Fosi ZA3- Teardown / Comparison / Review - Topping LA90 Who?

[@stevenhunter3454]

Nice to see companies like Fosi, Aiyima and Wiim pushing the envelope in this market segment . Nice commentary. 👍

[@MattCoykendall1]

Agreed, I like the high end gear as well but I want to see these budget brands push this as far as they can.

[@ryanchappell5962]

I love that this amp has an upgrade path. You can start with one and then buy a second.

[@MattCoykendall1]

True, budget enough that it gives you some viable options.

[@MindfulProgramming]

4:40 note: while there is no integrated *control* over crossover frequency, the subwoofer output features an integrated low pass filter to cover the 20Hz - 300Hz range. source: Fosi Audio's youtube channel. just sharing this info in case it is useful to someone

[@fosiaudio]

We have not integrated crossover control because most of the active subwoofers have it. So do you think we need to add it on our amplifier?

[@MindfulProgramming]

@@fosiaudio no, I agree with your assessment.

[@fosiaudio]

@@MindfulProgramming Thanks, most passive subwoofer owners may need the crossover. And we are planing to develop a crossover for those who need it.

[@Alim_Mohamed_salih]

@fosiaudio what's the quality of Power supply? Can you brief pls?

[@michaelwright1602]

Thanks Matt, you are a natural at this stuff. I want to throw this out there... This is more of a comment on the Texas Instruments amp chip, and would apply to most if not all of these amps using it, including the ZA3. I just bought the V3, ZA3 is a month out on back order, but I am really impressed with the internals of these little amps. I ordered a pair of the Sparkos with risers and am chomping at the bit to receive them. The sound of the V3 is quite impressive through my PS Audio DAC/Preamp. I'm using the WiiM Pro via digital coax to the PS Audio unit and it sounds darn good, not so much of that Class D sound, but more A/B through my Zu DW6 Supreme speakers. One thing though with the V3, it was rather thin and lifeless, until I dug up a pair of male XLR to RCA adapters and plugged those into the XLR output of my DAC, and ran RCA cables to the V3 inputs. That extra line voltage produced via the XLR connections really lit up the room in regards to overall sound quality, as did bumping up the WiiM EQ settings. So, I ordered a line level booster to see if we can really get this V3 to sing. I guess, at least from my reading, the TI amp chip likes higher voltages, and so far, that is exactly what I am discovering. I would assume the same applies to the ZA3. This TI amp chip is another beast, and I am surprised no one has mentioned the line level voltages, in regards to overall sound quality. The added power really boosts the overall soundstage, along with instrument separation and the overall dynamics of the recordings. And, I have both power bricks, the 32v and 48v, I heard no difference between the two in regards to driving my speakers or getting better sound. The Zu's are 95dB and 12 ohm, so only a few watts are needed to get great sound out of these. So, I am just letting folks know about these line voltages and the TI amp chip. I will have the line booster today, hopefully I will have time to install it into the system and see what happens.

[@Douglas_Blake_579]

Hello Michael ... indeed you are correct, the TPA3255 chip expects 2 volts for clipping with a 48 volt supply and about 1.6 to clip on 36. These are pro-audio levels so naturally the added push from XLR is going to work better. Oddly enough the sonic difference appears to be more about the volume control potentiometer than the actual signal levels. Fosi are using 50k pots and their op-amps are generally exhibiting a 20k input impedance. So if you think about the pot at mid-value (not necessarily mid-rotation) you end up with both sides of the pot, in parallel and effectively in series with the op-amp inputs... so 12.5 k feeding 20k ... this amounts to a mid-value loss of about 3db, maybe a bit more. Taking the reactance of the signal coupling capacitor into account, this will produce a mid-volume loss of deep bass, which is audible. Subbing in a 10k audio taper volume pot makes a noticeable difference, particularly in the low bass; 100hz down...

[@Douglas_Blake_579]

A few suggestions for these ChiFi designers ... 1) Separate power switches. We don't always want to mess with the volume control. 2) Move the stereo/mono switches to the inside of the unit. 3) Make the leap to full auto-switching balanced inputs. 4) Include dip switch selectable high pass and low pass filters in the sub-out chain. 5) Start publishing *honest* specifications. 6) Include Clipping and Protect lights on the front panel. For #3 ... it's only a matter of a couple of resistors to make those XLR combo jacks accept Male XLR, TRS balanced and TS unbalanced then it's one more resistor to connect the RCA jack to the hot lead on the balanced in. ... no switching required. For #6 ... The TPA3255 supports Clip and Protect lights natively on pins 21 and 19 respectively. It's only a matter of 2 resistors and 2 leds to add them. If they want to swim in the big boy's pond... they gotta bring the right flippers.

[@fosiaudio]

Thank you so much for your suggestions. I will let you know if we have any updates. By the way, as per the switch selectable high pass and low pass filters, do you mean you can select any frequencies you want? Or just a fixed crossover frequency like 80Hz for high pass filter and 125Hz for low pass filter?

[@Douglas_Blake_579]

@@fosiaudio Thanks for your reply. If you use 8 position DIP switch modules, you would be able to set at least 16 frequencies for each. The filters aren't hard to design, it's just a matter of switching in different combinations of capacitors. The two things I *really* want to see are the separate power switch and that stereo/mono switch moved to a safer location. I won't be buying ZA3s until you do. I've already spoken with a couple of early-adopters who've had the ZA3s shut down on them when they flipped it into mono with the power on. That's not a good thing to have out in the open where curious fingers can cause problems. Really guys... you have good products, don't mess yourself up by being careless.

[@rochester212]

You should start your own company, since it's obvious you know your stuff. "AssholeFi Corporation LTD". No need to thank me, friend.

[@fosiaudio]

@@Douglas_Blake_579 Thank you for your kind suggestions, we will consider them carefully. And if you have any other ideas and suggestions, please let me know.

[@Douglas_Blake_579]

@@fosiaudio I just published a tech page about the TB10D and the issues with it. I sent you a link... If you don't find it, do a search for "The DBPages" ... it should be near the top of the list.

[@willbrink]

Hard to go wrong for the $ for sure, skeptical you get 180w x2 into 4 ohms from it. I'd use two as mono blocks for sure.

[@MattCoykendall1]

Hey Will, I would like to see a few more dedicated measurements here as well, something I plan to get into eventually. I hope to have that second amp in my hands today for testing.

[@Douglas_Blake_579]

It can do it... But I agree for 4 ohms or less you will want the PBTL configuration of the mono blocks and the advantage of dual power supplies.

[@rancosteel]

Texas Instruments is really on to something with the TPA 3255. I listened to an S.M.S.L. with the German Infineon chip and it had digital artifacts at higher volumes using CD’s, cassette tapes, vinyl and Apple AAC files. The TPA 3255 wins hands down.

