NOTE: The component at 7:06 is an inrush current limiter, not a resettable fuse.

Finally, someone mentioned the pop free on/off - volume. My main concern with vintage, efficient speakers.

I am new to this channel. Now I realised Cheap Audio Man's review is the cheapest in terms of review quality

Yesterday received my unit of V3, I must admit that I'm really really surprised how good it is. Best results you will get if you use it as a power amp with dedicated preamplifier. Just set the potentiometer to 3 a clock and use a preamplifier for volume regulation. I am using old Yamaha C40 preamplifier and the result is just amazing!!!

@Jeremy_810

Жыл бұрын

Will a preamp then also control the output of the V3's pre-out? I want to use it for a sub but others have stated the sub volume does not change when adjusting the volume knob.

@nikolastojsavljevic5469

Жыл бұрын

@@Jeremy_810 Yes preamplifier would control a pre-out 3.5mm on V3 since it's directly connected with RCA input

Occasionally with these relatively unknown cheapies you get a real happy surprise, very occasionally it is just mind blowing.. The early Tripath amps that were 30 dollars were pretty mind blowing at the time and started class D acceptability trend. This was a great review. Like the Tripath, this IS all about about the chip, the makers followed TI's basic application notes and did a nice job of packaging it. I have to get one I think. The Texas Instruments data sheet shows we have one of those mind blowing things.. The specifications for this chip. I couldn't believe it. I hadn't looked at what was available for a fairly long time and good grief, every parameter was beyond anything I thought possible not so long ago. Texas say the power rails can accept up to 53V for 315W in stereo or 600W mono! The Texas site is a goldmine for engineers. This chip has data and application notes and technical articles - You could be reading for days. Amazing product amazing site, literature and data. Well done TI. Though I am a member..But I think its available to everyone. Remarkable product.

@Cujobob

Жыл бұрын

The biggest problem with cheap Chinese amps is you never know if you’re getting genuine parts. I’ve tossed a few with bad parts that were otherwise well designed. The chips have been really good for a while. The Allo Audio Volt + D uses a chip that’s been around a while (I think 3116, from memory) and it’s really incredible, too. These claim to use really high quality parts (as you know, anything can be labeled as such), so I picked one up just in case they cheap out going forward. They are coming out with a bigger PSU which will be huge in terms of output power. They currently offer two PSUs. Really would have preferred they not integrated the power switch into the pot. In setups I use these for, I generally leave at one volume level.

@KGrasso89

7 ай бұрын

The TI power numbers you mentioned are measured at 10% thd which is unlistenable distortion. Realistically with a 48v PSU with 10a or more you'll get 150w x2 at 4ohms IF the board is designed well which most of them are not even close. I've already tossed 1 and returned another. First board would cut in and out around 50w like the PSU was way too small and it wasn't. 2nd board the chip burnt out after 3 days and it would cut out as well AND didn't sound right at all even at low volumes. Also the noise floor was ridiculously loud! For now I've given up on these 3255 boards until I do more research and feel like I want to possibly waste more money. Lol Meantime I picked up a tda7498e board and it's been excellent! I want a 3255 that's mono to power a passive Sub I have laying around and I'll pair that with the 7498e 2ch board for an incredibly loud and clean 2.1 set-up.

I adore simple designs ! What a beauty!

Amazing how much power one can control through a tiny box!

Thanks John & Snickers....

Thanks John!

Fosi makes great amps I have the BT30D thanks for the review.

Thank you. Looks like I'll pick up a few for around the house.

You are one of the few youtubers that i would listen to when buying a product, due to your truthful reviews. Looks ad sounds like a great amp, guess the lack of a power switch is easily resolved and i like the idea of socketed chips. Reaching for the plastic as I'm writing this comment.

@xaviermontalban717

11 ай бұрын

This guy is legit. He builds amps from scratch

@isoguy.

11 ай бұрын

@@xaviermontalban717 one of the best

@fins59

8 ай бұрын

Building the power switch into the vol control helps to minimize the power on thump.

I just received a SMSL SU-1 over the weekend and paired it with the Fosi V3 with the 48v power supply and it sounds really good. Using optical cable from TV and speakers are a pair of old Andrew Jones designed Pioneer tower speakers.

