I used 6 Fosi Audio V3 Monos in my Home Theater. Here's what happened.

[@Leo-tf7gu]

Maybe Fosi should just come with a 5 / 4 / 3 channel amps with built in power supply, fans, and save us a lot of trouble with cables etc.

[@ryanchappell5962]

@@Leo-tf7gu they seem to be going with an incremental approach. Adding one feature at a time.

[@NisuUuno]

For that money you could get a real reciever from a real brand

[@ryanchappell5962]

@ yes and if you put an slow moving fan on top of it blowing upwards, you can get high output for hours on end.

[@ryanchappell5962]

It would have been so much better if they used the za3 case for this. Just get rid of the volume knob and then everyone would know what it was. The ZA3 case is way better and allows better airflow underneath. This would also be nice when combining the “za3 mono” with the ZA3 stereo. The stereo would be fine for rear and height channels especially since the stereo amps have the same gain as the mono amps, the mono just has more current delivery capability. It’s basically the stereo amps running in parallel. An affordable class D amp with multiple TPA3255 chips is very doable, it would be excellent if it was built with fan cooling built in where the fan is directly mounted to the heat sink and spinning at a nice low speed. Then you could have a very compact multichannel amp. It would be pretty nice.

[@onionknight9431]

@@ryanchappell5962 Also more space for bigger discrete opamps

[@wa2368]

One may only need 3 of these mono ams for the front left/center/right stage. For all the other channels, monolith makes cheap multichannel amps, to streamline the whole setup.

[@ryanchappell5962]

@ I bet if you fan cool the monolith amps you can get as much as you would ever need out of them. They may not need fan cooling but class AB amps definitely seem to perform better when they are kept nice and cool. I have done this with many AVRs with great success. You can sustain high outputs that way.

[@Roof_Pizza]

Running 3- V3 stereo w 48v power supplies for Atmos channels, no issues, only run warm, not hot. ~100hz crossover to subs.

[@joentell]

Mine died when it was in idle. I highly recommend fans.

[@Roof_Pizza]

@@joentell Yeah, looking closer your speakers are 4 ohm and mine are 8 ohm. Mine also has it's cooling holes on top and bottom and that seems like that would work better to dissipate heat than the holes on the sides.

[@joentell]

@@Roof_Pizza ahhh, yes. I should've noticed you also said v3 Stereo.

[@jsclayton]

I think Buckeye Amps may be what you’re looking for. I’ve been saving up for an 8 channel for my bed layer.

[@andrewmcewan9145]

Absolutely want a affordable class d multi channel amp. But we also need a affordable decoder to go along with it. Having 5+ channels of amplification is useless when the codec can't be decoded. I have a old htib with a 1000w class d 5.1 ch amp for my cottage setup with some different speakers and it sips power compared to my normal avr's

[@annebokma4637]

@@andrewmcewan9145 just bought a Marantz atmos pre amp, 11.2 channels, used but with 3 months warranty for 400. Adding these amps would make a nice setup

[@notreallydaedalus]

FYI, ICs are comfortable at a much higher temperature than we are. Design spec for temperature can be above 150°F. I know more about CPUs than op amps, but thermal throttling in PCs is usually well above 175°F. Meaning that a case feeling hot but not burning you isn't in and of itself a cause for concern. If you touch a heat sink and it does burn you, even that may not be cause for concern.

[@Douglas_Blake]

The TPA3255 when correctly implemented will run at about 40c under normal listening conditions. The chip's internal over temperature warning fires at 120c and it will shut down at 130c. At idle most read about 25c (in a 20c room) and it will be at room temperature when in reset mode. The V3 has issues. There are reports on several channels of them blowing up, becoming unstable or making hissing noises... none of which are typical of that chip.

[@Douglas_Blake]

Unless you have speakers that get under 4 ohms, you will get the same bang for your buck from 3 stereo amps... V3, ZA3, A07, A70 etc. The only time you really need the monobloc (PBTL) versions of the TPA3255 are for low impedance speakers (3 or 2 ohms). There's no power advantage to the PBTL configuration at 4 or 8 ohms. Moreover, the hot running of the V3mono is a design flaw ... the Aiyima A70 mono doesn't have this problem.

[@trauma50disaster1]

the previous versions of these over the years are all cool, I forget to turn them off and the next day they are cool.

[@paulgyro]

@@trauma50disaster1 yep same here. I just leave it on all the time as a result.

[@dpernish]

Such a genuine video. Thank you. You clearly know a lot, but still pretty humble and not trying to look like you know everything. This is important to me. Glad I am a subscriber.

