Can this tiny amp really produce 600 watts? - Fosi Audio V3

I review the Fosi Audio V3 power amplifier for both professional and home use and investigate its real output power.
I mentioned a promo code in the video. The promo has now ended but you can buy the Fosi Audio V3 for a very attractive price at amzn.to/3MKroQD
AN INTERESTING POINT
As @AudioScienceReview points out in the comments, in this video I have talked about ‘RMS power’ in the manner often used in audio. To be correct, this would be average power, which is derived from RMS voltage squared divided by resistance. You can find out more in my video Your Power Amp is Average- Here's Why at • Your power amp is aver...
CREDITS
Sonab OA-5 - Orhan Kırali / @orhankrl
Expert measurements - Audio Science Review www.audiosciencereview.com/fo...
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Disclaimer: Videos on this channel may include affiliate links and may feature software that has been received free of charge with an NFR (not for resale) licence, equipment that has been loaned or donated by a manufacturer or distributer, or equipment that has been bought for less than full retail price.

[@user-bl7oe2md4p]

I really enjoyed the straight no nonsense no bs review style and his clear enthusiasm for a good bargain in high fi sound, well done!

[@richh650]

I have watched V3 reviews all over YT and I must say, your reviews are by far better and more enjoyable than any others. Very well done!

[@lu74wn2002]

The manufacturer is quoting what Texas Instruments is quoting and then not providing an adequate power supply. TI quote two power figures, one at 10% distortion and another at 1%. Let’s only consider the 1% figure. Remember that this is a full bridge converter so you don’t need to halve the voltage across the load (speaker). So for with a 51V supply with a 8R load then 51V gives 36V RMS and v^2/r = 36*36/8 = 162W and TI quote 150W at 1% distortion. So TI are correct. I get fed up with people saying that they powered it from a galvanised nail and a penny in a lemon and only got 3W. Give it a proper power supply and it will do what it says

[@lu74wn2002]

Have you tried retesting it?

[@ropeburn6684]

You have to cut the average customer some slack though, especially those without much education in the matter. They're fooled by two things: first, the manufacturer/seller claiming a rating at 10% THD, while at 1% is long established industry and commerce standard as a figure. Second, the underpowered 32V PSU coming with it in some markets, and even the 48V 5A one can't logically do more than 250W. It's the manufacturer being a cheapskate. It is not unreasonable for the average customer to assume you buy a thing and it does what it says out of the box. They don't even use the dreaded "up to" phrase. They know exactly what they're doing.

[@paulmcdonough9595]

Thank you for your 'useful contribution' to the excitement over small amps built around the Ti chips, the last 30 seconds or so of your video added an unexpected amusing finale, I thought you had finished and i nearly missed it!

[@tolun]

Thanks for this great review video. I learned good things from you about measurement. I've been using Fosi V3 for a while now. With its 48V power adapter, it surprised me during my first listens. I am very pleased. I have a few different devices at home, and Fosi v3 is quite sufficient for my daily listening.

[@cars654]

Perfect for my future garage system ! I remember an old article interview from an un-named amplifier designer that he could make a decent amp the size of a paperback book but no one would buy it. They would have to put it in a large case and add a metal plate inside to make it heavy.

[@HieronymousCheese]

I've worked in audio electronics manufacturing for donkey's years, and it's common practice to throw in a lump of metal to give a product a sense of "quality". Light plastic is cheap; heavy plastic (light plastic with a metal block) is expensive.

[@sonsenthoy7468]

This could easily be the best review of the Fosi V3! Many thanks

[@dj-kq4fz]

This is my first time watching your videos. I thoroughly enjoyed the review and your sense of humour. The end caught me by surprise. Well done, sir!

[@Douglas_Blake_579]

Okay lets untangle this power output and power supply issue... The TPA3255 chip in these amplifiers works in BTL, that is Bridge Tied Load mode. So this is a 4 channel amplifier bridged to 2 stereo channels. This gives you the full power supply voltage on each half cycle effectively doubling the speaker voltage. By measurement ... 32 volt power supply ... 50watts RMS per channel with both channels driven on 8 ohms with less than 0.1% distortion... 100 watts on 4 ohms. 48 volt power supply ... 100 watts RMS per channel with both channels driven on 8 ohms with about 0.1% distortion, 190 watts on 4 ohms. The 300 w/ch measurement is the chip's absolute maximum rating taken at 10% distortion. You might get 300 watts per channel out of it ... *once* Now this business about current... The only time you will have a steady current draw of 400 watts is during bench testing... On music the average power is much lower, often no more than 20 or 25 watts with 400 watt peaks. At that rate the 5 amp power supplies will work just fine since the amplifier's internal bulk capacitors can fill in the extra current for peaks.

[@byteborg]

TPA3255 performance is solid when sticking to the data sheet. All the magic is in the chip, so there isn't much that can go wrong. I bought several 3255 based amps over the years with one of them ending up powering my main listening setup on my work desk. They run cool, they are fast with pretty precise transients. 75W RMS per channel should be enough for most listening situations, so it's a very nice budget solution. And it's very efficient, considered the power supply has decent PFC.

