! Thanks!
Incredible amplifier! really powerfu, hifi taste and subwoofer. One of best power amps in the market!
I love big-chip AB amps, analog is miniaturized and it's smooth AND DMOS output is my favorite driver transistor. ST make great devices!
Yours are the best and easiest to understand specs/measurements for an old dafty like me. Great stuff John...
Great video! I prefer amps that can use simple power supplies or batteries though (also already assembled, lol). You are much more handy with a soldering iron than me 😁. Keep up the cool vids and get your hands on one of the TPA3116D2 2.1 amps...they are impressive!
I definitely want to get one of those boards in to test.
BidDWiz+ Need more mini amp test. Two different way of testing, you and John should look at using both ways.
@@JohnAudioTech Hey there is a prebuilt version of this amp that costs about half the price from aliexpress,you should check that out.some claim that ic used in that is actually 7294 but falsely advertised as 7293 so we need to change boot strap capacitor pin ( 12 /14 pins).that will be fun to test and check what actually is in it!
Definitely agree about the power supply. An 8 dollar amp is no good if you need an 80 dollar p/s.
I also prefer amplifiers with simple power supply (of course, does it simple to have got in praxis for ex. car acumulator or other batteries) but you have to count with one important thing - you never can reach most low frequencies with simple power supply amplifier's like by dual (symetrical) power supply amplifiers.
Maybe till 100 Wats audio power is possible to use single power supply. For higher audio power is recomembed use dual power supply amplifiers.
On your brief testing that must be one of the best chips around at present. Leaves the class D stuff well behind. Almost tempted to get a couple and do some full tests on distortion, frequency response power bandwidth to see how close it gets to a full Hi end amplifier. Interesting if nothing else. PS We would say IT'S THE DOGS BOLLOCKS!! Just a thought, I see many suppliers put 2 or even 3 of these in parallel to produce amazing power output for very little money. Forgetting about the extra power, the current delivery must be amazing. I think I will investigate this arrangement, should! sound better even at normal listening levels.
I'm interested in your thoughts regarding 'Leaves the class D stuff well behind'.
How so?
A disadvantage with this chip (TD7293( is that it must run via a dual-rail supply and the class-D chips don't.
Also from what I see, both this chip and the TPA3116 seem fine in relation to sound quality.
Hello Michael! I know this is an old thread, but i must respond: I originally built this kit, using the supplied components, as well as a kit using the LM3886 ics. They both promptly blew up!! I suspect the chips were poor counterfeits.! I'm glad John had no issues. I subsequently built the same kit, using chips purchased fron Mouser., and they worked fine...no issues. So be warned. BTW, I recently came into possession of a 1980 Sansui G5700 receiver, which was touted as sounding wonderful. I can honestly say I am much more satisfied with the sound of the LM3886 boards. Go figure! Best regards...
Hi, Thanks for this video, I bought 2 of these, but the version that you can use AC directly on them and they work very well.I use 2x30V AC 300VA transformer (measured is actually 32. something so it goes to the max 40V DC after rectifiing).I cool them with 2 AMD coolers (they are cold enough up to 30 percent power to not run the fans) and the fans are powered by a 5V USB adapter once I need more power.Most impressive is that they are dead silent when there is no input.I added a volume control and it started picking up some noise, but you can barely hear it and also is the same noise regardless of the potentiometer position.Anyway nice product and very cheap.
They are nice little boards. Amazing for the money. Be sure to ground the volume control's casing if it is metal to help shield from noise.
is it safe to connect 2x32VAC from transformer?
There's another version of this amp with a bridge rectifier on it to accept a 50 - 60 volt center tapped AC input and the issue with the amp is you get small but annoying AC hum in the amp. I've removed the bridge rectifier and I plan on setting it up with a decent filtered DC source and I think this will clean it up like what you have with this amp in this video. I am going to use this in a small bass guitar amp but I don't plan on pushing anymore than 50 or 60 watts RMS into an 8 ohm load with the option to run a second external 8 ohm speaker but still not push it past 60 or 70 watts RMS. I may reply back to this video and let you know if removing the bridge rectifier and setting it up for a split DC voltage cleans up the hum. I did add a steel plate to the bottom of the amp to deal with any grounding issues and it helped some so with a little bit of luck going to a DC input will remove any AC hum.
