Could someone please explain how Fosi amps work?

[Iggy]

Hi all,

Im still relatively new to this and currently running a WiiM Amp through Wharfedale Diamond 12.2’s and quite happy with it.

However I’m thinking of upgrading the speakers to maybe the Dali Oberon 5, and that’s started me thinking about doing the same with the source as well.

I’ve started reading about these Fosi Amps and how you can put two together (if I’ve understood correctly) and maybe getting a couple of these and WiiM Pro Plus or Ultra to feed some better speakers?

Would something like this be an improvement over the WiiM Amp or not?

There are so many Fosi models V3, ZA3, BT20…..and do you need one or two? From what I can see you can wire up two together, I assume one for each speaker, but does that mean you lose stereo imaging?

I’m old and confused, if someone could take pity on me and offer some clarity I’d really appreciate it

Thank you.

 

[Trekkis]

If you want to improve sound you should first of all consider better dac. Wiims have relative poor dacs. Dac is the real source of sound. So better dac and wiim ultra is far superior than wiim amp. As wiim amp can not use external dac - this is this model worst limitation.

Regarding fosi, if you use use two (in mono mode), result would be slightly better sound, slightly better stereo imaging and more power - so better dynamic in case of speakers with low sensitivity. But this is not so important in most cases as dac, or even used opamos. In fosi amp you can replace internal components - op amps - for better ones. Dac and op amps are far more important than mono mode.

Mono mode (pair) is not needed in case of better quality speakers, is needed only for high volumes and low sensitivity speakers.

For better quality speakers better dac is needed.

Only za3 and two times cheaper but basically the same aiyima 07 max can be used switchable as mono or stereo. V3 and others ale stereo only. There is separate v3 mono - this one is mono only. Can work only as pair.

Once again - in case of mono mode you would not lose stereo imaging, you would have little better. Each mono block is simply working independently for left and right channel, but from the same source - so power and separation are better. all other remain the same.

In case of such amps, used power adapter is important. There are different power supply with different voltage. Better power adapter with higher voltage results more power.

 

[Iggy]

Thanks for your reply….so to get a better sound with better speakers, I would need….

WiiM Ultra
Fosi x 2 (Za3 or V3?) in mono mode with one amp to the left speaker and the other to the right speaker?

Is that correct?

If I’ve got the above right, which Fosi do I connect the WiiM Ultra to in order to get a stereo output?

Why is this all so complicated

 

[Doublej]

You can easily go down the audiophile rabbit hole spending upwards of $100K per component if you have the funds and the desire. Sine you are quite happy with your speakers I would recommend adding a active subwoofer ($~300-$500 if you are in the US) to your existing setup.

Here's why from a publication that caters to those folks spending mega bucks on systems:

Adding an actively powered subwoofer can greatly increase your system’s dynamic range, bass extension, midrange clarity, and ability to play louder without strain. The additional amplifier power and low-frequency driver allow the system to reproduce musical peaks at higher levels. Moreover, removing low frequencies from the signal driving the main loudspeakers lets them play louder because they don’t have to reproduce low frequencies. The midrange often becomes clearer because the woofer cone isn’t furiously moving back and forth, trying to reproduce low bass. This improvement in a small speaker’s performance can be dramatic. The small woofer’s excursion is no longer a limiting factor in how loudly the system will play when low frequencies are filtered from the signal driving it. The midrange is much cleaner, and the overall system sounds like a large, full-range speaker.

From the Absolute Sound, https://www.theabsolutesound.com/articles/subwoofer-basics/

 

[Trekkis]

As I said, there is no need for 2 fosi. One would be enough in most cases.

Main difference between za3 and v3 except option to work as mono or stereo are connections. Za3 and v3 mono have balacend connection. Original v3 has not. And za3 (and aiyima 07 max) has switchable mono / stereo modes. V3 / v3 mono are not switchable. But v3 mono has better mono mode than za3.

But all above is irrelevant. What is needed for better sound is better dac. Connected with even simple original v3 (stereo version) or cheaper 07 max. Or mc101 - this one looks a lot better due to vumeter (and with bt and tone regulation, but without mono mode, switchable op amps, and with lower power)

Also post above is correct. Adding subwoofer can bring a lot more in practice. Fully true.