[@riccitone]

Yes! Was waiting for your review on the ZA3 in particular. Balanced, precise, concise, solid tech comparo, comprehensive as always. Plus, realistic expectations. looking forward to your impressions with two! Thank you, thank you, thank you 🙏🙏

[@MattCoykendall1]

More to come! I am a day behind the rest of the reviews it appears but I was trying to hold out for the second amp, looks like it should arrive today or tomorrow.

[@oliverosrecki7421]

​@@MattCoykendall1Good day! What do you think about Fossi devices? Another thing I wanted to ask you. Is it true that Fossi devices can match the PP quality of devices that cost $1000 and up? For example to compete with devices such as McIntosh, QUAD, Pioneer?

[@tablameister]

Great review - subscribed! The TPA3255 is a very versatile device and has been used in some higher end products (LSA Warp One etc.) so its great to see this available at such an affordable level. Your comment on the mono/stereo switch is spot on - they should have this switch at the back or the bottom of the unit and it should use a sliding or a push in/push out switch to prevent accidentally changing the mode. The RCA/XLR selector could also be relocated to the back for a cleaner front. Great to see a sub out but a variable sub crossover would have been nice.

[@MattCoykendall1]

I completely agree, its a good product but could step it up further with a few modifications.

[@peterbaugh51]

Douk Audio ST-01 Pro has variable pre out. And tubes.

[@peterbaugh51]

TUBE tip: If your amp came with Chinese 6k4 tubes (has a red star printed on the glass), mine caused distortion. I upgraded to much better sound for $17 with GE JAN 5654W matched pair tubes. 6k4 tubes can be replaced by 6J1, 6J2, 6J3, 6J4, 6J5, 6"1N, 64N, 65N, 5654/5654W, 5725, 6AK5, EF95, 6BA6, 403B, etc. Your tubes may be ok. Just an FYI free tip. Thanks for the video.

[@AlanFenick]

Bought a pair of Fosi ZA 3’s and a 48volt 10amp power supply. I bi-wired my speakers and noticed a small change in the loudness and increased dynamics especially in the lower frequencies. I tried the 10 amp power supply in stereo mode and not bi-amped the difference was not as great, but noticeable. While the 10amp power supply is $30.00 more than the 5 amp, I think it’s worthwhile. Fosi has addressed noise problems some evaluators have talked about in the 10 amp power supply by offering a noise filter to those who pledged on Kickstarter for the V3 Mono Blocks for free and 2 op amps also. Fosi has been responsive to problems and that’s impressive for a small low priced manufacturer. I hope Fosi comes out with a DAC using paired chips at a reasonable price. Received notice on 6/1/24 that they will start shipping the mono blocks 6/15/24

[@roysonparsons3300]

ZA3 looks like a winner. I wish Fosi would introduce a preamp and DAC in the same form factor with a matching cosmetics. It would be sweet to put together a system of all Fosi components that didn’t look cobbled together.

[@MattCoykendall1]

Completely agree!

[@dylanmosley3030]

Matt! Masterclass on getting the bullet points out/ some opinion/ use cases/ comparisons/ and humble delivery. One of the best 10:00 min vids I’ve watched.

[@MattCoykendall1]

That means a lot, thanks!

[@shipsahoy1793]

ZA3 was tested into 8 ohms and did 90+ watts per channel into 8 ohms with less than 1% THD using the 48V, 5A supplied brick.

[@tikblang1]

I like the value already for stereo. And, I believe Fosi have a 48v/10A in the works so people wanting to buy two can really appreciate the power increase.

[@icncwx1790]

tpa 3255 (this unit chip) can output 220w per channel at 4 ohms with good power supply 1% thd you need 48v10a or even 12a supply though

[@shipsahoy1793]

@@icncwx1790 I hear you, 👍but at that point, I'd be concerned about manufacture and how robust the thermal design is. Pushing 20w average per channel might not survive long term. Better to use speakers with some efficiency to get your higher SPL's with the amp running more backed off with more headroom. Just a thought for those that want a PS brick that can push those to their limit.😉

[@booobtooober]

According to Williston Labs, similar Fosi amps with the same Ti 3255 chip are producing 42w @ 8 ohm, 71w @ 4 ohm with the 32v power supply and 92w @ 8 ohm, 172w @ 4 ohm with the 48v 5 amp power supply all these measurements are driven @ 1% THD The video and full info Williston Audio Labs, Fosi V3 Con: In mono mode this amp is just that, MONO, not bridged. There is some benefit but not what you would expect.

[@tikblang1]

Not even a 10% power increase in mono? ;-( ..

[@chuckmaddison2924]

The one big plus of using 2 would be that the cross talk would improve dramatically. Limited by only the input device.

[@AlanFenick]

I tried the Fosi ZA3 with a 48volt 10amp power supply (I have the 48volt 5 amp power supply also) there was a noticeable difference in output from my inefficient speakers. I’ve taken advantage of the Kickstarter reward for pre-ordering the new Mono Block V3 (2) with another 48volt 10amp power supply for shipping in June 2024. I own a Van Alstine Dynaco Double 400 and the Fosi ZA3 at moderate levels can keep up with it! The difference comes in the low frequencies where the Double 400 excels. The Fosi ZA 3 is a rare bargain these days. PS: I didn’t try to drive the ZA 3 to clipping or make it go into protective mode. My speakers are 6 ohms and 86db sensitivity. Never thought a $150.00 amp could be so good. As for the spacing of the binding post being so narrow is a legal and safety matter as some European mains plugs are the same size as double banana plugs.

[@PhillioDoede]

Nice improvement over the V3 thats for sure.I would like to see full sized binding posts on something with this much capability, a volume defeat switch so you can use them as power amps, which would go on the front while the mono / stereo switch should be moved to the back. Hopefully Fosi has a new pre-amp coming to go along with this to expand I/O, and add remote capability as this is way more than a desktop class amp and not having a remote is kinda a big deal.

[@MattCoykendall1]

I was hoping to see a pre amp coming for this pairing as well, I know they have something in the works.

[@fosiaudio]

We are developing, but the case of ZA3 is too small, so we will use a different case.

[@PhillioDoede]

@@fosiaudio Good to hear, and looking forward to seeing it. These amps can definitely be a bit bigger given the systems they can power.

[@fosiaudio]

@@PhillioDoede If it is more bigger, I will add more inputs on it. Haha

[@pinusmasterful]

Great review. How would you compare it to your Aiyima A07 MAX?