[@joentell]

"Pretty humble." Not totally though. 🤣 I try to stay in my lane and defer to others when needed.

[@leetaylor13]

I'm also running a 6 pack of these for 3 way active speakers. I'm using them on their sides with push-pull 14cm Noctua fans top and bottom to assist in vertical heat dissipation. There are 3D printed brackets to keep the whole amp block stable preventing individual amps moving independently. Add in the price of 6 short right angled power cables and USB cables and adapters for fan speed control, an 8 way mains extension block, and a smart plug and the costs start mounting. Even with prudent shopping I've spent £150 on extras. The amps themselves are only a tiny fraction of the space it all occupies. It takes up only a little less space than 3 standard 2U ish power amps with a bit of ventilation space and a fair bit more space than many dedicated 6 channel amps. Then there's all the added cable spaghetti to manage. All in all, this route is hassly, messy, and has a hugely negative WAF. It does sound rather nice though and if anything breaks, I don't need to replace the whole lot.

[@sqcaraudio]

Nice one. 10 fosi v3 mono with fans still rockimg with me. Oh and 6 of them are chock full of Sparkos.. Dreamy.

[@Douglas_Blake]

FWIW ... the TPA3255 does not typically run hot. I have A07s which use the same chip and they never get more than gently warm, even when driven into clipping. If you have an AC voltmeter, take a reading across the speaker posts when the amp is on but idle... A sure indication the amplifier is unstable.

[@Monkeyseemonkey79]

I have been running two of these on my primary system since they were released and have had zero issues. I have positioned mine on a glass stand, with the amps sitting next to each other side-by-side, but with approx a 3" air gap between them. Yet to have any issues.

[@joentell]

I would recommend fans if you want them to last.

[@Monkeyseemonkey79]

​@@joentellcan I ask how the two amps were positioned relative to one another when one of them died? Your video includes lots of shots of amps stacked on top of one another, or sandwiched next to one another tipped on their sides - with no air gaps between each amp. Did you actually run them like that for prolonged periods? Or was that just for production purposes?

[@eriklamelakillingspree7690]

I would buy a 5.1 channel class D from Fosi! Make it happen!

[@scottishdouglas4214]

I thought about using these for my lcr but i ultimately bought a 8 channel buckeye amp 4 at 350 at 8 ohms and 4 at 150 at 8 ohms

[@anthonyperez_audiophile]

Great review Joe! FYI, I have used the Tricklestar power strip for about 5 years for my vintage 2 channel system and it works great!

[@hcho8164]

I think far field sound scape expectation is driving the motivation to go mono. Multichannel platform poses a challenge to maintaining identical circuit traces. And even a slight extra distance in a signal travel could become detectable by a super duper trained ear.

[@DonnieMulligan]

Agreed! Not to mention finding space for those 6 giant power supplies. Hopefully your power strip and wall outlet can handle that kind of draw.

[@leetaylor13]

I've blutacked mine into 2 stacks of 3 and along with the added mains distribution block needed, they do add quite a bit of bulk, pretty much negating the benefits of the small size of the individual amps.

[@joentell]

Blutack everything!

[@bizmofunyuns6463]

I have 3 of these rolled op amps to the sparkos, running my front sound stage. Love them!

[@johnbilke9464]

What timing. I am getting ready to do this with some Aiyama A70's tomorrow. Nice insight.

[@ChihuAudioMan]

I bought 3 of these on the kickstarter, and they run warm. I bought some heatsinks and double sided thermal tape to see if it would help at all. Contemplated using them for LCR in main system but they dont seem to be reliable enough.

[@theoracleprodigy]

Have two seven channel osd amps. Work great for a thirteen channel theater. Can't imagine trying that with fosi

[@90sNintendoKid]

Great video Joe, as always. I've got 3 v3 monos for my LCR and a stereo v3 for my rear speakers. I've got the Fosi fans too but I didn't know about the problems with the Auto off feature. I am going to use a smart plug to turn them off when not in use. Going to be using Magic Beans on my setup this weekend.

[@joentell]

🙌🙌🙌

[@JMJM75257]

Run them at 42v and apply decent non conductive thermal paste. you will have no heat issues. Imo 48v is too high for this chip long term. 42v is peak efficiency range for the chip.

[@editorjuno]

Running two stacked A07s @ 46-47 volts -- I don't run them any at higher than that due to their 50 WVDC shunt capacitors -- with zero issues pretty much 24/7/365 for 4+ years. No issues whatsoever "long term" AFAICT. How did you determine "peak efficiency?"

