Kuntal ghosh modokn?

There are a few three channel amps available so you could use a subwoofer. I probably will review one at some point.

They should all be noisy on headphones, and headphones don't need that much power. His design for a special purpose headphone amplifier is spectacular though.

Do you mean the LM1875 board? It is really designed for higher voltage dual supplies.

JohnAudioTech yeah that was the one one was referring to. I'd like to find one that can make decent power around 35 per channel at 13 to 14 volts but it just seems these boards won't come near that.

It is all about the supply voltage. The output voltage can swing only so high before hitting the rail voltage and clip. The best boards can put out around 8 volts rms into a 4 ohm load (16 clean watts b/f clipping). This accounts for some losses in the amp. 35w into 4 ohms requires about 12v rms which translates into over 20 volts for a bridged output or 40v (+20/-20) for a dual supply single ended amp. To get this kind of power from a 14v supply, you'd need a DC supply that would boost the voltage up for the amplifier.

Thats the part that loses me. Hard to find videos on 12 volt amplifier builds. Also bub, I have a car audio shop as you can tell from my channel and I have a ton of old amplifiers I am just going ot be melting down the aluminum from, These amps are not cheap, they range from 150 to 1500.00 per amplifier, all the boards and parts are going to do me no good, would you be intersted in them? No cost bub just shipping and were kinda close, I remeber one of your videos says your in the Dayton Ohio area, Im in the Ashland KY area if you want ot map it out to give you an idea. I know some of the parts in these boards are not cheap. Got some JL audio Slash amplifiers and Memphis Mclass amps, higher end stuff.

This video, although about transformers for audio amps, might explain it better: kzfaq.info/get/bejne/n9GZZdGFyMjPpnU.html Of course, car amps have their own built in DC booster supply so they can achieve very high wattage ratings. Yes, I'd be delighted to have the parts. Thanks for offering them. JohnAudioTech PO BOX 362 Vandalia, OH 45377 Since these won't physically fit in the PO box, let me know when you send them so I'll know to go get them. The post office will hold them for me for a while.

Yes, I'm a fan of the LM1875, but it has the performance to back it up.

I'm not John, but IMHO, the sound quality in LM1875T is so much better than TDA2030A, that I feel it isin't worth it... Also, as they are pin-compatible, I got literally dozens of TDA boards, wich I replaced with LM chips later :-)

I wonder whether LM1875 is even genuine...

@@SianaGearz he tested the short circuit protection on the 1875 chip and it worked tho.

@@damascenoalisson that s true

It all depends on the power he wants. You don't need a lot of power in a practice amp. Anywhere from a half a watt up to 10. You would need a pre amp for these boards as the signal from a guitar is quite small. It is best to use a speaker made for guitars for the best sound.

Good

Most of those amps will work. You might want to add a low pass filter and have an amp just for the subs.

It could work if cells are protected.

I am currently planning a DIY speaker build powered by two packs of 4s 18650`s. I`ll be using two TDA 7297`s and four samsung HT 15W 8ohm speakers. (and two tiny tweeters) I have been running a previous project with the same amp and speakers on 3s LiPo with no issues apart from low input sensitivity, which I am hoping 4s will help reduce a bit. The TDA7297 is fine with 15V, but I have yet to find out how they react to a max of 16.8V, don`t really think I`ll need a step down :/ LVC is a must though :) (btw, condition your cells and check for inconsistencies if you get junkyard batteries)

You can technically do it with the 12 aa batteries but i'd recommend making your life easier and just using two 9V batteries. I used two 9V batteries to test my lm1875s and it worked fine. Do you know how to set up the batteries to create the +,-? or do you need help with that?

mate, I need help with most of this stuff ha, but mmm I followed Johns 'How to use op amps with a single rail power supply' Vid and got the correct reading +,-, but I couldn't get it to make a sound, when applied to lm1875 board. (I may have damaged my LM1875 board some how, before)... And the batteries got so hot, couldn't even touch em... If you can check John's Vid I pasted that would be cool, see if i'm on the right track...... Any other suggestions would be great too. Thanks :)

So johns video that you talked about only shows how to give an output of about +4v and -4v. The LM1875 needs a voltage of at least -8v and +8v to work (which explains why you could not get anything out of the amplifier) I'd recommended trying this set up to power and test the amplifier www.instructables.com/id/Dual-Voltage-Supply-9V-batteries/ (you dont need to make it as fancy as the instructable but set up the batteries as shown and you should be able to power the amplifier properly) As for the batteries, they got hot because they were probably being shorted (which i've done before and know that they get as hot as you described). I don't know if the low voltage and you trying to power the amplifier with it would cause the batteries to get hot. i'd recommend just looking over your wiring just in case. (the two 9v batteries should not get hot btw if you end up trying it. if they do get hot then something is for sure shorting).