[@montynorth3009]

My advice to Fosi is to bring out a full sized unit incorporating the following. 1. Several switchable inputs, 4 off would be good. 2. Bass and treble controls, and whilst at it, why not switchable? 3.A separate on/off switch. 4. Incorporate the switch mode power supply within the case where there would be ample room. I am sure other potential customers have their own suggestions. Most integrated full sized amps already have these facilities, so why would I want to go backwards with this small unit which will run hotter as well. If the above materialised, I would probably buy one, but this version is too limited, mainly because I need inputs for CD player, Tuner, Tape deck etc.and I don't want to use a separate switch box with additional clutter.

[@MattCoykendall1]

I know they have something in the works like this but not sure how far out it is or what it will all include.

[@fosiaudio]

Thank you so much for your kind suggestions, we have a fosi audio BT40A under developing and you can keep an eye on it.

[@AdamsOlympia]

Recently returned a Cambridge CXA81 and swapped it out for this cheap little amp. Also “downgraded” my KEF 350s to q150 .. Saved a ton of money, but didn’t sacrifice any noticeable sound quality or features I needed. It makes for an incredibly capable 2.1 system for a single source setup. Got my LG C1 optical output feeding my RME audio interface, with its XLR going out to my ZA3 .. ZA3’s XLR input isn’t a true balanced connection, but there’s no noise/hiss anyway, so not a big deal to me. The only feature I’d love to see would be a high pass filter for sub integration. FOSI is talking about implementing a switchable HPF in future models, which would make it near perfect.

[@fonkenful]

Nice breakdown, Matt. I’m sure I’m not the only one to jump in to agree with your comments on the switching.

[@JayBeezy31]

I’m upgrading my system with tax money. Aiyima T8 DAC, Aiyima A08 pro. Speakers are Sony cs5 stock, but I bought the upgrade plans from Neil Blanchard for 20 bucks so I am building the new crossovers and fiberglass the inside of box and adding the brace from Neil Blanchard upgrade plans. Highly recommend it. I’m getting the SU9 pro DAC , and either the topping PA7 plus or two fosi audio ZA3….

[@TheMikecho]

Fantastic review. I watched all the reviews available on youtube for fosi za3. This review is best one b y far.

[@MattCoykendall1]

I really appreciate that, thanks for watching

[@mediapr4566]

Why not talking about the soundstage and instrument separation? Sure they sound good thats what we already know but how do they compare to more higher-end gear. I guess most people watching do already know the technical specs so a bit deeper dive into the sound would be much appreciated. Good review tho!

[@peterbaugh51]

My tubes create a great soundstage. Douk Audio ST-01 Pro.

[@D1N02]

It would be interesting to know how these fare against good sub $1000 amps like the Cambridge AXA35, Rotel A11 MK2 and Audiolab 6000a. Are they there yet? Especially using two of these with a pre-amp like the P3 or a good headphone amp.

[@34332]

Curious too, besides sceptic, and exactly what I'm about to find out, lol. I own the 6000a and tomorrow the ZA3 comes in. Speakers are the Wharfedale Linton.

[@angelheart7643]

​@@34332 I'm excited about your review ZA3 vs 6000A...

[@34332]

@@angelheart7643 I got the ZA3 today. Have to admit I was kind of sceptical, you know, Class D, flat or thin sounding, etc. It completely outperformed my beloved 6000a. It gets louder, bass is tight(er), deep and well controlled, mids and top end very clear and detailed, no hiss, good definition of instruments/voices and not sharp, sibilant or sterile sounding. I'm not sure if all this is because of good synergy with the Wharfedale Lintons, but I'm kind of impressed. So much so that I ordered a second one for a dual mono setup ;) Anyway, this changed my mind about Class D and 'budget' amps. I paired it with a MiniDSP Flex (Dirac Live enabled) as pre-amp and WiiM streamer. The big question may be how this will hold up technically in the long run, but it feels like a decent build. Lbnl, it gets lukewarm after hours of playing.

[@fosiaudio]

@@34332 Please let me know if you published your review. It helps a lot to improve our products.

[@ProffAndy]

​@@34332How do they compare ?

[@johnwhitehead8006]

The maximum RMS power output Wattage is limited by the power supply. In this case 48Vx5Amps = 240 Watts total or 120 Watts per channel. Class D amps are being relatively efficient, say 95%, would result in about 114 Watts/channel.

[@fridaynightsakesashimi1855]

Subscribed. Very good review. A video on changing to the Sparkos Dual Discrete Op Amp SS3602 would be fantastic. Probably simple, but I'm new to all this. Thanks!

[@MattCoykendall1]

Thanks for the sub! I actually have a Sparko's install on another amp if you check out some of the previous.

[@eriklscott64]

Hey don't worry about that. My settings on my tablet wouldn't allow me to see the whole page once I got that fixed I found out they're stating it's 300 w * 2 into 4 ohms 150 watts * 2 * 8 ohms and the difference in the Bluetooth of about $7 is ldac support. If I end up getting it I'll let you know. I wish it had an external power supply. Although, looks wise it is very handsome and the venting on the top looks excellent. I'm leaning towards getting it but trying to at least find some sort of review written or video. Might have to look at other countries in Google translate works good. LOL. Keep up the great work thank you Erik

[@alexw890]

All that’s missing is a switchable 80hz high pass like the RSL mini amp has. That’s key for pairing with a sub.

[@MattCoykendall1]

Agreed, selectable would be even better.

[@fosiaudio]

Cant agree more, thank you so much for your suggestions, what I can tell you is that we have amps which have HPF and will be release in 2024, but we need time.

[@montyk324]

I just bought and built the css torii. And I love these little speakers! I use a Yamaha as 500 to power them. I watched the video of your build of the torii and those are nice.

[@MattCoykendall1]

I like that kit too, it’s a fun speaker.

[@NeilBlanchard]

If you use banana plugs, then the tiny binding posts don't matter much. But as you said, if they were staggered and larger, that would be better.

[@MattCoykendall1]

Hey Neil, you are correct, my largest banana plugs fit fine. Good news is this should be a simple improvement in later models, if they go larger they likely will need to find a bit of room for the stager.

[@Douglas_Blake_579]

Hey Neil! Don't know how true this is but apparently the closer spacing is a "safety feature". Apparently the standard spacing also fits European two pin power plugs...

[@fosiaudio]

Most of our customers think fosi audio amplifiers are compact and powerful, so instead of staggered we prefer smaller. And yes, thank you for your suggestion, if we have larger space, we will consider staggered.

[@NeilBlanchard]

@@fosiaudio Right, for bare wire, you need to get your fingers on more of the post to tighten them better.

[@fosiaudio]

@@NeilBlanchard Yes, totally know that, it is compact vs convenient.

[@RJohnODonnell]

Hi Matt. Did you try the Sparkos op-amps in this? If so, how did they do?

[@edmerkel2407]

I'm almost sold, but what kind of home audio gear is out there with XLR connectors? I guess a sub out would be nice. Gotta think on this more. Still, running two of them in a 'bare bones' system would be sweet,

[@34332]

Some 'affordable' Topping DACs have XLR.

