Fosi Audio V3 Mono Amplifier Review

[antcollinet]

An affordable pre-amp/dac for these monoblocks? looking to drive them paired with DBR-62's both on PC and TV, thus USB and Optical ports are probably needed. I'm having a hard time finding a proper solution, any recommendations? remote control would be a nice addition, thanks

If you describe the problem finding a solution you are having it would help. From my point of view there are many affordable DACs with remote that have optical and USB ports.

EG : https://www.audiosciencereview.com/forum/index.php?threads/smsl-su-6-review-desktop-dac.28402/

 

[DavidM1]

An affordable pre-amp/dac for these monoblocks? looking to drive them paired with DBR-62's both on PC and TV, thus USB and Optical ports are probably needed. I'm having a hard time finding a proper solution, any recommendations? remote control would be a nice addition, thanks

Another possibility. Costs a bit more but has balanced outputs and a headphone amp and remote. This, along with a WiiM mini, a $20 Sony blu ray transport and a pair of B&W 601 v3 speakers makes up my entire system… including the v3 monos of course.

AOSHIDA SMSL C200 Review (DAC & Amp)

This is a review and detailed measurements of the AOSHIDA SMSL C200 balanced DAC and headphone amplifier. It costs US $210. The unit looks attractive enough for a desktop product. The LED is function but sadly displays the sample rate rather than volume (until you change that). Navigating the...

www.audiosciencereview.com

 

[SMen]

You can run input to + if you want a non inverting circuit, but feedback must always go to negative. So connecting negative to ground ain't gonna work.

In this case, they have a circuit that creates two gain options as well as balanced output. One possibility is a first op amp to create two gains with a switchable feedback resistor - likely an inverting configuration since this is simpler, and then a second op amp to provide an inverted version of the amplified signal. It would be an easy mistake to take the output of the first amplified (and inverted) stage and connect it into the + input of the amp IC.

This is something I wondered about just looking at the layout in the V3 monos - I've understood the RCA opamp converting single ended to balanced, but the two opamps that follow are set one behind the other, as if something sequential is going on ... and not parallel - which looks rather different than say the 3eaudio 3255 mono layout pictured down the page a bit in Amir's review here. Not sure I understand where the second op amp comes in.

Above my pay grade but just curious.

At least Fosi could say something along the lines of "in some scenarios where the v3 monos are being used in a multi-amp set up it may be necessary to invert speaker outputs when used in single ended mode because ____ ____ ___ ... ... " fill in the blanks here.

 

[JohnWo]

It is difficult to get my head around this type of performance is such a small and inexpensive package. I have been looking to add an amplifier to my Onkyo RZ50 to drive my front speakers-ML Vistas (4 Ohm). I have no complaints with the RZ50, but the V3 Mono Blocks appear to perform better on the bench. I would be interested if people think that there would be a noticeable difference (Better or Worse) in sound quality.

 

[Freezak]

Another possibility. Costs a bit more but has balanced outputs and a headphone amp and remote. This, along with a WiiM mini, a $20 Sony blu ray transport and a pair of B&W 601 v3 speakers makes up my entire system… including the v3 monos of course.

AOSHIDA SMSL C200 Review (DAC & Amp)

This is a review and detailed measurements of the AOSHIDA SMSL C200 balanced DAC and headphone amplifier. It costs US $210. The unit looks attractive enough for a desktop product. The LED is function but sadly displays the sample rate rather than volume (until you change that). Navigating the...

www.audiosciencereview.com

Damn thank you, this is golden, not sure how i've missed the SMSL on the forums here.

 

[antcollinet]

I've understood the RCA opamp converting single ended to balanced, but the two opamps that follow are set one behind the other, as if something sequential is going on ... and not parallel - which looks rather different than say the 3eaudio 3255 mono layout pictured down the page a bit in Amir's review here. Not sure I understand where the second op amp comes in.

Not possible to say without either a circuit diagram, or some time spent tracing out the PCB. Even if I had one, I'm not interested enough to spend the time doing the latter.

But position of the components on the board has nothing to do with the circuit. You don't need to place parallel circuits side by side.