[@avasolaris1]

Thanks for your time. Good and clear review. I fired mine up for the first time today.

[@yipfred1751]

I just watched a great lecture here without falling in to sleep XD , well-prepared, no BS, great tone ~

[@gregbailer8701]

Engineering, Science, Math, Physics, ...all in one video. Well done David. I'm not a $100 Class D fan currently. My 20-year-old Pro Level A/B stage gear is: Loud, clean, and reliable. The amp gain level is set @ 50% with superb headroom for clarity. Pre-amp level 20%. Easy 80 DB SPL. No flowery adjectives are needed. Seat belt suggested.

[@sonsenthoy7468]

Really like your review..you're so humble

[@LordPapula]

My man! You and I think a lot alike, from your casual and pragmatic approach to audio tech to the range of system style (JBL in place of Yamaha in studio, Ohm in place of Sonab, Klipsch in place of B&W… not that those are wildly similar…) I like your style, friend.

[@robertwestinghouse4098]

Love your no BS delivery and content. I have the V3 and the binding posts are a joke. The power is also a little ambiguous. When I swap my circa 1980 Aiwa SA-P22 Power Amp (30 watts stereo into 4 Ohms) within the Aiwa Mini 22, the 44-year-old Power amp was was much louder and drove the speakers with more authority than using the Fosi V3. But using my PC the volume was OK.

[@jimc9823]

LOL that last bit with the girls made me crack up. Terrific review. I'm pretty sure this is the first review on YT I've seen from someone that has the technical knowledge to understand what they are speaking about. Very refreshing.

[@AudioMasterclass]

Believe me there are plenty of people with more technical knowledge than me. What I’ve seen though, in any subject, the real experts are not on KZbin. DM

[@ericbain507]

Omg, absolutely brilliant vid. I laughed, I cried, I learned a thing or two. Finally a review with context.

[@paulyoung4817]

Thank you for the review, really honest i thought, and the hilarious ending, I laughed a lot!

[@anonamouse5917]

It's good to see that class D amps continue to improve. My power bill needs all the help it can get.

[@bgravato]

Coincidentally I was testing a Fosi V3 today. One of the tests was measuring power consumption and the it was down to a mere 6.4W from the wall (with the 48V PSU), which I think is amazing. When turned off, the PSU only consumes about 0.3W of residual power. Which is nice too. Sound wise I was pleased with the Fosi V3 too.

[@peters7949]

Great video as usual David. And lovely view of the C414EB, when you spoke about valve mics I hoped it was a C12A, but a screen grab confirmed it’s a 414. Class D seems like the work of the devil, but you can’t argue with the performance & number of Roadie’s backs being preserved by lighter amp racks & PA systems, they are in fact a God send. And even true audiophile manufactures like Bryston use them: PMC speakers recommended brand (and integral in their active speaker systems) PMC are definitely Audiophile, so QED as you put it.

[@AudioMasterclass]

The C12A is a very nice mic. I've used them but I very much doubt I'll ever own one myself. DM

[@Stuartrusty]

As someone (like yourself) who has and still does dabble in audio electronics projects, I have a certain fondness for LM741s. I used them extensively in active filters for in car audio projects with a modicum of success. Also used them in many other applications such as temperature control and regulation in my linear power supply designs. Presently, I work for a well known calibration and precision electrical measurement instrument manufacturer as a repair tech. This is why I note with interest your mention of electrical power output measurement of AC signals. Indeed, as stated elsewhere in the comments, I would always use the Root Mean Square as the calculation for true power of AC signals. It's a measurement industry standard. Also, you are correct about RMS value measurement, within the circuitry of all modern precision electrical measurement equipment, RMS is measured by the thermal conversion method for greater accuracy. I'm also old enough to know the old marketing trick of stating PMPO instead of RMS. Think flashy 1980s boomboxes (yes, I still have one) with big stickers saying "100 Watts*" with the all important asterisk leading to the small print "*PMPO" at the bottom of the sticker. Peak Music Power Output is a cheap audio manufacturer's dream marketing ploy, or as we engineers called it, lying. In engineer parlance "P*ss Miserable Power Output." More on AC RMS power measurement here if you want to nerd out (like me!) eepower.com/technical-articles/how-to-ensure-correct-rms-measurements/#

[@99Duds]

Found your channel few weeks ago, I like your style. I explain class D to people as follows, add a HF carrier to the signal run it though the amp then filter off the carrier. I do like how you explained it and mite start doing that instead.

[@mypetdrgn]

great stuff along with the interspersed puns. the end was icing on the cake. 🤣

[@LeeBergerMediaProd]

Really enjoyed your review. Your AKG mic sounds terrific! I bought this amp with the 48v supply, and based on similar criteria as yours I found it perfectly capable of driving my vintage Polk RTA 12b's. It also drove my much less efficient Polk SDA SRS 2.3's, although not as loud but still loud enough for everyday listening. I read that the advertised output rating comes from the TI data sheet which lists the output at 315 watts total Output Power at 10%THD+N. Who doesn't love the sound of 10% THD?