[@JRadian]

Why is "Topping LA90 Who?" even in the video title?

[@leodesforges161]

SMSL a300 remains the king, IMO. Good BT quality, more inputs, high pass-selectable sub out, good power, integrated power supply.

[@MattCoykendall1]

Good Option for sure

[@fosiaudio]

Thank you, we will do our best to develop the product you want.

[@leodesforges161]

You are doing a great job@@fosiaudio. I really like my v3.

[@fosiaudio]

@@leodesforges161 I am flattered, thank you.

[@gotenianiki]

Those two switches can be placed on the back and instead of them have a tone control potentiometers. That would have been great.

[@calvinnapier9977]

It's really good to see the sub out added while letting the volume control adjust both speakers and sub. I did hear other reviewers saying when used as mono blocks it really steps up in sound quality!

[@MattCoykendall1]

Just checked, its out for delivery today, maybe a follow up video to come.

[@tjeerdkruidhof5808]

Did you also compare these with the Aiyima A07 max soundwise?

[@microteche]

Enjoyed this review Matt these cheaper options are popping up everywhere.

[@MattCoykendall1]

Agreed!

[@tikblang1]

It would be great if the volume potentiometer can be bypassed in mono mode (set it to a fix value where and exploit the 'full' amp power capacity without hitting distortion). And I agree with all the comments on the toggle switch, how often will you swap cable out and setup between mono and stereo. And I am am the one designing this, switches can be at the back panel (using tiny slide switch) or underneath.

[@MattCoykendall1]

Agreed, it makes sense

[@Douglas_Blake_579]

A couple of words of caution when disassembling and reassembling these upside down chip amplifiers. 1) Do not operate them at high volumes outside of the case. The case is the biggest part of the heat sink and that heavy heat spreader will most likely be sitting on your table top. This presents a really really weak cooling solution and may result in the chip overheating. It's okay to turn them on at low volume just to be sure your new op-amps are working, but don't power test it outside the casings. 2) Since they've started using thermal paste on the heat spreaders, you really should clean away the old paste and apply new right before reassembling the amp. Picking up even a couple of larger dust particles can seriously degrade the cooling solution and it's almost certain the paste will pick up and hold onto whatever loose particles it comes into contact with while exposed. The new paste should be applied in a thin line inside the case, where the back of the heat spreader will sit. This allows the spreader to spread the paste evenly as it slides in. Putting it on the spreader itself will just result in the thermal paste being smeared all along the bottom of the case, not where it belongs.

[@MattCoykendall1]

Good news is I have some thermal paste laying around from previous PC builds, might as well apply it to the other two as well.

[@Douglas_Blake_579]

@@MattCoykendall1 As the wiley rabbit says ... "Couldn hoit" As always, use the smallest amount that will cover the contact surface. Too much is both messy and less efficient.

[@shinnoskenohara7037]

hi, great review! have you done the pair as monobloc yet?

[@gp2024-d2r]

Quick question, albeit possibly a silly one as I'm still a little fuzzy on which dac with a remote at a similar price point would anyone recommend that could control the volume ? Also Matt, great reviews and am now a subscriber.

[@fosiaudio]

Haha, Fosi Audio ZD3 which is still under developing, you can keep an eye on it.

[@peterbaugh51]

Douk Audio ST-01 Pro.

[@ryanolivier6929]

first time on the channel, enjoyed the content.

[@MattCoykendall1]

Welcome

[@gamerman644]

the fosi za3 has some issue, even tho they use the tpa3255 and learned alot from the v3, the za3 has more distortion and lower sinad and lower wattage than others using the tpa3255. strange how a balanced design somehow gained more distortion and less power in the circuit design. also wondering why they opted to make such a small heatsink connecting plate to the case, but i am, impressed with the addition of thermal paste, i did this first when i saw my v3 bare metal on metal ,there is a slight gap that should be filled to help transfer heat anyways

[@cosmiccharlie8294]

I have one one on the way. Trying to decide what to drive it with. These days I stream, tuner and vinyl mostly so an Emotiva basX. Pre amp looks appealing. I could save some money by just using it for streaming though.

[@MattCoykendall1]

I think you will really like it, especially for the price

[@eriklscott64]

Merry Christmas Matt and to everybody!!! Matt I found a balanced iamp that is being called the Aiyima D325x. Let's say it's the D325x. It is a balanced, bluetooth, separate bass and treble, and dual vu meters, with an internal power supply. So no power supply rolling. It also comes in two different Bluetooth versions with one being $10 more than the other. The average price is 98 - 120.00 shipped to the States. I don't expect you to purchase one but maybe you can find out what the manufacturer power rating is for it. Don't get me wrong I know it'll be excessive to reality. Other than wattage the balance part is what has me. If you feel up to it any help would be greatly appreciated. And again thank you for all of your awesome reviews. I have left a longer message believe it or not at the whim review. LOL take care BigE

[@MattCoykendall1]

That D325x is interesting, it’s the first time I have read on it. I don’t believe it’s being pushed to the US market.

[@jazzabana]

Well, here is my 2 cents. I have had aiyima t9, fosi v3 (for a brief moment), aiyima a08 and smsl vmv a1. I think t9 and v3 are in the same tier although v3 is more powerful. I think t9 had a more enjoyable sound due to distortion tubes were creating. I also tube rolled and sound signature changed for something else. Aiyima a08 was better and more powerful than the 2 forementioned amps in every aspect but with an aftermarket power cable. The cable that it comes with was crap. And smsl vmv a1, if a08 was a tier above the v3 than a1 is 3 tiers above the a08. I have to admit that vmv a1 is low powerwise but comes with a quality power cable and it sounds good enough for a nitpicking audiophile that I am. All my experimentation I never used the onboard dacs and bluetooth since I was testing forntheir limits. My main amp is yamaha 2100 btw. which I would consider another 3 tiers up on top of vmv a1. I was still curious what I would get if I would get 2 za3s, but I think I won't bother, I wouldn't think I would be happy with the sound quality.

[@peterbaugh51]

Bad tubes, ok sound. Good tubes, Great sound.

[@HoomanR17]

Nice review. Would love if you could share your impression of op amp rolling with this unit.

[@douglasmontgomery6315]

Matt, you made a comment that I've wondered for years (think solar catamaran sailboat, running as much from DC (leaving inverter off as long as possible). Does anyone that you know of make a modern video decoder only device ? IE, an A/V receiver WITHOUT the amplifiers, so one could decode the video/audio signals, but upgrade/add their own amps.

[@madcrabber1113]

Think I will try one of these when they add a high pass to the sub out.

[@MattCoykendall1]

I get it, I wanted that too.