@richi5831

Жыл бұрын

Thinking about the same set up. How did you connect the SU1 to the V3?

@greatpix

Жыл бұрын

@@richi5831 I had some good 3' RCA cables I've had for years. Thought about picking up some 1' cables so I wouldn't have so much mess behind the units.

@Douglas_Blake_579

11 ай бұрын

I have that setup here, in my living room ... NICE!

Good review.

thanks. I received a TPA 3255 2.1 amp with 32v5a adapter a few hours ago and noticed that the subwoofer sounds to be clipping above 80watts power meter at the wall. Turns out I was correct.

Can’t wait to get mine, I hope Fosi found my email with my shipping address!

Several things here. Yes, so far, the V3 is the best of the budget class D models and Fosi is leading the pack with their developments (subjective, I know. I got the 48V power supply and made sure to swap out the Op Amps with the absolutely superb Sparkos Labs SS3602 discrete Op Amps. The result was a sound level that I hadn't - up to this point - experienced with these budget class D models. In fact, mine now sounded closer to a Class AB amplifier than I had envisioned beforehand. Be careful though, because if you are going to invest in Discrete Op Amps (especially the much larger Sparkos Labs versions), not only will you need a riser, but you will have to slightly bend back some of the ELNA capacitors that border the Op Amp receptacles so that the Op Amp will fit. In the end, you'll enjoy the sound (most of you will). Also, I'd like to point out that the V3 enclosure can get quite warm - actually as warm as one of my hybrid tube amps, which surprised me. I guess that's why they gave it a vented top and bottom (not as a special feature as they advertise, but as a requirement due to the heat).

@Douglas_Blake_579

Жыл бұрын

With apologies to John for flooding his comment section... These op-amp swaps may not be the glory days people think they are. By several accountings about *half of the NE5532 chips currently in use are fakes* ... They are re-branded something-else chips. I have no idea what they started out as... but they are not NE5532s. The real deal shows a diode signature on it's inputs when tested and if it's not there... Now if you have fakes in your amp, the sound quality can suffer. I've seen surprising improvements simply by swapping in known-good NE5532 chips or RC4558 chips... either of which cost about 75 cents each. Of late I've taken to pulling out the NE5532s and replacing them with RC4558s, just to be sure. Beyond that initial "service swap" the more expensive op-amps really don't make any noticeable improvements... and especially not $140 worth. So here's what happens... you get your TPA3255 based amplifier. The sound is okay but nothing to write home about. So you roll in something like the Sparkos or Muse chips, which are quite expensive. The sound gets immediately better and you A) declare victory and B) become an advocate of wildly overpriced chips... *But* the improvement mostly comes from pulling out one or more fake NE5532 chips... not from the super fancy contraptions you shoe horned into the amp. Anyone wanting to chip roll these mini-amps would do well to lay in a stock of RC4558 chips, from a reputable seller, and do that swap first as a means to ensure that any further swaps are, indeed, doing as claimed.

@Douglas_Blake_579

Жыл бұрын

AND ... in case you don't believe me, do a search for "fake ne5532 chips" ... you could get lost for a week reading up about it.

@qddk9545

Жыл бұрын

@@Douglas_Blake_579 It doesn´t matter - they all belongs in the waste 🙂

@Douglas_Blake_579

Жыл бұрын

@@qddk9545 All ... what?

@lung-xl9zg

Жыл бұрын

@@Douglas_Blake_579 their opamps on V3 are not fake...fact check your info again. Also Sparkos are overpriced for what it is on a budget V3, OPA1656 is a much better alternative in term of cost

I bought a Fosi V3 along with a 48V 5A power supply. I'm using the amp right now. The V3 is OK but, as with a lot lower-end Class D amps, I find that listener fatigue sets in early when listening to music. I guess I prefer the warmer tonality of Class AB amps. Btw, the V3 will run quite warm when used with a 48V power supply, compared to the included 32V supply.

I hope you'll get the 48 volt power supply that Fosi Audio sells (you can buy the V3 with either PS) and retest. I did and it does improve results. If I were Fosi I'd only sell it with the better power supply.