Finally. A great video of the all mighty TDA7293 chip. Had been looking around for this kinda video from months. Thank you so much for this great video. (Coul you please suggest a good power supply for this amp. Can't use the toroidal Transformer)
Why can't use toroidal transformer for this?
That's a lot of power for such a small chip! I wouldn't have thought that could do any more than about 20 before clipping. Be a good subwoofer amp for a home theater sound system.
You are my go to source for testing these cheap chip amps.
There is TDA7294 100 Volts 100 Watts DMOS Audio Amplifier IC, TDA7295 80 Volts 80 Watts DMOS Audio Amplifier IC, TDA7296 70 Volts 60 Watts DMOS Audio Amplifier IC.
This DMOS audio amplifiers is aimed for the home audio market.
Excellent TH-cam video 10 out 10.
That's a fantastic rundown of that board, I've got a similar one (hope it's as accurate in spec as yours was).
But I've been having a heck of a time finding resources online that explain clearly enough for us newbies on how to properly power up a Center Tapped device like this in real world scenario (as in, not connected to a special bench-top power supply).
Could you possibly do a video where you explain where to get, and what kinds of supplies are needed, and how to figure out best transformers for your needs (and things like, what's the minimum size you can use for your project board, how to safely wire it up to mains, any additional parts needed (like what's this stuff about additional power bridge rectifier boards I've seen a bit of) ...etc)
Thank you so much.
I covered some of this in older videos, such as "selecting a transformer for audio amplifiers".
Woow Never thought i see this from integrated amp...Just wow..
You did a great job putting that board together. Great video, thank you.
Thank you for watching!
this chip is used in lots of active subwoofer used in consume eletronics.
the philips sw8000sa is one good example
Thank you so much for this video sir
Now i become more eager to have assemble this kit in addition to my collection 😻
Damn 11 watts per dollar? Not a bad kit right there.
This chip is used in the Marshall MG series amplifier.
Love the PhotonicInduction drop there!
I bough this same board awhile ago. But the 2 chip version w/ paralleled outputs for 160 watts max power. At the time I think it was about 8 or 9 bucks. shipped.
Amazing they can sell them so cheap.
hey John, when you review stuff like this could you please put a link to the guy/ item on ebay thanks mike
Hi guys if anyone interested this was a project in the Elektor Electronics Magazine November 1996 page 44 . search American Radio history should find it there . It uses a TDA7294 same chip configuration as there are 94s 95s 96 all different power levels 50 W 80W 120W same pub board. .as for power you need a Toroidal and 10000uf capacitors keep supply leads short . also recommended is the choke, ten turns on a pencil 18 G with Parallel 10R0 resistor and 100nF and 4R7 in series to ground, A Barkhausen circuit to prevent oscillation with certain loads, as they are not just resistive as in the test! inductance and capacitive play a part as well. would like to see some 1Khz testing otherwise good video
For Elektor, there is a message "Removed by publisher"
The TDA7293 is aimed more for PA amplifier or portable disco amplifier.
Impressive power in to 4 ohms at 92 Watts.
I got about 130w into 4,7 ohms with TDA7294 at 72V before clipping. And about 80 or 90w into 9.4 ohms. (only had 4.7 ohm resistors, so with 4 ohms and 8 ohms there would be even more power). At this power i don't think chip will last long.
I bought 2 of these preassembled from aliexpress. I opened the first one and connected it to a 12v-0-12v AC transformer. as soon as I turned the power on the tda7293 chip fried. smoked the thing. I believe the chip was bad from the start. I took a few pictures of the amp before I tried to hook it up, and the TDA7293 had several of the legs that looked burnt.. they were darker than all the others. and guess what, that is the side the fried. I'll try the other one later.. it looks ok,, but who knows with these Chinese sellers.
there is a few differences, the board I got, has a rectifier built in.
Greetings from Xenia, I just found your channel and love it. I have a question, is there an American supplier for some of these OP Amp bare pcb's? Looks like everything from China is taking 4-6 weeks.