[@leetaylor13]

I tried these with both 48V, 5A and 36V, 6A supplies. To the touch I found very little difference in temperature. The Aiyima A07 Max ran a lot cooler with the smaller PSU. The A07 runs cooler still.

[@garymcguire9463]

Very professional and informative channel! I very much appreciate your dedication.

[@garavonhoiwkenzoiber]

6:50 "heat, and using the case as a heatsink" the problem with that is heatsinks, and even radiators still need airflow. A heatsink with no airflow will only cool until the metal has saturated with heat. After that happens it'll start to get hotter and hotter.

[@joekelley9311]

I use a AC Infinity AIRCOM S7 fan under the pair of mine with an Apple TV in the center. At 1/4 power it is near silent and keeps them room temp cool.

[@TimSmith-db1iu]

Those smart power strips are cool!!

[@zihotki]

Something is very off with the sound. Somehow it sounds very artificial and I have a feeling that it's not well synced with the lips or something along the lines. The issue is subtle but noticable.

[@joentell]

You're talking about my video, right? I used the auto-sync function in Final Cut Pro to sync the audio captured with the mic with the scratch audio from the camera. Maybe it was slightly off.

[@editorjuno]

No heat issues with my two stacked TPA3255 stereo power amps running 24/7 driving the ambience/surround speakers in my 7.1 system -- and they're four year old Aiyima A07s, which have a well deserved reputation for *very* poor thermal design.

[@jdschatzberg6612]

I put an $8 heat sink i bought on Amazon under mine and they run nice and cool

[@jasonk5979]

The case is the main reason i haven't bought them. Its screaming for a real heatsink. Wouldn't even have to be a huge heatsink. I know it adds to the cost but i really would rather have a more reliable product. Too many people have had those die. In the middle of reviews.

[@kovrcek]

There is a version on Ali called YS-AS21, now delivered with 3255 chips. Using it for near field sub 300W 15inch and it rocks the house. It has built in active cooling (albeit fan is quite loud to my taste, but it's far from me so I don't care and night low volume listening makes it dissappear completely). I was even considering to remove the fan as the amp is quite cool. Hmm maybe I won't do it after watching this.

[@poyocru]

I'm very happy with fosi v3, with opa1656 sounds wonderful, (for the haters, yes I have good class ab amp aswell)

[@klc2578]

I actually think of active speaker for all speakers, but my way is even cheaper if just for under 300sf room. it's 4.4.4 setup with Edifier 4 pairs of active speaker + 4 subwoofer for each pair speakers.

[@Duggar200]

I use a CyberPower CP1500PFCLCD PFC Sinewave UPS System, 1500VA/1000W, 12 Outlets, AVR, Mini Tower on my Home theater set up. Marantz SR 7015, Panasonic DB-UB820, Technics SL 1300MK2, LG C3 77in. 2 SVS Pro 1000 subs.

[@tomlong5130]

Magic beans, really cool, recommended!

[@LeeLee-fi7mx]

I have been running multiple fosi v3 stereo amps as well as the tb10d and bt20a with the 48v power supplies turned on 24/7 for over 1 year now and have not had problems. If your stacking the amps as shown in your video, that may explain why you had an amplifer die, due to heat buildup from the lower amplifiers spreading to the amps laying on top of them.

[@joentell]

It was not stacked when it died.

[@impuls60]

@@joentell May not be relewant but for every 10c increase you HALF the lifespan of a capacitors. So stacking may have weakened a capacitor so it let go prematurely. Extra voltage margin and higher temp specs usally makes them live way longer. Like decades longer vs 82C 50V cap beeing used at 50V which was common in china amps years ago. Fake caps is till a huge problem and the temp rating and voltage tolerance can be lower in reality than what the prints says. So buying a known brand like Nichicon from a thrusted supplier actually means something in this situation.

[@joentell]

@@impuls60 it wasn't stacked when it failed. With the fans, they feel much cooler even when stacked in pairs, since the fan moves the hot air off the side of the case and upward. The amp on the bottom of the stack isn't much cooler than the top one. I found that putting them on their side with a fan forcing air through the vents kept them the coolest.

[@leetaylor13]

@@joentell I'm doing something similar with push-pull fans top and bottom. I found removing the gold grills from the sides of the amps and using flexible PC case dust filters externally instead seemed to increase the airflow and aid cooling.