Try using 2 lithium drill battery to equal 40v or a 40v drill battery should do some justice for the out put levels. 🎶💯🍻 good work as always

This is an amazing amp and paired with a good preamp like my Vincent Audio starts entering audiophile territory. I'm using the 48 v power supply. It does run warm but so what.

So much talk from everyone on heat my a07 runs 12hrs a day for over a year now and heat is never an issue. The chip in any PC runs very hot. Chips are made to run at a high temp. On the other hand I did get my fosi v3 and it sounds very good and it's very hard to tell the difference between this and the A07 maybe at loud volumes the V3 will be better. Specs and graphs are nice but just use your ears that all that matters. The base power supply gets very loud why would anyone need 400watts from a larger supply

@user-pq1hh7dk3c

Жыл бұрын

По даташиту рабочая температура чипа 70-75 градусов цельсия

@Douglas_Blake_579

11 ай бұрын

_"Chips are made to run at a high temp. "_ No they aren't. Keeping things cool is always the best way to go.

Specs are a little better then the Aiyima a07 but looks basicly the same amp with some upgraded components. Will you hear the difference? I run a tube A03 Aiyima pre amp to warm up the sound, to two 07 amps, one for 8 ohm 90 dB tower speakers on 26v 10A PS, and one for a subwoofer 2 x 4 ohm on a 48v (sett to 44v) 10A PS. Works great. Letts see the reviews about the V3, looks a great amp.

It comes alive with a 40v 10ah lithium battery bank

@ryanmccann2539

Жыл бұрын

What sort of dc barrel adapter do you use?

RE: PSU: A Philippine guy who has worked a lot with TPA3255 found out that the optimal supply voltage for TPS3255 is around 43v. Voltages above that generates a lot of heat. I suppose that is correct. I had a Fosi BT20A Pro with a 48v PSU, and that got very hot. The BT20A have 3 design flaws: Bad heat design, tone controls, and 2 SMD mounted LM5532 to give the chip a balanced input signal, the last 2 took all the details out of the amp. I had mine for just one week.

@Douglas_Blake_579

Жыл бұрын

With the fully enclosed casing I've been recommending that people stick with 36 volts at 6 amps... they run very nicely with that. As far as I know the problems with the 5532 chips are confined to the 8 pin DIP packages.

@qddk9545

Жыл бұрын

@@Douglas_Blake_579 No, the signal runs through the 2 SMD mounted ones, to be converted to a balanced signal to feed the TPA chip. And 5532s will ruin the signal no matter were they sits. Most TPA designs just use a direct unbalanced connection to the TPA chip, and that sounds much better than using a 5532 based balanced solution. The new V3 uses the unbalanced solution. So that is why I sold the BT20A and ordered a V3. They BT20A is really bad sounding, mellow without any detail.

@Douglas_Blake_579

Жыл бұрын

@@qddk9545 Based on board photos there are only 2 op-amp chips used, both in sockets and they will be the phase splitters, for the BTL outputs, probably operating at unity gain. The TPA3255 is actually 4 independent power amplifiers. The BTL configuration requires you to drive 2 amplifiers 180 degrees out of phase to form each channel. In that case you have to provide your own phase splitters or feed it a balanced input signal (that is already out of phase). There is no single ended BTL option on the chip itself. The extra chips in the BT20a were for the tone controls and line-out driver.

With a fixed output filter you have to choose which impedance to target, 2, 4, 8 or 16 ohms. If the actual impedance doesn't match what the output filter was designed for then you can get some extreme peaks in the high frequencies.

@Douglas_Blake_579

Жыл бұрын

Speakers are not a uniform impedance device. Many designs have dips in impedance well below 4 ohms, others have rises way above 16, sometimes in the same crossover design. Most class-D designers have settled on 6 ohms as an average and design for that.

@10100rsn

Жыл бұрын

@@Douglas_Blake_579 yeah, but his measurements are being done with a resister dummy load. It is why the peaks appear at predictable locations but I wonder what it would look like with an actual speaker as a load...

@Douglas_Blake_579

Жыл бұрын

@@10100rsn Hard to say ... probably about the same... and keep in mind it was way beyond audible frequencies where there wouldn't be any content to begin with.