Thanks in advance.
Thanks for watching! I can't say about that board, but there are some distributers in the US that sell on ebay.
@@JohnAudioTech I bought several preassembled boards, and all of the chips I could find on Mouser/Digikey. I plan to build my own from scratch using some of the chips, I'll most likely copy one of yours. We just moved to the Xenia/Yellow Springs area, it's nice to know there is someone in the area that shares my interest in audio and electronics. Thanks for the great videos.
I would totally love to see a video of this amp hooked to your active filter drive a sub woofer. Nice video as usual.
Hi, i was planning on reusing my transformer, its rated at 29-0-29 vac. Can this board handle that power after rectification and filter caps? Thanks a lot i hope you can reply on this
Hi John. Great video. Just wondering if you have any thoughts on higher voiltage rails. I can get my hands on a couple of transformers (for free) with 34VAC secondary. After rectification, with no load, I should have +/- rails around 46V to 47V. Should be within spec in theory. If I trim the gain back a touch to limit the power output, I figure I'll just have a little more headroom, less chance of clipping/distortion right? Any other disadvantages I need to consider? Look forward to your reply.
Love your channel by the way!
I don't feel comfortable powering these little chips at such high rail voltages. I'd stay under 40v for 8 ohms and 28v for 4 ohm loads.
Hi there john, i just recieve a couple of this audio amps, a good ebay offer, $3 - 4 dollars each, the board or pcb version is "yx-1536", with a couple of big 50Volts - 2200uF capacitors in it. (maybe a "nichicon" copy but functionals caps), i'm planning to feed this with a 40 Vac or 48 Vac central tap transformer, max 50 Vac. (possibly from a microwave, i built one lately at 36 Vac central tap and it kicks good!)
i have a couple of projects with this amps, power a couple of sub woofers; one sony 8" at 6 Ohms (SS-WG490) that i carefully reconstructed, and rescued from a very nasty hands and other handcrafted that i have around ages with no spk in it, but ready for action. it will recieve a 10" s.woofer probably.
seeing your video, i'm possibly changing my mind, because of the distorsion factor wich is minimum in this amp... im just thinking... well, what do you think about this amps for power a s.woofer? (max 10" s.woofer at 150-250 Watts) it is efficient or is too much for (i mean quality vs power) ? or is a better option for a full range amp with a decent preamp?
i hope to read a perspective from some else who make a similar project and can tell how was the experience too, it will be helpfull, and thanks in advance.
thanks for your videos john and sharing your work with all of us, greetings from Colombia.
Could you give more detail regarding the low pass filter input? Specifically, one that would allow speaker level/high level signal input into this little jewel!
Thank you for your hard work, time and attention.
If i'm not wrong this is the only chip that you've reviewed that puts out this kind of power (Class AB) with close to no distortion. I had these boards for a while now and I was waiting since a long time for you to review them. The only down side to this chip I can think of is the dual rail supply apart from that I am gonna use it in a Subwoofer. You should really check out NCS (No Copyright Sounds) on TH-cam, That might help you with the Sound test of these amplifier tests you do. Thank you for the Quality Content.
thanks for your videos. would love to see a test on ljm l15d pro. I built 2 amps with them and liked them a lot. but I don't have any instruments for testing.
As long as I know, TDA7293 is only chip-power-amp that can be paralleled.
Cheers from Indonesia
TPA3116D2?
Cocoknya di supply berapa volt si tda ini gan??? Ibles bosuok
No, you can parallel lm3886 also.
@@adhywaw2280 +/- 35 vdc
@ibles bosuok , lho.. njenengan disini juga to Mbah? 👍👍😄😄
Kebetulan saya baru beli kit tda7293,, di spesifikasinya tertulis input AC Dual 12-32 V.. emangnya aman Mbah disuplai CT 32VAC?
Nice job. Thank you! I wish you could have used 3 or 4 different frequencies to test for distortion though.
I'm so late to the show but DANG! been decades since electronics classes, but you could "probably almost" use a huge bridge rectifier into 110-115v AC ( x .707?) to get 75-80vdc?
couple big power caps to help suppress 60hz sliding past the rectifier.. and rock ON! (?)
