This Mini Amp Sold OUT in 24 Hours and Here's Why 

What about the remote?

Thanks for the link...but it is SOLD OUT

Can you provide a paylist for the songs that you have used?

Will this thing handle 60 volts? Thinking about putting a stereo on my 5600w electric scooter

@@buddsmokengood No. 48 max ...

Hi! Do you have a diagram for such wiring please? Woukd you know how to also add a Subwoofer to the setup in this case? Thank you

This is not the best idea due to crosstalk. It's better to use one amplifier for stereo low and second for stereo mid-high if you use an external crossover (a bit of crosstalk between left and right is perfectly fine, between low and high not so much).

​@@jd5787dude a lot of home audio amps are bi amp ready. What he is doing is ideal.

@@AdamsOlympia yes I been running it in mono mode bi-wire for past few months. It’s really good. I am considering getting another amp for my center channel. I also considered getting an internal chip upgrade, not sure if its worth it and also for mono do I need one or two per amp?

@Zeck88522 Sorry...this doesn't make sense....

Going to check out your channel since my uncle wants to buy that jbl Bluetooth speaker

can you say shill

I'm also doing 8 videos straight on my Old School Stereo YT channel starting tomorrow! An old school amp test each day for 7 days!

Can’t wait for those videos Big D!!! Thanks for the early Christmas present!!! May God bless you my brother!

Hopefully I won't have to remove it as the track itself is public domain, but not sure about the Telarc recording. I had a lot of fun listing to a ton of CD's with this setup! Too bad the experience cannot be shared over RU-vid

I recognize it but can’t remember that song. I think I used to own it. Help a brother out?

@@effectivetactics422 it’s a Telarc recording. I’ll find a link and paste it in the comments.

Bachbusters, an awesome sound quality disc.

@@550n440THANK YOU! I think I STILL have that disc! You rock

You should hear tocata and b by bass mekanik- I think that’s how he spells it…

The amp chip is voltage limited to 48v, so it won't make more power at 8 ohm.

@@SilmarilS79 i never said anything about 8 ohms Also given the 63v caps you can safely go to 50v however even though the chip is rated at a max of 54.5 i wouldn't go any higher because cooling might become an issue I had an aiyima subwoofer amp based on the 3255 and it also had 63v rail caps, i removed the top cover and installed a small fan to the heatsink and i was powering it from a 52.5v 12.5a PSU running at 2 ohms without issues for my 2 10" subs Good power from it, i still upgraded from it because it wasn't quite enough for 2 10" subs but it served me well.

@@Random_4400 "still upgraded from it because it wasn't quite enough for 2 10" subs but it served me" do you mind telling us, What;s that amp you upgraded to?

I don't plan on letting it go. Have the original box, manual, remote and it's such a nice piece and the sound is amazing

I have the 5es also weights a ton eh..problem being the laser failed after many moons and cannot get a replacement..bugger

Texas Instrument rated the chip in PBTL mode for 2 ohm loads.

They also rated it for mono into 4 ohms and 8 ohms and yet, measurements were taken by Williston Audio Labs to verify Texas Instruments chip rating. So why not take the final measurement for us at 2 ohms as well? The whole purpose of these mono amps is the ability to drive 2 or 3 ohm loads. I would have liked to see the results as I'm sure many others would. Of course, a current output comparison between stereo and mono mode may have been even more revealing. @@SilmarilS79

It's safe to assume 2ohm Mono isn't going to be too far off from @200w and dynamically around 260~280w.

Likely those are just "per-run" testing errors. It happens.

That switch definitely needs to be elsewhere, these companies almost get things right, they haven't made the complete package yet there's always something that is missing or misplaced. Very frustrating

@@crazyprayingmantis5596 Agreed ... It's almost like they have a "department of silly mistakes" to make sure of it. If it was up to me changing modes wold require removing the front cover.

@@Douglas_Blake_579 or maybe a recessed switch in the rear.

