Fosi Audio V3 Mono Amplifier Review

[Deleted member 72219]

Honestly, bro-dawg probably just yoinked an op-amp (swap). It's not hard to do, even with an IC extractor.

-Ed

 

[Guddu]

Gotcha.
Yeah from what I could gather from all the available reviews, the V3Ms get a bit warmer than their other models.

"a bit warmer" - my both the units have broken this barrier already, but I use in totally ventilated position for complete air flow it might need.

 

[SMen]

"a bit warmer" - my both the units have broken this barrier already, but I use in totally ventilated position for complete air flow it might need.

Can you explain this more?

 

[Guddu]

Can you explain this more?

I just meant mine are running more than warmer (more like a bit hot) as so much that I do want to put them in proper ventilated place.
Can this be an issue- I don’t know but probably not. (*** My AVRs have been running hot but still work even after 2 years ***).

But they, Fosi v3 mono, do their job very well that running a bit hot doesn’t bother me much, but doesn’t mean it won’t others.
While saying warm or a bit hot are subjective, a quick comparison for me is Fosi ZA3 which runs just warm in comparison.

 

[quocheiser]

I just meant mine are running more than warmer (more like a bit hot) as so much that I do want to put them in proper ventilated place.
Can this be an issue- I don’t know but probably not. (*** My AVRs have been running hot but still work even after 2 years ***).

But they, Fosi v3 mono, do their job very well that running a bit hot doesn’t bother me much, but doesn’t mean it won’t others.
While saying warm or a bit hot are subjective, a quick comparison for me is Fosi ZA3 which runs just warm in comparison.

That's great insight to have!
My ZA3 runs as warm/hot as I would like tbh... hmmmm...
Hopefully the V3M's heat is just the chassis doing its job as a heatsink...

 

[Guddu]

Anyone know the model # for the Fosi 48V 10A power supply?
Note some photos show the HuntKey HKA30048063-7D, which is actually a 48V 6.3A.

I have close pictures of the unit as well as PSU here:

Fosi v3 Mono - User Impressions | Owner's Thread

Dear FMs, [ what I get as a buyer or user of Fosi v3 mono amplifier pair > aspects other than measurements that you might be interested in > testing features & functions to see if there are any issues and how could get around those, if any > I also hope that this thread could provide...

audiosciencereview.com

(The Kickstarter page is not showing the model number... there is some chance they will change or tweak the power supply before shipping)

It is not uncommon.

 

[tjd]

Erin tortured that poor little amp to death, and Z has been poking around in it with his greasy sausage fingers.

If another reviewer smashes 2 more units with a hammer, you're gonna tell us '4 out of 20 died'?

Cause of amp death: Greasy sausage fingers.

 

[johnmartmill]

The place for Arctic Silver would be between the chip and the heat spreader block as the heat transfer is over a small area. The much larger area between the heat spreader and the case is less critical, and the rubbing removing the thermal paste is probably helps in avoiding there being too thick a layer of paste.

Given how cheap these amps are, how quick the tech is improving, the time/cost associated with the aftermarket thermal paste, the potential to messing up the unit and the likelihood of never needing it, why would anyone go down this path?

 

[Lednek]

This is a follow-up on the 48V/10A power supply. Our supplier Huntkey has provided us with a test report for this power supply, along with a video of the actual test, which you can review below. This power supply can indeed operate stably at a 10A current.

Noise & ripple test also included. @SMen

View attachment 368520View attachment 368521View attachment 368522View attachment 368523

Thank you! @Fosi Audio. Could you please post the same information for the 5A power supply? I'm interested to see if the ripple spec is equally good. Impressive!

 

[Cal_Cobra]

Given how cheap these amps are, how quick the tech is improving, the time/cost associated with the aftermarket thermal paste, the potential to messing up the unit and the likelihood of never needing it, why would anyone go down this path?

Probably a five minute job that provides cheap insurance if one is concerned about the thermal dynamics of the V3 mono, if not, party on.

 

[redstang]

Erin tortured that poor little amp to death, and Z has been poking around in it with his greasy sausage fingers.

