Fosi Audio V3 Mono Review

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Fosi Audio V3 Mono Review - Fosi Audio

Equipment Used:

Topping A70 Pro Preamplifier
FX-Audio Tube 06 MKII Preamplifer
Topping E50 and E30 DAC (plus others)
Fyne Audio F300i
Pioneer SP-BS22-LR (Modified)
Pioneer Andrew Jones SW-8 MKII (Modified)
Blue Jeans Cables for all interconnects and speakers

Albums Tested:

Herbie Hancock – Head Hunters
Miles Davis – Kind of Blue
Wayne Shorter – Speak no Evil
Bill Evans Trio – Live at the Village Vanguard
Michael Jackson – Thriller
Metallica – Metallica
AC/DC – Back in Black
Norah Jones – Come Away with Me
Macy Grey – Stripped
Daft Punk – Random Access Memories
DeadMau5 – While (1<2)
Thundercat – Drunk
Dire Straits – Brothers in Arms
Dr. Dre – 2001
A Tribe Called Quest – The Low End TheoryA

Fosi Audio has kindly provided these units to me to review as part of their consumer testing program. I was not paid for my review, and I will remain as neutral as possible. I am very familiar with Fosi’s products and have experience with the V3 Stereo and ZA3. For the purposes of this review, I will be comparing the V3 Mono to the Stereo V3 and my personal Topping PA5II stereo amplifier.

I’ve been in the audio business off and on since 1995, from car audio sales and installations as well as owning my own turntable brand and doing industry marketing consulting currently. I’ve had all sorts of audio products over the years, ranging from the mundane, to the spectacular to the spectacularly bad. It’s very rare that something comes across my desk that is revolutionary and I will say that the Fosi V3 Mono qualifies. It offers a level of price and performance that even as little as 3 years ago would have been considered unheard of in the industry.

I tried the V3 Monos with a wide variety of music that I am very familiar with and my listening impressions are a combination of all tracks tried.

Initial Impressions

The units come in the same type of relatively nondescript packaging as the rest of the Fosi Audio line, certainly a place where value was placed ahead of presentation. I’m fine with this decision if it means we get high performance sub $200 mono blocks. Upon opening the package, you are greeted with a tiny black metal box that may have some fingerprints on it from whomever placed them in the box. (These things are absolute fingerprint magnets, far more so than the V3 and ZA3. I hope Fosi takes note and adds oleophobic coating because it’s annoying.)

These units are as simple as can be, with a toggle on the front for power, auto and off and to switch between balanced and single ended inputs. One amber indicator light lets you know if they are on, off or in standby mode.

On the back you have well placed and reasonably well spaced 5-way binding posts for the speaker you are going to power, a TRS/Balanced input, and Single ended input with a 26/32db gain switch and the ubiquitous power supply input.

The design aesthetic can be seen as a more sculpted version of the V3 stereo, with a nearly identical form factor and a faceplate with a beveled top and bottom. It feels very solid and high quality. It has orange accented gills along the side as opposed to the top and bottom ventilation of the Stereo V3. More on that later.

Simple design leads to a great initial customer experience and these things are out of the box and set up in 5 minutes or less. No volume to fiddle with or settings to master, just plug and play.

My initial testing was done connected to a Topping A70Pro preamplifier, and additional testing was done with an FX-Audio Tube 06 MKII Tube Preamplifier with vintage GE tubes. I tried them with a variety of DACs I had around from work but primarily a Topping E50 Pro. I tested the units with Single Ended, Balanced and balanced TRS connections and full range and crossed over with a powered subwoofer. My testing for the most part was done with a pair of Fyne Audio bookshelf speakers as I listen to them for up to 8 hours a day and I am very familiar with their ins and outs with different DACs and Amplifiers. My application is desktop in this case as I spend the most time doing critical listening at my desk and as I from time to time professionally evaluate equipment quality here is more important than anywhere else in my home.

Test Results:

Out of the box, connected to the A70Pro via balanced inputs and powering my Fyne Audio Speakers, listening to my usual test tracks (a mix of Jazz, EDM and Vocals) I had a hard time believing what I was hearing. These little black boxes are amazing. Listening to Macy Grey’s “Stripped,” the first thing that sprang to mind is the width soundstage and instrument placement as the primary impressive point, with the depth of field and lifelike timbre of instruments and vocals a close second. I’d call this a main benefit of a dual mono type setup…you are getting stereo reproduction as the preamplifier puts it out there and the recording intends without any separation issues from the amplifier. With tracks from Daft Punk, Cage the Elephant and Lorde, the wide-ranging capability of the V3 Monos on more electronic/rock music showed itself. The power output is amazing and the ability to run my Fyne Speakers and the modified Pioneer Andrew Jones speakers I tested to uncomfortable levels with no sense of distortion was something I didn’t expect. The control of the bass drivers was really something, even without running a powered sub (which I usually do with these speakers). I could honestly say using the output from the V3’s, I didn’t find myself wanting the subwoofer output, they were able to get the most out of bookshelf sized speakers. That said, going one step further and adding in the subwoofer….I could be fooled into thinking I was listening to one of my much larger setups with tower speakers.

