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Fosi Audio V3 Mono Amplifier Review
- Thread starter amirm
- Start date
Do you really have to keep repeating the same thing over and over?
Fosi have sent you a very polite personal reply already on the forums, I must confess that I would have less patience than Fosi and would probably return your purchase money saying that you aren't wanted as a customer.
I received my V3 Mono amplifiers and 48V5A PSUs on June 24th. Maybe it’s because I’m in East Asia and chose 5A PSU.
(The previous kickstart project I back : Timemore 078S coffee grinder delayed almost 1 year )
I'm sharing my experience with the auto-on function and power consumption in hopes of helping other users and providing feedback to @Fosi Audio.
Depending on the source device you connect to, you may or may not encounter the same issue.
I originally used two ZA3 amplifiers as external power amplifiers for the center and surround channels of my AV receiver. The downside of using a 12V trigger is that when the AV receiver turns on, the ZA3 amplifiers are also woken up, even if it is only playing 2.0 audio.
Since the V3 mono has an auto-on function, I plan to replace the ZA3 with the V3 mono. My goal is to only wake up the V3 mono when I am playing 5.1/7.1 audio, similar to the auto-on function commonly found on subwoofers.
I encountered an issue with the auto-on function causing the V3 Mono to turn on unexpectedly. This seems to be triggered by power noise from other devices.
My current setup is as follows:
TV -> Yamaha Rx-V773 Pre-Out -> Wiim Pro Plus -> Purifi 1et400a (L/R)
-> V3 Mono (C)
-> ZA3 (SL/SR)
-> Velodyne Impact 10 (SW)
The V3 Mono turns on when the TV is turned on, even if the Yamaha Rx-V773 is off.
The V3 Mono turns off after 10 minutes and turns on again when the TV is turned off.
The V3 Mono turns on when the ZA3 is turned on or off, even if the TV and Yamaha Rx-V773 are off (see video).
It seems that power noise from the TV or ZA3 is triggering the V3 Mono's auto-on function. While this could be attributed to the Yamaha Rx-V773's noise filtering, other devices with auto-on functions (Wiim Pro Plus and subwoofer) do not experience this issue.
Typically, auto-on functions are designed to use continuous signal detection to ensure that the device is not triggered by power noise or other interference. However, it seems that the V3 mono does not implement such a detection mechanism. A more sophisticated auto-on function that can differentiate between actual audio signals and power noise would be beneficial.
I am not sure whether the V3 mono's auto-on function is controlled by MCU firmware or a hardware detection circuit. @Fosi Audio Is it possible to fix this issue through a firmware update or a simple circuit modification?
While not a major issue, this behavior is inconvenient and defeats my original goal of only having the V3 Mono turn on for 5.1/7.1 audio.
As a workaround, I'm using smart plugs to manually control the V3 Mono's power. But this isn't as automated as I'd like.
Using smart plugs, it provided the measurement of the power consumption of the amplifiers. The V3 Mono consumes around 4W in standby mode in an AC110V environment, higher than the 3W reported by Fosi in AC220V testing. In contrast, the ZA3 consumes less than 1W in standby mode.
This difference could be due to the ZA3 shutting down most modules in standby mode, while the V3 Mono keeps some components active to support the auto-on function.
If you are really concerned about power consumption or surface temperature (the V3 Mono remains warm even after being in standby for a day), it's recommended not to use the auto-on function.
I hope this information is helpful to other users and @Fosi Audio. I appreciate their efforts in creating high-value performance audio products and look forward to future improvements.
(The previous kickstart project I back : Timemore 078S coffee grinder delayed almost 1 year )
I'm sharing my experience with the auto-on function and power consumption in hopes of helping other users and providing feedback to @Fosi Audio.
Depending on the source device you connect to, you may or may not encounter the same issue.