[@AudioMasterclass]

Heavy metal guitarists love the sound of 10% THD. Things can only get better from there. DM

[@Billfish57]

This guy is my favorite for audio info.

[@alecbruyns4490]

I use a couple of Fosi amps, coupled with small but decent speakers, with my computers. They take very little space, and produce enough volume for near-field listening, sounding pretty good.

[@gamerman644]

i use this amp as a desktop amp with ELAC b6.2 attached to my wall above my monitor. works perfectly with a proper dac preamp to help make sure my noisy pc doesnt introduce a bunch of noise from its onboard , people mention that because TPA3255 designs have never really implemented that volume dial in the past and most are commaring it to the A07 that has prior recommendations over a year or two ago

[@BrianHall-Oklahoma]

I just got one of these to power the monitor speakers in my home recording studio. I'm impressed with it.

[@obscurazone]

Thanks for being the voice of logic and sanity in a stadium of "audiophile" twaddle. Amp makers must be peeing themselves with laughter, at just how easily it's been convincing customers that amplifiers have a critical influence on sound "colouration" (beyond distortion). Laughing all the way to the bank.

[@scottlowell493]

Only when the amp is strained or distorted, otherwise....it's pretty much impossible for a human to hear the difference.

[@psysword]

But i hear the bass control at high volumes is better with my much more expensive Burson Audio monoblocks class AB

[@Cujobob]

@@scottlowell493 people pay for distortion “tuning” essentially. We need products that allow us to tailor distortion to our liking. Start from ideal and modify to preference, always the best way to do it.

[@clicks59]

Great review. Thanks.

[@mike_lowndes]

Based on various reviews I bought one for my garage / gym system. They power a couple of old Ruark Prologues. Loud is at about 2 o’clock, further gets too loud! Front end is a raspberry pi 3 with a DAC hat. Whole setup under £300 and sounds as good any 1-2k system I’ve heard.

[@benegesserit9838]

very good review!!

[@tobiasrybing5631]

Fantastic video, thank you!

[@shipsahoy1793]

I don’t really think there’s a flaw in that argument. I have $7000 speakers too and to tell you the truth, if you hook up but a crappy amplifier to it, it knows. It’s all about the bass tones because that’s where the power is needed, down at the lower end. At the higher frequencies, if there’s no noise, you don’t need a $3500 amplifier; but you need that amplifier at the lower frequencies. The irony is that most people don’t have speakers that go low enough; they use subwoofers that have their own amplifiers.😂

[@erwintimmerman6466]

I found out about the logarithmic volume control in the 80s when I was a teenager and fumbled with taken-apart boomboxes and soldering irons. Not knowing any better, I bought a linear potmeter for volume control and thought it was broken because it went from almost silent to maximum volume over the last 2 % of the turning range 😆

[@Smithy225]

I could listen to you all day

[@joelcarson4602]

I have a Fosi TB10-D, the improved recent version, uses the same TI chipset, and iirc a 32 volt PS brick. Works well, I first hooked it up to a pair of Infinity Reference 2001 8 ohm bookshelf, 6.5" woofers and 1" soft dome. Infinity speakers are not usually noted for high efficiency, but initial testing with some Rush CDs at genre appropriate volume levels, I'm quite happy. The Fosi is currently utilized as a "Handy Amplifier" for various audio shenanigans, and is quite-er- handy.

[@Douglas_Blake_579]

Check your TB-!0D ... plug it in, use it, then leave the AC on and turn the amp off by the front panel switch ... check it in an hour... is it still warm? If so, contact Fosi for a replacement. Your unit has a known problem in the standby circuits that will eventually result in the amplifier failing.

[@Aubury]

A master class in audio. With a human touch..

[@diment0857]

Excellent as usual, the Edgar Winter Frankenstein bit was comedy gold

[@ronaldmcdonald2456]

I was coming of age in the Sound By The Pound days. It would be a lot of years before I could afford pounds. I started rolling my own just over a decade ago, and a 45 pounder was first off the workbench. Everything I build has VU meters with bouncing red needles and lights that give a golden glow. They warm my heart. Like you said, you just want what you want. BUT, now that I'm into active open baffle stuff, and also SWARM lusting, it's imperative that I lighten up. Of course, there's also the issue of an old creaky back. I'm using four channels of my diy Big Berthas for highs and mids, AND, four channels of Hypex class D units for woofers. I've used the class Ds for full range duty as well, and I hear a distinct difference from my class AB home grown items which to my ears are better in every category. I even think they do bass better, but not enough to justify the expense of running 8 to 10 channels of them.

