Fosi Audio V3 Mono Amplifier Review

[Bernard23]

Probably - most likely the gain of the two amps is different. Try the V3 mono on the higher gain setting.

If you are on the balanced input this is limited to 20dB which is on the low side - so not surprising you need more volts from the source. (ZA3 is about 26dB on XLR)

Getting slightly nervous about pairing a Wiim ultra with the V3 Monos. The Wiim is limited to 2V output

 

[Bernard23]

Yes I know this. Will be delighted. I have also measured my hearing (used to pretty regularly, must do again).

But:

Taking balance between channels specifically rather than distortion. How consistent are the V3 monos outputs (for example) between units and batches of units? Measuring one in isolation does not measure this.

I think we are on page 173 ...

The two I have sound very well matched (subjectively) ... I have just bought a phono stage and a volume control where the emphasis is on very tight channel matching.
These work very well with the monos. Channel matching has often been an issue for me so +1 for my pair anyway - and my perception of far better balance with the new gear in this combination.

DAC's these days all seem to measure spectacularly well - nothing these days seem to come with balance controls! I suppose room correction can handle a fair bit.

Every digital and analogue device I own to play music has a L/R adjustment.

 

[courtesy]

Getting slightly nervous about pairing a Wiim ultra with the V3 Monos. The Wiim is limited to 2V output

This the combo I am using and it works well. Driving Ascend Acoustics Luna v2's.

 

[Bernard23]

This the combo I am using and it works well. Driving Ascend Acoustics Luna v2's.

Presumably at the 2Vrms output setting on the ultra?

 

[Brian Hall]

Probably - most likely the gain of the two amps is different. Try the V3 mono on the higher gain setting.

If you are on the balanced input this is limited to 20dB which is on the low side - so not surprising you need more volts from the source. (ZA3 is about 26dB on XLR)

Yes, was using balanced out of the DMP-A6. I just moved the V3 monos back to my office setup and using the ZA3 in stereo mode for the main setup's stereo mode.

Was using a Loxjie A40 in there. Moved that to a new bedroom setup. The Loxjie has more apparent power than the ZA3 and V3 monos.

 

[Brian Hall]

Getting slightly nervous about pairing a Wiim ultra with the V3 Monos. The Wiim is limited to 2V output

The V3 monos still have plenty of power. I was just surprised at needing to use a higher level on the preamp vs the ZA3.

 

[DCinATX]

Long time lurker, first time poster.

The F3M solved a problem for me. Namely, my Rega Brio was underpowered for driving a newly acquired pair of Buchardt S400 MKII speakers. My first thought was that these speakers had too much bass energy for my basement listening room. Turns out, the amp simply couldn’t drive the speakers tightly.

Bass integration is great with the F3M. Since these units came out of the Amazon inventory, I did have to reverse the polarity on my SVS sub. Otherwise, super easy start up. (Luckily, the reverse polarity problem and solution are well documented here.)

 

[Brian Hall]

I wasn't too concerned about the phase being off, but did a "test" for fun (non measured, and not blind).

Moved the Fosi LC30 amp/speaker switch to my office. Same speakers (Sony SSC-S5), but two amps. The older Fosi V3 stereo vs the V3 monos.

The V3 stereo was louder at the same preamp level on the Wiim Ultra. The V3 stereo seemed to have a tiny bit more treble, but the subwoofer bass sounded better.

I changed the phase switch on the subwoofer and now the bass sounds better with the V3 monos, so I guess I did receive a set with the reversed phase. Expected as each only has one QC sticker.

It doesn't seem right to me for the V3 stereo to be louder than the V3 monos since they have more power on paper, but it is. Other than the slightly increased treble, I do not hear any difference in sound quality. I guess the V3 stereo was actually better than I thought it was.

I recommend the LC30 to anyone that wants to do a simple, quick comparison of amps or speakers or have two setups like my main system (stereo and atmos).

Had to compare the V3 monos vs the ZA3 with the LC30. Again the ZA3 is louder as previously determined. The subwoofer sounded wrong with the ZA3 as expected since I changed the phase for the monos. Switching the phase back corrected that for the ZA3.

Did a compare between the V3 stereo vs the ZA3. ZA3 slightly louder at same preamp level. Not as much difference vs the V3 monos. V3 stereo still seemed to have more treble. Both sounded great. Subwoofer phase needs to be the same for the ZA3 and the V3 stereo. Needs to be switched for the V3 monos.

Knowing what I do now, it doesn't seem like there is really any advantage in my two setups to having the V3 monos vs the ZA3 Stereo or maybe even the V3 stereo. All of them sound great.

I've also "tested" all of them driving my new Klipsch Heresy IV speakers. All sounded equally great as did the Loxjie A40 which seems to have the most power of any of them. Still noticed a slight treble boost with the V3 stereo vs all the others.

