Fosi Audio ZA3 Balanced Stereo/Mono Amplifier HiFi with TPA3255 Chips, Mini Audio Amp Monoblock with XLR RCA Inputs and 12V Trigger-in for Desktop Bookshelf Passive Speakers with 48V5A Power Supply

What a great little amp. I have had a few expensive HiFI set ups in my life, but now that I have downsized, I wanted something smaller. This, when hooked up the the WiiM Ultra that I also bought recently and a good pair of bookshelf speakers (Dali), sounds way more impressive than it should. The fact that I can use this as a mono or stereo is something I've never come across before, and that opens up its versatility even more. Recommended for those looking for a less expensive, but still good quality, amplifier base.

So...in my opinion...this is were Class D now defeats Class A-B amplifiers.I have these with the ZD3 - running in mono. The installed NE5532 op amps in the ZA3's are ok but after doing research I found the best op amps that are inexpensive. The LM 4562 Op Amps...provide stunning clarity and resolution. Even without this modification..the ZA3 is a truly innovative product.The ZA3 has dual amplification chips...not a single unit. This provides the greater resolution and fidelity.The ZD3 already has these installed and the resolution is superb.Don't forget the ZA3 has balanced XLR inputs..which is class leading in terms of inputs. In such a small unit !The sound is so refined and detailed.Buy yourself a power supply filter for your wall sockets and some ferrite cores and this further improves detail for any sound system.I did buy a second ZA3 - added the LM 4562's of which 3 are required for left - right & XLR input. 5 - if you have a subwoofer.The 12v trigger is so convenient...just by a good length 3.5 jack splitter cable to control both ZA3's with the remote.So I purchased the extra ZA3 and upgraded to mono. Each dual amp chip in each ZA3 - now controls one speaker - providing greater power and detail. I'd say it has boosted speaker detail and power delivery by 40%.What's interesting is that this isn't just about volume/gain...it increases depth and detail greatly. Is it necessary? No.Other amps in Class D - have only one amplifier chip and can't match the resolution of the ZA3. What's interesting...if you check vastly more expensive amps - check what op amps they are using. Very often it is the standard NE 5532's or OPA.The LM 4562 chips are sort of a hidden gem in op amps...fast and detailed and the fosi ZA3 is hardware compatible with their greater resolution and depth. It's only £10 for two chips...but make sure they are genuine.I have wharfdale 9.1 diamond speakers...and for the first time..I modded the crossover to film foil capacitors which I didn't think I would be capable of doing. Just takes a little time and I have never soldered before...but I gave it a go and it improved the quality of output greatly.The ZA3 is a power efficent and small device with just about everything you'd want for a high end audio system.I think it is a genius product that is vastly underrated. Even prestigious audiophiles are using the ZA3 in mono configuration.

Hi. Absolutely fantastic amp. I have it connected to 20 year old mission m762i speakers. Sounds fantastic. Great bass and treble and mid too! Even on tricky to plat bass heavy tracks. Beyond my expectationsCheersQuick update - i bought another one and use then to power left and right speakers in stereo mode. The difference is amazing both in terms of Clarity and power.

Some time ago, I decided to move to headphone listening in my study so I bought a Naim Uniti Atom HE. It's good but the Grado headphones I am using are a literal pain. I decided I needed a power amplifier to get some sound back in the speakers which are still hung on the wall. I was toying with buying a couple of Exposure monoblocs but the room is fairly small. I saw some online reviews for the Fosi and concluded that £149 wasn't a lot to lose.In short, I've bought another to bi-amp. I am more than happy with the sound that they are pumping out. I struggle to try to put it into words how they sound as I'm no hi-fi reviewer. But the sound is clean, incisive and well-balanced (at least to my ears). There's not much bass - but that's more a product of the speakers - wall-mounted QAcoustics.I am very tempted to move them into the living room where I've a pair of Falcon Acoustics transmission line speakers to play with....