Fantastic video! Keep it up!
John, I'm wondering if they sent you authentic chips for the test. I built these boards, and they promptly blew up! I also built a LM3886 kit from AliExpress...same thing. I subsequently built another 3886 amp, using chips from Mouser and they are working great.
You never know what you are getting. In my case, I think the chips were authentic given the high output power I measured without any smoke :-)
hi john! fantastic video! I just wanna ask, would a 24 - 0 - 24 V DC supply 4A suffice for the amp power supply requirements? thanks in advance!
Yes, that would be fine. For 8 ohm loads, +/- 35 v rails for more power.
thanks john!
This chip schematics for slave mode and 200W high eff. w/boost transistors. MOS transistors sound great.
John, i would really like if you could provide the link where to buy this amp and all others that you review. I am trying to find this TDA 7293 kit and can't find it... I am a new sub, love your work.
I have a question-
1. What should be the power supply capacity for this amplifier ( Volts and amperage) if powered by unregulated supply like a transformer ?
2. While calculating a power supply for an audio amplifier (voltage and amperage) whether a person should take the maximum Wattage of an audio chip as given on datasheet in consideration or the actual maximum power before Clipping ?
Actual maximum power is the better metric to use, this just makes sense as noise is completely unwanted. I usually use +-25-35VDC for a 50WRMS design accompanied by proper gauge wiring at least 18 in my opinion. Keep in mind transformer secondaries are always 1/sqrt2 V less than VDC rail voltage. I would use at least 10000uF per rail for proper supply filtration.
Very clean power, but I REALLY hate the three power inputs, i can't use it portably with a voltage booster on pure DC power.
I ordered a bord that looks alot like this only with out the IC and its made for the lm3886 which i have some OG lm3886's so i hope it works well
Hi John, I am interested in buying this kit, but does it come with proper build instructions? I am a complete novice where it comes to electronics, for example I will have no idea where to install the resistors on the board if they have different values. If there are no proper instructions ,do you know where I may purchase a completed unit.
These kits rarely have detailed instructions or anything included at all. The nice thing is the part value is clearly silk screened on the board. You just have to be careful and read the part value carefully before soldering. Also be sure polarized components like capacitors and diodes are in the right way around.
Very good reviews
I wana drive two 12Ohm speakers at about 40Watts and one 4Ohm Subwoofer at about 75Watts
Im planning to use 3 of these
hello friend: very interesting review of that integrated circuit and very well explained, I congratulate you for that good explanation, I also wanted to ask a question, would it be possible to build an amplifier for guitar with that kit?
Thank you in advance for your response.
wow, that is a power house!!!, hi John, looks like I'll be getting some of those too.
Hey John, just so I'm clear, the total voltage of the chip is the total between the rails and not the voltage per rail? So 50 volts total means 25 volts per rail and NOT 50 volts per rail?
That is correct.
Have used upto +/- 36.... NEVER MORE...
& with good reliable working in Prof. Audio equipment for 4+ years
Very good test John and very cheap amp but the power supply must be very expensive.....
Yes a 300 VA transformer you'd need to make a power supply for two of these to make a stereo amp would be relatively expensive if bought new.
@@JohnAudioTech This is the same chip in a MG250DFX Marshall guitar amp.
Question John...I thought these amplifiers were AC input thats what the eBay listings say only reason I ask is because you're powering it with your DC power supply. And another question around the 5 minute mark you have 25v by 25v is that considered 50v or 25v together? I'm looking for a transformer.
I'm trying to power it at 50v to get the 60w output and I can't find a transformer. all my searches are coming back with absolutely no returns.
There might be a version of this for AC supply but would have a bridge rectifier and large capacitor on the board. If it looks exactly like the one I have in the video, it is split DC supply only (could be mislabeled in the listing). A transformer with a 28-0-28 volt, 4 or 5 amp secondary is what you want for 60w @ 8 ohms stereo (two amps used).
