Fosi Audio V3 Mono Amplifier Review

[Mort]

I will definitely test and report.

The line out tests around 88dB Sinad in the pro, I assume it's the same or better here.

 

[burkm]

Balanced, i.e XLR and TRS, are normaly converted to single ended within the amp, because it is supposed to help with problems (screening) concerning long cable length (screening against induced electrical disturbances).
There are very few amps, which carry and amplify the input signal balanced (symmetrical) throughout the gain stages. The opinions on this are divided, if this will be an advantage or not. To avoid XLR or TRS, because a balanced input signal is transformed within the amp into single ended is thus quite "strange" and probably a misunderstanding of the reasons, why this is been used...

 

[somebodyelse]

Balanced, i.e XLR and TRS, are normaly converted to single ended within the amp, because it is supposed to cure problems (screening) with long cable length.

In a domestic setting it's mostly about avoiding possible ground noise issues. Common mode interference rejection is an added bonus, but rarely needed in domestic settings.

 

[gwing]

Are there any good reasons to put a DAC in between a Wiim Ultra and a pair of Fosi V3 monoblocks? I have an extra DL200, for instance.

Yes.

Not for sound quality but maybe for other features the specific DAC might provide e.g. possibly a physical volume control or extra inputs or a good headphone amp etc.

 

[antcollinet]

More like 13-14dB at the same voltage and different,highest gain (Arch also measures XLR with 2V output,so it's easy to compare)

I was referring to Amir's measurement here. It has yet to be explained why Archimagos measurements for RCA are so much worse than XLR, compared to Amir's results.

 

[Lux_ury]

So did some testing and the one way Dc filter has stopped the feedback from one amp to another with just buying the one female splitter to two males and one single male to male. Hopefully the diagram shows how the DC stops the feed back from crossing over Compared to the original supplied spliter by Fosi.
This method has eliminated MY feed back noise at a cost of about £8.50 DC supply cable, male to male 5.5*2.5mm 2.5mm. Second cable splitter 5.5x2.5mm 1 female to 2 male 5.5mmx2.5mm DC Y splitter £6.88.
Total expense £15.00 or U$20.00
Cheaper than running two DC filters and two psu bricks!
Feel free to report if this helped.
Your welcome.

 

[Sokel]

I was referring to Amir's measurement here. It has yet to be explained why Archimagos measurements for RCA are so much worse than XLR, compared to Amir's results.

Actually are not very different,is just at different levels.
And the THD+N vs level chart shows a very steep curve even in XRL input which is 100dB SINAD at 4-5V but only 90dB at 2V or so (should be around 95-96dB in a very linear device)

 

[SMen]

So did some testing and the one way Dc filter has stopped the feedback from one amp to another with just buying the one female splitter to two males and one single male to male. Hopefully the diagram shows how the DC stops the feed back from crossing over Compared to the original supplied spliter by Fosi.
This method has eliminated MY feed back noise at a cost of about £8.50 DC supply cable, male to male 5.5*2.5mm 2.5mm. Second cable splitter 5.5x2.5mm 1 female to 2 male 5.5mmx2.5mm DC Y splitter £6.88.
Total expense £15.00 or U$20.00
Cheaper than running two DC filters and two psu bricks!
Feel free to report if this helped.
Your welcome.

I did not really understand your post.
But neither did I understand Fosi packaging another split cable with the DC filter they sent to me later so I have two split cables!

I am using one of the split cables to supply the other! If that is understandable. So I have one loose, unconnected split cable!

I was thinking about getting a junction connector and I am wondering if that is the male to male 5.5*2.5mm 2.5mm you are talking about? Then I could just connect to one split cable.

All very confusing!!

 

[ninetylol]

So anyone here "upgraded" from a WiiM Amp to these Monoblocks? From what Ive seen you get a bit more SNR and about 2db more max volume with the V3 Monos. On the other hand the Wiim Amp got better multitone and better intermodulation and ofc dsp more connections and a sub out.

While 200W on paper sounds great its really not much of difference in total db against the 120W of the Wiim Amp.

Any opinions or experiences?

 

[Lux_ury]

I did not really understand your post.
But neither did I understand Fosi packaging another split cable with the DC filter they sent to me later so I have two split cables!

I am using one of the split cables to supply the other! If that is understandable. So I have one loose, unconnected split cable!