 

[alpha_zulu]

But all above is irrelevant. What is needed for better sound is better dac.

Why is there such a disgusting faith in DACs here in the forum (and many others)? I will never understand it.
Yes, DACs are important parts of the playback chain. But modern DACs are almost universally very good. To say that the DAC in the WiiM amp is too bad to be used with better speakers is ridiculous. Sorry!

 

[Trekkis]

Modern dac are in most cases simply terrible. Especially in wiims. Even Ultra has cheap and bad dac. To understand this, basic knowledge what is dac and how it is working in principles is required. And some experience.
It's really very hard to force sigma (artifical from nature, with no micro details, lossly compressed, interpolated, oversampled with lot of oversampling artefacts) to sound acceptable. Even RME despite been much better than Ultra, is not good dac (so I sold it, also later sold eversolo, but still have a lot of toppings and similar, Akm and ESS). Difference between dacs is huge and can totally change sound of whole system.

Sigma glare is term known basically for everyone with basic experience. And it is very, very real thing. Directly, easy Audible, and possible to directly be observed on oscilloscope image - this is simply technical issue, resulting directly from laws of physics. Sigma is simply kind of artifical sound synthesizer. Created directly with goal to be cheap. NOS dacs are technically better (much faster impulse response, no filters and oversampling artefacts) , and much more natural and pleasant to listen.

Something like RME or eversolo can be acceptable for some people, but dac used in ultra is not only sigma but much worse, low level Sigma - which is very audible. Even cheap fiio r2r NOS is uncomparably better.

 

[alpha_zulu]

It's not my experience. YMMV.

 

[slartibartfast]

Thanks for your reply….so to get a better sound with better speakers, I would need….

WiiM Ultra
Fosi x 2 (Za3 or V3?) in mono mode with one amp to the left speaker and the other to the right speaker?

Is that correct?

If I’ve got the above right, which Fosi do I connect the WiiM Ultra to in order to get a stereo output?

Why is this all so complicated

I wouldn't take just one person's opinion. There is very little wrong with the DAC in the WiiM amp, the Mission 778X uses the same one.

 

[Doublej]

Modern dac are in most cases simply terrible. Especially in wiims. Even Ultra has cheap and bad dac. To understand this, basic knowledge what is dac and how it is working in principles is required. And some experience.
It's really very hard to force sigma (artifical from nature, with no micro details, lossly compressed, interpolated, oversampled with lot of oversampling artefacts) to sound acceptable. Even RME despite been much better than Ultra, is not good dac (so I sold it, also later sold eversolo, but still have a lot of toppings and similar, Akm and ESS). Difference between dacs is huge and can totally change sound of whole system.

Sigma glare is term known basically for everyone with basic experience. And it is very, very real thing. Directly, easy Audible, and possible to directly be observed on oscilloscope image - this is simply technical issue, resulting directly from laws of physics. Sigma is simply kind of artifical sound synthesizer. Created directly with goal to be cheap. NOS dacs are technically better (much faster impulse response, no filters and oversampling artefacts) , and much more natural and pleasant to listen.

Something like RME or eversolo can be acceptable for some people, but dac used in ultra is not only sigma but much worse, low level Sigma - which is very audible. Even cheap fiio r2r NOS is uncomparably better.

Do you have any graphs showing the much faster impulse response of NOS dacs compared to current generation ones?

 

[slartibartfast]

Do you have any graphs showing the much faster impulse response of NOS dacs compared to current generation ones?

Audiophiles don't believe in measurements or graphs

 

[Iggy]

I wouldn't take just one person's opinion. There is very little wrong with the DAC in the WiiM amp, the Mission 778X uses the same one.

That’s good to know….one of the options in my head was to swap the WiiM Amp for a Mission 778x plus WiiM Pro….Sounds like I already have that

 

[Mr Ee]

It sounds like Trekkis greatly prefers nos dacs to delta sigma dacs. Nothing wrong with that.
For some folks it's the other way around.


Anyway,

"so to get a better sound with better speakers, I would need…."
Whether an ultra and two fosis ends up being better is entirely up to you.
imo (and don't take just one person's opinion ) as far as components themselves go, speakers make the biggest difference.
Note the word difference - something I like that is 'better', you might hate.