JohnAudioTech Thank you for the reply, I knew it was most likely a typo but needed some clarity as the board I ordered is practically the same as yours. I will be using two boards to get stereo. So I'm looking for a 28v multi tap transformer at 4 or 5. and it is at 8 ohms that i'm going with. does that sound right to you? I'd usually ring my dad or grandfather because they're in this field of work but I can't do that right now. thanks again.
Just to be clear, it is a 56 volt secondary with center tap. Typically notated as 28-0-28v.
Please link us to a video for making an appropriate power supply.....one that doesn't cost ten times what the amp is worth.
Unfortunately, a decent power supply isn't cheap. You could use a switch mode power supply, much cheaper, but they're unreliable, and apparently produce noise. Ideally, you'd want a centre tapped transformer that gives about 24-0-24 vac, and a linear power supply board, available on ebay, with at least 2 capacitors of 10000uf. This would give you about 35vdc at the output, which would be ideal. A little less is ok, just less power as a result. As a suggestion: look for a transformer salvaged fron an old receiver or amplifier. You should be able to find one easily if you look around, as a new one would cost you 60-100 dollars.
John I enjoy learning from your videos. Would it be possible for you to add Frequency Response/Range test to these AMP? The RMS Output and THD is good, but would love to the what range they will play.
Well, who wants to "sit and listen" to music at 100 watts anyway? ST isn't the only manufacturer that rates them that way, and honestly, I don't blame them. A lot of people do just want it as loud as they can get it for a party or their car or PA, and often they don't even notice the distortion. People will even deal with distortion from their laptop speakers just to get it loud enough to hear sometimes.
They are probably up and dancing at those power levels :^) Back when there was National Semiconductor, you'd not see the 10% figure on most of their "hifi" chips. ST always used it to "balloon" the wattage figures on comparable chips.
I Don`t know any of those people..
10% is closer to "this much power before something breaks". Probably bearable with subwoofers, but makes no sense otherwise.
This magical thing called headroom.....
Rock ON! Who knew you could get a hundred watts for that...I'm in!
Looks good. I bought 3 ready made kits for £3.50 each so maybe they're lower spec. Components don't look as fancy and mine is rectified. I am guessing I don't need to Insulate them from the heat sink?? Looked at the data sheet and it said only power transistors needed insulating in one of the schematics. Did you just use paste?
Hi John, People selling these boards are also selling the chips for $2.89. Digikey or Mouser sells the chips for $6.26, or $4.69 if you buy 100. Do you think those are real chips for $2.89? I know the boards tested well with the provided chips, but that's quite a discount!
I can't be 100% sure but they seem authentic based on their performance. The TDA2050 chips I bought from China were always counterfeit because they didn't perform as well as the authentic ones. When I opened the IC package they had much smaller silicon die inside.
DMOS = Dual (Complimentary) Metal Oxide Semiconductor ...also liked n sub'd! :D
DMOS "D" stands for Depletion Mode (as opposed to enhancement mode, not "diffused"
if you were to use this full time, what would be the best power Transformer to use?
Hey John how about doing some active filters?
John, I received one of these assembled.
I have a Hammond 56V CT transformer.
I see some kind of monolitic IC on it which I presume is the rectifier bridge.
Is there any other external components beside fusing and the transformer that is
required to use this amp?
I have a large heatsink for it and it is also mounted to the inside of a aluminum chassis with thermal grease with the heatsink mounted on the outside of the chassis.
What kind output power does this amp produce into 8 ohm load?
Great review as always.Thanks.
Hi John, greetings from Brazil. How we can specify the transformer current to feed this IC, let's say, on your examples for 32V+32V both 4 and 8Ohms loads?
Hi John, great video as always. Would it be possible for you to upload that test tone of yours with the 1% distortion harmonic to somewhere like filedropper? I know you can make them in audacity but I'm not very confident in using it. Thanks.
I put them up a while ago. You should be able to download them. There are tones with other % levels of reference signal as well.
drive.google.com/open?id=0BwoY8sWBPT5odTl3MlFIcmJUSXM
Just don't click to play the signal because it is recorded at the highest digital level and might give you a bit of a headache! Let me know if you were successful in downloading them.
They downloaded fine and work great, thanks!
thank you very much sir!
