• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Fosi Audio V3 Mono Amplifier Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 8 1.5%
  • 2. Not terrible (postman panther)

    Votes: 15 2.8%
  • 3. Fine (happy panther)

    Votes: 108 19.9%
  • 4. Great (golfing panther)

    Votes: 413 75.9%

  • Total voters
    544
Well according to Rod Elliot:

I stand by my statement
Which is incorrect. If you had not cherry picked but had posted what Rod said it would have included what he said - if you want to go 'fully active' THEN you disconnect the passive x/over entirely - otherwise you leave the mid/tweeter section of the x/over in place.

My post was 'that if you want to 'try bi-amping' you will get a real taste of what is possible. Using 3 amps - one for bass, one for mids and one for the tweeter, than go active. The guy from Fosi has two way speakers, so using 4 amps makes sense. I think using 4 monos is overkill but why shouldn't he try that configuration.

My speakers use Tonigen ribbon tweeters that are now properly sealed from the mids which is also sealed from the bass section - there is an awful lot of energy generated by the bass unit. The wiring is protected from this energy inside FEP tubing. If you were to attach sensors to the wiring and as usual the passive x/over plate you would soon see just how much the function of the bass unit, inside it's enclosure generates sound pressure which changes in intensity all the time aka energy is moving/shifting. The Sextet has a downward firing port at the bass. If there was no energy being generated by the bass transducer there would be no point in having ports of any kind.
 
Can you help me check if this diagram shows the right connection of bi-amping using 4 sets of V3 Monos? We're going to make a video to introduce it.:)
View attachment 374697
Hi @Fosi Audio
It's your product and your marketing strategy.

My only comment is that the key information here is that the crossover is before the amplification. Implicit is that there is no crossover in the speaker. That's not made very clear in your diagram, it's easy to miss.

I would appreciate your professionalism if you made that very clear, and made it equally clear that there is little benefit (if any?) in bi-amping when there is still a passive crossover downstream of the amplification.
 
Hi @Fosi Audio
It's your product and your marketing strategy.

My only comment is that the key information here is that the crossover is before the amplification. Implicit is that there is no crossover in the speaker. That's not made very clear in your diagram, it's easy to miss.

I would appreciate your professionalism if you made that very clear, and made it equally clear that there is little benefit (if any?) in bi-amping when there is still a passive crossover downstream of the amplification.
You are of course entitled to your opinion, on the other hand there are others who would really quite like to have a high pass filter in their pre-amp specifically to drive normal speakers with inbuild passive crossovers in conjunction with a sub.
 
You are of course entitled to your opinion, on the other hand there are others who would really quite like to have a high pass filter in their pre-amp specifically to drive normal speakers with inbuild passive crossovers in conjunction with a sub.
I think that this whole topic probably needs its own thread. Fosi posted one for suggestions regarding a pre-amp (I am presuming) for the v3 monos here: https://www.audiosciencereview.com/...-a-balance-preamplifier-should-be-like.47481/

But the whole subject of active crossovers would be beyond this also.
 
You are of course entitled to your opinion, on the other hand there are others who would really quite like to have a high pass filter in their pre-amp specifically to drive normal speakers with inbuild passive crossovers in conjunction with a sub.
That's nothing to do with my comment

Agree that high/low pass filtering in amp for the purpose of subwoofer integration is a very nice feature. There are signs that more inexpensive equipment is offering this now, or at least talking about it, which is brilliant.

Nothing to do with bi-amping though, at least nothing in relation to my comment on Fosi's diagram and proposed video
 
It would be interesting a thread about speakers with the possibility to bypass the passive crossover.
I think you only have the DIY path.
 
Sincere question: where does one purchase such speakers as this?
Mostly in the Pro audio scene.

The JBL 705i and 708i are two examples.

Keep in mind that unless the manufacturer provides filter designs for the external crossover, it'll be up to you to match levels between drivers, find a suitable crossover frequency and slope, and fix any inherent driver response issues.
 
It would be interesting a thread about speakers with the possibility to bypass the passive crossover.
I think you only have the DIY path.
There are threads like that.
They usually end when they realize that you have to measure the speaker in anechoic conditions (or similar,like the nice guide here) all over again,on and off-axis,etc.
It's not a modified speaker any more,it's a whole new one.

Plus,one has to take care of a fail-safe scheme,actives are no joke if something go south.
 
Just got an email reply from Fosi. The V3 Mono amps are shipping to end users from China next week. I chose 2 amps with separate 5A supplies. They will eventually be used to power a couple of DIY SB Acoustics passive subs.
 
thank you @rgpit
I have orderd the same package, they will drive the lower section of an active 2 way system (2x15OB350 by SBA per channel).
Depending how this solution performs, I may postpone the PuRiFi option ;-)
 
Just got an email reply from Fosi. The V3 Mono amps are shipping to end users from China next week.
I recently ordered a u-drive from Fosi on the 18th of May and received it from China on the 29th of May in Virginia, USA. I'm guessing the same time frame for the amps.
 
Sincere question: where does one purchase such speakers as this?
I’d guess they’re rare, but that’s what the diagram looks like. I bypassed the passive low pass crossover on my Acoustat Spectra 1100s myself (they’re vintage and of course out of warranty.)
 
Can you help me check if this diagram shows the right connection of bi-amping using 4 sets of V3 Monos? We're going to make a video to introduce it.:)
View attachment 374697

Yes, this is correct Fosi.

This scheme is valid only if there is an active crossover in the preamplifier, if there is a passive crossover in the speakers, then this scheme cannot be applied.

This is incorrect. Most commercially available retail speakers come with internal passive crossovers so all that is needed is a + and - input from a single amplification channel. Most commercially available retail speakers that come with the ability to be bi-amped still utilize the/an internal passive crossover, it's just that they allow one to separate the inputs to individual drivers for amplification individually - no other filtering or active crossover is needed. Sometimes they come with separate inputs for individual drivers but I think they most often come with a removable jumper so one has the option to bi-amp or not ... as in the graphic below.

Most of my experience is with DIY speakers which is probably where active crossovers and multiple amplification channels are most often used, but I would think that even for commercially available speakers with multiple amplifier inputs there would usually be some some sort of outboard or individual active crossover component being used (internally or externally - such as with active monitors which also often include amplification) because the filtering and crossovers are more complex than any standard preamplier could ever handle and because the average user would not know how to implement such filtering on their own.
 

Attachments

  • conventional-wiring-setup.jpg
    conventional-wiring-setup.jpg
    37.8 KB · Views: 40
Back
Top Bottom