Fosi v3 Mono - User Impressions | Owner's Thread

[SMen]

Whatever you are hearing (if anything) is very unlikely to be the SINAD difference.

Possibilities are:

Load dependent frequency response on the A07 (No PFFB)
More available power (A07 overloaded and clipping)
Nothing at all (sighted listening impacted by perceptive bias). This is IMO the most likely.

Yes, I think power would be an obvious one, and PFFB on 8ohm speakers too. I have certain 60s albums that are painful if there is high frequency response 'uplift'.
The completely different volume control would be another factor - balanced relay vs unbalanced basic volume pot in the Aiyima.
Unless my perception of improvement regarding the balanced relay is perceptive bias?

But as with diminishing returns in terms of how much we spend, or diminishing returns as advances are made in measured technical excellence, there are diminishing returns on certain arguments. There comes a point when two pieces of equipment do, in fact, sound different to each other when level matched and so forth, and the perceptive bias opinion becomes a form of bias .

You can't stir a volume pot! Surely?! I think you probably can, (and it is all good fun).




I'll be self-arming myself with the perceptive bias argument for the op amps...

 

[antcollinet]

Unless my perception of improvement regarding the balanced relay is perceptive bias?

If you don't do a level matched blind test, you'll never know.

There comes a point when two pieces of equipment do, in fact, sound different to each other when level matched and so forth, and the perceptive bias opinion becomes a form of bias

If you don't do the level matched blind test, you'll never know where that point is.

I'll be self-arming myself with the perceptive bias argument for the op amps...

Well, I think you know how it goes from here.

 

[SMen]

If you don't do a level matched blind test, you'll never know.


If you don't do the level matched blind test, you'll never know where that point is.


Well, I think you know how it goes from here.

You managed it...

You stirred a volume pot!

Amazing !

 

[norcalscott]

@Miley_B since you ordered and received the same package from Fosi as I did (single 10A power supply and filter) I am curious if you received op amps? I don't really care as I have doubts about op amp rolling, but I seem to remember that I "should" have received alternate op amps, but none were in the package.

Did anyone else here with that combination receive op amps?

 

[early rejecter]

Did anyone else here with that combination receive op amps?

I got that combo. The package included the t-shirt and RCA cables, but not the promised hex driver or op-amp. I’ve been meaning to follow up with them.

 

[DavidMcRoy]

@Miley_B since you ordered and received the same package from Fosi as I did (single 10A power supply and filter) I am curious if you received op amps? I don't really care as I have doubts about op amp rolling, but I seem to remember that I "should" have received alternate op amps, but none were in the package.

Did anyone else here with that combination receive op amps?

I received 4 V3 monos and 2 10A power supplies for all of them and filters. No additional opamps, which I don’t care about since I’m not in “the faith” that thinks there’s anything significant to be gained by bothering with it. (I indulged once with an Aiyima A07 et, voilà: no difference.)

 

[Sokel]

I can look at the measurements and say, okay, 80db SINAD vs 100 ... that would appear to be audible,

Does anyone has an SMSL or Topping with the various tube,transistor modes and stuff?
We're talking 40dB and 60dB SINAD there.

Audible?
You be the judge since user impressions is the subject here.

SINAD is a single freq measurement,useful to judge device's health at some point but does not tell the whole story.

 

[SMen]

Does anyone has an SMSL or Topping with the various tube,transistor modes and stuff?
We're talking 40dB and 60dB SINAD there.

Audible?
You be the judge since user impressions is the subject here.

SINAD is a single freq measurement,useful to judge device's health at some point but does not tell the whole story.

Thank you for feeding a curious mind...
I am inclined to agree about SINAD because I listen to records!
Probably the audibility factors lie in frequency response, speaker handling (in the case of amplifiers), application of feedback (ditto), and distortion, those second order harmonics I read about.

I will be back to play more with my v3's from tomorrow.