@birdyflying4240

Жыл бұрын

@@10100rsn Good observation, will depend but you don't know before you buy it.. my speakers have a magnetostat tweeter and a liniar load. No peaks to notice. Better take a look before at the impedance curve of your speaker.

@ 7:07 - this is not a fuse. It is a Negative Temperature Coefficient Thermistor.

@JohnAudioTech

Жыл бұрын

Yes, It is an inrush limiter.

Your amp can only be as good as your power supply. You tested the upper limit of your power supply, not the amp.

Would you be able to provide or share the test results when utilizing a 48V 5Amp configuration? That specific data is of primary interest to many who buy that adapter for an upcharge!

I noticed (online) that the AC cord on the power supply on this amp has no ground prong. Would it be possible/easy to find a replacement for this AC cord that has the ground prong present?

Does the Fosi v3 has better components under the shell than their upgraded versions viz BT20A Pro and BT30D Pro ?

Thanks for the complete test but im skeptical for fosi audio because the bt20 i have its the worst amp i ever heard and i listen music a lot even with a good dac the sound was muddy fool off distortion. Maybe because i test every amp with very good speakers. I will rather wait a while for this v3 amp. Appreciate the test keep up the good work.

@fins59

8 ай бұрын

" even with a good dac the sound was muddy fool off distortion" you say, well you certainly sound like you know what you're talking about.

I like my v3, wish it had a 12 volt trigger

There is some heat when using 48V power, will this affect the life or performance of the product?

@ 6:47, looks like the chokes are Sagami 7G14D/J, 10µH. @ 11:44, the amp's filter is tuned for 4Ω. So for 8Ω load, it will be under-damped for high frequencies. Apart, wish you can test the power output with the maximum supply voltage for this amp (50-53V). Also, have you noticed the temperature of amp's case at the end of the power test? If yes, is it at acceptable level?

@danielh12345

Жыл бұрын

There's a video online where someone tests that, look for fosi v3 vs aiyima a07

@franklekwan5860

Жыл бұрын

@@danielh12345 Yes, I noticed that there are other test videos on V3 are releasing to YT (partly of the effort of the Fosi marketing team). However, different KZreadr has different style, and there suite of tests are different as well. Some has sophisticated test equipment and others have different insights. I would still like to see John to test this amp to it's limit, using John's unique approach. 😀

@user-pq1hh7dk3c

Жыл бұрын

В разных ревизиях плат ( за март и за апрель) ,- разные версии дросселей. С разными характеристиками по даташиту дросселей. Почему?

@Douglas_Blake_579

Жыл бұрын

@@danielh12345 Is this the one you mean? ... kzread.info/dash/bejne/qKCf1bKMmprUY6w.html

@Douglas_Blake_579

Жыл бұрын

@@user-pq1hh7dk3c Product development. It is extremely rare that the initial 'white paper" design is the one that reaches the end user market. Things are tested, revised and improved many times in the prototyping phase.

7:55 I wonder how much of an impact spreading some thermal compound on that metal slab would make... I will do that with mine and see how it goes

@andymouse

Жыл бұрын

Let us Know please!

@Douglas_Blake_579

Жыл бұрын

That could get messy ... the heat spreader is exposed through the lower cooling holes. But yes, it would be an interesting experiment.

@user-pq1hh7dk3c

Жыл бұрын

Нанесение пасты улучшит теплоотвод. Что и сделано в аналогичном усилителе BRU5 Wondom

I have some 16ohm 75w rms speakers I wish to use with an amp like this, do you know what sort of undistorted output power I would be able to get out of this setup?

@JohnAudioTech

Жыл бұрын

Roughly 1/2 the power measured at 8 ohms. Best to use a higher voltage supply (40 to 48v) if you need higher power.

Wouldn't it been a good idea if an 'Optical Toslink' connections too existed along with the RCA Line in ?

@cherryy7609

7 ай бұрын

Maybe they’ll do one with an internal DAC included. It’d probably have optical/coax and USB digital inputs, with switching for analogue inputs, but the question is whether the final product would still be great value once it gets the extra features.