Ta, before I check instructables out (soldering a little LM386 guitar amp right now :)...) but, 12 x aa batteries = 18v as do 2 x 9v batteries. Isn't that the same? I went with aa for longer life... Is the a difference?

Theoretically yeah 12 aa batteries = 18v but they all have independent voltages and 1.5V is like brand new and best case scenario. lets say the 12 actually only output 1.3v each. 12x1.3 = 15.4 volts /2 = 7.7 volts +,-. The minimum voltage the lm1875 must have is 16v so your 12 aa setup would not work. the two 9v will only stop powering the amplifier when both 9v go down to 7.9-8v (mine even got down to 7.8v each before it could not power the amplifier any more). but yeah as you can see having two 9v instead of 12 1.5v batteries mean that you have more control over the total voltage.

It is possible to bridge and/or parallel them for more power.

JohnAudioTech hey was just waiting for this ok now can u make a video on the best filter boards and other accessories best speakers in different sizes etc

Can you provide a link to the amp you ordered? Normally a TDA2050 would require a dual polarity supply. It can be setup for single polarity but it is not often done that way with kits.

JohnAudioTech yes I can, it was this m.ebay.it/itm/TDA2050-DC-12-24V-5W-120W-1-Channel-Audio-Power-Amplifier-Board-/291984374564?_trkparms=aid%253D222007%2526algo%253DSIM.MBE%2526ao%253D1%2526asc%253D20150519202400%2526meid%253Dde0d5d567f1c404db39aa2d65990666d%2526pid%253D100408%2526rk%253D7%2526rkt%253D25%2526sd%253D272729726360&_trksid=p2056116.c100408.m2460 the beautiful thing is that the exactly same board is sold among different sellers as 100 watt 5-24 volt class D amp or 12-24 120 watt amp or 30 watt class AB amp..

Aha! It does appear to be setup for single supply. Ignore the silly power rating. The best you can do with 8 ohms at 24 volts is around 6 or 7 clean watts. Forget 4 ohm loads with that thing because the heat sink is too small for anything over 15v. The TDA2050 was discontinued 4 years ago and the one used there is probably a fake. There is not much beyond hooking up the wires to the board, so it could simply be defective, causing the distortion.

JohnAudioTech good bye to my 2.87 USD I paid for this thing XD so there is no hope to get a decent sound supplying it with 20 volt instead of 12 ? Thank you John , great YT channel, fan of you ! Continua così !

Yes those boards are easy to use plus are stereo where the LM1875 board is just single channel (unless you buy a stereo board). Still, I like the 1875 more.

vaser888 Are you using a logarithmic potentiometer?

No, it's a linear potentiometer. It is technically a 25k pot but i put a resistor in parallel between the wiper and an input to make it a 10k pot.

Is the resistor connected between the wiper pin and ground? Are you sure the wiper (normally the center pin) is connected to the amp's input (not the source input side)?

Yes the resistor is connected between the wiper pin and ground. I could have possibly mixed that up but i believe I tried both just in case. I'll set everything up and try it again. if it does not work then ill make a quick video to show you how i have everything wired and set up. Thanks for the help. I really appreciate it.

I replied to your video.

+18 / - 18 volt supply for 4 ohm loads or +22 / -22 volt for 8. It is a dual supply amp meaning a positive and negative voltages are needed (3 wire supply) relative to common ground. Supply should be able to handle 2.5 amps.

JohnAudioTech thanks for replying John. It's a great channel and I'm really interested in these small boards and just how good some of them can sound especially since I'm looking into replacing my Sony amplifier of 20 plus years

@@martinvaldez8745 Why not repair it? What model SOny?

Looking at the video, I agree. This is unusual and I think a fault of the board you have. When done right, class D can be fine but these boards are cheap for a reason. I always find small faults with them, like a hiss noise you hear in my videos. I like linear amps the best but for battery use, I'd try to find a good class D board.

Noted! Tks John!

Yes, those speakers would work. They are small and won't play very loudly. If you want higher volume, you can try a more powerful amp board, or more sensitive speakers.

thankyou for the respond john