[@littlewicky1]

Notuca sell the NF-F12 5v fan that comes with a USB adapter to power the fan. Cheap way to go some airflow

[@AeroCluster]

Have you heard about OSD's new HTX Class D amplifiers? I haven't used one myself yet, but the HTX8150 seems like a cheaper/better solution for someone interested in using Class D for home theater. It's the same price as that Class AB OSD amp you mentioned but much less heavy.

[@joentell]

I haven't yet. Thank you.

[@kittykatking7882]

I was hoping this would be about how they perform over just using the theatre receivers' own amps. My denon on its own sounds horrible compared to using amps on the pre outs. But I got no information on that at all. The info on the power bar made up for it, considering I didn't know that existed.

[@joentell]

I was planning on doing just that, but keeping these running cool took precedence once one failed and I realized how hot they got. How they sound isn't important if they aren't working. Having said all of that, it sounds good. They can probably deliver more power than my Denon X4700H and X6700H with all channels driven, but truthfully, with a sub, I can already play those loud enough without any signs of distortion. People shouldn't expect a huge improvement in sound quality by upgrading amps unless they're reaching distortion.

[@ediarapi2213]

Bro what happened to the Novus A5 review? Been looking forward to that for a while now. Great job on this review tho, real one

[@joentell]

It's next up. I had a long queue.

[@ediarapi2213]

I see. Thanks Joe

[@OperationNorthwoods]

Off topic, but what camera do you use for video?

[@joentell]

Sony A7SIII

[@Pabula]

How do you buy form OSD, went to the page and didn't see any values or amount?

[@joentell]

Amazon or outdoorspeakerdepot.com

[@jason_mc77]

Give it a month and one of these companies with these types of amps will have a "new" version with a builtin fan

[@phillipmorris9847]

If you use the 32v 5a ps = lower power, less heat, and cleaner

[@mistakeapp]

Best are aktiv Speakers with a canton smart 5.1 amp ;)

[@gsanchez922]

How about a power strip that use the 12v trigger?

[@joentell]

I think I saw one, but it wasn't cheap

[@gsanchez922]

@ by the way I have a idea for a tool that could a perfect complement for the calibration tool kit

[@joentell]

@@gsanchez922 hit me with it

[@kadajawi2]

If they are so efficient, why do they run hot?

[@joentell]

Too much power is my guess. Efficiency just means there's less wasted power, but these are nearly 5X the power of that original SMSL SA50 in nearly the same size enclosure.

[@turbomustang84]

Not to knock Fosi Audio but I've had a couple of their amps and had issues and I've yet to have a problem with the Aiyima amps I presently have 6 and gave away or sold another 4

[@joentell]

I bought an Aiyima A07 and it didn't work out of the box.

[@ErinsAudioCorner]

😊

[@desoll11]

The Aiyama a70 mono's run cooler and are cheaper for similar sound

[@Douglas_Blake]

In General, Aiyima products are better engineerd than most of the lower price chi-amps.

[@daleboylen6427]

PFFB is the only thing that makes sense in these cheap class D amplifiers. Negative feedback is used to broaden bandwidth and reduce distortion. The problems arise when you apply too much feedback as then you create transient related distortions such as TIM. Of course you'd want the feedback loop to be post digital filtering. MY big issue with these tiny amps or any IC chip output amplifier is they cannot output high current. Wattage, yes. Current, no. Speakers demand CURRENT, ESPECIALLY in home theater with sound effects.

[@Grommet2007]

But Watts = Voltage X Current, so high current is required to produce high wattage ...

[@yosyang]

Yes, so true. After years of using tiny class D amplifier. I switch to large size class AB amp from CN, sound so much better, almost no hizz noise, no on/off pop, very efficient standby watt. class D amp sounds like choked sound, but the class AB amp sound much more alive.

[@tallpaull9367]

flip the amp upside down and mount a aluminum heatsink where the chip is. passive cooling, no fan

[@joentell]

Have you done this?

[@tallpaull9367]

@@joentell Not on this particular amp yet but I have done all sorts of similar work on other amps, computers... I do have a set of V3 Monos and will do this. I plan on having them sit in a rack on their side, orient the heatsink so the fins are vertical for better cooling. On their side so that air can still flow holes in the case vertically as well. Should work great

[@joentell]

@@tallpaull9367 I'm curious to hear what you find!

[@adsph]

Thanks for sharing

[@Grommet2007]

If one of those little class D things is running hot at idle, I'd be concerned about the design. What's the idle current?

[@joentell]

I'm not sure what the idle wattage is. I think it's around 10 watts from what I've read online. Please double-check.