I was thinking about getting a junction connector and I am wondering if that is the male to male 5.5*2.5mm 2.5mm you are talking about? Then I could just connect to one split cable.

All very confusing!!

The original issue from where I can see is the original splitter shares an equal DC path to both amplifiers.This is where the feed back noise bleeds into each path. The new splitter cable in my diagram shows the PSU supplys one amp direct, and the other via DC filter one way. This means any feedback will stop dead at the DC filter and separate any feedback noises from each amp.
Nothing wrong with DC filter or psu, it was always the original splitter cable that was the issue post DC filter!
I'll take separate pictures of each cable so you know what to buy. I'm sure someone can explain in detail what I have done more eloquently.
Or I could say I have split the DC path pre filter and post filter, where Fosi decided to split the DC path post filter together.
It's right in my head and it works.(Lol emoji)

 

[SMen]

The original issue from where I can see is the original splitter shares an equal DC path to both amplifiers.This is where the feed back noise bleeds into each path. The new splitter cable in my diagram shows the PSU supplys one amp direct, and the other via DC filter one way. This means any feedback will stop dead at the DC filter and separate any feedback noises from each amp.
Nothing wrong with DC filter or psu, it was always the original splitter cable that was the issue post DC filter!
I'll take separate pictures of each cable so you know what to buy. I'm sure someone can explain in detail what I have done more eloquently.
Or I could say I have split the DC path pre filter and post filter, where Fosi decided to split the DC path post filter together.
It's right in my head and it works.(Lol emoji)

I have two splitter cables thanks to Fosi ... But if I understand you correctly, we could junk the DC filter and just have a better splitter cable.
So the problem was with the splitter cable? Thank heavens they sound good despite all this (the V3 monos)!

 

[Lux_ury]

I have two splitter cables thanks to Fosi ... But if I understand you correctly, we could junk the DC filter and just have a better splitter cable.
So the problem was with the splitter cable? Thank heavens they sound good despite all this (the V3 monos)!

Try it!, but using the DC filter is what is separating the two paths of power.
Pre feed to one amp, and post feed after DC filter

 

[Mort]

So anyone here "upgraded" from a WiiM Amp to these Monoblocks? From what Ive seen you get a bit more SNR and about 2db more max volume with the V3 Monos. On the other hand the Wiim Amp got better multitone and better intermodulation and ofc dsp more connections and a sub out.

While 200W on paper sounds great its really not much of difference in total db against the 120W of the Wiim Amp.

Any opinions or experiences?

I did, or rather I have both setups on the same speakers. For my purposes, nearfield listening into 4 ohm speakers with 88db sensitivity, I don't need more than the Wiim amp.

I'll be testing the monoblocks later this week, but I've been using an a0300 which is 165w into 4 ohms. (I don't know what its or the wiim amps input sensitivity is but it's presumably ~2v?)

I can get to 50 (nearfield) on the Wiim amp before it's loud and about 33 with the a0300. I predict it'll be about 25 with the monoblocks assuming diminishing returns as you point out.

My AVR is 125w over 5 channels for a bigger room and it gets loud although those speakers have higher sensitivity.

 

[Mort]

I did, or rather I have both setups on the same speakers. For my purposes, nearfield listening into 4 ohm speakers with 88db sensitivity, I don't need more than the Wiim amp.

I'll be testing the monoblocks later this week, but I've been using an a0300 which is 165w into 4 ohms. (I don't know what its or the wiim amps input sensitivity is but it's presumably ~2v?)

I can get to 50 (nearfield) on the Wiim amp before it's loud and about 33 with the a0300. I predict it'll be about 25 with the monoblocks assuming diminishing returns as you point out.

My AVR is 125w over 5 channels for a bigger room and it gets loud although those speakers have higher sensitivity.

I'm going to edit this and say although 33 with the AO300 was excellent, it turns out to be about the top reliable setting before the AO3000 clips. Not a lot of headroom there.

So yeah, I would probably need more than the Wiim Amp. I'm getting the Fosi monoblocks today. I'll report back

 

[louwii]

I'm currently driving my ELAC DBR62 with a Topping E50 and a Fosi BT20A Pro. I'm curious if switching to 2 Fosi v3 mono would make a significant change. I've never tried mono amps. And according to ASR, the BT20A Pro isn't as good as the v3. Any thoughts will be greatly appreciated.

I'm also unclear about a 2 things with those:
- I read about the reversed phases. Is that still a thing? Would I have to check upon receiving them?
- 1 PSU for 2 mono amps with a splitter, or 2 separate PSUs? Does it even matter?

Thanks

 

[SMen]

I'm currently driving my ELAC DBR62 with a Topping E50 and a Fosi BT20A Pro. I'm curious if switching to 2 Fosi v3 mono would make a significant change. I've never tried mono amps. And according to ASR, the BT20A Pro isn't as good as the v3. Any thoughts will be greatly appreciated.

I'm also unclear about a 2 things with those:
- I read about the reversed phases. Is that still a thing? Would I have to check upon receiving them?
- 1 PSU for 2 mono amps with a splitter, or 2 separate PSUs? Does it even matter?

Thanks

Regarding your 2 things:

1. The reverse phase should be fixed so long as you verify with the supplier. Even if not, you would not need to worry with a stereo set up.
2. There will be diverse views regarding the PSU but for me it is a question of how your kit is set up. Do you have power sockets near the speakers to run two power supplies to the amplifiers near the speakers, with short speaker cables, and do you connect with balanced cables to have a long interconnect run from the pre-amp / DAC. If not, and you run a compact desktop system, then the single power supply will be fine, and use up one power socket less.

Regarding making a significant change I don't own a BT20A.
I love my V3 monos. I'm connecting with balanced cables from source, through balanced volume pot to the amps. Your E50 should do a good job controlling the volume, and maybe going balanced with amps close to speakers is worth a go ... but the little BT20A Pro still seems a cracking little amp, and powerful with the 48v supply!

Short answer I suspect you can improve on the BT20A - unless you need the tone controls. For me vs the Aiyima A07 or A08 the V3 monos are much better (for me subjectively). There may be new stereo 3255 amps coming out soon too that might measure superbly - we shall see here I guess. 3e audio seem to have one or two pending. You don't necessarily have to go dual mono, but you might have fun doing so with those ELACs.

 

[Sokel]

I'm currently driving my ELAC DBR62 with a Topping E50 and a Fosi BT20A Pro. I'm curious if switching to 2 Fosi v3 mono would make a significant change. I've never tried mono amps. And according to ASR, the BT20A Pro isn't as good as the v3. Any thoughts will be greatly appreciated.

I'm also unclear about a 2 things with those:
- I read about the reversed phases. Is that still a thing? Would I have to check upon receiving them?
- 1 PSU for 2 mono amps with a splitter, or 2 separate PSUs? Does it even matter?

Thanks

I'll give you another view.
Each time you have an urge to "upgrade" amps,DACs,preamps,etc take this money and hide it.Promise yourself you won't use it for thingies.

After doing it sometimes and when enough get nicer speakers.And I mean really nicer,going from a small two-way to a similar one doesn't cut it,next day's feeling will be the same.Go WAY nicer.
That's the only upgrade that worth its money at this hobby.

 

[SMen]

I'll give you another view.
Each time you have an urge to "upgrade" amps,DACs,preamps,etc take this money and hide it.Promise yourself you won't use it for thingies.

After doing it sometimes and when enough get nicer speakers.And I mean really nicer,going from a small two-way to a similar one doesn't cut it,next day's feeling will be the same.Go WAY nicer.
That's the only upgrade that worth its money at this hobby.

Magnepans?

The thing about the V3 monos (for me), is that I can't think of a speaker I could not match them with. There are some great 10 / 20 year old designs out there too (I'm using a pair of Triangles). But the BT20A Pro still seems a cracking little amp for desktop speakers in a desktop system...

 

[Sokel]

Magnepans?

Can't tell you.What dictates speakers is first room and then taste if all else are in check.
About amps,I would get what gives me complete peace of mind at all aspects,safety and reliability been first.
But that's me,everyone's mind is different.

 

[SMen]

Can't tell you.What dictates speakers is first room and then taste if all else are in check.
About amps,I would get what gives me complete peace of mind at all aspects,safety and reliability been first.
But that's me,everyone's mind is different.

With these latest Class D's (and for me the 325*'s) they have moved the equation as you point out, towards the speakers.

It is the same with DAC's. The bar is so high now with both DAC's and these amps, that speakers that only a few years ago would have been out of picture are now well and truly in it. So I agree with you on this.