• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

New Fosi Audio V3 Mono vs Topping PA5 II vs Topping PA7 (inc. 'Plus' versions)...and Aiyima A70

ScofieldKid

Member
Joined
Feb 23, 2019
Messages
99
Likes
30
Location
Northwest, USA

YesChickenNuggets

Active Member
Joined
Nov 11, 2022
Messages
103
Likes
81
Is channel separation that significant irl that monoblocks would have an advantage ? Or what would be significantly different about monoblocks?
Also the Pa7 plus seems to be in a different price bracket, doesn't fit here.
I have this question also. How relevant, EVEN IS, channel separation as a metric for driving speakers.

Unlike headphones where pollution is minimal, with 2 speakers in the same room operating the same volume of air, is channel separation that critical ? Seems like this would be a number that just has to be, good enough.
 

kemmler3D

Major Contributor
Forum Donor
Joined
Aug 25, 2022
Messages
3,694
Likes
7,552
Location
San Francisco
is channel separation that critical ?
In a word, no. Crosstalk in modern amplifiers is basically never high enough to be audible. Channel separation (and level matching) is pretty important to sound quality but isn't a problem with any of the amps mentioned in this thread.

Monoblocks are a practical solution if you have an odd number of channels you need to power, or if you want to put the amp close to the speaker for some reason. They can also be useful for powering passive subs, and if you need so much power for each speaker that one circuit in your house can't provide it, a super-powerful monoblock may be the answer. (NB: this is usually 1500-1800+ watts in the US, so not relevant to this unit... or most home speakers in existence!)

Otherwise, as a solution for audible sound quality they won't give you something you can't get from a stereo amp in 2024.
 

YesChickenNuggets

Active Member
Joined
Nov 11, 2022
Messages
103
Likes
81
For me the real take-away of this thread is I probably never need to spend more than $300 on an amp again, unless I get some very big speakers in a very big room someday.
I'm in your camp as well. No matter how good speakers are, you get more than 8 feet away from them, they'll start to muddy as more of the room factor into the sound. So if you want the best clarity, regardless of the size of the room, you have to be decently close, and if that's the case, you won't be pushing much past 80db, which is already too loud and exhausting to listen to at length, and at 80db, how much power do you really need in real musical content, <1 watt ?

The wattage race has always seemed more a point of marketing than realistic usage.
 

YesChickenNuggets

Active Member
Joined
Nov 11, 2022
Messages
103
Likes
81
Otherwise, as a solution for audible sound quality they won't give you something you can't get from a stereo amp in 2024.
Another question kemmler3D, if I am feeling insecure about my masculinity, do you know if the V3 Mono supports 1x 48v 10amp into each amp for 500watts of power per channel ?
 

kemmler3D

Major Contributor
Forum Donor
Joined
Aug 25, 2022
Messages
3,694
Likes
7,552
Location
San Francisco
The wattage race has always seemed more a point of marketing than realistic usage.
So, there is a "wattage race" in low-end mainstream consumer stuff where companies basically just lie about their products' wattage as a proxy for how loud they go. Bluetooth speakers and whatnot.

That said, there is a real need for a lot of watts in hi-fi. Consider that you need 2x the watts to hit every 3dB of additional volume. For most speakers 1w gets you into the mid--to-high 80s at 1m. But if you sit 3m away (normal) from an 85dB sensitivity speaker, then you already need 8 watts to hit 85 dB SPL where you're sitting. If you want peaks at (a mere) 100dB at your listening position then you're going to need 300 watts.

In-room the numbers are usually a little more forgiving, but when you consider that 115dB peaks are considered desirable by the truly hardcore, the crazy high wattages start to make sense. And so do the >100dB sensitivity super-giant horn systems.

For me, I don't want or need to go that loud so ~250w is fine...
 

staticV3

Master Contributor
Joined
Aug 29, 2019
Messages
8,443
Likes
13,646
Another question kemmler3D, if I am feeling insecure about my masculinity, do you know if the V3 Mono supports 1x 48v 10amp into each amp for 500watts of power per channel ?
You can definitely plug a dedicated 48V10A supply into each V3 Mono.

How much power you gain over a standard 5A supply remains to be seen (=measured).
 

YesChickenNuggets

Active Member
Joined
Nov 11, 2022
Messages
103
Likes
81
In-room the numbers are usually a little more forgiving, but when you consider that 115dB peaks are considered desirable by the truly hardcore
Kemmler3D, are these truly-hardcore just saying that, or do they critically listen to music at 115. Is that not masochism more than audiophile?
 

kemmler3D

Major Contributor
Forum Donor
Joined
Aug 25, 2022
Messages
3,694
Likes
7,552
Location
San Francisco
Kemmler3D, are these truly-hardcore just saying that, or do they critically listen to music at 115. Is that not masochism more than audiophile?
Big difference between peak and average values. The use case is basically classical music with "front row" volume where the average level is around 80-85 but the peaks hit >100dB.

That, and home theater where you want the gunfire to be almost realistic levels...
 