 

[SMen]

Not possible to say without either a circuit diagram, or some time spent tracing out the PCB. Even if I had one, I'm not interested enough to spend the time doing the latter.

But position of the components on the board has nothing to do with the circuit. You don't need to place parallel circuits side by side.

Thank you, yes, that last point about the parallel circuit was the one nagging at me, and (and I don't want in any way to bring up op amp swapping) the confusion I was being caused by the proposal that one half of a parallel circuit should favor an op amp swap over another! Or be prioritized (so I am talking about confusion being caused relating to the circuit by this proposal).

 

[DavidM1]

Damn thank you, this is golden, not sure how i've missed the SMSL on the forums here.

Thanks. Another thought… I don’t actually use the usb input for computer but I leave a short gtg cable plugged in for hi res listening from iPhone or iPad.

I use Apple but if you’re using a PC you might need a driver from the SMSL web site.

 

[Bleib]

Damn thank you, this is golden, not sure how i've missed the SMSL on the forums here.

It's my favorite DAC, tested up to 20 or so. Never seen reports of SMSL suddenly playing high volume out of nowhere like some Topping products
I'd still recommend turning down the volume of the DAC to lowest before turning on any power amps

 

[Freezak]

It's my favorite DAC, tested up to 20 or so. Never seen reports of SMSL suddenly playing high volume out of nowhere like some Topping products
I'd still recommend turning down the volume of the DAC to lowest before turning on any power amps

Gotcha it's my favourite one right now - I'm guessing you've tested the Topping D50 III one or perhaps you, @DavidM1 ? it appears to have similar functionality with a slightly lower price tag, though i'm guessing only one of those will act better as a preamp combined with two Fosi V3 monos.

 

[Bleib]

Gotcha it's my favourite one right now - I'm guessing you've tested the Topping D50 III one or perhaps you, @DavidM1 ? it appears to have similar functionality with a slightly lower price tag, though i'm guessing only one of those will act better as a preamp combined with two Fosi V3 monos.

C200 was an a deal quite recently, and yes I prefer it over D50 III as well, as I don't like its BT remote which goes to sleep too quickly and takes some time to wake up.
To me this is poor functionality, the C200 remote is far more responsive.
Obviously D50 III PEQ and 5v out can come to use for some, but I'd rather get a HQ headphone amp included for the price.

 

[Freezak]

C200 was an a deal quite recently, and yes I prefer it over D50 III as well, as I don't like its BT remote which goes to sleep too quickly and takes some time to wake up.
To me this is poor functionality, the C200 remote is far more responsive.
Obviously D50 III PEQ and 5v out can come to use for some, but I'd rather get a HQ headphone amp included for the price.

Unfortunately from what i see i can only find the C200 on aliexpress (i'm located in Europe), where i'd probably have to pay for some custom duties. I happen to own the DX1 headphone amp and it does the job pretty well driving my HD560s with peace apo applied. Headphone amp is a bonus obviously, but in case i want to use it, it would be pretty problematic though, having my HD560s connected to C200 and DBR62 and using both on the PC where i'd have to disable the peace apo eq whenever i use my DBR62s on my PC, thus, i guess i'd rather use headphone amp and preamp/dac separately. In this case, if C200 does not get discounted any soon, would SMSL D6s be a good enough alternative? i'm reading conflicting descriptions on whether it supports remote control or not.

 

[Bleib]

Unfortunately from what i see i can only find the C200 on aliexpress, where i'd probably have to pay for some custom duties. I happen to own the DX1 headphone amp and it does the job pretty well driving my HD560s with peace apo applied. Headphone amp is a bonus obviously, but in case i want to use it, it would be pretty problematic though, having my HD560s connected to C200 and DBR62 and using both on the PC where i'd have to disable the peace apo eq whenever i use my DBR62s on my PC, thus, i guess i'd rather use headphone amp and preamp/dac separately. In this case, if C200 does not get discounted any soon, would SMSL D6s be a good enough alternative?

Yes, or DL200 if you want a headphone amp in the same class as C200. DL200 is quite a lot bigger though.

SMSL DL200 AUDIO DAC & Headphone Amplifier MQA-CD ES9039Q2M

SMSL DL200 AUDIO DAC features MQA-CD ES9039Q2M, Bluetooth APTX HD, OPA1612 XU-316, and DSD512 compatibility, plus 6.35mm & 4.4mm headphone outputs and a handy remote control. Support MQA decoding, support MQA-CD; ESS new generation high-end digital-to-analog chip ES9039Q2M; Qualcomm latest...

hifi-express.com

Never had to pay toll or extra shipment costs through here, just make sure choose the free shipping, express can add extra costs

I bought my C200 through hificat but they have a normal price atm

 

[DavidM1]

Gotcha it's my favourite one right now - I'm guessing you've tested the Topping D50 III one or perhaps you, @DavidM1 ? it appears to have similar functionality with a slightly lower price tag, though i'm guessing only one of those will act better as a preamp combined with two Fosi V3 monos.

It’s my favourite DAC but my only other for comparison is a Cambridge Audio DacMagic that I bought more than a decade ago.

 

[Freezak]

It’s my favourite DAC but my only other for comparison is a Cambridge Audio DacMagic that I bought more than a decade ago.

Are you talking about the D50 III? thanks.

 

[DavidM1]

Are you talking about the D50 III? thanks.

Nope. Never met it. I was talking about the C200. But, as I mentioned, I’ve only had one other.

 

[gelo_mc]

Can someone with a measuring equipment confirm the phase when using rca? If out of phase, fosi should fix it

 

[JeremyFife]

Can I play back my understanding of the inverted phase issue?
With thanks for all the investigation and explanation that members have given - really helpful.

#1 Fosi amps connected as Balanced = no issue at all
#2 Fosi amps connected single-ended, no other amplifiers / active subs in the system = no practical issue

#3 Fosi amp connected single-ended but with other amps / active subs in the system = Fosi amps will be out of phase with the other amps.
In this case, solution is to invert the phase of either the Fosi amps or of the other amp.

@Fosi Audio ?

Thanks

 

[gwing]

Can I play back my understanding of the inverted phase issue?
With thanks for all the investigation and explanation that members have given - really helpful.

#1 Fosi amps connected as Balanced = no issue at all
#2 Fosi amps connected single-ended, no other amplifiers / active subs in the system = no practical issue

#3 Fosi amp connected single-ended but with other amps / active subs in the system = Fosi amps will be out of phase with the other amps.
In this case, solution is to invert the phase of either the Fosi amps or of the other amp.

@Fosi Audio ?

Thanks

Maybe I'm wrong but I don't think there is any intrinsic standard for whether amps are phase inverting or not so I would expect to have to check phase (by listening) whenever I had disparate amps in a system.

I think it's to do with amp design, each stage in an amp is generally going to invert phase so if mixing even and odd amplification stage designs you'll likely have to switch terminals for one of them. It isn't a correct or incorrect sort of thing.

Also - using the balanced inputs seems to have reversed the problem in the example given above - that could make sense as using RCA inputs goes through an extra opamp to convert to balanced so possibly there is the extra amplification stage flipping polarity. (That's just a guess, I'm not at all familiar with opamp internals and whether they count as a single or multiple stage device).

 

[JeremyFife]

Maybe I'm wrong but I don't think there is any intrinsic standard for whether amps are phase inverting or not so I would expect to have to check phase (by listening) whenever I had disparate amps in a system.

I think it's to do with amp design, each stage in an amp is generally going to invert phase so if mixing even and odd amplification stage designs you'll likely have to switch terminals for one of them. It isn't a correct or incorrect sort of thing.

Also - using the balanced inputs seems to have reversed the problem in the example given above - that could make sense as using RCA inputs goes through an extra opamp to convert to balanced so possibly there is the extra amplification stage flipping polarity. (That's just a guess, I'm not at all familiar with opamp internals and whether they count as a single or multiple stage device).

It's never simple, is it

Yes - agree.
As I understand it, using balanced connections the Fosi maintains the input signal phase. Using single-ended connections, the Fosi inverts the phase.
What that means in a system with more amplifiers/devices depends on their behaviour too.