[@HiFiMods]

I wonder if one could just solder a small capacitor or an inductor, inside on a sub output for a specific low pass filter for the sub ... 🤔 This won’t help the speaker high pass filter situation, but may help for subwoofers that don’t have low freq. management.

[@michaelsparrow4798]

@madcrabber1113 | You want a low pass for a sub. (To pass only low frequencies to a sub.) And a corresponding high pass for the mains. (To remove the sub's low frequencies from the mains.) (Commonly misused.)

[@fosiaudio]

Got it. Thanks.

[@mikecampbell5856]

I always enjoy your videos Matt. Would it be possible to add thermal paste to those other amps to increase thermal transfer? I have remote control power switches hooked to my vintage gear so I don't have to change any settings. Maybe that would work to maintain your volume settings.

[@MattCoykendall1]

Yes, absolutely you can do that

[@fosiaudio]

Thermal paste can indeed increase thermal transfer according to our test, but it is not convenient for this pull-push assembly.

[@mikecampbell5856]

@@fosiaudio Neat, good to know.

[@williambracken9339]

Thank you for this informative, succinct, and hype-free review. You say this won’t be replacing your higher end amps anytime soon. Is that mainly because the higher end stuff has more features you want in your main system amp, or does the higher end stuff (Audiolab 9000 & …?) sound that much better? If the latter, it would be great to get your take on the ways specific higher end amps sound better. Some youtubers make it seem silly to buy higher end amps anymore (cough, CAM, cough, cough).

[@MattCoykendall1]

Hey William, you can get an absolute ton of enjoyment AND quality out of something like the ZA3 and for a lot of people its more than enough, the reason something like my Audiolab 9000a wont be listed on ebay anytime soon is because it offers alot more input and output options, more flexibility. The amp also carries advantages in areas like the power supply, the audiolab has a Class A/B power amplifier arranged in a dual-mono configuration, with a 320VA toroidal transformer and 60,000uF of capacitance. Its a slippery slope, the more you spend doesn't always mean better and certainly spending double doesn't double the sound quality delivered.

[@williambracken9339]

Thanks for the prompt response, but you are just saying things that should be obvious without actually telling me whether the Audiolab 9000 actually sounds better to you and, if so, how. Only a fool would expect sonic improvements to be directly proportional to price, and anyone can read the specs to see the differences in amp class and power supply. Only you can say how the one amp sounds to you compared to the other.

[@iikatinggangsengii2471]

its the he-1 kind of experience, so yes true haha terrific sounding iem, not many can hear/own this

[@34332]

​@@williambracken9339 Those are good questions. To make it perhaps more equal, how does a dual mono setup compare to the 9000a, including a good pre-amp. Btw, I have a ZA3 comin' tomorrow 😄

[@wyup]

@@williambracken9339 I have the same question, but he's not going to answer because he is "selling" these amplifiers. I am afraid the only way to know is buying and trying. Saying he paid 2k$+ for the Audiolab for more connections is irrelevant, you do it mainly for the sound quality. However, probably the Fosi offers a lot for the money which is good for Hifi, but is good enough for you? We know HIFI pricing is speculative, and follows diminishing returns and a exponential curve, that is the ugly truth and not capacitance.

[@user-ys4og2vv8k]

Does it make sense to choose ZA3 instead of V3 from purely audio quality point of view if I don't need XLR and mono configuration?

[@jamesbennett1634]

Hey Matt, thanks for the timely review. If you have two of these running as monoblocks, how would you work the sub out? Have one sub out go to the right RCA in on your sub and the other to the left RCA in?

[@Douglas_Blake_579]

Yep.

[@D1N02]

get a second sub, one for each. Otherwise run it of your pre-amp

[@CharleneUSA]

Yeah, the front panel sucks. It's like they put a 110/220V switch on the front panel. The Stereo/Mono setting is a one-time setup thing. But this seems to be the case with many cheap audio components made in China. They always seem to have at least one WTF design decision.

[@Douglas_Blake_579]

Thanks mostly to the "Department of silly decisions", most companies have in their basements.😵‍💫

[@outolempinimi5165]

It supposed to be a power on/off switch but then someone invented a cooler design

[@Douglas_Blake_579]

@@outolempinimi5165 They can't turn it completely off. If they did the 12v trigger would not work.

[@outolempinimi5165]

Yes of course, should be on/off/trigger switch as in many other similar devices. Hope they will come with revised version of this as apart of its design flaws it offers the best value for money in its category as of now. I'd still go for Topping PA5 II Plus or some other alternative over this despite it costing twice as much until they come with more practical/safer design features and preferably true bridgeable monoblock as well.

[@Douglas_Blake_579]

@@outolempinimi5165 Actually there is good sense in keeping it on but in a deep standby mode. It helps avoid large current inrushes when charging up the bulk capacitors. This can be between 5 and 10 times normal current, for a fraction of a second and it will shorten the life of the power supply significantly. So keep it on, in standby, and no inrush to worry about. The ZA3 is _already bridged._ Both of the stereo channels are bridged to give maximum output on 8 and 4 ohms already... it's called BTL (Bridge Tied Load). I've pulled an honest to goodness 200 watts per channel out of a TB10D (4 ohms,

[@richh650]

I agree with hiding the stereo/mono button as that is not something you want to hit often and could even cause major issues. Also, would prefer a line out button that would remove the variable output volume turning knob to disable the volume knob completely and the noise I am sure it adds to the signal.

[@myaudioquest]

I bought the Fosi ZA-3 (with 48V power supply) thinking it might be a keeper. What I discovered was a mixed bag...thin in the mid-range and bass. I also did not care for the volume control, cheap like in build and function. On the plus side is exceptional clarity in the treble but requires a sub-woofer to add body and weight to the music. Best used with a bass centric loudspeaker or possibly use two amplifiers. My two cents!

[@JukeboxAlley]

What preamp was you using? That low end and midrange can be stacked and added depending on the preamp combo.

[@DistroUser]

I don't understand your question, the Fosi ZA-3 is an integrated amplifier so I am using it's preamp section with it's amplifier section. I am aware of buying two of them for more power and in a balanced configuration, but, I was using only one of them. @@JukeboxAlley

[@JukeboxAlley]

@@DistroUser it would give you a lot more gain and bass and treble gain and control over the amp, basically what I'm saying is they do much better with a dedicated preamp, like the p3, they'll literally feel like they have double the output with a decent preamp.

[@michaelwright1602]

You need to up the line level input voltage to open these TI amp chips up. A good preamp is required, or even a line level booster or an EQ with a gain function. I discovered this by accident with my V3, just as you described your experience with the ZA3. I started boosting the line levels and she really opened up and started to sing. If not for that discovery, I would have returned the V3. And this has nothing to do with the power bricks, I have both the 32v and 48v, no difference between the two in regards to speaker output or SQ improvements. It is not a power brick issue, it is a gain issue.