[@AudioGuyBrian]

6 mono amps for a typical DTS-MA or Dolby Atmos 7.1 system? I think you would need at least 15 mono amps to do that right. LOL.

[@joentell]

Yeah, I had to use other class D amps to keep the experiment going. It sounded good!

[@mkhaudio]

I use za3 amp to power my frint wide speakers

[@kevinwest1607]

All my class D amps hardly ever get above room temperature.

[@leetaylor13]

My class D amps in coolest to hottest order. SMSL 36A Aiyima A07 and Fosi V3 Aiyima A07 Max Fosi V3 Mono.

[@dfknyc78]

Some of your technical details are incorrect. For example, an EQ will not do anything for load dependency of an amp.

[@joentell]

Do you know for a fact that the frequency response effects from load dependency don't scale linearly with volume? If they do, then eq can compensate for it. If not, then it cannot. I do not know the answer. Which other technical details do you think are incorrect?

[@dfknyc78]

@@joentell All speakers are complex load. It's complex load because the music signal going in is not a constant tone, and then depending on the frequencies (because again music is not one frequency, it's combinations of different frequencies at different level) it activates different driver(s) of the speaker. How do you EQ that? If a system's level is non linear in the frequency domain, then that can be EQ'ed (except speakers with terrible radiation pattern, you will be fixing the direct sound but messing up the reflected sound). But you are talking about a system's level is non linear in the load domain.

[@joentell]

@dfknyc78 that is my question though. I get that music will activate different parts of the frequency range compared to full range pink noise. But, the question is whether it changes with loudness. A full-range EQ can be put on a speaker, but only parts of it will be noticeable when activated with certain frequencies from music. I've asked Erin about this when he does his reactive load testing and he says he doesn't know either. If you know for sure, then please explain more. I'm here to learn as well.

[@dfknyc78]

@@joentell I'm not understanding what you are asking. Let me see if I can simplify my comment. When a system is frequency dependent, it means the level varies based on the function of the input frequency. So let's say at 12kHz, the level is +3dB too high, you can specifically EQ that down 3dB to compensate. But if a system is load dependent, it means, the level varies as a function of a load; but the load is complex (like all speakers are), how do you know what the load is at any given point in time of the input signal (music)? I can further simplify this some more: if you are saying you can EQ these Fosi amps (or any amp for that matter) based on load, then tell me which hardware/software you would use to do this?

[@joei4ever]

this is solving a problem that doesnt exist. Why go through hassle of pile of cables, power adapters, cables, when there are better solutions that already work as good or better.

[@joentell]

I did mention that

[@electronash]

I just started watching - I hope this goes well, as this is pretty much exactly what I'm using in the DIY AVR. lol TPA3255 chips in Stereo BPL (bridged) mode, with a big 48W SMPS, differential input, and PFFB.

[@joentell]

You're my other electronics expert.

[@MohsinWadee]

It seems to much of a faff. Yes they're small, but you're still getting cable spaghetti, then a power supply for each amp etc etc. Not worth the trouble.

[@joentell]

Agreed

[@Grommet2007]

@@joentell Use one larger PSU and multiple DC feeds from it to the amps. Ain't no way your HT system is going to call for 200+W from all channels at the same time.

[@richardoates8103]

talk about underdelivering on the promise of the title, he never actually shows the 6ch monoblock system or any measurements

[@joentell]

I explained that I didn't do measurements as they've already been done by others which I linked to. You want to see them connected to my Pre-Pro? Just ask me what you want to know and I'll do my best to respond.

[@richardoates8103]

@@joentell your tilte claimed you made a multi channel audio system with these low cost hi performance monoblock amps , but the video felt like a commercial for the fan device

[@joentell]

@@richardoates8103 I did set it up in a multi-channel setup. Do you have a question or are you just looking to complain?

[@thinkIndependent2024]

Get with your buddy I built a 12 Channel(2 boards 3 TPA325 each) with a 3000 watt Power Supply and cooling fans and case for under $350

[@jacobsgarage1458]

Class D 😂

[@joentell]

That's funny?

[@saltzine]

:: 🤠👍

[@eddietours3728]

cool

[@DamionG1987]

I'm just wondering....why?

[@joentell]

I answered that at the beginning. Because I can. 😉

[@crazyprayingmantis5596]

Op amp rolling is the biggest load of BS.

[@joentell]

Maybe for people who don't know how to EQ with DSP. 😁

[@scrout]

Each 10 deg C cuts electronic parts lifetime in half....

[@Roddy451]

mhtirogla