TheBatsEar

Major Contributor
Forum Donor
Joined
Jun 16, 2020
Messages
3,246
Likes
5,309
Location
Germany
I'd wanted to get the fosi V3 stereo but have opted to wait for the version with PFFB.
I would agree, where it not for my own experience with the V3. I usually run a MiniDSP Flex into a Yamaha A-S1200, which certainly is a good device, into a pair of Wharfedale Linton 85th.
When i exchanged the Yamaha with a Fosi V3 i couldn't tell. I let it run for a few weeks and never once could tell the difference in terms of fidelity. Not when i play with my regular volume, not in "party" mode.
I went back to the A-S1200 because it looks awesome, has headphone out and two switchable speaker outputs, a remote and a proper standby circuit and all that stuff.

But for driving speakers, it doesn't matter ... TO ME. I know people claim to hear all sorts of things, but i can't. I never could. Not in the 90ies when people heard differneces in RCA cables, not in 2010s when people heard differences in Hires sources, not today when people hear differences in power supplies.

Will be interesting to compare Mono with the stereo version.
The PFFB version will likely look like the mono blocks in terms of measurements, with roughly half the power and less stable with two ohm loads.

Is channel separation that significant irl that monoblocks would have an advantage ? Or what would be significantly different about monoblocks?
The difference is you can put them apart (unless you buy their one powersupply with the Y-adapter) and you can buy an odd number of channels, say 3 or 5.

I personally would rather see them go the "more functionality" route instead of squeezing SINAD out of this very limited platform.
 

TheBatsEar

Major Contributor
Forum Donor
Joined
Jun 16, 2020
Messages
3,246
Likes
5,309
Location
Germany
You can definitely plug a dedicated 48V10A supply into each V3 Mono.
Instead i would go for slightly higher voltage, maybe 52v.

We are aware that the Texas Instruments chip inside is more or less at the end of the rope here, aren't we? Both, in terms of thermal dissipation as well as SINAD.
They need to use other chips soon, if SINAD is to go up.
 

staticV3

Master Contributor
Joined
Aug 29, 2019
Messages
8,443
Likes
13,646
We are aware that the Texas Instruments chip inside is more or less at the end of the rope here, aren't we?
Here's TI's datasheet graph, with the Fosi's performance according to Amir's measurements marked with little X'es:
Screenshot_20240406-113124_Drive.png Fosi Audio Mono V3 amplifier power Reactive Power measurement.png

There's an extra 100W left in the chip at 4Ω and an extra 200W at 2Ω.

Technically, TI specs the max supply voltage as 69V, and that may boost the output power even further, but it's probably sensible to stop where even their engineers stopped: 57V @4/3Ω and 54V @2Ω.
 
Last edited:

TonyJZX

Major Contributor
Joined
Aug 20, 2021
Messages
2,085
Likes
2,019
the A70 is marked as 'sold out' and 'unavailable' so dont know how such a new product ended up like that

a07 max is fine

so you may speculate wildly why the a70 went out so quick
 

Sokel

Master Contributor
Joined
Sep 8, 2021
Messages
6,402
Likes
6,555
In-room the numbers are usually a little more forgiving, but when you consider that 115dB peaks are considered desirable by the truly hardcore, the crazy high wattages start to make sense. And so do the >100dB sensitivity super-giant horn systems.
Yep,nothing wrong being faithful to the signal :p
 

Sokel

Master Contributor
Joined
Sep 8, 2021
Messages
6,402
Likes
6,555
Do you guys have any example of this music material where it goes from 80 to 115 and back to 80 ? I would like to listen to this.
Here's 85db (A) average to 112db (Z) peaks,which I have on hand example.
Bedřich Smetana's - Má Vlast JB 1:112: No. 2, Vltava · David Parry & London Philharmonic Orchestra (2009) Warner.
(sorry,I found no nice YT version of it,they're all horrible)

And I can assure you it's not as loud as you think,peaks is not the same with max.

1712424294152.png 1712424323093.png


It's really the norm with classical,many have a lot more.

Edit: Weighting
 
Last edited:

Sokel

Master Contributor
Joined
Sep 8, 2021
Messages
6,402
Likes
6,555
Do you guys have any example of this music material where it goes from 80 to 115 and back to 80 ? I would like to listen to this.
Also,weighting is important and has to be reported.
Here's how different Amir's reference bass "Fading Sun" by Terje Isungset looks at exactly the same level but with different weighting:

1712425824762.png

(A) weighting

1712425875386.png

(C) weighting
 

DavidM1

Member
Joined
Feb 7, 2023
Messages
71
Likes
61
You can definitely plug a dedicated 48V10A supply into each V3 Mono.

How much power you gain over a standard 5A supply remains to be seen (=measured).
Pardon the newbie question but, in general, isn‘t the determining factor how much current a device needs to draw? If a device draws less than 5A then shouldn’t it function the same with either a 5A or 10A supply, all else equal?
 
Last edited:

staticV3

Master Contributor
Joined
Aug 29, 2019
Messages
8,443
Likes
13,646
Top Bottom