Well, idiot me just did that today messing with cables on the fly. The amp stopped playing, but after a switch off/on, it worked again with apparently no issues, guess I was lucky, idk. However, it can't hurt to put the switch somewhere else and kinda foolproof.

@@34332 Oh man, that could have been a shitty Christmas present, for sure. I'm glad it came back on! But now we know... it's not a safe thing to do while the amp is powered up. I can't offer a guess how often you would get away with that, but I'm thinking you were lucky. Now I wonder if that's why one of the amps failed during Dereck's rather gushy video... Let me be plain here... I like Fosi and it's ambitions to bring excellence to inexpensive audio, but of late I seem to have a habit of calling them out on some pretty serious engineering mistakes... If you look at my other posts you will find one about the TB-10D, where they not only misunderstood the chip's control logic but left the thing in a state where it would actually play music while turned off. Now this stereo/mono thing. I wish I could say I didn't see it coming a mile away, but I did. Even worse is the matter that literally dozens of reviewers extolled the virtues of the TB-10D after Fosi's supposed upgrade... and none of them caught the problems. Not one of them. Not even the guys doing hardware testing caught it. Now, after more than a dozen ZA3 reviews and the only way this one is caught is by accident. This is not good. I'm betting the AO7Max has the same issue, except that they had the common sense to hide the switch in a spot where the kids won't play with it and it's unlikley to be flipped by accident. Dumb mistake Fosi ... really dumb!

2 for the XLR differentiators. 2 for the Sub filters then 2 for each channel's phase splitter ... total... 8 op-amps. The extra 2 are in the sub filter... so maybe it's got a really sharp cutoff.

Interesting. Thank you for the breakdown. @@Douglas_Blake_579

So if you were to swap the op-amp for the xlrs would you need one or 2?

2 op-amps, but only 1 chip package. @@c34webb

@@c34webb 1 chip ... 2 op-amps. The board is marked. so you know what you're messing with. But if I might suggest, leave that one alone. The differentiators for XLR are a rather sensitive balance. They have to be just so to minimize distortion. Try leaving it alone at first. Change it only if you need to and be prepared to change it back later.

If they wired it up correctly, inserting a TS to RCA cord should also work as an unbalanced input.

Wow! Thank you for the reminder. It's easy to start thinking in terms of big fat XLR cords and overlook TRS connectors. 👌

Or a strong preamp would do the job. I don't get why people are expecting these to perform perfect standalone, you MUST have a decent preamp to get solid performance.

The truth ... "No" ... until your Yamaha breaks it should be just fine for your needs.

Unbalanced is subject to noise from errant electromagnetic sources. Balanced is not. It is not dogma, it is a technical solution.

@@AdamTait-hy2qh, quite honestly for most hifi-applications in residential environments, XLR is very much a nice-to-have for most people. The advantages are larger for longer cable-runs or much noisier environments than a normal living space. If you have long runs of RCA running along power cables or in-walls or such, there's a good case for XLR, but it's rarely necessary for things like hooking up a separate power amp with a cable of a few feet.

@@AdamTait-hy2qh Try measuring/hearing that noise on a 1M interconnect and compare that to the noise floor of the equipment and recording.

I could not get it to trigger a 2nd ZA3, but the 2nd one I have would not turn on. Fosi didn't provide info on the cable needed, but I believe it is just a TS 3.5mm, but TRS will work as well.

The standard trigger cable is a mini-TS (mono microphone) cable. I doubt the 12 volt trigger is bidirectional ... more likely it's just an input.

@@wal Doesn't look good when they send you a dud as a review sample!

It's already bridged in stereo mode.

Hello, Doug. Can you provide details about those mods?

