Fosi Audio V3 Mono Amplifier Review

[Down South]

No one responded to my input about bi-amping, if you've already bought a Fosi V3 stereo and are about to receive 2 x V3 monos why not try using the monos for bass and the V3 stereo for mids and treble. Of course Rod Elliott's active x/overs would be better but as the experiment costs nothing it's worth a try

 

[DavidMcRoy]

No one responded to my input about bi-amping, if you've already bought a Fosi V3 stereo and are about to receive 2 x V3 monos why not try using the monos for bass and the V3 stereo for mids and treble. Of course Rod Elliott's active x/overs would be better but as the experiment costs nothing it's worth a try

I ordered four V3 Monos to biamp a pair of Acoustat Spectra 1100s, to replace the pair of V3 Stereo amps that I’m currently using for that purpose. (It’s a 2-way design.) They actually work fine, but being a retired broadcast engineer I have an urge to add just a little more headroom. I’m using a Dayton Audio DSP-408 for crossover and EQ, but the Spectra 1100’s integral 1st order high pass filter and transformer for the electrostatic panel above 250Hz must remain in the signal path. I use DSP to realize 4th order filters acoustically for both high pass and low pass. Going for “belt and suspenders” dynamic range here. My guess is I'll hear zero difference...which is fine...except that the system will be less likely to go into clipping on some ridiculous movie soundtrack, which is my goal.

 

[Down South]

I ordered four V3 Monos to biamp a pair of Acoustat Spectra 1100s, to replace the pair of V3 Stereo amps that I’m currently using for that purpose. (It’s a 2-way design.) They actually work fine, but being a retired broadcast engineer I have an urge to add just a little more headroom. I’m using a Dayton Audio DSP-408 for crossover and EQ, but the Spectra 1100’s integral 1st order high pass filter and transformer for the electrostatic panel above 250Hz must remain in the signal path. I use DSP to realize 4th order filters acoustically for both high pass and low pass. Going for “belt and suspenders” dynamic range here. My guess is I'll hear zero difference...which is fine...except that the system will be less likely to go into clipping on some ridiculous movie soundtrack, which is my goal.

You might be surprised. I bought a s/hand pair of Heybrook Sextet Mk1V's which got very good reviews in the 90s'. This pair was made after Peter Comeau had left Heybrook.

The only reason I can see for putting x/overs whether passive or active inside speaker enclosures is that it looks neater and makes it easier to package the product. Plus these x/overs are put inside the bass section where they experience the greatest amount of energy and vibration.

I was appalled at what I found especially the bodging around the Tonigen ribbon tweeter. Huge amounts of excess glue which I removed and properly sealed the bottom wooden plate so that the Tonigen tweeter operated without any interference from the mid.

Removing the x/over and suspending it outside the enclosure, removing the crappy plastic plate with a wooden plate and placing the wiring inside FEP tubing means cleaner signal transfer.

I can understand the appeal of active speakers but why repeat the mistake of decades by putting the amp/x/overs inside the enclosure.

 

[Electric_Haggis]

Hi all. I have 2 x PSB Imagine Surround S bipoles for side surrounds, yet to be installed.
(Presonus actives for all other channels).
These side surrounds will be 1.8m on either side of the MLP in a 3.5m wide x 5.5m deep room.
Pre-pro will be an Anthem AVM70, balanced cables to the amp.

How would these compare to the Topping PA5 II or SMSL AO200 Mk2 ?

Thanks in advance!

 

[gwing]

I can understand the appeal of active speakers but why repeat the mistake of decades by putting the amp/x/overs inside the enclosure.

It isn't really a mistake. I'd guess that significantly more than 99% of the market for speakers wouldn't want the clutter of an external crossover and certainly wouldn't want to cover the extra cost of one. That said external crossovers are desirable for multiple reasons and I once had some even on passive speakers (Maggies).

 

[Rafaille]

It isn't really a mistake. I'd guess that significantly more than 99% of the market for speakers wouldn't want the clutter of an external crossover and certainly wouldn't want to cover the extra cost of one. That said external crossovers are desirable for multiple reasons and I once had some even on passive speakers (Maggies).

How much is significantly more than 99%?

 

[antcollinet]

How much is significantly more than 99%?

99.99 of course (99% of the remainder.)

 

[Fosi Audio]

No one responded to my input about bi-amping, if you've already bought a Fosi V3 stereo and are about to receive 2 x V3 monos why not try using the monos for bass and the V3 stereo for mids and treble. Of course Rod Elliott's active x/overs would be better but as the experiment costs nothing it's worth a try

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.

 

[Ricwa]

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

You have the left speaker on the right side of the diagram which is confusing. I understand that this is a view from the rear but I don’t think everyone will understand that. My opinion is that anybody who actually wants to bi-amp won’t need the diagram in any event.

 

[Down South]

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

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

 

[LeonidKogan]

Are they going to be sold anywhere else than Kickstarter? I see their campaign is now over but can't find any info on official release date.
I assume return is not an option while ordering on Kickstarter?

 

[Down South]

It isn't really a mistake. I'd guess that significantly more than 99% of the market for speakers wouldn't want the clutter of an external crossover and certainly wouldn't want to cover the extra cost of one. That said external crossovers are desirable for multiple reasons and I once had some even on passive speakers (Maggies).

You've given a perfect example of commercial 'reasoning'. External x/overs don't have to have the appearance of 'clutter'. They can be contained within an enclosure which would also eliminate any air borne vibration, could look very neat BUT harder to package and transport. With expensive speakers this additional cost should be very easy to assimilate but that's not how commercial reasoning operates.

As to why I used FEP tubing to contain the internal wiring. Firstly even though FEP belongs to the same family of fluorocarbons, dielectrically it's far superior. Just think of the energy bouncing around inside the bass enclosure.

I've always thought that open baffle speakers 'should' have a cleaner sound simply because the transducers are not 'contained' within an enclosure nd neither is the wiring or x/overs.

 

[Zek]

Can you help me check if this diagram shows the right connection of bi-amping using 4 sets of V3 Monos?

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.

 

[staticV3]

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.

Why not?

 

[Zek]

Why not?

Because the crossover for the speakers would be in two places.

 

[staticV3]

Because the crossover for the speakers would be in two places.

Wdym?

Bi-amping a pair of bi-amp-able speakers is perfectly fine, even without an external, active crossover.

The passive crossover built into the speakers is designed specifically for this purpose.

 

[activewire]

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

Please don’t create this HOW to video Fosi without first articulating WHY one might do this. I believe that anyone who owns the distinctly exotic equipment necessary for bi amping to provide ANY real benefits does not need such a howto video. Likewise, anyone who needs the howto does NOT own gear that would benefit.

 

[Down South]

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.

Just how do you work that out? I've never heard of a x/over, active or passive ever built into a pre-amp.

I suggest you visit Elliott Sound Products where he explains the whole point of bi-amping. He recs. active x/overs for maximum benefit. I think the guy from Fosi using 4 x Monos is a bit OTT since it is the bass that uses by far the most energy. Rod also debunks bi-wiring. His site is well worth a visit.

 

[mike70]

Wdym?

Bi-amping a pair of bi-amp-able speakers is perfectly fine, even without an external, active crossover.

The passive crossover built into the speakers is designed specifically for this purpose.

I think the reason for external crossover (normally digital) is to bypass the passive crossover components and their power and sound quality losses.

 

[staticV3]

I think the reason for external crossover (normally digital) is to bypass the passive crossover components and their power and sound quality losses.

Sure sure, I'm not arguing against that.

Just stating that bi-amping is possible, safe, and ok even without external crossover, even if it's not smart.