 

[Miley_B]

@Miley_B since you ordered and received the same package from Fosi as I did (single 10A power supply and filter) I am curious if you received op amps? I don't really care as I have doubts about op amp rolling, but I seem to remember that I "should" have received alternate op amps, but none were in the package.

Did anyone else here with that combination receive op amps?

I received everything in one delivery, which included a rather large T shirt and 2 Muse02 op amps.
Odd that they gave no size options for the T shirt, I would rather have had no T than one that I will never wear.
As I got the op amps whether I wanted them or not there will come a point where the curiosity will become to great and I won't be able to resist having a look at how they affect the response of the unit, I expect magic!

 

[Giro413]

I have no turn-on pops through the speakers (I think it may a 10A PS problem)

I am getting very audible pops from my V3 Mono's when they are turned on by my Wiim ULTRA or are in auto and then wake up to start playing throgh it. Unless the volume of my Wiim ULTRA is all the way down of course. Could this simply be solved by two separate 5A power supplies (am running a single 10A PS)? Would that also help with amps randomly turning on and off while in Auto mode?

 

[Lux_ury]

Just came through the door.
Pop first switched the amp on in rush expected since then on off no pop can be heard. I can hear Relays' when switching to auto.
Impression over V3 fosi audio amp waaaaay more power, the sealed woofer on my Infinitys can push the membrane and I'm only half volume dial around 72odd dB.
The woofer punch can match one of my AR AB amps low end is punchier IMO. I'll test temps once I've had it on for a few hours but T1 right amp 35.7C T2 34.5C left amp.
running 20mins.Both rising differentials of T1 T2 1.3C
D10 loxije Dac
240v
Power brick 5v
Bluetooth via Note 10 ultra.
48v 10amp DC filter.

 

[Guddu]

I am getting very audible pops from my V3 Mono's when they are turned on by my Wiim ULTRA or are in auto and then wake up to start playing throgh it. Unless the volume of my Wiim ULTRA is all the way down of course. Could this simply be solved by two separate 5A power supplies (am running a single 10A PS)? Would that also help with amps randomly turning on and off while in Auto mode?

It isn’t power supply issue, it’s how amp is releasing buffered power.
try not using auto, just use on/off and see you have pops.
My units have it since day one, as I captured in the first post as well.

 

[norcalscott]

I received everything in one delivery, which included a rather large T shirt and 2 Muse02 op amps.
Odd that they gave no size options for the T shirt, I would rather have had no T than one that I will never wear.
As I got the op amps whether I wanted them or not there will come a point where the curiosity will become to great and I won't be able to resist having a look at how they affect the response of the unit, I expect magic!

I am not sure if I care enough about the op amps to ask Fosi, although if I had them at some point on a boring winter day I imagine the curiosity would have gotten to me also.

Regarding the T-Shirt, mine had like an XXXL size on it, but after washing it actually fits, and I normally wear a medium or large. Chinese T-Shirt sizing is a mystery.

 

[Otac0n89]

Hi there,
I'm new to the Forum here and have some connection questions regarding the Fosi Mono V3.
I Have a Setup for Music and Movies / TV. My Setup for Music is Wiim Ultra (soon also a record player) --> 2x Fosi Mono V3 --> 2x Polk ES60 and for Movies / TV Marantz Cinema 70s with a 5.1 Setup from Polk, but through Pre Out --> 2x Fosi Mono V3 --> 2x Polk ES60.

I tried now different cable configurations with a RCA Switch and also simultaneously RCA to RCA and RCA to XLR to use both outputs from the Fosi. Both Connections are working. My Goal is to use the Fosi Mono for both systems with no quality loss and easy switching. What is the best cable configuration for this or maybe the Switcher for this kind of situation ?

Sorry for my bad english, I'm a German Guy

 

[antcollinet]

Hi there,
I'm new to the Forum here and have some connection questions regarding the Fosi Mono V3.
I Have a Setup for Music and Movies / TV. My Setup for Music is Wiim Ultra (soon also a record player) --> 2x Fosi Mono V3 --> 2x Polk ES60 and for Movies / TV Marantz Cinema 70s with a 5.1 Setup from Polk, but through Pre Out --> 2x Fosi Mono V3 --> 2x Polk ES60.