@@MiguelAngelVelazquez Here ya go: As long as you can do some minor SMT soldering it's pretty easy... 1) At the left front corner of the main board there is a zener diode (tagged D1, I believe) that sets the logic control voltage. On the version 2.1 and earlier board it's setting that at 5 volts. You can test the voltage on the centre pin of the power switch. The control logic for the chip is 3.3 volts. You will need to parallel another zener onto the existing one to reduce that voltage for proper operation. I found the right value by experimentation, but IIRC it's 3.9 volts. 2) When off, the reset pin on the TPA3255 (Pin 18) is left floating. This actually allows the chip to remain on with the power switch in the off position. The fix here is to scratch away some of the solder resist, exposing copper on the bottom of the board, at the bottom of the rear leg of the power switch. Now solder bridge that pin to the exposed ground to force the chip to shut down when the switch is off. (Later versions have this done already) 3) The last mod involves a problem with the output coils. They're too close to the main heat sink. This causes all kinds of inductive eddy currents in the heatsink, and cross coupling between the coils which causes all kinds of minor havoc, including inductive heating of the heat sink. The fix here is to remove the heat sink, being careful not to lose the spacers and cut away one fin smooth with the bottom of the second fin, effectively making it one fin smaller on one side. Now, clean up your cut, redo the thermal paste and replace the heatsink so that the missing fin is nearest the coils. This creates about a 1cm gap which is sufficient to avoid most of the inductive coupling. The first two are for longevity of the amp. The last one cleans up the sound quality quite noticeably. Best of luck with it!

@@MiguelAngelVelazquez Also note ... these mods apply to the TB10D *only* .

@@MiguelAngelVelazquez Just a quick update ... I've just gotten TB10Ds in. The board version is now 2.2. The power switch problem is fixed, that back pin is now firmly grounded as it should have been. The logic voltage is still sitting well above the 3.3 expected. I just read 4.7... so you will need to fix the zener diode controlling that. On the V2.2 board it is at the board edge next to the power switch, tagged as D3. Of course the heatsink is still touching the coils which affects the sound quite noticeably. Comparing the new stock with one of my modded units the bass is a bit boomy, not clear and the highs are less distinct. So cutting one fin off the heatsink is still a viable modification. Hope this helps.

​@@Douglas_Blake_579thanks for sharing

What a deal!! I need to find that deal. I just bought two ZA3’s and a wiim amp to try these smaller amps out but unless you’re in need of every single inch of space why not just get what you did. I’m guessing the Emotiva would sound night and day better than these small class D amps. I have a Onkyo A/V amp running at the moment and I’m curious how all these would compare including against your Emotiva. Great find!!

Do a search for "TPA3255 data sheet" everything you need to know is there... The chip is fixed gain at 21.5db ... Voltage gain of 12

In a stereo bi-amp setup you actually do get twice the overall power where in dual mono mode you get the same power as in stereo mode.

Thanks so much for your response! Happy new year!@@Douglas_Blake_579

The best use case would be for very low impedance speakers, under 4 ohms.

@@Douglas_Blake_579 Thanks. That won't be my use case, so I'll just stick with one and put the rest into an svs sub. 👍

@@NWGR Sure thing ... and a pretty good choice too.

Its same power. Same output filter . Interesting is 3e audio tpa3255 . Wondom have little bit more power.

I prefer it over my Fosi BT30D. Mainly because it has the large heatsink with a fan. If Fosi would use a vented case with ALL of their amps, they would greatly benefit. Keeping any of of these chip amps in an enclosed case isn't the best design, especially higher power chips like the tda7498 and tpa3255. The Fosi case gets SO HOT, especially at 2ohm. Had to disassemble it and drill holes in the case and that helped greatly with cooling. But none of that is a huge deal. I feel if Wuzhi put their amps in a case with banana plugs..etc. they would be a VERY GOOD competitor. These amps sound wonderful, obviously run cool, have most of the same features eq wise, 2ohm stable on all channels, protection circuitry. These Wuzhi amps also have LOTS of capabilities for add ons. Like adding a separate sub amp to a 2.0 amplifier..etc. aftermarket bluetooth chips, dsp chips..etc.