[@howardskeivys4184]

Your analysis of amplifier power ratings and measurements was interesting. Echoed many my own thoughts and experiences. Very recently I watched a KZbin review of an amplifier which the reviewer confidently claimed output 6000w rms into 2 8 ohm channels. The reviewer is known for reviewing and retailing ‘ultra high end’ components. He is also known for being strongly and controversially opinionated and claims to have won awards for products he’d designed. I commented that his amp would need to be connected to a minimum of 8 US wall mains outlets or 4 UK wall mains outlets to even draw that amount of power and then would need to be 100% efficient to output that power. His response was classic:- “I don’t give a shit. I just know it works”! I’ve recently upgraded my 120w integrated amp for a pair of momoblocs rated at 300w. My normal listening SPL is around 78db. To achieve that using the integrated I needed to turn the volume up to 45% but to achieve that same SPL using the monoblocks, the volume has to be ramped up to 70%! I put this down to the very low gain on the monoblocks of 25db.

[@victorjohnson7512]

My heavy class A/B amp makes 200 watts per channel (RMS). And I'm happy with it.

[@jlinkels]

Totally correct what you say. I tend to trust the datasheets from a reputable manufacturer, like TI. Then for any amplifier I look up the chips being used, and whether they are connected Single Ended (SE) or (Bridge Tied Load) BTL. Most datasheets give a method as to how to calculate output power given a certain power supply voltage. So I disregard the amplifier marketing specification which mentions the total output power over 2 channels, preferably at 2 ohms with 10% distortion. Which produces a large figure, but totally unrealistic. I have seem many cass-D amplifier products which verbatim copies the manufacter's applicaiion note. (That is OK, why not) So again, the chip's datasheet provides the best source of information.

[@BurnsRubber]

As you referenced, Audio Science Review Amir measured this Amp with the 48V power supply where output is much higher. I run a pair of these to biamp my speakers. Ordered direct from Fosi to get the bigger PSU. It works out to about 400W channel of clean power for $200. Amazing value. Plays very loud and clean.

[@JR-lx8nn]

I enjoyed this review, especially the extra information and commentary about power measurement, RMS and all that. Seems the US Federal Trade Commission, a governmental agency that regulates commerce, promulgated a Rule that stereo gear had to be rated for RMS power, and specified a standard technique for measuring the same. I suppose that is historically true, but irrelevant as I see power specs all over the place these days. So, I appreciated your commentary thereon. Great fun. Thanks. TT

[@jimw7ry]

Loud and CLEAN explosions! Indeed!

[@bigcassssino]

OMG Your girls at the end!!!! Priceless!!!! I got a good laugh!! Keep up the good work! Cheers!

[@carlsitler9071]

I bought the original little powerhouse, the Aiyima A07. The new one (Max) is just like the V3 but can be bridged. My second system has omni-directional speakers as well, the Mirage OM-9s. Not audiophile but good enough.

[@AdamsOlympia]

Last year I returned a $2500 stereo setup w/ KEF 350s, a Cambridge CXA81 + SVS sub, due to buyers remorse. I just couldn’t shake the feeling that I overspent and could achieve just as good sound for a fraction of the price. Though I’ve really missed that sound ever since I let it go! NGL, that setup was the best I had ever heard - But I think I can get damn close with the V3, an entry level SVS sub and KEF 150s for under $600. Just need an HDMI to RCA converter and I’ll be set. (Mostly listening to Apple TV/iTunes content)

[@C90C60C30]

Mate. I stayed with you there until at least 5 minutes in 😃. Doesn’t matter. I’ll listen to you all night mate. Brilliant. (Ade, 1968)

[@willbrown8433]

Until today I was the only person I knew that owned Sonabs. I have the OA12 with only 2 tweaters pointing in different directions. They often sound terrible but I love 'èm.

[@scottwolf8633]

Over the decades, via observation and building, I've noticed its difficult to build a superior sounding, low power,6 amp. But its damn near impossible to build an extremely high powered amp that sounds good. "Scale up = screw up". I really enjoy the TS Minibeast, kit, a Single Ended, OTL employing in the output stage, the JJ Electronics EL 509's, whose cathode is directly connected to the loudspeaker terminal. Yet with 4 Watts @ 8 Ohms, 7Watts @16 Ohms, the retail loudspeakers on the market are wanting. A better methodology for generating high SPL's is to employ multiples of the transducers in the typical loudspeaker system. This entails building your own from the myriad of really fantastic drivers available to Us today.

[@Dj-Jon-E-C]

I put together a class d tda7498 amp just something to mess with but I was so impressed I now use as me main amp and put it into a case. Watts was not quite how it says but sound wise I liked it and plenty power for my likening as I have very rarely got to quarter of the volume so see no point having more watts. Only thing I hate is when they claim more watts than what it really is.

[@tonyjedioftheforest1364]

Love mine, perfect for my bedroom streaming music from my iPhone phone. Well recommended.

[@andymouse]

Nice review, punchy and to the point and 5532's are a great start. Must admit if somebody is amazed at a volume pot for being Log I would question their background! I'm sure the orange anodised knob will help dissipate free radicals and transit the electrons from your hand more efficiently for cleaner and less veiled sound....cheers.

[@Douglas_Blake_579]

Audio taper pots are not a universal standard. Much of the HiFi gear produced in the orient has always used linear pots.