 

[courtesy]

Presumably at the 2Vrms output setting on the ultra?

Yes

 

[Doodski]

I wasn't too concerned about the phase being off, but did a "test" for fun (non measured, and not blind).

Moved the Fosi LC30 amp/speaker switch to my office. Same speakers (Sony SSC-S5), but two amps. The older Fosi V3 stereo vs the V3 monos.

The V3 stereo was louder at the same preamp level on the Wiim Ultra. The V3 stereo seemed to have a tiny bit more treble, but the subwoofer bass sounded better.

I changed the phase switch on the subwoofer and now the bass sounds better with the V3 monos, so I guess I did receive a set with the reversed phase. Expected as each only has one QC sticker.

It doesn't seem right to me for the V3 stereo to be louder than the V3 monos since they have more power on paper, but it is. Other than the slightly increased treble, I do not hear any difference in sound quality. I guess the V3 stereo was actually better than I thought it was.

I recommend the LC30 to anyone that wants to do a simple, quick comparison of amps or speakers or have two setups like my main system (stereo and atmos).

Had to compare the V3 monos vs the ZA3 with the LC30. Again the ZA3 is louder as previously determined. The subwoofer sounded wrong with the ZA3 as expected since I changed the phase for the monos. Switching the phase back corrected that for the ZA3.

Did a compare between the V3 stereo vs the ZA3. ZA3 slightly louder at same preamp level. Not as much difference vs the V3 monos. V3 stereo still seemed to have more treble. Both sounded great. Subwoofer phase needs to be the same for the ZA3 and the V3 stereo. Needs to be switched for the V3 monos.

Knowing what I do now, it doesn't seem like there is really any advantage in my two setups to having the V3 monos vs the ZA3 Stereo or maybe even the V3 stereo. All of them sound great.

I've also "tested" all of them driving my new Klipsch Heresy IV speakers. All sounded equally great as did the Loxjie A40 which seems to have the most power of any of them. Still noticed a slight treble boost with the V3 stereo vs all the others.

They should sound fantastic. They are a modern class D amp with a good IC chip. What is the comparative expense for the various models you ran in this test?

 

[antcollinet]

Getting slightly nervous about pairing a Wiim ultra with the V3 Monos. The Wiim is limited to 2V output

That will be fine with the RCA input to the mono. Even on the lower gain setting it will most likely drive more volume than you can use. If you select the higher gain, then 2V is more than enough to drive the monos to full power.

 

[antcollinet]

and also distortion rising the closer you get to recording silence.

Where is this coming from?

 

[antcollinet]

The Loxjie has more apparent power than the ZA3 and V3 monos.

Don't mix up gain and power. Two different things.

 

[Bernard23]

That will be fine with the RCA input to the mono. Even on the lower gain setting it will most likely drive more volume than you can use. If you select the higher gain, then 2V is more than enough to drive the monos to full power.

Thanks. presumably for optimum SINAD I'd run the Ultra at highest output and the Fosi at lower gain setting?

 

[burkm]

I wasn't too concerned about the phase being off, but did a "test" for fun (non measured, and not blind).

Moved the Fosi LC30 amp/speaker switch to my office. Same speakers (Sony SSC-S5), but two amps. The older Fosi V3 stereo vs the V3 monos.

The V3 stereo was louder at the same preamp level on the Wiim Ultra. The V3 stereo seemed to have a tiny bit more treble, but the subwoofer bass sounded better.

I changed the phase switch on the subwoofer and now the bass sounds better with the V3 monos, so I guess I did receive a set with the reversed phase. Expected as each only has one QC sticker.

It doesn't seem right to me for the V3 stereo to be louder than the V3 monos since they have more power on paper, but it is. Other than the slightly increased treble, I do not hear any difference in sound quality. I guess the V3 stereo was actually better than I thought it was.

I recommend the LC30 to anyone that wants to do a simple, quick comparison of amps or speakers or have two setups like my main system (stereo and atmos).

Had to compare the V3 monos vs the ZA3 with the LC30. Again the ZA3 is louder as previously determined. The subwoofer sounded wrong with the ZA3 as expected since I changed the phase for the monos. Switching the phase back corrected that for the ZA3.

Did a compare between the V3 stereo vs the ZA3. ZA3 slightly louder at same preamp level. Not as much difference vs the V3 monos. V3 stereo still seemed to have more treble. Both sounded great. Subwoofer phase needs to be the same for the ZA3 and the V3 stereo. Needs to be switched for the V3 monos.

Knowing what I do now, it doesn't seem like there is really any advantage in my two setups to having the V3 monos vs the ZA3 Stereo or maybe even the V3 stereo. All of them sound great.