I use it inline with a Schiit Audio Modi 3e and a Schiit Loki eq for a little extra low end Oomph(loki starts from 20hz)

??? TRS can also carry a balanced mono signal just like XLR.

maybe eventually. RU-vid compression kills the SQ for you guys anyway, so not sure how much sense it makes to use really high end speakers

I hooked the amp up in mono mode as shown and described by Fosi Audio. It's also labeled on the amp to use R input and only R output

Correct the XLR Op-amp is a dual chip. Correctly done the two opposing signals of XLR are received differentially, and summed to create a single phase signal for the internal electronics. This is how the noise canceller gets enacted. The Hot and Cold audio lines are out of phase... but any noise on the twisted pair is almost certainly in phase. Out of phase signals pass through while the in phase signals are cancelled. To not do this, means doubling every circuit in the device. Not only does it make the device more power hungry and more failure prone... it fails to cancel noise on the inputs.

Yep... and when sitting on a bench or table likely to pick up lumps of dust that can degrade the cooling quite a bit. Best bet... buy some thermal paste, clean and re-paste every time. The fun part is that unless you want to waste a ton of paste, you need to put a thin line of it inside the case so the heatspreader will pick it up as it moves over it. Putting it on the spreader will just result in a big smear of wasted paste all the way along the case.

​@@Douglas_Blake_579 Good info, tx!

ALWAYS attach the shield at both ends unless you want to build an antenna.

Follow the instructions ... also the amplifier case is marked. Pre-out right -> za3 1 right in -> right out -> right speaker. pre-out left -> za3 2 right in -> right out -> left speaker

They're both based on the same chip. The difference in distortion specs is probably due to the extra Op-Amps (the NE5532 chips are a bit messy). The Mono mode parallels the two stereo channels for more output current. It's no surprise the power ratings are nearly the same.

Mono use will gives you more control of a 2 ohm load than in stereo configuration. Might be better for hard to drive speakers that dips below 4 ohm. Running a 6-8ohm load, it won't matter between stereo/mono.

@@SilmarilS79 The only real difference at 6 and 8 ohms is the chip will run a bit cooler in Mono mode.

@@SilmarilS79 I'm actually using the Fosi V3 with my Magneplanar 1.7's (amazing isn't it?) I bought the ZA3 wondering if using it in mono and getting a second one would be worthwhile and it is not for my purposes. Actually the V3 sounds great - currently playing wonderful Christmas Music - Merry Christmas to all.

​@ernestojajan1419 I did the same thing , had 2 za3's and tested and compared against my v3. The 2 za3's vs my v3 was only 1 decibel louder but more harsh compared to my V3, to me the V3 sounds much nicer. All the za3 is doing is killing off 1 channel nothing more in my opinion, you can get technical all you want but 1 decibel isn't adding any power increases. Back to back the v3 wins in sound but looses with no sub out.

The TPA3255 chips won't even start up on 12 volts. This is not a car amp.

@@Douglas_Blake_579 I understand, I have 2 of them powering a system now. I'm trying to make a DIY 12v trigger module, but I've never done anything with those triggers.

@@MacCelium Okay, now I understand your question ... The trigger will use a 12 volt supply, any old regulated wall wart will do fine. Be sure to check, because some actually output 13.8 volts... The trigger cables are 3.5mm TS mono microphone cables. Nothing fancy. The wiring can be as simple as cutting the wall wart DC cord and adding a switch inline, then hooking up 2 of the TS cables to it. The Tip is positive the Sleeve is Negative. Switch on... amps on... switch off... amps off. It's pretty easy.

@@Douglas_Blake_579 Thanks a ton, that is exactly what I hoped the solution looked like but one of forums said it was a crazy idea. I just did not want to start playing with things until I had some confirmation. Appreciate the info and Happy NewYear.