Any chance youd measure it with Sparkos op amps?

I wish it had normal RCA pre out and not 3.5 mm.

John I am not sure how to reach you but you seem to have some very sharp people reading and responding. My question has nothing to do with this amp. Its more to do with building generic class a and class a/b amps. I like the PCBs with two halfs on one board like the Rod Elliot P3A. As a hobby I pickup these PCBs and then build them as per schematic. Then I start to make changes and see if that change improved the music or not. I get some friends over and we do blind tests to see if they can spot the difference between sides. And then we see which side is more popular in terms of votes. The only gear I own is a 100 Mhz scope 2 channel. How can I use this analyze and pick which mod or part improved the amp and which did not. My scope has a FFT function but its very basic. It does not give me any numbers. One idea I was thinking off was put one channel on input and the other on output. Then do a Ch1-Ch2 and see which side gives me less variation in signal. Am looking for ideas that will help me speed up my testing. My objective is to have the best amplification while still being true to the input signal. I know your super busy with the move but think about how much this would help us DIY guys who are constantly tinkering. Right now P3A says use BC546 I want to test BC547, 549c, 560 and see what changes. Thing is Im not even sure what to monitor and how.

Would the output wattage increase at all by using a 48v 10a supply?

@birdyflying4240

Жыл бұрын

about 2 x 150 watt 8 ohm

@Douglas_Blake_579

11 ай бұрын

That's a bit complex... The chip itself has a fixed gain of 21.5db (12x by voltage) so, for a fixed position of volume control, with the same source, the output power and thus the loudness will always be the same. What you gain with the higher voltage supply is more headroom for large transients like gunshots in movies or drum crashes in music. Typical max power on 48 volts is about 100watts on 8 ohms, 200 watts on 4 ohms, with less than 0.1% distortion.

I see a potential problem with this amplifier, it's flat and wide frequency response is fantastic but herein lies the problem... Eventually someone is going to play a piece of music with a lot of heavy bass content and this amplifier is going to try and give you everything you asked for all the way down to 10Hz if not lower and the supply capacitors fitted to this amplifier are not going to cut it! I think that it would have been interesting to scope the supply voltage for sag and also at the speaker output for clipping at the same time... I know that you have some great bass test tones to complete the test... I expect to see it become quickly apparent that tone controls would benefit this amplifier, currently you don't have any means to cut back on the bass when you want to play it a bit louder... I have run into this problem before, I had the sound as I wanted it but I could only manage to get to a certain amount of volume before the amplifier would cut out and need a restart... But by having a bass control, I realised that if I cut back on the bass, I could get it to play louder and remain stable... Those supply capacitors are rated for 63V at 2200μf, they could have been a bit larger in capacity... The voltage rating suggests that you can use the amplifier at a decent amount of input voltage... I think that I saw up to 48v... That would change the output power of this amplifier, having the extra voltage might mean that the amplifier won't need to consume more current for the lack of voltage at the level of volume you require... So yeah, that bass test I mentioned above would make a great video.... It's a nice amplifier no doubt and at lower levels it's going to put some depth into the music especially if your speakers can punch that low, you might even have no need for a subwoofer... I really like this amplifier from what I have seen thus far but I would definitely have to check and see if the supply can keep up with the current demand...

@Douglas_Blake_579

11 ай бұрын

This is why these mini-amps all use switch mode power supplies. Your analysis would be correct for the 120hz refresh rates on linear supplies. There's no way 2200uf will hold the supply up at 100 watt levels in that case. However; with a SMPS driving the show, the charge in those 2200uf caps, as well as the supplies internal caps, are refreshed about 30,000 times a second so they don't have to prop things up for very long at all.

its a nice amp but the thing is with this amp is $69 with 1 input.. You can get a 200W Sony strdh190 or a yamaha a-s301 for $99 to $150

I’m using the better 48 volt 5amp power supply. Can you give me an estimation of power outputs with that unit?

@JohnAudioTech

Жыл бұрын

Probably around 125 watts into 8 ohms.

@christophedecavalla2941

Жыл бұрын

@@JohnAudioTech nice. Thanks

I think a budget class A/B amp is still better than any class D amp that I have heard.

