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Fosi Audio V3 Mono Amplifier Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 8 1.6%
  • 2. Not terrible (postman panther)

    Votes: 12 2.4%
  • 3. Fine (happy panther)

    Votes: 100 19.8%
  • 4. Great (golfing panther)

    Votes: 384 76.2%

  • Total voters
    504

Fosi Audio

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Dear @Fosi Audio

I have pledged, almost sound a religious thing to do. Yesterday was full of excitement. Today however I am now faced with five concerns:

1 Heat - ie total amount of. Videos are now showing amps as running hot. Will total heat output be less than standard A/B amp which runs hot and is large (think baby Krell)?

2 Power Supply crosstalk (noise) - per YouTube review - will this be fixed?
Will Fosi offer second power supplies if not, either free or discounted?

3 Op Amp Rolling - Why does Fosi not simply put the best in to start? (or maybe you do?)
I want flat, my dac/pre-amp does all I need from a musicality perspective. If op amp options are offered, it is not clear how many are needed, nor where to put them, and what difference they make, nor the spec needed to not invalidate warrantee? (unless I missed the small print).

4 I actually needed more amps than I was able to pledge for. 4 amps (2x2) is a start (I actually will need a potential total of 21! for my Kitchen (2), Hall(2), Lounge(7), Lounge II(2), Garage(4), Shedquarters/Office*(4) - and that is before going crazy - (crazy:bi-amping large speakers).
*Thus far, the Office will be the only place I can use them. Unless pledge can be added to? (did I miss something?)

5 There is no Sub out - so what do I do? Anyone, any ideas? (Stereo amp has one, but not the monos?) Or will there be a "Pro" version coming with Sub out?

I look forward to some great feedback.
I'm glad to respond to all your concerns above.:)

1. V3 Mono employs a unique cooling design. We closely attach the amplifier chip's heatsink to the chassis, effectively turning the entire chassis into a radiator. Additionally, we have included vent holes on both sides of the chassis to enhance air circulation. Since the chassis serves as a radiator, its surface temperature may seem a bit high. However, this indicates that the heat from the TPA3255 amplifier chip is being effectively transferred to the chassis, allowing the V3 Mono to stably maintain high power output continuously. So, there is no need to worry.

2. We are currently resolving this issue. If it is not perfectly resolved, we will offer you the dual power supplies set instead.

3. The standard op-amp in V3 Mono is the NE5532, which is known for its ability to reproduce sound in a true and natural manner without altering the original timbre. If your DAC or preamp already has tone-tuning functions, there is no need to roll the op-amp. The design of replaceable op-amps is particularly favored by many DIY enthusiasts. Among our fans, many users opt for renowned op-amps like the Sparkos SS3602, Burson V7/V6/V5i, and MUSES02. They enjoy experimenting with different op-amps to experience various sound signatures, which they find quite intriguing.

4. Yes, you can add more sets if needed. Please leave a message for our team on Kickstarter, and my colleague will guide you on how to add them.

5. V3 Mono is designed as a power amplifier; hence, it is typically used in conjunction with a preamp. You can connect a subwoofer to the preamp to setup your system.
 

Dr. Noooooo

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I have never heard any differences in this guy's comparison, except today, even if it was just a tiny bit. I preferred candidate B.
I have to admit that YT‘s compression is the bottleneck here. What would make it really interesting is if the creator could provide a download link for a lossless or even better HiRes soundtrack to be played along with the video. I’m still doubtful there would be any significant audible differences between the op-amps or the D class amps. However, the differences between V3 Mono and the A/B and A class amps (2nd part) were audible here, for one amp B had reversed L/R channels and amp C had a tad more midrange presence and top end clarity in my opinion. Whether that alone would justify the price difference is “highly subjective“.
 
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drmevo

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We're looking forward to your sharing of comparing the two setups.:D
As it turns out the Pascal module blew last night, so I basically have a preamp only. I’ll be (maybe not so) patiently awaiting the V3 Mono ship date!
 

Guddu

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When a device is pre production it is because the development is not finished. More often than not the product testing is still ongoing. It would be a surprise if pre production devices didn’t have some issues.
Pre-production units are sent to people putting videos on youtube, specially when has issues that could be tested so easy!!!
Doesn’t seem like a good idea, does it!

It is what it is.

PE. By the way, it is an observation to improve on but not a criticism, if you like.
We know what happened in case of PA5 (first release) after all.
 