I think fake chips work well upto +-32V. You should test at +-40V.
Hey John. Can I use two audio outputs(a Bluetooth and a mic preamplifier output) into one amplifier board input?
Yes you can, all you need is some kind of switch be it rotary or slide or whatever, such that you switch signal in from each source. Or you could manually change wires yourself. Just make sure the device has an output of something above 500mV rms. Lower and you won't get proper gain
Impressive performance - makes me wonder how the TDA7293 compares with the ubiquitous LM3886.
The 3886 has lower distortion at high frequencies (probably not a real issue in normal use) and it has a slightly lower power rating although I think National was conservative in rating it.
7293 more natural
That's a dang impressive chip! I wonder if I got one maybe it could power my big 18 inch pa subwoofer!
Did it work?
So, what are the voltage rating on the polarized capacitors? Is it safe at +40vdc rails?
out of all the DIY kits out there which would you recommend preferably one I can wire right to a AC120V wall outlet and stereo that can also use one of those cheap Bluetooth mp3 decoder boards ?
Can you show me how to power the amp I dont have that machine you have?
Awesome, there is any replacement in 2024 (A/B) not Class D?
Hello secret viewer here😅 can i ask is it possible to load 4ohms speaker even i use 32vac? Because i use 8ohms load at this little amp but sometimes i testing 4ohms connection like u said 4ohms load is for 29vac only. What if i don't change the transformer still 32vac then i load 4ohms speaker will it burn ic or explode? Hope you answer me thank u😊 btw i watch your other vidoes😊
You can run it above +/- 29v with a 4 ohm load temporarily but it may activate the current limiting circuitry inside the IC which will result in distortion. I would not do this long term.
@@JohnAudioTech oh i see thanks for the info sir😉
can l parlel the speaker out for higher power for subwoofer amp
Are you measuring the supply voltage? or the voltage at the speakers?
What is the pilot signal for and how do you generate your test signal?
I plan to do a video on this soon.
hi john, i hope you can point me to the right direction, i am planning to build a six channel amp using these kit/ module and i am wondering how can i wire it to a single output bridge rectifier, can i just parallel the supplies or should i have multiple rails?
You can supply all six from one supply provided there is enough current for all six amplifiers. I'd have a supply per two amplifiers. You could have 1 supply for every amplifier, but that could be expensive.
i highly appreciate the response john, now i can proceed with my sorround sound project
Hi. For the missing RF lowpass on the input, can you use a little toroid core on the input lead, or best stick with an RC network?
Best just to stay with RC network.
I have tried the same amplifier and I hear a quite unpleasant hum/white noise passing to the speakers. Do you have any explanation/solution to this? I tried it with 18 volts. Could this be the problem? Thanks.
John.... I wanted to make one of these.... Can you give me your diagram? With the values of components... Plz... & how much voltage can it take...?
Can u please tell me how much power i could get into 4ohm load at 12-0-12v 6amp transformer??plz reply ..
Oh one other thing, any turn on thumping or is it silent at power on?
I think that IC is better than using a pair of 5198/1941
I wonder why they are not using this TDA for an ouput of 60-80w at 4ohms load eg powered 10inch car sub
What is the least supply voltage / amperage it needs to work?
I believe the data sheet says the device turns on at about +-18, with less than 100mA but this would be a BARE minimum
What wattage would you get with your test setup into 8 ohms @ +/-15v and +/-18v please if it's not too much trouble? I figure it's probably about 12w & 17w respectively but I would like to have those values confirmed if at all possible.
dear john
can you tell me
how much current and a voltage transformer is it needed for normal (not over driving these ics)
working of this ics if I needed a sterio set up with two of this
Hi jhon,Can This thing can be powered by a dual 30v DC or 30 0 30 ac transformer ?I just bought this board but don't know what is cheapest power supply I can buy
For this one?
That's a bit high. I'd go 25-0-25 for a 6 or 8 ohm speaker. 20-0-20 for a 4 ohm speaker. This is the transformer voltage only. After rectifying and filtering, the voltage will be higher.