@@MacCelium If you want to play it extra safe wile testing put a small resistor in series with the switch... 100 ohms should do the job, at least that will prevent you from dumping half an amp into that socket. Best of luck with it.

Easily

The amp chip has 4 output channels and is technically running bridged in 2 channel operation. Fosi choose to run the 2 Bridged channels in parallel for mono mode for quality and stability over higher wattage. 2 channel is BTL, mono is PBTL. bridged tied load and parallel bridged tied load

What Josh said^^^ The outputs are already bridged in stereo mode. The mono mode parallels them for more current. The only real advantage of the monoblock setup is that you are using 2 power supplies for increased current output into low impedance loads.

I just thought the power would of came close to double, not 10 to 20 watts over than running in stereo mode. To me it looks like one channel shuts down as if you did the same in stereo mode but unplug one channel. 🤷‍♂️

@@mattburgess2 First, since the outputs are bridged already in stereo mode you're not going to bridge them again. Thus the output voltage across the speaker _will not change_ If the voltage doesn't change, neither does the wattage. What they are doing is hooking the outputs from the left and right channels together to form one monophonic bridged amplifier. This gives them more current capacity for low impedance loads but doesn't increase power on the more common loads. Where the extra power comes from is lower speaker impedance... For example, if you are running 50 watts on 8 ohms, the same speaker voltage would produce 100 watts on 4 ohms... or 200 watts on 2 ohms. It's that last step that requires the Parallel Bridge Tied Load mode of the chip. So, if like most of us you're using speakers in the 4 - 6 - 8 range you won't get higher power in mono mode.

I think I understand now, thank you

Continuous RMS. In class-d designs with requlated supply the two are almost the same anyways.

You should hear what an A07 or TB10D can do on floorstanders. I've got mine hooked up to Pioneer towers and there's a pretty significant wow factor... Heard a V3 on a friend's Heresys and OMG that was sweeeeet! I really do wonder if these guys know what they're selling...

I did not pay for the amp but this doesn’t matter as I have more amps than I need and my goal is to share the info for others and not to promote any amplifier brand

Awesome, thanks for watching and commenting!

Yes

@@Douglas_Blake_579 thanks i'm getting one when it gets back on stock in amazon

_" In fairness though, audiophiles probably drive the advancement of music reproduction technology. "_ Listening to them bragging about tubes and giant amplifiers designed 30 years ago lends considerable doubt to that thought. If anything, jealousy is holding us all back as these ijits go out of their way to trash and dump on advancements in technology.

@Douglas_Blake_579 Good thing I'm not an audiophile. You make good points though.

@@troyhartley9681 I gave up the appelation years ago. There's way too much "science" in the audiophile community that just doesn't hold up anywhere else. Being a technician really makes it obvious, too.

@Douglas_Blake_579 What do you think really drives innovation in audio? Have we hit a plateau somewhat? It feels like there hasn't been any significant improvement for awhile.

@@troyhartley9681 To be honest I don't actually know what the driver is in Audio right now. Certainly the chip designers are pushing the edge as are the sub-assembly makers but a lot of that is just "next generation" stuff, not brand new invention. More channels, better encoding, lower distortion, are all tweaks not inventions. Probably the last true Audio invention was Class T which came along in the late 1990s, a quarter century ago. The TPA3255 chip, patented in 2015, is a breakthrough design, incorporating extra feedback paths for Class D, derived from Class T. But even that is just a "next step" in the design. The one thing I can promise you... It is not our hobby. Most audiophiles are stuck in a very deep rut that was dug in the 1980s as class AB was developed to it's limits. The reasons I would cite are complex, well beyond a comment level reply. But the short form is that the smarter our devices get the dumber their users seem to become. Some days I fear the power is going to go off and there won't be anyone left who can get it back on again.

yes real 'entry' and affordable gift would be awesome, sort of limited yuins, these op buds just too generous, but suit the 11+ yrs i guess