@Douglas_Blake_579

Жыл бұрын

LOL ... Take these new TPA3255 amps and blind test them against an AB amplifier making sure they are precisely level matched. and I'll bet you 3 manhole covers (already placed on your street for easy collection) you can't tell them apart.

@lio1234234

Жыл бұрын

​@@Douglas_Blake_579many ABs are worse than these too 😂

@Douglas_Blake_579

Жыл бұрын

@@lio1234234 yep, some are ... The whole "The D in Class D stands for Dump" thing is way off base.

@HeyYall398

11 ай бұрын

​@@Douglas_Blake_579Moving beyond basic sound tests, have you evaluated the distortion and clipping thresholds on 4 ohm speakers?

@Douglas_Blake_579

11 ай бұрын

@@HeyYall398 I've been evaluating a number of TPA3255 based "Chi-Amps" of late. We ca'nt post images or links here, so the best answer I can give you is to look at the "TPA3255 Spec Sheet" (do a search). The chip's performance is accurately described there and, except for minor implementation variations my measurements match the specs quite nicely. The thing I have a problem with is very low levels of distortion... my current test rig bottoms out at 0.1% ... so I keep getting 0 as a result (which is a good thing).

i received mine also... I'm not that blown away!... 😂

I hate tone controls. Well not really, bass boost for low volume listing is okay, but thats it 😊

Hi, Can it be used as a mono block (PBTL)? Thanks!

@jimfarrell4635

Жыл бұрын

The Internet says it can't, but that is pretty much top of everyone's wish list for the V4 if they make one.

Hey anyone know what the input impedance is on this amp? would highly appreciate an answer!

@Douglas_Blake_579

11 ай бұрын

20k ohms

At 4 ohms. Your curve has a lot of zigzags inside the curve. Which was not there when you were testing 8 ohms. Can you explain that

@Douglas_Blake_579

11 ай бұрын

That is PWM leakage on the 4ohm frequency response test. But you need to understand that the PWM pulses are in phase, across the BTL bridge, so while they will show on the scope when measuring one side of the bridge, they do not produce any output. That is... "you can see 'em but you won't hear 'em" If, by chance you are referring to the little bit of fuzz on peaks at clipping, those are narrow pulses inserted into the PWM carrier to prevent output transistor lockup. Like the leakage signal, these are also in phase across the bridge and do not produce any output.

Notice for not technical viewers especially the ones not familiar with electronics: This review up to today( 29 July 2023) is the only competent technical review of the amp. The other reviews unfortunately are made by people with no engineering background whatsoever, youtubers who don't know the difference between subjective feelings and actual measurements and facts.

I was interested in the V2 that was doing the rounds recently. Regarding the heat spreader, I would think be better to mount on top side, under vents?

@Douglas_Blake_579

Жыл бұрын

Agreed .... I wonder if it's possible to install the front face upside down and just flip it over?

@andymouse

Жыл бұрын

@@Douglas_Blake_579 Nope it has a pad for the pogo pin.

@Douglas_Blake_579

Жыл бұрын

@@andymouse Good point ... But it would have been better if the hot spot was on top. I suppose you could add your own rubber feet and just turn it upside down...

@andymouse

Жыл бұрын

@@Douglas_Blake_579 Yep ! thats what I would do.

@Douglas_Blake_579

Жыл бұрын

@@andymouse Thing is, the larger finned heatsinks on the TB10d would have been totally adequate if they'd added a screened opening in the case directly above it.

Thanks John ... Fosi has been bugging me to test their stuff ... I think you just did it for me. For me this amp has two deal breakers in it ... 1) The power switch on the volume control was a mistake. It means you can not use the amp at fixed gain behind a pre-amp or any other device that has it's own volume controls. You would have to reset the gain every time your turned it on. 2) The line out is coupled to the inputs at fixed level making it useless to control a subwoofer. Also... I suggest you test those NE5532 chips and see if they're fakes... if they are replace them with RC4558 chips (about 75 cents each). Aside from that it looks very impressive.

@JohnAudioTech

Жыл бұрын

Ah! that's one thing I forgot to include. I like to have a separate power switch. Less wear on the volume control as well.