Amplifier Comparisons:


My Topping amplifier is no slouch….and does a great job, but the V3 Mono is clearly an order of magnitude better. There is a marked difference in the power output especially on dynamic demands such as drum solos, bass lines, etc. And the depth of field with the V3 Monos is much greater. I think the midrange on the Topping is cleaner and more lifelike, but the overall presentation is less energetic. The comparison with the Stereo V3 isn’t fair at all. While it does a great job as a stereo amplifier, it cannot compete with this level of pinpoint accuracy and the tonal qualities are quite different. The V3 Stereo midrange and treble, my chief complaints from day one with this unit, are markedly inferior and instrument separation just isn’t there. It presents a cohesive stereo image but not to the same degree as the V3 Monos. The energy level is relatively comparable but not quite on par. Speed and accuracy with both speakers tested was better with the monos….I believe owing to having two separate 3255 chipsets and more headroom to play with as a result.

The next point is the ability to power difficult speakers. My Fynes are 8 ohms and not particularly efficient. They’re also EXTREMELY detailed and can be harsh with the wrong amplifier. This is not the best type of pairing for a Class D amplifier, and up until this point I have not had 100% satisfactory results with any Class D amps I’ve tried with them apart from an $800 Hypex amp I tested. The Stereo V3 was good but the lack of PFFB did cause some issues on the top end and I eventually shelved it in favor of the Topping. At higher volumes while both did exhibit good driver control, there was a tendency to break up a bit and sound muddled. The Topping being a slightly different design with PFFB and some proprietary circuitry did a better job (it was also nearly 3x as expensive) but it always seemed to run out of gas. The problem here was the power limitation, in both cases, of using an 8 ohm application and why I use 8 ohm speakers for this type of evaluation. It’s easier to power a more efficient 4 ohm in this type of environment and get good results, but a great amp can run anything well.

The monos break through this issue with aplomb. They sound reminiscent of a good Class A/B amp and power the Fynes like they were a set of 100DB efficient 4 ohm speakers. They very, very easily get louder than I am comfortable listening and have amazing bass control even at high volumes. It’s like a never-ending wellspring of amplification that I don’t get from the stereo amps. This isn’t something I’ve ever seen in this size class, even with a Hypex amp. The highs have no issues whatsoever and regardless of the volumes I listened or the music type, I heard no distortion. And again, there was a lot of headroom left on the table. I would say anything short of a giant multi-driver tower you’d be able to run anything with these. I can also see them excelling in an application where you use them to Bi-amplify or Tri-amplify a set of high end speakers.

Solid State Vs Tube Preamplification



I next connected the unit to my Tube 06 MKII via RCA with a subwoofer. This combination was vastly different than the setup with the Topping A70Pro. The A70 has a leaner presentation with a high degree of accuracy and I think with rock and EDM it’s much better than a tube setup on all amplifiers tried. With a tube buffered front end however….listening to jazz, classical and certain types of acoustic rock, the Monos exhibited very class A/B type performance. In a good way. You’d never think these little guys were in any way related to the chip amps we got in the first days of class D. While we’re not talking about a level of pinpoint accuracy I was seeing with the Topping preamp, with the tubes I was reminded of the presentation of something like a Rogue Audio, Vincent or Musical Paradise hybrid amplifier. The touch of warmth and ultra-wide sound stage made a very positive impact. Again, not as much of a fan with rock or EDM with this setup (it felt a little flat) but with the right music….magic. Luckily, I’m set up so I can just flip a switch and and go with either preamp depending on my mood, or if it’s too hot to run tubes…and using the Monos as the power amplifiers takes the best advantage possible of this flexibility.

Testing Notes

The dual power brick arrangement is annoying. There’s no getting around it. If you’re using these in a stereo setup, get the single 10 Amp split power supply. The bricks are large and hard to put out of the way. If you’re powering a home theater setup I’d recommend two on the single 10 Amp and then the others on the singles.

There does seem to be a greater degree of sensitivity on the RCA inputs than the balanced ones….and they seem a tad more prone to picking up noise. This was likely a function of the amount of equipment I have in proximity to the amps and preamps but that’s something to keep in mind. Also, I had some issues with the higher gain setting with the RCA’s. When using the tube amp, hiss was apparent. I am using vintage tubes, so this is partially a “user beware” kind of thing but I’d thought I’d mention it. Also, it’s easy to forget there are two gain switches and you’ll wonder why one channel is markedly louder than the other.

In listening to certain types of music with female vocals and horns, with my Fyne speakers, the midrange can be a bit forward. The tube pre definitely fixed this but at the expense of some detail and power on more bass heavy tracks. Using DSP on the solid-state preamp definitely fixed this “issue” if you can call it that. I wouldn’t call it harsh or sibilant, just a bit mid forward. This was there to a degree with the Pioneers but only a tiny bit. And again, this may be a function of my particular setup. I’m going to do a second test with some larger tower speakers (Paradigms) at a later date and in a surround setup on a Yamaha preamp just to see if that remains.

The turn on/turn off behavior can be a little odd, with the amps not turning on at the same time every time and turning off earlier than you’d expect, but it’s nothing you can’t get used to over a few uses.

Finally, they get warm. Much warmer than I expected, and I suspect that’s a function of how they’re vented relative to the Stereo V3 with the same case size and the power they’re kicking out. Nothing to be concerned with but just be aware. I would run them separately instead of stacked if you can, but they’ll be fine either way (I asked.)

Conclusion

Without trying to sound like a paid spokesman for Fosi here, I’m going to say these things are a home run. I was just about to pull the trigger on an $800 Compact Hypex amp and these have me reconsidering that investment. With something like this out there, I just don’t see the need. Are they going to replace a $5000 stereo amplifier? Probably not. Could they? Most likely yes, depending on how much you attribute cost to your equipment’s performance. The bottom line is through some sort of technological witchcraft, we’ve arrived at high quality $1000/100 watt performance at 1/5th of the price. I can’t wait to see what they come up with for a preamp for these little guys….we could have something truly world beating.

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