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TonyJZX

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i feel like anything that isnt the least bit 'well worn and tested' will have issues like this

eg. what happened to the A70 max?

if you are releasing a plain A07 max you should have little issues but the 48v 10a dual head psu is a new thing so... expect some oddness

i give them pass for this
 

amper42

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The maiden voyage of the Titanic was epic. Glad I decided to wait until it was broken in. :cool:

ASR reviews are great for measuring SINAD and distortion. The company should have tested the product for heat dissipation after 3 hours running, energy efficiency and longevity. A chassis that reaches 120F within 3 hours is not something most of us consider a feature. The buzzing noise with one 48V power supply powering two V3 amps might be a good way to remind you to unplug it before something burns up.
 
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TonyJZX

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this sort of launch gives you an idea of what companies have to do when they release new products

i'm not in the consumer electronics space but i've been in the background of a few large product launches here and this sort of thing isnt unusual

and these are relatively simple devices
 

SMen

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It occurs to me that the people here who want to try op amp changes could usefully A/B a mono track, and switch between one mono unit with one set of opamps, and the other with stock NE5532's. Put the speakers next to each other. Get a mate (or suitable relation) to switch so the listener is blind. This ought to settle things for the experimenters (themselves) - could they identify which was which?

A whole new purpose for mono power amps :D. Think I might give this a go for the hell of it. Rope in my kids.
 

iLoveCats

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Looks like the full ASR lifecycle on this has been reached before it's even been in the average consumers hand. The foreshadowing, the reveal, the test and now the peanut gallery burying the product before it ships.
 

olieb

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Looks like the full ASR lifecycle on this has been reached before it's even been in the average consumers hand. The foreshadowing, the reveal, the test and now the peanut gallery burying the product before it ships.
Yep!
Hey @Fosi Audio !
When do you plan to bring us the version 2? Everybody is eagerly waiting already.

At least it is now clear, why they did not start with the stereo, but brought a niche product first.
 

EddNog

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Looks like the full ASR lifecycle on this has been reached before it's even been in the average consumers hand. The foreshadowing, the reveal, the test and now the peanut gallery burying the product before it ships.
Really…although the short story really seems to be that if you just use separate power supplies, it will sound great, even single-ended, where an imperceptible reduction in SINAD will occur.

None of this banter about noise with shared PSUs or running somewhat hot (yet WELL within acceptable parameters) is dulling my enthusiasm at least. ¯\_(ツ)_/¯

-Ed
 
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For 200 bucks, it seems like a fun opportunity to experiment, test, listen. I pledged. See if they sound good, see if they let the smoke out. I will hook these up to an old Yamaha RX V630 to drive old Paradigm monitor 7 v3s. The gain should help with the lower volt pre-out (i think).

I’ve been out of the hobby in any serious way for nearly 20 years and really enjoying Amir and ASR to get reoriented and updated. Thanks everyone!
 

SMen

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Really…although the short story really seems to be that if you just use separate power supplies, it will sound great, even single-ended, where an imperceptible reduction in SINAD will occur.

None of this banter about noise with shared PSUs or running somewhat hot (yet WELL within acceptable parameters) is dulling my enthusiasm at least. ¯\_(ツ)_/¯

-Ed
Yes. I'm seriously looking forward to trying mine with just one, noise and problem free 48v 10A power supply
 

sl1982

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I am interested to see if there is any additional headroom in these if we hook only one up to a 10A power supply. If thats the case ill add another power supply to my kickstarter.
 

Great Sun Jester

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Strange to think how may this be possible that they didn’t find it in their product before sending it to so called youtube influencers.
What happened to internal testing and all!
Inexplicable.
 

Guddu

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Inexplicable.
pre-production unit is also a finished product after all, and is subject to testing.
At the end of the day, if this is helping buyers to get a problem free product for their money then let’s keep it coming else it’s all good.
 
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TonyJZX

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it used to be saleable products first off the production line AFTER all teething and QA QC issues are sorted
 

iLoveCats

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I thought Fosi stated the noise issue is only if you use one mono amp off the Y cable at one time. Nobody would use it like that, there's no real world use case for this. Fosi also said they would fix it or send 2 power supplies. When I bring on new equipment, I ALWAYS think I thought of everything, and I never did. I deal with this constantly at work in oil/gas.
 

Guddu

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I thought Fosi stated the noise issue is only if you use one mono amp off the Y cable at one time. Nobody would use it like that, there's no real world use case for this. Fosi also said they would fix it or send 2 power supplies. When I bring on new equipment, I ALWAYS think I thought of everything, and I never did. I deal with this constantly at work in oil/gas.
Interesting that many measurements and tests are still there even though those aren’t practical in real world used case, its a big debatable topic here on ASR but I am not going there.
Appreciate what you said but IT change management process made me learn the need of testing in every way possible, every possible issues if possible.
You never know how creative a user could be using what they buy ;).

PE. and that’s where disclaimers can help, like if you are buying one psu to power up 2 amplifier units then “xyz” is expected……..
 
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