@Douglas_Blake_579

Жыл бұрын

@@JohnAudioTech Yep. I've been watching this mini-amp market for a few years now and it strikes me like they must have someone on staff to add one dumb decision to each design. Really... amid a whole swarm of good ideas, they did this??

@user-pq1hh7dk3c

Жыл бұрын

@@Douglas_Blake_579се покупатели отметили эти 2 вышеуказанных недостатка. Отсутствие отдельного включения питания и фиксированный линейный выход! Также присутствуют разные ревизии плат и отдельных элементов.

@Douglas_Blake_579

Жыл бұрын

@@user-pq1hh7dk3c No surprise there. These are pretty obviously bad decisions on Fosi's part.

@armandosinger

10 ай бұрын

@@JohnAudioTechis the power switch in the volume knob really a deal breaker? I’d prefer a separate switch, too, but can’t you solve this by just using a power strip with a switch? Also, if you are using multiple of these in an active speaker design, you can turn them all off with one switch, rather than hitting power on 6-8 of these units for a 3 or 4 way system, respectively.

В разных видео Fosi audio v3 наблюдаются разные версии, ревизии плат. Например ранние за март месяц, а здесь более новая за апрель месяц. Также разные версии катушек индуктивности наблюдаются. Почему так?

@Douglas_Blake_579

Жыл бұрын

Product developement.

What was wrong with your previous method of showing distortion. It did have the advantage of being visual and simple.

@JohnAudioTech

Жыл бұрын

I get harmonics showing when there should be none. I need to sort that out.

@Douglas_Blake_579

Жыл бұрын

@@JohnAudioTech Are you sure it's not the sample frequency of you scope beating against leakage from the PWM pulse chain? If your scope has a low pass filter try setting it at about 100khz and see if the problem persists.

@JohnAudioTech

Жыл бұрын

@@Douglas_Blake_579 I'm getting a notch from that too, but also getting other harmonics of the fundamental.

@Douglas_Blake_579

Жыл бұрын

@@JohnAudioTech That's odd ... On my Hantek, setting up averaging and a low pass filter tames it down pretty nicely. I'm not familiar with the Siglent menus, so I'm kind of at a loss.

Using Old fashion measuring techniques.

What amplifier chip does it use?

@antibrevity

Жыл бұрын

TPA3255

@gillanland

Жыл бұрын

@@antibrevity Thank you!

@Douglas_Blake_579

Жыл бұрын

@@gillanland You're welcome... Good chip, look up the spec sheet.

To really test the max power output, it would take about 3 (or even 4 for 48VDC) large 12V lead acid batteries in series. How about 3 12V, fully charged auto batteries.

@Douglas_Blake_579

Жыл бұрын

OR ... a standard industrial 48v 10amp supply.

i Have 2 different TPA3255 Based Amps and the bass on these are non-existent , how is it when lessening to bass on that one? Anything......

@Douglas_Blake_579

Жыл бұрын

Are they ampliers or boards ... if they're boards you may need to tamper with the input capacitors and add a pre-amp stage to get them going. As John commented in the video a lot of these china-amps were designed to be -3db at 20hz, which just kills the bass. The low frequency roll off should be -3db at about 3 or 4 hz, for a proper amplifier.

@Douglas_Blake_579

Жыл бұрын

An afterthought, if I may ... Check that your speakers are hooked up in phase. I've done that one to myself more than once....

@StarDollar

Жыл бұрын

@@Douglas_Blake_579 Everything checked, two different models, same bass response, direct comparisons ageist solid-state amplifiers. They are not even competing.

@StarDollar

Жыл бұрын

@@Douglas_Blake_579 Boards. one from an DIY Audio Designer/seller and one from 3E audio; 3E AUDIO. An pre amp was used.

@Douglas_Blake_579

Жыл бұрын

@@StarDollar Okay ... one more time ... check the wiring between the amplifier output and speaker inputs ... are they hooked up in phase? (Red to Red, Black to Black) Second... are they hooked up independently ... on a BTL output, like those of the 3255 boards, both Red and Black speaker posts have active audio on them. So you can't, for example, hook them up through a switch with common grounds... The reason I raised this is that 1) I've made this mistake myself and 2) I'm using an AO7 that has almost too much bass.