[@andymouse]

Oh thanks, I don't have a great deal of experience with many types of equipment, I only have had British stuff that plus an electronics background I suppose I took it for granted !...cheers.@@Douglas_Blake_579

[@Douglas_Blake_579]

@@andymouse Hey no worries ... I did the same thing until an oriental friend of mine clued me in.

[@GK-vj9dz]

i'd love to use a power amp for my living room rig (bluesound node 2, kef Q350s, JBL 10" sub), but the only way I can get good bass management is through my Yamaha AVR. It suffices, but I'd love to get an amp that could do that. My room is atrocious for sound. Tile floors with minimal damping, left speaker near a wall, right speaker in an open are. Angular vaulted ceiling...on and on. It's all a compromise on my end. But thanks for another good review/video. I'm a recent subscriber. I enjoy your content. cheers from across the pond.

[@EsotericArctos]

Sometimes, as straight and no nonsense as you are, it does feel like a subtle dig is being given to those people that insist more expensive is better. Now, I am not saying that dig is not warranted, but I definitely sense that :).

[@Douglas_Blake_579]

The plain truth, if you are keeping up, is that cheap audio is getting better and better audio is getting cheaper every day.

[@chelfyn]

I used to run a super cheap ($15 ish) class D amp that ran off a wall wart, or 4 AA batteries, into some mid range wharfdales and it sounded fantastic. I couldn't believe the quality for the price. it was about 15W per channel iirc, but loud enough for my tiny apartment.

[@Bastelcontainer]

The Sonab OA5 MK2 are really great. I grew up with the sound of these unusual speakers

[@Coldgecko]

Man, you are great. The best stereo product review I have heard in more than 10 years. You keep the BS out of the discussion.

[@ianl.9271]

Some of my favourite opamps for audio in the order of preference.. OPA2228, OPA1612, LM4562, TL072, NE5532.

[@leeoooooooooooo]

Gotta say the current crop of TPA3*** series of chips is really moving forward at a pace. Some serious power levels being achieved in such small packages. I was blown away by the TPA3116, seems everything's moved on once again

[@Douglas_Blake_579]

IT should be noted that TPA31xx and TPA32xx are two completely different designs. The older TPA3116 was a pretty decent little Class-D chip. The Newer TPA3255 incorporates better feedback and regulation as well as producing a lot more power; clearly a far superior design.

[@m0rjc]

I use Class C - for transmitting Morse Code at radio frequencies 🙂 300W is ridiculous. We used to fill a theatre on a few channels of 150W stage amplifiers. We barely warmed them up. Back in the 80s we had advertisers using "Music Power" and "PMPO". They cover things like "Hey - we have 2 drivers on these speakers, and there are two speakers, and PMPO is peak to peak, so let's multiply!!!"

[@pimianimavdo1523]

Good one! This reminds me of the 1980's "ghetto blasters" portable all in one "Boom Box" that presented/announced many hundred watts (!!!) on 10x "D" 1.5 volt batteries! RMS and PMPO wattage ratings are worlds apart, but that never stopped the good people in the marketing departments to not give their target potential clients the real info. By the way, you do not need tons of watts if you have good efficiency loudspeakers and you like to remain in good terms with other tenants in your building... Just saying ;) Plus room saturation and distortion sucksé ;) As for Class D amps, in general, they are getting better. Me, I still prefer a good Class A or AB, but I do own 2 Class D amp units for convenience's sake... Those are for my computers. Cheers! :)

[@G6JPG]

You took a very long time to get to whether it meant RMS or not. (Another aspect that used to be [mostly mis]used in the '70s/'80s was peak vs. continuous: mainly influenced by the size of the smoorhing capacitor[s]. Since this has a separate power supply, probably not relevant.) There seem to be a lot of these tiny sinple amplifiers about; I think for _most_ people, they're excellent - other than, as you say, their size isn't going to impress! For someone who knocks audiophiles (I've seen some of your other videos, and you do a bit in this one!), you're well into that area in the way you talk about your various speakers. Keep doing the videos though!

[@AudioMasterclass]

Yes I should have mentioned that I’m only scratching the surface of power measurement. I’ll definitely be diving deeper in a future video. DM

[@chinmeysway]

I love the gentle jabs at audiopervs (audiophiles) but don’t gotta be that easy on them! Exposing the flat earthers of audio bafoonery is a good thing!

[@tekanova7480]

Before social media there was the Saturday afternoons "on location" from the local Fm radio station telling you to come on down to XYZ Electronics store. Spewing all the juicy specs about the prowess of the systems for sale.

[@zorst99]

Seeing that you have the same 801s that I did I would highly recommend that you upgrade your internal capacitors if you haven't done it already. I used the Solen BP400 series. The clarity and imaging improved dramatically. Bass actually showed up. Then ended up having better bass than I ever remember them having. I had taken them apart a couple of times thinking the woofers might be out of phase. I purchased these as used speakers a year and a half old. I used them for a long time then bought my 802Ds, then I had the balls to work on the 801s I wish I had done it sooner I would have never bought the 802Ds. They ended up sounding as good as the 802s the midrange wasn't as good but I would have to say the bass was a little better. Oh, and I am using tonight a very small class D amp, which can be had for less than 30 dollars and I like the sound of it better than my other expensive amps.