[@JukeboxAlley]

@@michaelwright1602 exactly, that's what it of people need to know, when running "separates" which is basically what your doing it's always much more grunt and gain. An amplifier isnt really made to be used standalone, it will be anemic in the bass and output usually, need a preamp or EQ for certain.

[@gregbailer8701]

A pre-amp (with bass management) is my long-term preference. The common (80HZ) high pass (if included on the amplifier) may not sound best with your future speakers. This amp is built to a price point of $100 for a reason. With 48V brick, and pushed to max...going to get hot. The enemy of long-term survival in electronics gear.

[@EricRosenfield]

I don’t think a $100 speaker amp is built for longevity in general…

[@gregbailer8701]

@@EricRosenfield yes. agree. LIke a $100 plastic plate in a microwave oven. Schitts gonna melt. Haha!

[@shipsahoy1793]

sorry, but this ZA3 was reviewed by a couple channels already on KZbin that said this amp doesn't get hot using the 48 V, 5A brick.

[@gregbailer8701]

@@shipsahoy1793 Wilson Labs tested ZA3 to have 1% THD and to me, that is not high-quality output. The ZA3 uses Thermal Paste for a reason, and most of the other $100 Class D amps do NOT use paste. The sub-out still retains a full-range signal to your speakers. Not ideal. Finally, the XLR inputs are low-cost plastic combo units, and likely only wired to a single end internally. These are the facts. It's a $100 amp and electronic parts are relative to results attainable. Great for a small space budget-driven system, The HYPE on KZbin is all about the ZA3 (x2) being a MONO BLOCK killer setup for under $300 with HUGE 4 Ohm ratings. I choose not to believe the output claims as many other amps tested lower in real usage situations.

[@EricRosenfield]

When you say this sounds better than amps that cost more, it’d be useful to say what those amps are so you’re actually getting a sense of what would be a waste of money

[@bartartybart5677]

great, thank you; but 'I learned' that Topping PA 7 plus is ' the king' of all class d amps ... so...(?)

[@fosiaudio]

We are about to be crowned.

[@34332]

Based on your review I got one. Can't agree more with your review,so thank you. Further in this topic I placed my findings. One thing to note: I saw a topic about the XLR inputs not being 'true' XLR internally. Not sure if that will make a big difference, because it sounds impressive as is.

[@Douglas_Blake_579]

There's an easy test for this ... Select the XLR inputs... with a sewing pin gently touch the contacts in the connector (don't worry it's perfectly safe). If it is true XLR pins 1 and 2 should both result in a buzzing sound from your speaker. If only one of them buzzes, it's probably just a single ended input hooked up to an XLR connector. (And you might be surprised to find out how common that is.)

[@34332]

@@Douglas_Blake_579 Now that you said XLR to single ended input, that's it. I read that on a thread from ASR (with pics) pointing this out. Thanks for the suggestion re. testing this, appreciated!

[@Douglas_Blake_579]

@@34332 You're welcome.

[@tonym8358]

The big missing how the compare sonically to each other? There is no sound difference, then I will go for the cheapest

[@MattCoykendall1]

Biggest difference between the Za3 and A07 Max will be the features, ZA3 having more inputs and the true sub out.

[@iikatinggangsengii2471]

its not certain for the moment but yes, judging from what ive heard it wont be too different

[@Douglas_Blake_579]

Hey, if this thing won't run my 51 speaker setup at the local cattle auctions, it's not good enough! 😁

[@eddievega1100]

Thanks , curious to see if they can power my Def tech Bp 9060 , 3 channel set up in mono . Thanks again

[@RanTausi]

I have just connected the Fosi P3 preamp to my Beast ADCOM GFA 555MK2. It works fine and sounds great , regarding the ZA3 I think I will pass for now until they will improve it and hopefully they will add a remote control will be a plus.

[@MattCoykendall1]

One thing is certain we will see another revision!

[@fosiaudio]

Whats your suggestions for the improvement?

[@RanTausi]

@@fosiaudio Well ,as a dedicated power amp you can remove the volume and make it fixed, take the mono/stereo toggle switch to the rear, maybe put a better power on/off switch, now regarding the P3 pre amp , I like the build quality and overall appearance better then the P1 I also have but I think it is about time you will provide us like P3 preamp with a remote control and RCA pre out for active subwoofer. Thanks

[@fosiaudio]

@@RanTausi Thank you, we are developing P3 MKII that has remote control but without tubes. Thank you for your suggestions for ZA3.

[@cedricjoly7695]

@fosiaudio maybe a pffb too ? And better speaker terminal block..

[@jonathannieto8377]

Hello Matt good morning. I've a question. I have a pair of ZA3's in mono using XLR inputs. If I want to switch op amps,would you recommend changing just the right channel op amps? Or just the XLR op amps? I only have a pair of sparkos. Fosi replied I can try changing just the right channels, but they also added "if you're an audiophile" you want to change both channels for better sound.

[@Panslapper]

JBL 305p mk2 vs ZA3 mono. I reckon the 305p is better value.

[@Crashbanksbuysilver]

I need a high pass filter on the sub.

[@eriklscott64]

Sorry I forgot to mention that it's at several AliExpress stores. And it is not at the official store. Is falls under that weird category where these things end up with several manufacturer names.

[@antenorjunior3221]

I cant believe. How? 2× 180w from a power suply of 48 volts 5 amperes? Its a creation of energy???? What kind of watts????

[@bilguana11]

How do they compare to the Orchard little monoblocks?

[@Douglas_Blake_579]

Spec wise they're pretty much the same. But at $1,500 + power supply for a pair I'd say you have a good opportunity to save yourself $1,200+ with the ZA3s.

[@urka-off-world-adventures]

After a long absence from hifi gear, I have a pair on order to use as mini mono blocks. Checking out a suitable balanced DACs to pair them with. Any suggestions?

[@jimbanville]

The only seriously wrong thing with these is lack of remote control. These are fine for a desk where you’re within arm’s reach. Beyond desk use, these need remotes or it’s a no sale for me.

[@34332]

Get a WiiM with trigger out, solved.

[@jimbanville]

@@34332 if using this as an integrated amp, lack of remote control for volume is a big negative unless you keep it within arms reach.

[@Gadgetdad007]

I too have the Audiolab 9000A, but have you purchased the additional 9000A series components ?

[@MattCoykendall1]

I am interested in the cd player but the price on the N streamer is a bit much… interesting but rough

[@ericperry72]

I wish they drop a true mono amp based off of this design and maybe have like 300watts rms @8ohms. Same form factor and add a volume defeat switch. Id buy 2 right away and then grab a pair of LRS speakers

[@MattCoykendall1]

I believe they plan to come out with something soon that is more of a dedicated mono but I don’t have any details on changes.

[@Douglas_Blake_579]

Look up the Fosi M03.

[@Douglas_Blake_579]

Hey Matt ... I really wish I could say that I didn't see this coming a mile away... On the Williston Labs channel I just got confirmation from another commenter that flipping the stereo/mono switch with the ZA3 powered up is *not* a safe thing to do. By his report the amp shut down immediately when he accidentally flipped the switch. Fortunately it came back on... but that might have been dumb luck. As several of us have said ... that switch has no place on the front panel where it can be flipped out of curiosity or by accident.

[@daveme3582]

As a dinosaur with loads of quality vintage audio gear. Im lost on how these modern day premium affordable chip amps get so much right but fail to include a BT input. So close yet...

[@MattCoykendall1]

Yeah… it’s a process haha

[@peterbaugh51]

Douk Audio ST-01 Pro has BT and plenty of power for 88 DB peaks, which is loud enough for me. It will get louder... With upgraded tubes it has Great sound.

[@degreesdegrees-jr4eg]

try SMSL A300

[@mikepxg6406]

You’re wrong about the V3 volume control. I leave mine set in one position. It turns on without rotating it after powering back up.

[@Douglas_Blake_579]

You're turning off the AC, right?

[@MattCoykendall1]

Right, you would have to power it off externally from the amp to accomplish this which is fine and what I would suggest to avoid using the volume control. A smart outlet or switching power strip are potential options.

[@Douglas_Blake_579]

@@MattCoykendall1 Yes this can be done ... but there is a downside to that. When you turn a device completely off, the bulk storage capacitors inside will drain to zero charge. Then, for a brief moment when you turn things back on, there is a huge inrush of current as they are re-charged. The device actually looks like a short circuit to the AC line. This can be somewhat mitigated by using NTC resistors to limit this initial burst of current but it will still be several times the normal running current of the device. With both the brick and the amplifier on this turns into a double whammy of both higher and longer inrush currents. The usual effect of this is micro-damage to the power brick's rectifiers that accumulates over repeated on/off cycles and it can shorten the life of the power brick substantially. You can manage this with an inline DC power switch between the brick and the amplifier. (Yes they do make them) That way you can leave the power brick on all the time and use the inline switch to turn the amplifier on and off. It's not a perfect solution but it's better than cold starting the whole setup every time.

[@peterbaugh51]

​​@@Douglas_Blake_579Ahhh, so that's why the Douk Audio ST-01 Pro goes to Stand by... Also good for the tubes. Many hi-fi components have a standby setting.

[@Douglas_Blake_579]

@@peterbaugh51 I'm not familiar with the ST-01... so I can't really give you much of an answer.

[@jimbanville]

I need a “truly” MONO 300 watts into 4 ohms mini amp. As in 1 input and 1 speaker +/- output. Not an amp where just half of the unit is bypassed in mono “mode”. Truly mono.

[@Douglas_Blake_579]

Half the unit is NOT bypassed in Mono mode. The two stereo channels are paralleled together to give increased output current for lower impedance loads.

[@jimbanville]

@@Douglas_Blake_579 Wrong. A REAL MONO mode “bridges” an amp. That would double the output. That is not happening with this unit. Just watch the dyno results in this video… kzbin.info/www/bejne/nHqmfphmhtuMqKcsi=LIX4zxz347vdPA2P

[@Douglas_Blake_579]

@@jimbanville No sir. Mono simply means 1 channel. It does not imply bridging at all. I get that you had some wild expectation but right now you're just tripping over your ow false assumptions.

[@jimbanville]

@@Douglas_Blake_579 Bwahaha! Stop being an apologist for fosi. Show me any other amp that advertises a MONO mode where it doesn’t mean BRIDGING. I’ve been in AV a looooong time. Car audio amps and home audio amps that have MONO modes they actually BRIDGE the components, doubling the power. That’s the PONT of a MONO mode. Look at the dyno results in that video. You gain almost nothing from MONO mode on this amp. It’s a joke. You can just use one channel and leave the switch in stereo mode and get the same results 🤣🤣🤣

[@Douglas_Blake_579]

@@jimbanville Oh for crying out loud. Get a copy of the "TPA3255 spec sheet" (do a search it's easy to find) and read the thing. All of the chip's modes are fully explained there. I really don't give a crap how long you've been in audio... you're wrong about this.

[@Sunrazor]

Would buy it in a heartbeat if it had Aptx-HD enabled bluetooth. But as of now, Aiyima A08 Pro both looks nicer and have that functionality.

[@MattCoykendall1]

Nothing wrong with the A08 pro, I have it too!

[@pavlo687]

Would you chose the Rogersound over this Za3?

[@tpn8402]

"I can say this easily sounds as good as many amps costing substantially more." What are these amps you're comparing it to?

[@MattCoykendall1]

I honestly feel that many but not all would have trouble picking between the ZA3 and the LA90 in a true double blind test. Even if one sounded "technically" better many may lean to the ZA3's less sterile delivery. I cant speak on the newer LA90D though, haven't spent time with the new revision. This example could be repeated over and over as the 3255 isn't a prize winning amp chip but it can deliver a really clean sound, getting PFFB implemented on these is the next step as certain speakers will experience slight load dependency issues, so speaker pairings are still important here.

[@tpn8402]

@@MattCoykendall1 Less sterile sounds good to me! What's PFFB?

[@MattCoykendall1]

Basically a way for the output signal to be accurately reproduced no matter the speaker attached to it

[@Douglas_Blake_579]

@@tpn8402 It stands for "Post Filter FeedBack" . It works by sampling the actual speaker signal and returning it out of phase to the inputs. This aids in cancelling anything from the output that is not present on the input. It will reduce distortion somewhat and even out any irregularities in the frequency response.

[@fosiaudio]

@@MattCoykendall1 Haha, I would say we have a big improvement on the development of PFFB.

[@pipilangstrumpf7076]

Haha I have Balanced AAVA and za3 uses two Volumepoti at Mono

[@TokeBoisen]

How does the 12V trigger work with that kind of volume/power combo? Usually you'd leave the volume at what you prefer, power off the amp and let the 12V trigger trigger a power-on. But here you're constantly on anyway if you've set your gain

[@Douglas_Blake_579]

The power switch is controlled by a microcontroller. If you disconnect power it reverts to off, but you do not lose the volume setting. The 12 volt trigger would be used to pull it out of standby.

[@TokeBoisen]

@@Douglas_Blake_579, ah, so if the controller senses the presence of the 12V trigger cable, it disables the power on/off on the dial?

[@Douglas_Blake_579]

@@TokeBoisen No ... If it's done properly it works like an or gate ... if you push the volume it will come on, if you feed it 12v on the trigger it will come on ...

[@TokeBoisen]

@@Douglas_Blake_579, ooooh. I thought it was still a click at the bottom of the volume control. My mistake. Yeah, then I get it. I made an analogue or-gate with a relay in a similar amp with a switch on the front for power. If the trigger was used, the relay switched the amp to on regardless of the power switch position, if you used the switch on the front, it didn't care about the trigger.

[@Douglas_Blake_579]

@@TokeBoisen Yep ... that's how it's supposed to work. I haven't tested it to be sure.

[@thelowprofile9767]

In terms of sound how much better is ZA3 than Aiyima T9 Pro?

[@jimfarrell4635]

I just finished tearing the innards out of a pair of 1970s Wharfedale Dentons and replacing them with modern drivers and crossover. They were a bit too bright initially, but strangely sounded at their best with a P3 Pre and V3 power amp. My least expensive (by far) amps. I now wonder what the P3 and twin ZA3 in mono mode would bring to the table.

[@MattCoykendall1]

I have a feeling you might find out! haha

[@jimfarrell4635]

@@MattCoykendall1 You are just as cynical as my wife, Matt, but you may be right. Having said that, sometime in the next few days a vintage, recapped, Sansui AU7700 and TU7700 tuner will arrive in a big box, eroding any goodwill I may have accrued recently, starting the new year with a deficit in the husband/ wife hifi account. So the Fosis may need to wait till the inevitable discounts start and I am back in the good books. In the meantime, from the land of Tartan and Hogmanay, have a great New Year !

[@HappyHighwayman]

Any balanced source is going to cost more than even 2 of these.

[@csdstudio78]

If it's even true balanced input. May just be single ended.

[@wric01]

Tell us the amount of upgrade in sq with sparkos on Za3.

[@m4nc1n1]

I have way too many of them in that intro shot, lol. Just ordered two Fosi ZA3 (with 48v), lol

[@MattCoykendall1]

Enjoy! Yes...I do have way to many but at least it offers a lot of comparison.

[@erichudson3307]

So if im running the A07 max in mono and I want to upgrade the op amps like a sparkos ss3602 would i only need to purchase 2 chips? One for each of the left signals since mono is only using one channel in each amp?

[@michaelwright1602]

Yes, two chips total, just as you are thinking.

[@wilsonlee5590]

I recently tested my Fosi Audio BT20A amplifier with my floor-standing speakers. According to the amplifier's specifications, it should output 100W at 4 ohms and over 200W at 8 ohms. My speakers, which are rated at 6 ohms, have a recommended wattage range of 20W to 160W. Based on these specs, the BT20A should easily drive the floor-standing speakers. However, in practice, the amplifier seems to lack sufficient power. I find myself having to turn the volume above 50% just to achieve a reasonable sound level. This issue doesn't occur when I use my integrated amplifier, which provides 80W at 4 ohms. I'm puzzled and unsure whether the Fosi Audio BT20A is actually delivering the power it claims in its specifications.

[@xlr82bgr8]

I had the same problem, turns out it’s best to turnthe volume to say 3 to 5 o’clock.

[@wilsonlee5590]

@@xlr82bgr8 I have a suspicion that the Fosi amplifier might not have enough power to effectively drive the hi-fi speakers. Although I'm not an expert in electrical matters, based on my personal experience, I've observed similar situations where insufficient amplifier power led to performance issues with high-fidelity speakers.

[@Douglas_Blake_579]

@@wilsonlee5590 It's not a power issue. It's about gain. The TPA3255 chips are fixed gain at 26.5db (voltage gain of 21x). This means that if you are using a 32 volt supply you will need an input level of at least 1.5volts to drive the amplifier to full power. That increases to 2.5volts for a 48volt supply. Most consumer pre-amps output a maximum of 1volt so it's unlikely the amplifier was being adequately driven.

[@wilsonlee5590]

@@Douglas_Blake_579 I use the 48v is still same , now I prefer branded Hifi products rather than the cheap HiFi equipments. I have more confident and less weird problem with branded Hifi products included China branded Hifi products

[@michaelwright1602]

@@Douglas_Blake_579 Not my experience, I own the V3 and both power bricks, the 32v and 48v. I heard nothing sonically different between either. Now, when I bumped the actual line input gain going into the V3 via two male XLR to RCA adapters hooked to my PS Audio DAC, that is when that TI chip opened up. It has nothing to do with the power bricks. I have a line level booster coming and will add that into the stream. From what I have seen so far, and heard, that line level booster should take the V3 to new levels in regards to overall sound quality. That TI chip is looking for power, power from the line output of the device sending the signal to the amplifier.

[@reileymckerracher9181]

Great video,! I'm thinking of buying one of these. Has anyone test if this amp hisses/hums with no input? I have a DAC that when it goes to sleep it is the same as unplugging the RCAs (happens about 5 seconds after it finishes playing audio). Hoping to find an amp that doesn't hiss when my DAC sleeps.

[@oahupc4688]

From your title you are saying this sounds close to or as good as the topping la 90??

[@larrygaines7462]

Ebay has 10 amp 48v . Y the power cable to monoblock s , a big sub is needed or monoblock will over play it

[@larrygaines7462]

I use 500watt plate amp with control and duodayton18s monoblocks have 70hz hi pass fmods and douk pre amp .in use for year,got the boards from Amazon, they don't get warm driving 8ohm load.

[@Apichart_Wong]

I'm considering buying a Fosi ZA3 but I'm not sure if it has HISS Noise when there's no signal input. I would appreciate it if you would answer my questions. Advance Thanks..

[@Douglas_Blake_579]

No hiss.

[@EvenHarmonics]

Mr. Coffee, I’m worried I don’t understand the value of a sub out here. If I am trying to offload the bass to the subwoofer, yet it still continues to send the same bass frequencies to my regular speaker, I have 2x (or so) the bass and am not giving my normal speakers the ‘rest’ of not having to produce deep bass. My understanding is that offloading deeper bass allows the speaker to more tightly control upper bass, being less ‘muddy’. So how does this work? Also confused how the bass crossover can be controlled “in the subwoofer” when there is no ‘cross’ ‘over’ from main speaker. Does plugging something into the sun out port somehow limit the ZA3 bass output and if so, at what frequency. Thanks very much to anyone who can shed light on this.

[@MattCoykendall1]

You wont get the advantage of true bass management like your mentioning here, the full range will still go to the speakers. It would have been ideal to apply a crossover so that you could take the burden of deep bass away from the speakers and pass it over to the sub but in this case the only option would be full range to the speaker and a crossover on the sub set to the driver roll off or a sub that has bass management built in, some offer this today, you can output from the sub to your speaker amp.

[@chinmeysway]

amazing review! those ventilation holes though woof so ugly!

[@Douglas_Blake_579]

But completely necessary. The amp would overheat and shut down without them.