I originally used two ZA3 amplifiers as external power amplifiers for the center and surround channels of my AV receiver. The downside of using a 12V trigger is that when the AV receiver turns on, the ZA3 amplifiers are also woken up, even if it is only playing 2.0 audio.
Since the V3 mono has an auto-on function, I plan to replace the ZA3 with the V3 mono. My goal is to only wake up the V3 mono when I am playing 5.1/7.1 audio, similar to the auto-on function commonly found on subwoofers.
I encountered an issue with the auto-on function causing the V3 Mono to turn on unexpectedly. This seems to be triggered by power noise from other devices.
My current setup is as follows:
TV -> Yamaha Rx-V773 Pre-Out -> Wiim Pro Plus -> Purifi 1et400a (L/R)
-> V3 Mono (C)
-> ZA3 (SL/SR)
-> Velodyne Impact 10 (SW)
The V3 Mono turns on when the TV is turned on, even if the Yamaha Rx-V773 is off.
The V3 Mono turns off after 10 minutes and turns on again when the TV is turned off.
The V3 Mono turns on when the ZA3 is turned on or off, even if the TV and Yamaha Rx-V773 are off (see video).
It seems that power noise from the TV or ZA3 is triggering the V3 Mono's auto-on function. While this could be attributed to the Yamaha Rx-V773's noise filtering, other devices with auto-on functions (Wiim Pro Plus and subwoofer) do not experience this issue.
Typically, auto-on functions are designed to use continuous signal detection to ensure that the device is not triggered by power noise or other interference. However, it seems that the V3 mono does not implement such a detection mechanism. A more sophisticated auto-on function that can differentiate between actual audio signals and power noise would be beneficial.
I am not sure whether the V3 mono's auto-on function is controlled by MCU firmware or a hardware detection circuit. @Fosi Audio Is it possible to fix this issue through a firmware update or a simple circuit modification?
While not a major issue, this behavior is inconvenient and defeats my original goal of only having the V3 Mono turn on for 5.1/7.1 audio.
As a workaround, I'm using smart plugs to manually control the V3 Mono's power. But this isn't as automated as I'd like.
Using smart plugs, it provided the measurement of the power consumption of the amplifiers. The V3 Mono consumes around 4W in standby mode in an AC110V environment, higher than the 3W reported by Fosi in AC220V testing. In contrast, the ZA3 consumes less than 1W in standby mode.
This difference could be due to the ZA3 shutting down most modules in standby mode, while the V3 Mono keeps some components active to support the auto-on function.
If you are really concerned about power consumption or surface temperature (the V3 Mono remains warm even after being in standby for a day), it's recommended not to use the auto-on function.
I hope this information is helpful to other users and @Fosi Audio. I appreciate their efforts in creating high-value performance audio products and look forward to future improvements.
No more order status posts in this Review Thread. Start an Owner & Ordering Thread in the Desperate Dealers section.Shipped already.
You'll receive a shipping notification email later.
Sokel
Master Contributor
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The early days of signal sensing had these problems so some rough thresholds established (they differ between companies)
Here's an example:
I posted a similar observation in the owners thread. Just turning on my lights on the same circuit engages the auto-on, with everything else in the chain powered down. Now, I also have a Yamaha AVR in my system, which is connected from its L/R pre outs to my Parasound pre-amp via HT Bypass input. Maybe it’s a strange Yamaha issue? Still, that means the “signal” makes it through the Parasound NewClassic 200 Pre.
No pops or anything when using smart plugs to turn them on? And what mode do you use in combination with smart plug, “on” or “auto”?
keith_h
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I politely disagree with your assertion. It performs much better than the distinguished amplifiers that it replaced in my system and is a bargain at the price. It measures at the top end of amplifiers tested by Amir which backs up my subjective assessment.
Did you face any sort of issues following installation in your system we should know of please document them here so we might learn about them and discuss.
When they are on they get warm, around 40deg centigrade, regardless of what they are doing. This is the temperature of the metal vent grills. I cannot comment on life expectancy but it does feel like leaving them "running hot" might be worth minimizing.