[@QuinnKallisti]

love your delivery and the tongue in cheek mate. haha Do you have a lecture on Amp classes and calculating apparent wattages between classes...

[@AudioMasterclass]

That would be a complex topic considering that some people believe that tube watts are louder than transistor watts. I might bear it in mind. DM

[@QuinnKallisti]

Bless @@AudioMasterclass

[@thesilverfish]

Oh what a great review. Glad to see you mention Yamaha NS-10s. I have this idea to use one of these D-class mini amps to drive my guitar cabinet. Recently got a guitar modeling pre-amp and looking for a small amp to drive to 12" speakers which can be wired at 4 or 16 ohms. Wonder if you have and advice? There are multiple modeling amps that use d-class power and mark up the price to "guitar players do not understand" prices.

[@AudioMasterclass]

Free advice comes without guarantee but I can't see why this wouldn't work, and work well. If you go for it, I'd be interested to know how it works out.

[@thesilverfish]

@@AudioMasterclass Thanks for your reply. Looking at Fosi ZA3, AIYIMA A07 Max 2. Love the high power and bridge-able. Also looking at the amps with bass/treble amps.

[@Justwantahover]

With a volume control you can still use it as an integrated amp by plugging it into the headphone jack on your phone. I got one and going to buy a tiny cheap Blutooth dac unit for it.

[@msingh1932]

Now that the Master says he is not an audiophile, it makes me more comfortable stating that I am not one. And will wrassle to the ground anyone who accuses me of being one. After all those zero-substance-full-of-noise reviews about the Fosi V3, I am glad we have the Master giving a meaningful opinion on this tiny amp. I think I will buy it for a back up. Thank you. As usual, the ladies have the last word. I always wait for it.

[@marxman00]

You perfectly described some of the 600 Whats Your 414 sounds good

[@TheEulerID]

The peak to peak measure is only valid if the amplifier you are using has differential output. That is one terminal is producing a mirror image output to the other. In effect, the signal across two amplifier outputs with one inverted relative to the other, a configuration known as "bridged mode". The majority of power amplifiers have one fixed voltage reference terminal, often to ground, and only one terminal is actually outputting a varying voltage, then the peak output is the peak voltage to fixed voltage terminal. However, the TPA3255 does have bridge mode output, which means the theoretical maximum voltage range across the load is, effectively, doubled.

[@HaraldBergTechTv]

Yes it can drive a pair of speakers, my main gripe is it´s tonality as well as how it is handling speakers when reaching higher volumes

[@user-pp6jd6qj4x]

Loved it, brilliant. I am your age and appreciate your comments very much!

[@peterdavies5358]

I've a Nobsound class D amp, smaller and down market from this and it's great. I have to leave any audiophile pretenses at the door but I have other stuff for that. Come on, it's called a Nobsound, you can forgive a lot for that and it was about £20.

[@aldogentile245]

Thanks for a a very clear approach. There is also an interesting video from Fosi Audio "V3 with Various Op-Amps Demonstration". Talking about the power supply type, Should it be a linear PS or a switching one? What PS did you use in your review?

[@AudioMasterclass]

I used the 48 volt supply Fosi sent me. I don't currently have thoughts on the type of power supply but I might develop some in future. DM

[@volkiruski1221]

The V3 together with the new P3 and the recent K5Pro DAC, all together would be a perfect system for new users but also experienced users. Find some nice speakers and you go....musthaves from Fosi.

[@georgecorey1320]

I use two similar inexpensive (TPA 3116 D2) digital amps regularly, at home and work. I think that they sound very nice for near field, listening running at up to 4 W per channel. I think that they actually sound excellent in driving speakers that are easy to drive, at a volume suited for conversation. The real discrepancy between their useful output, wattage, and their advertise output wattage comes from two factors, I think. If you test with a dummy load and a sine wave input, for instance, one of my amps will put out 40 W per channel. With music programming, it drops to 4 W. I think that the variable pulse duration mechanism that these amplifiers use does much better with a sine wave because this wave form has a minimum of slew rate for a given amplitude. reproducing, actual music is more challenging. The second major limitation is the limit in increasing current sourcing for demanding speakers and demanding passages of music. And you can demonstrate this easily by diminishing dummy, load, and seeing if the output wattage actually drops fairly sharply. Used with these limitations in mind, I like these amps.

[@keithstafford1331]

Arthouse movie “Fast and Furious” had me dying 😂. Great video.

