LM1875, TDA2050 & JAT501 amplifier distortion measurement at 8 ohms 

Measurements start at 11:36 if you don't want to watch me discuss some of the settings in the ARTA software.

that jat501 is looking better each time you test it

That's a really nice amplifier you have designed.

It would be great to take your amp to the next level and do PCB tests !...cheers.

My experiance is: when testing distortion with Arta, the quality of the soundcard matters. It is not so much depending on the soundcard chip, but the design of the card power supply/filtering. Nowadays audio-enthusiasts mostly are using high quality USB soundcards - but PC USB power delivery is always very spiky/nasty. While being OK for normal audio/listening applications, it might be not enough for deep THD measurements. I could improve my card by adding high quality electrolytics and ceramics in the power section (ferrit coils were already present), and 1uf multilayer ceramic blocking caps piggy-backed over every chip found on the soundcard. Perhaps you give it a try - for me it expanded the THD measuring headroom (if I correctly remember it was about 10db to 15db plus). You can easyly test the progress by using line in-out loopback/shortening.

Hello. Hope you can help me? when I connect a stereo potentiometer correctly to an amplifier, there is a short circuit between R. L. on the output when I turn the potentiometer to one side. this is because minus GND. on R. L. is connected. together. Miter stick goes to amplifier and one side is audio input and the other side is GND you ruin the stereo image in the

1:25 The S/N ratio for x effective bits is dB(x) = -20log(2)x, so for 8 bits it's -48.2dB.

You have shown in all videos that while measuring Watts of an amplifier a load should be connected to its output but if an amplifier output is connected to a Woofer of say 4 ohms and also a tweeter in parallel of 8 ohms via a simple capacitor used as crossover, then how much resistance will the amplifier see as load since a multimeter can't measure the tweeter resistance (DC) due to capacitor connected in series and only woofer resistance is measured by it (4 ohms) ?

Hi John. How many watts were the amps running in these tests ?

Sir, I want to ask about Pulse induction, how does it work? I am curious about metal detectors? thank you for your answer!

Here I was just thinking about how the JAT501 amplifier was doing. Get KiCAD and design a board. It's easy peasy lemon squeezy.

I'd like to try the JAT501; did you release a final schematic?

There is Open Source Spectrum display software.

So, I have a stupid little project I wanna do, Bluetooth Senheiser Hd280 Pros. So I need a nice tiny amp I can use with a 3.7v battery. Im planning on using a BK8000L chip for the receiver. Any suggestions? The headphones have a set of 64ohm .5watt drivers.

Hi John I have a question why does my preamp starts humming even though the capacitors is right next to the chip I'm using NE5534

Hi john, could you do a review and technical test of a cheap ebay dac? i have a dirt cheap one and sounds nice, i would love to see the numbers. Greetings from Argentina, i watch all your videos for years now. (this is not my main yt account)

Which attenuator are you using?

niice.

Why don't you put JAT in nice box like you preamp?

Now that's interesting! Unfortunately tda2050 is now obsolete(genuine 2050 available only in europe at the price of 1euro each).

Lor - I looked at the price of 'decent' audio measuring equipment - and theyre not cheap ! $28,300 for an APX555 anyone ?!?