So, could you get more power out of it by using your own power supply?

@Douglas_Blake_579

Жыл бұрын

Yes. You can go up to 48 volts with the TPA3255 chip. At that level you probably want at least a 6 amp current rating. BUT ... even with the improved cooling solution, the chip is still going to run hot if you're pushing it at 48 volts.

@briangoldberg4439

Жыл бұрын

@@Douglas_Blake_579 gotcha. it might need a fan at that point or something

@Douglas_Blake_579

Жыл бұрын

@@briangoldberg4439 From other videos I see that the V3's cooling solution appears to be adequate for 48 volts on music, even though it will overheat on full power test tones (most amplifiers will). So you may not need a fan but I would suggest you put on a set of extra tall rubber feet to increase the air circulation under the case. On music with peaks almost clipping, you'll probably be averaging about 30 watts of power, which is going to be ear-bleed loud. Most reasonable listening happens in the 2 to 5 watt range, so you should be good to go.

@briangoldberg4439

Жыл бұрын

@@Douglas_Blake_579 makes sense. i do not listen to music very loud anyways. this looks like a very good little amp for small spaces like a computer speaker setup

@Douglas_Blake_579

Жыл бұрын

@@briangoldberg4439 LOL... Consider staying with the stock 36 volt supply, unless you're trying to make your ears bleed. Many people tend to rather wildly over-estimate their power needs these days. Since the HiFi heyday of the 70s and 80s we've gone from bragging about 40 watts per channel in our fancy listening rooms to putting 100 watt per channel behemoths on our desks. There's really no good reason for it. Most desktop systems are good to go with a 10 watt amp. I have an old Muse T-Amp on mine, using a pair of 50 year old Minimus 7 speakers and I never get past half volume. Sounds perfectly nice to me. My A07 (36 volts) is hooked up to a pair of Pioneer towers in the living room. I live on the 6th floor half way back the hallway and during a recent full power test it was heard in the lobby. (Yikes!) This hobby is a "ball of confusion": We go on and on about headroom and high SINAD values, but we listen to music with almost no dynamic range at all. We fret and fudder over .01% distortion while playing music with 20% imbedded distortion and listening to speakers that easily hit 10% on peaks. If we stop and think about it, it really is a comedy of contradictions. Cue the drum solo... Peace!

36 volts are You sure ? Not 32 volts

I’m surprised it has Through Hole components with sockets. That’s a selling point for me.

Which is better for v3, swap an op amp or just add a dac. Anyone?

@lio1234234

Жыл бұрын

Well you need a DAC no matter what. The opamps included should be more than good enough

@rodplanet5901

Жыл бұрын

@@lio1234234 thank you. I am using a marantz receiver and an Aiyima AO7 with Aiyima DAC A2. I am surprised that I am leaning a bit to the sound quality of the Aiyima combo. Im planning to purchase this V3 soon.

@lio1234234

Жыл бұрын

@@rodplanet5901 if you're using a receiver you probably don't need anything other than the amp. The shorter the run of shielded RCA you have the better though. FYI. If your room is very electrically noisy, long unshielded cables can act as antennas. Don't need anything exquisite though

@rodplanet5901

Жыл бұрын

@@lio1234234 I mean I am running 2 systems. I am using a receiver on 1 and a combo of those aiyimas on the other one. Sorry for my English.

From what I have seen, usually those cheap class D amps are noisy because they are using a volume pot with too high of a resistance. Like 100k when it should be more like 20k. No excuse for that other than using the cheapest pot available.

@Douglas_Blake_579

11 ай бұрын

The A07, TB10D and V3 are all dead silent when idling.

You make very good educational videos, the problem is you cannot evaluate sound with a mobile phone and the junk speakers you have in your workshop. Build a new set of good speakers. This amps does not sound good at all. It has a much to soft sound, without any details, it is totally uninspiring to listen to. I hope the new V3 sounds better.

hi,can you help us do a review on youtube

🙋👍🫂

Cost less than $5 to make in China lol