[@petesjk]

Class D amplifiers are something I’m not familiar with, so thanks for your review of this. I’m also a fan of Audioscience’s reviews, so it’s a nice cross reference. I’m certainly curious about Class D amps, and the price point of this Fosi is nicely accessible. 50-60 wpc amps are also a sweet spot for me, since my listening rooms are usually relatively small, and my ears seem to prefer efficient speakers, so larger rooms still get plenty loud. However, it turns out my ears have also already led me to good amp choices, since my amps have tested well at Audioscience. What I would be more interested in is higher quality lower power amps, maybe in the 30 wpc range, more or less. There are some rooms where 50-60 wpc are just too loud, and one of my setups is so efficient it just doesn’t need 60 wpc to fill any size room. One day I may splurge on some nice B&W speakers like those shown in this video, and I may have to look for more wpc.

[@edwardasmannjr.2438]

Damn you with you your facts, knowledge, experience, and, and, and, sense of humor! (Crap! Now he knows I’m a Yank.) Thank you, I thoroughly enjoy these videos, and learn useful things too. : )

[@danielduesentriebjunior]

Already 20 years ago Bang&Olufsen introduced 1000 Watt class D amps in the Beolab 5 about the size of a cigarette package.

[@stevenmann9769]

I have one of these. It sounds absolutely fine. However, my 53-year-old A/B Sansui integrated amp is quite a bit louder (and beefier).

[@user-yk4gd1fl4z]

bahaha, girls on point here. Love to see more of them.

[@spacemissing]

I have heard a couple of class D amplifiers that sounded pretty good, but I haven't yet heard one that was as good as a well-designed AB model.

[@alittlebitgone]

There is zero chance you could consistently tell the difference blindfolded.

[@ericmc6482]

​@@alittlebitgoneGarbage.

[@ianl.9271]

Use the class D in a bi-amp setup to drive the woofers and use a class AB to drive the tweeters.

[@jayantadakable]

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

[@stevenrayphoto1280]

Hi David, I'm a new subscriber and so glad I found you! Your videos are spot on and full of quality information. I monitor at modest volumes and want to fire up a pair of NS10m studio monitors that have been in storage for 20 years. In my studio I originally used a Bryston 4b with them. I realize the Fosi is way less money than the 4B. Do you think at modest volume levels the Fosi will not disappoint with the NS10m Studio monitors?

[@AudioMasterclass]

I tried the Fosi with my NS10M Studios and it was fine. I'm sure audiophiles would have their quibbles but for practical purposes it does the job.

[@stevenrayphoto1280]

​@@AudioMasterclass Thank you for the response. I just received my Fosi V3 with the 48v power supply and shot my room with Sonarworks. The frequency graph I got from Sonarworks looks pretty much the same as the published specifications for the NS10's so I think the Fosi is doing fine.

[@stevenrayphoto1280]

drive.google.com/file/d/1_SpdEnkH1Sm5877r8rySeSQ9BdFtKWCO/view?usp=share_link Here is the graph

[@evanmcdonnal]

I keep tuning into the Audio Masterclass but I still can't get my audio quality to match yours! And in this video you're even using a mic which I use a clone of in the WA14. Perhaps it's the noisy city environment in which I live but I simply cannot bring my noise floor nearly as low as yours is here. Even when you're likely using a much higher preamp input level than mine, you manage to have less ambient noise. I think maybe it's because I have my level down to reduce ambient noise and instead get passive noise out of other parts of the signal chain.

[@AudioMasterclass]

It's probably city noise, which is bound to be higher than my country noise, though if I record on a weekend I'm plagued by swarms of vintage motorcycles passing outside. It would be worth checking there's no source of noise inside your room. Using a lower gain won't work because the background noise is always in proportion to the signal. As a last resort there's iZotope RX or similar. I don't use it for my videos, but I have for podcasts. With any noise reduction software it's important to be careful that artefacts don't make things worse than the original noise. DM

[@nelsonclub7722]

I have a 500W lightbulb in my garage - although to be fair it doesn't go very loud Watts have always meant nothing in Hi-Fi Terms

[@carlitomelon4610]

Entertaining, thanks. I have a tiny class D Dalton Audio amp hooked up to a pair of Minimus 7 speakers with the third channel driving a salvaged (no plate amp) REL T3 in my spare bedroom. It works up to maybe 80db. I take the setup with me on trips to B&Bs. I believe no room is complete without a music source or a subwoofer! *However* my Hi-Fi speakers are notoriously difficult to drive 4ohm models: I drive my KEF LS50s with a pair of Mu-Fi bridged amps. The Magnepan LRS with a class AB Bryston B3sst pro amp, formerly used in a recording studio. (I previously tried an el34 chi-fi tube amp that choked on the load! That experiment lasted 30 seconds;-) Can anyone here save me £100 by claiming this amp could possibly drive the above speakers as more than a party trick? I know @Jim Farrell has an op amp modified, Mondrian decorated copper knob one.... I wonder if he took it with him on holiday? 🎶🤔🎵

[@carlingtonme]

When you tube first started "suggesting" your channel I thought it might be another grumpy boomer yells at audiophiiles deal..but this was a great review with the right mix of wit ,tech stuff and of course the two digital women at the end...good stuff,I'm subscribing

[@ricktotty2283]

The Yamaha AS 2200 at 90watts runs any speaker we have but I also have Yamaha AS 701 at 100 watts sounds just as good, much cooler, and 3,000 DSA less. I would rather have the class D Amplifier. I wish the 701 had a pre out so I could run L& R Subs. Enjoy you content.

