I'm not qualified to leave comments 🤣 In college many moons ago I took electronics and computer science, I was tutoring half of both classes, and enjoyed both but I enjoyed computer science a little bit more so I focused on that. My Dad would build the Heathkit kits pretty often, and I built a few kits in my teens, but mostly just followed directions rather than having an understanding. Bought a TS100 digital soldering iron for raspberry pi projects, and stumbled on your channel. Very enlightening!
Finland is still here! ..it's not the quantity but quality, right! :D Just got my (guitar) tube amp build ready for testing, sounds good and no smoke or explosions! :) I'm loving these tube amps, but i have few toroidal transformers waiting to be used for audio, so maybe next build will be digital. I can't be the only one from Finland watching your videos, but a shoutout would be cool! :)
I have to correct something i wrote. I quess i'm so "deep" in this tube stuff, that i thouhgt in my head that opamps and transistors are "digital"! 😁 ..so will stick to analog! I had a reverb spring tank witch is normally been drived with opamps/transistors and is 300ohms imedance vs 8ohms normally used with tubes. I had small audio transformer, and calculated its impedance to be around 300ohms. Went with it and tubes, and they drive it perfectly! I'm so happy how it worked! Now i have tube amp, witch has all the audio tones from different amps that i love, nice cleans and lovely breakout when pushed hard and even raw distortion when i need it. And of cource the reverb, it is delisious!😋 And this thing is builded to 50's tube radio enclosure, for the old radio look. Did not think i could make it sound so good, life surprises sometimes!🙂 -Anssi
Good video. A lot of it was pretty advanced for an amp hobbyist like myself. Had to do some resarch on Toroidal transformers on how to drive this amp. Would love to see a video on filtering with caps. Really like the THD meter.
Thanks Tron! I have a playlist with other videos that might help. Here is one on the transformer: Power Supply Design #3 the Toroidal Transformer ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-FvyXKN4EZj8.html
Excellent project into transformer power losses and power conversion. Answer one problem leads to 10 questions. 👍 Because sometimes with a math or a book or specifications sheet will tell you is the right size transformer (supposedly) in real life is not always delivering you all the power that you thought you were going to get. A capacitor’s video will be excellent. Explaining the difference capacitors purpose built for power supplies and capacitors purpose built for audio.
Excellent channel , hello from Brazil ! About this class D amp, it is interesting one video comparison from AB amplifiers to class D , especifically at high frequencies (tweeters) of a real loudspeaker(crossover included) ... Usually , this is the point of difference (your local loudspeaker hearing, comparison) Thanks for the video...
Power Factor, if it's 1, it's great...anything less than 1 not so desirable. The Real Power is used to drive the load and the Apparent Power (or VA Power) includes the reactive components which don't help Real Power. So if I've got a 1200W equipment rack that is drawing 20A at 120V my apparent power is 2400W and my power factor is a lousy 0.5. (Time to buy a PF corrector!) It's a complex subject but that's my understanding simplified.
Thanks Eddie, One note on toroidal transformers, hum is capacitive not inductive so toroidal xformers are more prone to hum because of the interlacing than a conventional transformer especially with separate input and out coils. We got on this toroidal transformer kick somewhere but I'm not so sure they're better. I have a bunch of old transformers around that have to get used so that's my story and I'm sticking to it! I did some testing but I have to go back and look at the class D I have lying around here somewhere. I definitely like the sound of the Aleph clone even with it's lower power, very tube like to my ears, I can see why people like it - nice soundstage too. If I remember the class D's were very 'antiseptic'. So I guess it's what you like in music, if it's gritty rock than you might go for the class D sound. I remember in the 80's there was this big thing about having all kinds of power because you got better transients or something but then Japan came along and started this single ended low power tube stuff which a lot of people like. Personally I like tubes in preamps but for power I like solid state stuff, they just drive outputs better in my view. I think some of the hybrids with low end SS and high end tubes might be interesting to explore. Thanks again Eddie - lots of fun!
Thank you for this feedback! I think the best thing about a toroid is that the magnetic field is contained and doesn't need the shielding. Regarding the hum, I think varnish is the best method to hold the windings still;) I think at low frequencies, these power transformers can be noisy, but I've had pretty good luck so far and it hasn't been a problem.
@@KissAnalog Thanks Eddie, That's just real estate. Manufacturers can make smaller boxes with toroids , they don't sound any better or reduce S/N any better.
Good Video Eddie, i think we need to get you a SMPS, and then show people what the difference in power & other measurements a SMPS will do to CLass D amplifier. Class D likes a SMPS because it really wants a constant voltage. Single Rail SMPS should be easy to get, shal I get you one ?
just a stupid question related to the next video (maybe). If you knew the THD of the UNI-T signal generator, wouldnt you need to subtract that from the THD measured at the amp's output to only get the amp's THD? looking forward to your next videos, many greetings from Deutschland :)
The experiment was awesome 😎. Still I have a question how you are sure about the power factor of the circuit? Under heavy load the circuit can be capacitive. But on no load considering the transfomer it should be inductive right? Is there something I missed? Any clarification is well appreciated. Thank you for making such detailed videos, it's very informative 🙏
Thanks for the great question! Ok at no load the input capacitors are still there pulling current but little actual load so poor power factor. When load goes up the capacitive portion drops in its ratio to power dissipated by the load so power factor improves.
Thank you! I agree - I don't like the 10% distortion power specs. I think the distortion has to be down about 0.1% to call out the real max power level.
Thanks for the great question! It depends on the size of the capacitor and the load. It could be as high as 34V. That would also be the peak of the voltage, so a cap can charge to that value.
@@KissAnalog thanks, I have another question. What is the meaning of this, the recommended power supply voltage should be 300w AC24V-0-AC24V? One more thing, what's the amperage of this amplifier?
Great question! The AC24V - 0 - AC24V marking means that you need two windings on the transformer output (secondary side) and they each need to be 24 Vrms rated. Then with the two windings they can share a center tap (one terminal in the middle, or connecting the top of the bottom winding with the bottom of the top winding) which is the 0 (or zero/ground reference). The 300 Watt is probably actually 300 VA rating.
If you have DC power instead of AC power, you can use DC as I have shown in other videos. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-kFBz05eeXfQ.html