They consume a combined total of approx.15W when on, I have not measured the consumption when they are idle in auto mode.
Ah, yes. Misleading, sorry. I have the DAC / Mini PC and Monos on one energy plug. I was interested in what the combined power consumption was with music playing 35W ....versus me leaving the system on but not playing music 18W.....which I want to do as I have a multiroom LMS setup where I leave the players awake.....nice to know what the background energy consumption is. When the chief goes to bed the smart plugs are powered off so zero energy used during dream time.
That may well be true, but it's not as good as other amps in the same neighbourhood of the SINAD list or amps with the same chip. If you look at 32 tone test, 19 & 20 kHz test and power vs distortion test at different frequencies (higher than 1 kHz) (where measurement available) of this and other amps, you'll see that this mono is behind.
https://www.audiosciencereview.com/...io-p122-class-d-amplifier-measurements.11801/ (NCore)
https://www.audiosciencereview.com/forum/index.php?threads/ati-at522nc-stereo-amplifier-review.9999/ (NCore)
https://www.audiosciencereview.com/...dio-tpa3255-260-2-29a-amplifier-review.50208/ (TPA3255)
https://www.audiosciencereview.com/...topping-pa5-ii-stereo-amplifier-review.47362/ (TPA3255)
Peace.
How? It has a Y cable for the power? Cool.
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The P122 costs US $750.
The 522NC costs US $2,195
3e audio 260-2-29A US $109.00 = has less power
Topping PA5 II stereo US $289.50.
The neighborhoods of price or power change things for me, I'll take higher
Actually, the PFFB configuration was documented from the beginning. But the TPA3255 being an inexpensive chip aimed at inexpensive devices, most manufacturers were using it without PFFB to save even more.
keith_h
Member
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Point well made. If dyno testing equipment only is the criteria then of course no argument. There's no denying the science of measurement in that respect. However as noted there's a need for willingness to pay more and in some cases substantially more to get those slightly better numbers. And of course the results at the ear depends on upstream component and a whole other bunch of variables as to what is actually delivered. While measurements may be more impressive my ear is insufficiently golden to notice the numbers. They are to my way of thinking indicative only and a good guide to what is possible under ideal conditions - for one component of a system. Plus its been noted that the upper high frequencies are unlikely to be something most of us can perceive to any significant degree anyway. If your hearing has been tested and proves otherwise then obviously that's a consideration for you.
Some context, the head unit is a NAD M10 V1 which is nCore powered and generally considered a good thing. I'm running an NAD sub from 120Hz. The M10 V1 measures midrange so far as its amplifier performance goes but sounds just fine as installed in my room with the sub. This unit has Dirac which when tuned properly elevates what comes out of the speakers. DSP is a whole different discussion but its very effective in this case.
I had been contemplating an Eigentacht update either NAD or VTV. The Fosi bench marks similarly at a fraction of the cost. The difference in sound clarity is noticeable. With Dirac on top its just great - for peanuts. The quibbles over whether it measures better or worse than others don't really matter to me. Its quite a bit better than what I had, job done and for not much money for even more win. And therein the lesson, everyone has different motive and priorities. Horses for courses.
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A more inaudible difference ... is inaudible anyway. Numbers are good to know if you're buying a decent level of engineering and (of course) a transparent amp
Up from that ... there's no better for your ears in a blind test. So, buying one amp because at 18khz have 1% less distortion ... don't work for me.
If 200 watts at 4 ohms is enough for you, I don't think you'll have "better sound" from other amp.
Up from that ... there's no better for your ears in a blind test. So, buying one amp because at 18khz have 1% less distortion ... don't work for me.
If 200 watts at 4 ohms is enough for you, I don't think you'll have "better sound" from other amp.
No, not at all.
You'll be far better off selling them to someone like me who would like a pair
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