[@Douglas_Blake_579]

If you have active subs, you most likely have high level inputs on the back... so you hook V3 to Sub... Sub to speakers.... the sub will take it's input from the V3's speaker wires.

[@user-bu4wg1ok5n]

Back in the 1970s, outrageous power claims gave rise to the Federal Trade Commission (FTC) requiring amplifier power claims to be RMS, continuous power, at the rated distortion, from 20Hz to 20KHz, both (or all) channels driven. I think there may have been other requirements, such as warm-up time and stabilization. I don't remember. I do recall, prior to the FTC crack-down, all sorts of power claims, such as peak-to-peak, peak, music power, and rarely continuous RMS. Music power was based on the idea that the filter capacitors in an unregulated power supply would charge up to a higher voltage between musical peaks, and so the amplifier might be able to deliver brief surges of power until the capacitors discharged down to a lower sustaining level under a continuous load. So the FTC refused to allow inflated claims due to bouncy power supplies. You could make any other claims you wanted, but somewhere, your advert had to state the continuous RMS power over the entire audio range at the rated distortion.

[@AudioMasterclass]

This is a topic I'll be covering in a future video. I say 'covering' but there's so much to it I think it will be merely dipping in. DM

[@rogerblackwell]

I always turn my power amp up full by default and use the mixer to control volume. It remains quiet if no signal is going into it. I have another amp for the woofers, and a built in amp for my sub woofer which doubles as a table.

[@AudioMasterclass]

It’s a practical way to work. DM

[@scottnj2503]

Great review. I was taught P=IE. Ergo high voltage (E) and low current can create seemingly high "power" (P) in terms of watts. You touched on this in the end re: the power supply. I've always thought of current (I) as electromotive force. In grossly oversimplified terms, audio speakers are simple electric motors. Current IMHO may be a better index of an amps ability to produce a given volume of sound with a given speaker. Using Ohm's formula for power appears to mask the truth.

[@Douglas_Blake_579]

It does make sense but not until you understand Ohm's law which says that "Current is the result of applying a voltage across a conductive load". I = E / R The P=IE formula is Watts equation and is only applicable when I and E are both known. These amplifiers are voltage sources. They take an input voltage, multiply it by their gain and then present the appropriate output voltage... This voltage is then placed on the speaker terminals and current flows according to the speaker's impedance. You can measure the voltage easily enough. From that, knowing or measuring the speaker's impedance, gives you the other piece of the puzzle ... now you can calculate the current and knowing both voltage and current you can calculate the power.

[@scottnj2503]

@@Douglas_Blake_579 Thank you! I squeeked through BE&E at NAS Memphis long enough ago to have been taught valve theory and only Watts formula, as I recall these years later. I've not touched a multimeter to a circuit in a long time. Yet, I get what you've set before me and am grateful.

[@Douglas_Blake_579]

@@scottnj2503 Okey dokey ... glad I could help. Once again, for clarity... the key insight is that Current is a result not an independent factor.

[@fredygump5578]

LOL! A British person calling British Imperial units "American units"! Now I've heard everything!

[@Stuartrusty]

He is partly correct, US and UK imperial fluid measurements differ. A US gallon for instance is only about 83% of a UK gallon as well as differences in fluid ounces and pints. But, yes, he is using sarcasm here of course.

[@natetete1379]

They're called Freedom Units. It's Americas FU to the world😂😂😂😂

[@fredygump5578]

@@Stuartrusty The American gallon is the original Queen Anne gallon. The Britts later changed how big their gallons were! Americans are just trying to stay consistent, but the Britts and the French both have a thing for changing measurement units!

[@peters7949]

While inches are imperial units, the official UK measurements have been metric since 1965.

[@fredygump5578]

@@peters7949 And your point is? Disowning your kid doesn't stop it from being your kid.

[@stephenmcbride6359]

If you want a real hoot try a pair of Aiyinma A3001 200w mono blocks.I hadthe fosi V3 but wanted to dable (play) more. hence orgered the mono blocks on a lark.rated a 200 watts into 1 channel wirh a 32v, 5A power supply still means that it can only produce 160 watts, but that is only through one channel.This seems to take some of the load off and opens up for greater reolution and a larger soundstage(lol). Also with the flip of a second switch it becomes a dedicated subwoofer amp with controls going from 20-160 hz. This amp uses the same chips as the V3 and is priced at 89.00 Canadian or about 115.00 pouns for a pair. Try them out you will be pleasantly surprised. more so than with the V3.

[@stephenmcbride6359]

Hopefully this reply goes to the right place. You asked either how would I feed the mono blocks with only one audio signal, the answer being a y-adapter. I however have discrete outputs for each channel on my pre amp so this is not an issue. Cheers and I hope this helps.