"I would need ...
WiiM Ultra
Fosi x 2 (Za3 or V3?) in mono mode with one amp to the left speaker and the other to the right speaker?
Is that correct?"
Yes.

"If I’ve got the above right, which Fosi do I connect the WiiM Ultra to in order to get a stereo output?"
Both of them!
i.e. the Ultra left line out goes to one fosi and the right line out to the other.

As you've no doubt realised, you're not just updating the amp and speakers, you're completely replacing your setup with an entirely new setup.
Well, speaker cable aside.
Please, let's not get into cable discussions too.

 

[Iggy]

It sounds like Trekkis greatly prefers nos dacs to delta sigma dacs. Nothing wrong with that.
For some folks it's the other way around.


Anyway,

"so to get a better sound with better speakers, I would need…."
Whether an ultra and two fosis ends up being better is entirely up to you.
imo (and don't take just one person's opinion ) as far as components themselves go, speakers make the biggest difference.
Note the word difference - something I like that is 'better', you might hate.

"I would need ...
WiiM Ultra
Fosi x 2 (Za3 or V3?) in mono mode with one amp to the left speaker and the other to the right speaker?
Is that correct?"
Yes.

"If I’ve got the above right, which Fosi do I connect the WiiM Ultra to in order to get a stereo output?"
Both of them!
i.e. the Ultra left line out goes to one fosi and the right line out to the other.

As you've no doubt realised, your not just updating the amp and speakers, you're completely replacing your setup with an entirely new setup.
Well, speaker cable aside.
Please, let's not get into cable discussions too.

Thank you, that’s really helpful and filled some gaps in my knowledge!

 

[alpha_zulu]

@Iggy

Here are the ingredients for good sound in order of importance (from most important to less important). All my own personal experience. Others will see it similarly or completely differently.

1. the quality of the recording. By this I expressly do NOT mean hi-res or not.
2. the sound quality of the playback room and how the speakers are placed there.
3. the quality of the speakers. This is by far the most important aspect of the technical system. If you are starting out, invest most of your budget in really good speakers. If you want to significantly improve an already decent chain, this will also only work with even better loudspeakers.
4. the quality of the amplifier and how well it harmonises with the speakers. Here, too, it usually pays off to spend a little more money.
5. the DAC. Opinions often differ here. Some prefer R2R DACs, others Delta Sigma. Modern amplifiers often have decent DACs built in, so you don't necessarily need an external device.
6. Nothing for a long time
7. all the other stuff like cables, power supplies etc.

Interestingly, most of the ‘voodoo’ discussions centre on the most insignificant points.
As I said before: All my personal opinion and experience. YMMV!

 

[MCG555]

@Iggy

Here are the ingredients for good sound in order of importance (from most important to less important). All my own personal experience. Others will see it similarly or completely differently.

1. the quality of the recording. By this I expressly do NOT mean hi-res or not.
2. the sound quality of the playback room and how the speakers are placed there.
3. the quality of the speakers. This is by far the most important aspect of the technical system. If you are starting out, invest most of your budget in really good speakers. If you want to significantly improve an already decent chain, this will also only work with even better loudspeakers.
4. the quality of the amplifier and how well it harmonises with the speakers. Here, too, it usually pays off to spend a little more money.
5. the DAC. Opinions often differ here. Some prefer R2R DACs, others Delta Sigma. Modern amplifiers often have decent DACs built in, so you don't necessarily need an external device.
6. Nothing for a long time
7. all the other stuff like cables, power supplies etc.

Interestingly, most of the ‘voodoo’ discussions centre on the most insignificant points.
As I said before: All my personal opinion and experience. YMMV!

Totally agree!

Ps: Fosi what?

 

[Burnside]

Ps: Fosi what?

Fosi bear?

 

[Mr Ee]

Fosi bear?

For some reason, I thought of Fonzie (The Fonz, Happy Days, Henry Winkler.)
Ayyyy.
I'm a Muppet.

 

[dangermouse]

Modern dac are in most cases simply terrible.

I’m sorry, but this assertion is utter nonsense. I accept that people are entitled to their opinions, but this sort of supposedly helpful drivel oversteps what can be considered acceptable.

 

[guy48065]

@Iggy

...All my own personal experience. Others will see it similarly or completely differently.

You're absolutely right.