@@JohnAudioTech thanks a lot for reply.can you please tell me if I can use 24 0 24 instead of 24 0 -24?its hard to find 24 0 -24.
tech plus-reviews and gaming! Are you confusing the ‘-‘ sign with a minus sign? The ac transformer voltage is AC so no polarity. The ac voltages are commonly shown with dash’s (-) between them.
@@KissAnalog thanks for reply.I am asking about DC dual supply. luckily jhon made a video on how to convert single rail DC supply to 24 0 -24 supply that helped me.
Would there be a simple way to add a volume control to that board?
Yes, after your source, connect a dual gang potentiometer logarithmic of about 50-250Kohm, smaller if possible depending on your output impedance. Google a picture of potentiometer volume control for a pinout of how to do this
Hey john I just receive mine and is ac volt it mark on it and it as a bridge rectifire on board
I have two of these modules and plan to install them in the amplifier with +/-65V DC power supply. Will TDA7293 survive this voltage?
no
max +/-40
all the bits!
I keep hearing about it, but I can't for the life of me find any information about it: What are those input RF low pass filters people keep talking about?
A low pass filter is simply a resistor and capacitor on the input to eliminate unwanted (ie radio frequencies) from infecting the amp. Examples can be found online.
Hello. Can this be as loud as a 100w guitar amp? Planning to use this to power a 12inch 8ohm speaker. (Is it possible?)
Some 100 Watt amplifiers used this chip, or its 7294 relative anyway. The older Marshall MG100DFX for example.
I have an amp based around this chip for which the manufacturer claims 40 watts into 8 Ohms. I measured it to the onset of clipping at 52 Watts, and the claimed 65 Watts into 4 Ohms was just over 80 Watts :-)
The built in 'overdrive/gain' sounds are not that nice, but the cleans are fantastic. Loud as all heck too. Real trouser-flapping audio torque
The audible difference between 50 Watts into a 100db/W speaker and 100 Watts into a 97db/W speaker is precisely zero, which is nice.
Don't skimp on the transformer and smoothing caps and they make great, loud amps. Something like a Boss ME-80 as a front end into one of these amps in a powered cab and you're good to go.
How many volts and amps power supply do you recommend to come up with the maximum potential of this kit? Apologies I don't know much about electronics but I can pretty much wire kits like this.
I am actually planning to use digital preamp simulations (either from my laptop or something like AxeFX) in front of this. Basically all I need is a clean and loud (enough to jam with a band) power amp.
A transformer with 2x32V outputs will do the job. Winding 1 start as one rail, winding 1 end joined to winding 2 start is 0V, winding 2 end is the other rail.
Meaty ( really, go meaty :-) ) bridge rectifier package capable of 10~15A and at least 4700uF for each rail. That'll give +/- 45V or there about. A meaty ( see earlier comment ) transformer will give a lower voltage drop under load. Look for a transformer capable of delivering ~10A, ~15A would be better.
Up to the point of clipping, they make a great sounding amp, which is why they feature in so many guitar amp power stages. When they clip, they do get a bit harsh.
If you've got a heatsink from a Pentium 4, that'll do. They do need quite a large heatsink.
Take care, don't blow yourself up and use a fuse!
John , can you explain how the power drawn by tge amp is just 3 watts (+-30 volts 50 milli amps) but output power is around 56 watts for 8 ohms resistance. How this is possible? output power can never be greater than input power.
The 50ma measurement is the amp powered on but idle (no output signal).
JohnAudioTech thank you for your reply, I have one more doubt, so when the amp is working it can draw more current right? so for a 100 watt stereo amp we need atleast 200 watt power supply for the amp to function without clipping?
Hi can i ask again😂 what if i use 2pcs tda is it suitable with 1 transformer if yes how many vollt AC transfo is needed and ampere or it's okay if i use 2pcs 32-0-32 transfo for 2pcs tda or separate transpo for each tda? Or 1 transfo for 2pcs tda what do you recommend sir thank😊
I have never been a fan of TDA7293 type amplifiers! they break easily and when you connect several in Parallel that you can buy many of on ebay, they do not like 4 ohms. I have seen many active speakers with this type of amplifier and they break fast.
So you need two of these for stereo sound and what kind of transformer would be needed?