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

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.

These are an amazing amp for the money. There’s plenty of reviews on YouTube comparing them to £7000 amps they are that good. Brilliant as a stereo amp and even better as a pair set in mono connected via xlr. Great paired up the pre amp ZD3 if you’ve using a streamer or CD player as source. Ignore the audiophile snobs and the lack of reviews on sites like what hi-fi that depend on pushing big names to fund their site. What’s even better is you can crack these amps open and swap out the opamp chips for even better performance. There’s so much power in these that you could easily power big 100w speakers as well as 30W book shelf speakers. Sleek and clean look small in size so two fit nicely side by side. Easy to connect put blistering performance for the money. Only sight negative if used in mono it lowers the subwoofer volume . So you may need to up the gain to compensate.

After much thought, I purchased two of these Amps to work in conjunction with the Fosi DAC ZD3 that I had previously purchased. I have both Amps set up in Mono to the DAC. The DAC does the channel separation. I have not lived with the system for very long, but initial impressions are that these are incredibly good amplifiers that really punch out good clear sound. They are also now possibly exposing the weakness of my speakers, but that could also be just another head rouse to purchase a different set of speakers. I like the fact that I can later play around with Op Amps, and that will take my Hi-Fi hobby into another dimension. I did have a little trouble setting up the triggers to both Amps, but that was easily overcome by purchasing a 3.5mm male jack headphone splitter that goes into two 3.5mm female ends. I have then added two short 3.5mm male to male cables to go from the DAC (now doubled) trigger to the amps. It works perfectly and the trigger does not seem to mind a double (stereo) 3.5mm lead for it to work. CEC works brilliantly on the DAC, so I can now turn on the whole set up from my smart television. The television is hooked up to the DAC via eArc HDMI, so a digital signal is received at the Fosi DAC, which is in turn doing all the heavy lifting to convert sound to an analogue signal, which it passes to the Amps. The Amps are turned on by the 12v triggers rather than the CEC signal.

I purchased the za3 to power a pair of surround speakers in my HT rig. To test the za3, I connected it to a pair of older Polk RTiA1, Anthem avm70, and Sony SACD player. I chose Rickie Lee Jones Pirates SCAD to demo the Fosi. The sound was very impressive from the start and only got better as the amp continued to play. It barely got warm and the speakers were completely quiet when no source material playing and the Fosi volume set to max. Impressive! I connected the Fosi to surrounds, re-ran the sound calibration, and, again, the Fosi did not disappoint. This little amp proves that spending big dollars isn't always needed. The Fosi has a 12 volt trigger. Sadly, I did not have mono cable on hand with a male 3.5 mm connector on each end. The cable I had was stereo with 3.5 mm male on one end and 2.5 mm male on the other. Through a bit of simple improvisation, I spliced the 3.5 mm connector to a 12 volt DC power adapter, connected both the Fosi and power adapter to the same power bar. Now, turning on the power bar powers on the Fosi.

where to begin! My previous setup was Marantz PM6007 with WiiM Ultra & Elipson Planet L Speakers. I was ok with the setup but I knew, was missing something on the higher frequencies & details. just heard about this product on youtube channel "VirtualHiFi" - found many good videos with sound test comparing with 10k - 15k USD costing amps. I took the decision & bought this today with 48V power supply & right now its been playing for 3 hours replacing the marantz PM6007 only with rest of the same setup. I have no words to say - Man! it's blown away the marantz right out of the box and my elipson planet L speakers have come to life. it's a night & day difference. I kept the volume at 75% position & controlling the volume from wiim ultra and it's running cooler now than at 100% position. i am seriously thinking about the reason why it is sounding great than the marantz. Hmm.. may be one reason - the frequency range with 0.1+-DB? I don't know but it's sounding fuller, detailed, airy high-frequencies & analogue kind of texture. ZA3 changed my mind to join in the class D era as I have ordered another now to try as Monoblocks. I am totally happy & the value for money is top of the roof! I really appreciate the FOSI TEAM behind this to design such a great product! Best of luck for your next musical invention!!! Got the second one & set them as monoblocks - sound stage is wider now & details are more cleaner especially the vocals & mid range. I started enjoying my setup now with peace of mind!

I used this amplifier to drive the JBL 530 which is a 6 ohm nominal load and 86 db/w sensitivity speakers and it drives them at all levels easily with no noise whatsoever, the character of this speaker/amp pairing is a bit laid back in mid range, fast and tight thumping bass, slightly rolled off in the treble, I’ve found the best dynamics with the potentiometer somewhere between 11:00-01:00 o’clock and the windows volume betwen 60-70%(Vrms of 1.95V DAC line-level output), this gives me about 70 db average listening level with 30+ db of dynamics headroom. I’m looking to try other op-amps in this amplifier and see how it affects it tonally, overall I’m plenty happy for such a good price and lower size profile that this amplifier provides, well done Fosi!

48v 5A adaptörü takıp kendi dahili dac.ı rca ile denedim evet ilgi çekiciydi fakat standart bi d -classtı. Daha sonra 3 adet muses02 opamp sipariş verdim ve elime ulaşıncaya kadar amfinin yanmasını bekledim. Nihayet geldi opampları değiştirdim ve sub opampı devre dışı bıraktım(kullanmadığım için) vee Xlr (cardas golden cross) ları bağlayınca vaaay müthiş ses!! Birçok pahalı amfiyi sınıfta bırakır çok net!! Opamp yükseltmesi yapıp güzel bir Xlr ile kullanınız şaşırcaksınız....

Klinkt echt prima. Aanrader. Werd ook tijdens een hittegolf nauwelijks warm.