I tried now different cable configurations with a RCA Switch and also simultaneously RCA to RCA and RCA to XLR to use both outputs from the Fosi. Both Connections are working. My Goal is to use the Fosi Mono for both systems with no quality loss and easy switching. What is the best cable configuration for this or maybe the Switcher for this kind of situation ?

Sorry for my bad english, I'm a German Guy

Hi - and welcome to ASR.

Your only issue with using the XLR input is that it has only one gain setting of only 20dB. Depending on the output voltage from your source (almost certainly only 2V or less if from and RCA connection), you might not be able to drive full power from that input.

If it were me, I'd try using one source into each input (one RCA, and one XLR). As long as you can get the XLR input source loud enough for you - then that is fine. If not go from both inputs into the RCA via a switch box. Either way, there will be no audible quality difference between the two solutions.

PS Dein Englisch is viel bessere als mein Deutch

 

[dilu]

Hi,

i just ordered a Fosi Mono V3 to drive the center Channel of my 5.1.4 Home Cinema System.

It should arrive today. I am using a complete arendal speaker system and my LCR is 1723s (2x Tower, 1x Center).

The L R Front Speakers are powered with a XTZ Edge a2 300.

As AVR i am using a Yamaha RX-A6a.

Remaining speakers (Surrounds and Heights) are powered by the AVR.

I got 2 questions. Ive read about the problem with the polarity of the Fosi when integrating it with other speakers. For center channel i just got RCA Pre Out on the Yamaha. So as i understand i should change the polarity on the speakers wires connected to the Fosi then?

The other question is. I am thinking about changing the XTZ Edge with 2 additional Fosi V3 - because of the oppurtinity to use XLR for the L R speaker connection.
And looking on the measurements it seems that the Fosi is slighlty better (but my knowledge isnt so big in case of reading the measurements).

So what do you think - would it be an upgrade to have the complete LCR stage powered by Fosi V3 Monos or should i use the combination of the XTZ for LR and Fosi for the Center channel?

Thanks for your support.

 

[antcollinet]

So as i understand i should change the polarity on the speakers wires connected to the Fosi then?

Probably - but we don't yet have a very clear statement from @Fosi Audio !!!

The other question is. I am thinking about changing the XTZ Edge with 2 additional Fosi V3 - because of the oppurtinity to use XLR for the L R speaker connection.
And looking on the measurements it seems that the Fosi is slighlty better (but my knowledge isnt so big in case of reading the measurements).

The difference is unlikely to be audible, and the XLR connection won't bring any significant benefit unless you are currently suffering from audible ground noise.


You will need to match the gain between the two amps though, and then let the AVR room correction have a go to match everything up. (that should also tell you if you have a phase mismatch)

 

[dilu]

Probably - but we don't yet have a very clear statement from @Fosi Audio !!!




The difference is unlikely to be audible, and the XLR connection won't bring any significant benefit unless you are currently suffering from audible ground noise.


You will need to match the gain between the two amps though, and then let the AVR room correction have a go to match everything up. (that should also tell you if you have a phase mismatch)

thanks for your reply.

So if its no benefit to exchange the XTZ with 2 Fosi - i will keep it. I am not suffering from any audible ground noise.

How should i gain match the XTZ and the Fosi?
I wanted to make the normale automatic YPAO and afterwards level match the speakers with my db meter like always.

But gain matching the 2 different amps - i dont know how to do that.

YPAO sould be able to find a possible phase mismatch, yes.

*edit* did a short research. When i got it right i sould be able to gain match them with a multimeter and a test tone?

 

[renoxd]

I received my Fosi's and I don't like the fact that the video says the maximum temperature is 38C, while mine are 45-50C

 

[Lux_ury]

I received my Fosi's and I don't like the fact that the video says the maximum temperature is 38C, while mine are 45-50C

What is your ambient in the room?
Have you contacted Fosi to see if there could be issues?