Fosi Audio V3 Mono Amplifier Review

[SorenTyson]

That's amazing, thanks for the review.

I would pair three of those with an Onkyo rz-50. Since I have to buy cables anyway, are there any benefits in going rca-xlr vs rca-rca?

According to Amir's review of the rz-50, it can output up to about 3.5 volt

 

[Matias]

The low price saves it from a few criticisms on IMD and multitone I would have. Very good performance, excellent value imo.

 

[thunderchicken]

Well, I think we've all been clamoring for these. How fast will they sell out?

 

[staticV3]

@amirm May I ask why this is your new recommendation? I'm glad you post the gain figure. I'm just curious on that number and why.

This spreadsheet may be useful to you:

Amplifier input voltage vs output power

Sheet1 Amplifier gain [dB]:,20

docs.google.com

To use it, login with your Google account and go to File->Make a Copy.

In that copy, you can change the Amplifier gain and the graph will update automatically.

 

[Fosi Audio]

Great review Amir! Thank you!
Looks like I need to return my Topping PA7

@Fosi Audio How do we use the Fosi Audio V3 Mono Early Bird Discount? And how do we pre-order?

Please subscribe from our official site and we'll update you once the campaign on Kickstarter is ready!
https://fosiaudio.com/pages/monoblock-power-amplifier-v3-mono

 

[Velocipede_Acoustics]

It doesn't matter what the sensitivity of the speaker is. The only thing important is whether the max power of the amplifier can be reached given the input voltage you have. As I noted, this amplifier needs 2.8 volts input to do that. Since most DACs have 4 volts output, you are good to go regardless of speaker you use.

How does speaker sensitivity not matter? I don't understand is why the speaker sensitivity would not matter in combination with the amplifier's gain when I have a target SPL. I think I lack an understanding of these relationships.

 

[Bruce Morgen]

I used to think of these Fosi and Aiyima chip amps as a useful and economical way to power your surrounds on a budget

That's how I use mine -- it's a very undemanding application that won't benefit from an upgrade. If I was still using passive L+R speakers, I'd be all over a pair of these for that job, but the ambience/surround mission doesn't need more power, more linear FR (DSP fixes that easily), or sky-high SINAD. So, why do I still want one?

 

[Guddu]

How does speaker sensitivity not matter? I don't understand is why the speaker sensitivity would not matter in combination with the amplifier's gain when I have a target SPL. I think I lack an understanding of these relationships.

You aren’t wrong as such, but….
I think the context of the statement was in relation with the gain of the amplifier, speaker sensitivity doesn’t change the gain of the amplifier.
However, lesser the sensitivity of the speaker more it needs amplification power to produce a certain SPL at certain listening position or distance.

 

[dzerig]

Wow. I have two Schiit Gjallerhorn in mono so I can use XLR as my main stereo is 30' from the tv, where my favorite speakers sit. I am very happy with those, but if I needed more power than my current 30ish watts, these would be at the top of my list.

 

[Velocipede_Acoustics]

You aren’t wrong as such, but….
I think the context of the statement was in relation with the gain of the amplifier, speaker sensitivity doesn’t change the gain of the amplifier.
However, lesser the sensitivity of the speaker more it needs amplification power to produce a certain SPL at certain listening position or distance.

Indeed. Amir quoted THX for amp gain and I used THX headroom recommendation which I think is reasonable. I think the most common scenario for amplifiers is that they run out of current before they run out of voltage. I think this may be what Amir is ultimatly getting at. That and the input can drive the amp to max gain. I understand that. However, there are times when I just need more gain, such as when a movie, for some weird reason, it's largest peak is -10db or some such number that makes everything unnecessarily quiet, all the time, including dialog. This is why I've been gain hunting. Dialog isn't going to draw 250watts. That's not my concern. It's that it's loud enough to be "reference level". There are TV shows that the dialogue is so quiet, that I need subtitles to be turned on. I literally run out of gain knob. This isn't a problem now that I have way more sensitive speakers.

It's my opinion that this amp is probably just good enough for 84db speakers at 2meters for THX volumes. Assuming the damn material isn't artifically quiet.

 

[surroundman]

Great work! Can we expect a stereo version of the amp?

 

[Billy Budapest]

Please subscribe from our official site and we'll update you once the campaign on Kickstarter is ready!
https://fosiaudio.com/pages/monoblock-power-amplifier-v3-mono

Thanks! Just filled out the early bird discount form!

 

[MidnightCarouselRider]

I want a 4 pack!

 

[lxg208]

I'm tempted , when will this be available?

 

[lxg208]

Thanks! Just filled out the early bird discount form!

Could you please let us know the link?

 

[JW001]

Indeed. Amir quoted THX for amp gain and I used THX headroom recommendation which I think is reasonable. I think the most common scenario for amplifiers is that they run out of current before they run out of voltage. I think this may be what Amir is ultimatly getting at. That and the input can drive the amp to max gain. I understand that. However, there are times when I just need more gain, such as when a movie, for some weird reason, it's largest peak is -10db or some such number that makes everything unnecessarily quiet, all the time, including dialog. This is why I've been gain hunting. Dialog isn't going to draw 250watts. That's not my concern. It's that it's loud enough to be "reference level". There are TV shows that the dialogue is so quiet, that I need subtitles to be turned on. I literally run out of gain knob. This isn't a problem now that I have way more sensitive speakers.

It's my opinion that this amp is probably just good enough for 84db speakers at 2meters for THX volumes. Assuming the damn material isn't artifically quiet.

Amir was referring to the voltage gain. Every amplifier has a parameter called input sensitivity specifying the input rms level at which the output reaches a maximum voltage (and power, for a given load). Above that level the amp will start clipping or may go into protection mode.

 

[Ze Frog]

Well, that's just gone on my list of possibilities now. Very impressive.

Big brand companies must be in sheer panic regarding relatively new companies providing such quality for such a price. Great stuff.

 

[Rja4000]

Many thanks for this review.

This sets a new reference for affordable amplification !
Very well done !

 

[Abstracted]

That's amazing, thanks for the review.

I would pair three of those with an Onkyo rz-50. Since I have to buy cables anyway, are there any benefits in going rca-xlr vs rca-rca?

According to Amir's review of the rz-50, it can output up to about 3.5 volt

Ha! I'm planning on using a couple of these for my RZ50 as well

 

[Guddu]

Could you please let us know the link?

Fosi Audio V3 Mono Monoblock Power Amplifier

The V3 MONO is a monoblock high-power amplifier integrated with the Texas Instruments TPA3255 amplifier chip, suitable for speakers of 2Ω to 8Ω impedance. It implements Post-Filter Feedback (PFFB) technology, addressing the long-standing issue of load-dependency in Class-D amplifiers.

fosiaudio.com

look for: