Fosi v3 Mono - User Impressions | Owner's Thread

[PJ_Schmidt]

This is a strange one because one thing you would expect subjective reviewers (and there were a fair few who received early units) to hear and report on would be obvious noise, and they mostly received 48v 10A supplies. Noise did not seem to be a problem. Then there was a surge in 'concern' about synchronization and oscillation but this in the end seemed to be a bit of a storm in a teacup.

Does anyone know exactly where and why Fosi offered to include the filter?

I thought, when I found out, that it seemed to be a way to reassure more than anything else. I'm not expecting to hear noise with or without.

Has anyone received the Fosi10A supply out of interest with their monos?

This is a known issue that Fosi has addressed:

Fosi Audio V3 Mono Amplifier Review

Youtube reviewers say scorching hot after 3 to 4 hours hits 120 degrees, first 1 to 2 hours 100degrees. Good thing my za3 monos are larger box and just warmer all day loads.

www.audiosciencereview.com

The filters they are providing with the 10A power supplies are to address this issue.

 

[PJ_Schmidt]

Did they?
Lets leave aside the calc I have posted about heat dissipation and go to some serious implementation.
Let's use comparable (in power) amps in a no BS application:

View attachment 378609

(I think we all know what this is)

So,dimensions are 253 x 383 x 292 mm,so lets say 200 x 350 mm for the back plate?
It all acts as a heatshink but they didn't stop there as you see,they also added finned heatshink .

Is Neumann so generous wasting metal?I don't think so,they just did the calcs so they make sure their (pro) costumers won't waste time from stuff shutting down,etc.

This is a class AB amplifier. It will be much less efficient than the V3 Mono which is class D. For the same wattage, the Neumann needs to dissipate much more energy, hence the very large heatsink.

 

[Sokel]

This is a class AB amplifier. It will be much less efficient than the V3 Mono which is class D. For the same wattage, the Neumann needs to dissipate much more energy, hence the very large heatsink.

Yes it is but upon calculating this specific application has more or less the same thermals needs,specially at normal levels.

Here's the calculator and a good read,once again:

How to Select a Suitable Heat Sink

Laptop computer designers, audio amplifier makers, and power supply manufacturers can keep their products cooler by following these fundamental heat-sink

www.designworldonline.com

And here's TI's data to consider:

 

[SMen]

This is a known issue that Fosi has addressed:

Fosi Audio V3 Mono Amplifier Review

Youtube reviewers say scorching hot after 3 to 4 hours hits 120 degrees, first 1 to 2 hours 100degrees. Good thing my za3 monos are larger box and just warmer all day loads.

www.audiosciencereview.com

The filters they are providing with the 10A power supplies are to address this issue.

Thank you yes I remember this now.

But with both switched on there is no 'noise'. A useful clarification.

 

[joostdh]

I received my set V3 Monos earlier this week and they are purring away nicely. I haven’t swapped the opamps yet.

Will be pairing the whole thing with a couple of Dali Oberon 5’s

This is similar to my intended use. Once the Ultra is released it will replace a Wiim Amp and together with the Monos they will drive a set of Dali Oberon 7’s.

 

[PJ_Schmidt]

I assume most people in this thread are also watching the main Review thread, but I did some more testing last night with 2x mono on a single power supply and posted the results over there.

Fosi Audio V3 Mono Amplifier Review

Good morning, I tested my 2 mono with 2 5A for 2 hours on Saturday. No pops or other noises to be heard. Good sound with lots of detail.

audiosciencereview.com

Probably would have made more sense to post it in here, but it was late and I wasn't thinking.

 

[Guddu]

I assume most people in this thread are also watching the main Review thread, but I did some more testing last night with 2x mono on a single power supply and posted the results over there.

Fosi Audio V3 Mono Amplifier Review

Good morning, I tested my 2 mono with 2 5A for 2 hours on Saturday. No pops or other noises to be heard. Good sound with lots of detail.

audiosciencereview.com

Probably would have made more sense to post it in here, but it was late and I wasn't thinking.

I have had similar observations, but not quite such detailed.

 

[MCH]

I assume most people in this thread are also watching the main Review thread, but I did some more testing last night with 2x mono on a single power supply and posted the results over there.

Fosi Audio V3 Mono Amplifier Review

Good morning, I tested my 2 mono with 2 5A for 2 hours on Saturday. No pops or other noises to be heard. Good sound with lots of detail.

audiosciencereview.com

Probably would have made more sense to post it in here, but it was late and I wasn't thinking.

Your test is very interesting.
Is there a way to capture a screenshot of your measurements and post it?

 

[PJ_Schmidt]

Your test is very interesting.
Is there a way to capture a screenshot of your measurements and post it?

I'll try to get FFT screen shots when I'm next able to test.

 

[Megaken]

So is it worth swapping Muses02?

 

[Hot Mason]

Any problems with v3 mono after using it?

 

[Guddu]

Any problems with v3 mono after using it?

There has only been 2 issues reported:

1) Excessive Noise when using single psu but only 1 amplifier, Fosi said they have resolved the issue and issue is limited to pre-production units
2) Heat or thermal performance- many users here, including me, have reported that the units are running on hotter side. Even you reviewers have said the same thing.

By the way, I am running v3 mono pair with 36v psu from last 2 days and I am not seeing any thermal performance improvements.

 

[T&T]

T-shirt is my guess. I ordered the Muses too and they didn’t mention them as a cause for delay. I would write them.

They just send it, received email.

 

[Giro413]

They just send it, received email.

Glad to hear it. I am backer 1427, but am expecting Fosi to send mine shortly as per their email regarding the filter

 

[Sgt. Pepper]

Fosi is a month behind on their own shipping schedule. From the end of May. To the end of June, now all units shipped by July 15th. That's 11 days from now. I believe many won't see their units until August. They haven't been upfront with their customers.

 

[Giro413]

Fosi is a month behind on their own shipping schedule. From the end of May. To the end of June, now all units shipped by July 15th. That's 11 days from now. I believe many won't see their units until August. They haven't been upfront with their customers.

I really have no use for mine till I can get my hands on a Wiim Ultra, so I guess I am in no rush. Live in Northern Europe.

 

[GoDawgs]

Fosi is a month behind on their own shipping schedule. From the end of May. To the end of June, now all units shipped by July 15th. That's 11 days from now. I believe many won't see their units until August. They haven't been upfront with their customers.

You are the one who is being deceitful, see screenshot from Kickstarter. May isn't mentioned, the month of June is:

People started receiving them in June, why are you crying? Again, like you were told in your other anti-Fosi thread, this was a Kickstarter campaign. You do not order and expect a definite shipping date, you are investing and no product is guaranteed to even be produced, much less a specific delivery date. They began shipping in June and you begin whining 4 days into July, stop your crying!

 

[drmevo]

I’ve had the amps for a few days now and am very pleased with the performance. The only slight oddity is that I’m using auto power on and other things on the same circuit will often turn them on - namely lights. Maybe my preamp isn’t doing a good job filtering electrical noise?

 

[renoxd]

Can someone measure for me the real height with feets of these monoblocks? Audiophonics website says 41mm. Is that true? How about front of this monoblock? Seems to be a little taller

 

[Guddu]

Can someone measure for me the real height with feets of these monoblocks? Audiophonics website says 41mm. Is that true? How about front of this monoblock? Seems to be a little taller

38-39 mm, 41mm clearance is good enough from height prospective but ventilation is recommended.