I've also "tested" all of them driving my new Klipsch Heresy IV speakers. All sounded equally great as did the Loxjie A40 which seems to have the most power of any of them. Still noticed a slight treble boost with the V3 stereo vs all the others.

My guess: Most V3 mono have only 1 QC sticker on the bottom, meaning they are still delivered "reverse phase", because delivery of the corrected version for many Fosi Audio partners might take some time to spred due to their existing inventory. All of mine had a reversed phase on the V3 mono amps, allthough I got them from Fosi Audio (German warehouse) directly, because of that inventory situation.
Phase reversal (polarity change) is quite simple, because you need only to reverse the speaker connections (no soldering needed: (+) => (-), (-) => (+)).
But You have to remember it...

PS.: This will change as soon, as all "reversed phase" units have been delivered, because new units are then already "fixed" during its production and therafter they will all have just 1 QC sticker again.

 

[galego100]

Dear Galego.
I am more than sure that Fosi Audio will eventually respond for this problem. I can attest that their customer service is of an excellence rarely seen. I am really convinced that they will try by all means to solve your problem, but what you describe is strange, to say the least.
I am from Argentina and my V3 mono They left Hangzhou (China) passing through Shanghai, Sennan (Japan), Anchorage (Alaska), Oakland San Francisco (USA), Campinhas (Brazil) and finally arrived in my country. Throughout this itinerary there was no problem since all of them are transit places and not destinations.
It is not appropriate for ANY customs in ANY country to retain your shipment. The control must be done by the customs of your country.
Therefore, I believe that the problem lies with the logistics service provider and not with Fosi, although I repeat, you can be sure that they will respond.
Greetings!

If Fosi have a warehouse in Spain, it´s normal spanish customs involved.

 

[Brian Hall]

They should sound fantastic. They are a modern class D amp with a good IC chip. What is the comparative expense for the various models you ran in this test?

The Loxjie A40 amp (also includes a pretty good dac and a phono preamp, and an HDMI ARC input) was $255. V3 stereo amp was $80 or $90. ZA3 stereo amp was $149. Paid $240 for the pair of V3 monos with separate 48v/5amp power supplies.

The Loxjie A40 is a nice unit with a functional remote.

The Fosi LC30 amp/speaker selector was $149.

 

[Brian Hall]

Don't mix up gain and power. Two different things.

Ok, it makes my speakers put out louder sound and can obviously go much louder than I would ever want to hear.

 

[Endibol]

I wasn't too concerned about the phase being off, but did a "test" for fun (non measured, and not blind).

Moved the Fosi LC30 amp/speaker switch to my office. Same speakers (Sony SSC-S5), but two amps. The older Fosi V3 stereo vs the V3 monos.

The V3 stereo was louder at the same preamp level on the Wiim Ultra. The V3 stereo seemed to have a tiny bit more treble, but the subwoofer bass sounded better.

I changed the phase switch on the subwoofer and now the bass sounds better with the V3 monos, so I guess I did receive a set with the reversed phase. Expected as each only has one QC sticker.

It doesn't seem right to me for the V3 stereo to be louder than the V3 monos since they have more power on paper, but it is. Other than the slightly increased treble, I do not hear any difference in sound quality. I guess the V3 stereo was actually better than I thought it was.

I recommend the LC30 to anyone that wants to do a simple, quick comparison of amps or speakers or have two setups like my main system (stereo and atmos).

Had to compare the V3 monos vs the ZA3 with the LC30. Again the ZA3 is louder as previously determined. The subwoofer sounded wrong with the ZA3 as expected since I changed the phase for the monos. Switching the phase back corrected that for the ZA3.

Did a compare between the V3 stereo vs the ZA3. ZA3 slightly louder at same preamp level. Not as much difference vs the V3 monos. V3 stereo still seemed to have more treble. Both sounded great. Subwoofer phase needs to be the same for the ZA3 and the V3 stereo. Needs to be switched for the V3 monos.

Knowing what I do now, it doesn't seem like there is really any advantage in my two setups to having the V3 monos vs the ZA3 Stereo or maybe even the V3 stereo. All of them sound great.

I've also "tested" all of them driving my new Klipsch Heresy IV speakers. All sounded equally great as did the Loxjie A40 which seems to have the most power of any of them. Still noticed a slight treble boost with the V3 stereo vs all the others.

The v3 mono’s don’t have the load dependency the others two models have. If your speakers have an impedance tending to be higher than 4 Ohm, the treble in both stereo units will be enhanced a bit.

 

[Freezak]

The v3 mono’s don’t have the load dependency the others two models have. If your speakers have an impedance tending to be higher than 4 Ohm, the treble in both stereo units will be enhanced a bit.

Lack of load dependency is honestly a big deal and this alone makes the Mono V3 model worth purchasing over any other Fosi amp.