If another reviewer smashes 2 more units with a hammer, you're gonna tell us '4 out of 20 died'?

Considering one of the "rewards" to kickstarters is an op amp chip, many of us might be "poking" around in it with our sausage fingers, so the anecdote about Z is noteworthy. Not at all a serious concern, unless quite a few others mention the same issue.

 

[Doodski]

Might be worth applying something like Arctic Silver. It's used for CPUs and claims to have superior temp reduction capabilities than generic heatsink grease.

No, do not use Arctic Silver. It is outdated, has a short working life and is conductive. Use MX-4 or MX-6 which guarantees a 8 year working life, lower thermal resistance than Arctic Silver and it is not conductive.

EDIT: Arctic Silver Ceramique is very outdated and is not conductive but has a short life and not very good thermal conductivity.

 

[Lee T]

Use MX-4 or MX-6

Well, I've got the best part of a 14g tube of Noctua paste so I'll be using that if I take the Zeos punt and swap my op-amps.

Earlier today I was looking at small heatsinks I could use instead of the supplied rubber feet. I figured getting more air circulation under the amps and more effective case surface area can only help. Would 5mm slab of metal sheet sat on top of the amps help too?

 

[Doodski]

Noctua

Is good stuff although it does not have the 8 year guarantee rating. I have used Noctua in a pinch and it performed very well for a PC overclock.

Earlier today I was looking at small heatsinks I could use instead of the supplied rubber feet. I figured getting more air circulation under the amps and more effective case surface area can only help. Would 5mm slab of metal sheet sat on top of the amps help too?

Replacing the rubber feet with small heatsinks seems a futile effort to me. Placing a metal sheet across the top will reflect the heat back and will stop air flow that is cooling the case and interior of the amp. If you want to cool it very effectively make sure nothing is on top of the unit and there is free air flow all around the amp. If you want even better cooling then get a small fan and have it blow over, under or across the amp.

 

[Lednek]

No, do not use Arctic Silver. It is outdated, has a short working life and is conductive. Use MX-4 or MX-6 which guarantees a 8 year working life, lower thermal resistance than Arctic Silver and it is not conductive.

EDIT: Arctic Silver Ceramique is very outdated and is not conductive but has a short life and not very good thermal conductivity.

I have an unopened tube of TF8 I was planning on using. Is thr mx-6 much better. I mean it's only $10 for a 4g tube, but if the TF8 fits the bill I'll use it . Also it's probably going 2 years old, but unopened.

 

[Anton D]

Small desk fan?

Some claim as low as 25 dB.

 

[Doodski]

I have an unopened tube of TF8 I was planning on using. Is thr mx-6 much better. I mean it's only $10 for a 4g tube, but if the TF8 fits the bill I'll use it . Also it's probably going 2 years old, but unopened.

I have not read test reviews comparing the Thermalright TF8 to the MX-4 or MX-6 so I can't speak to that. There are no ratings for thermal conductivity for the MX-4 and MX-6 so I can't use those to compare with the Thermalright TF8. Thermalright has been a great provider of very good product for my overclocking adventures over the years and so I have trust in it but I don't see that 8 year working guarantee again.

TF8 2g – Thermalright

www.thermalright.com

MX-4 | Premium Performance Thermal Paste | ARCTIC

The ARCTIC MX-4 ACTCP00007B is a multiple award-winning thermal paste | exceptional thermal conductivity | optimal for any PC | Fast processing and delivery | ARCTIC Store

www.arctic.de

MX-6 | ULTIMATE Performance Thermal Paste | ACTCP00079A | ARCTIC

Newly developed premium paste from ARCTIC: The MX-6 ACTCP00079A | Especially thin application, high thermal conductivity, very low thermal resistance | ARCTIC MX-6 | Simply the Paste | ARCTIC Store

www.arctic.de

Why doesn’t ARCTIC communicate thermal conductivity values?​

Why do we not specify the thermal conductivity?

In this article we explain why ARCTIC does not specify the thermal conductivity in its thermal interface materials | Thermal interface materials | ARCTIC Store

www.arctic.de

 

[sl1982]

Having the Yamaha's Line level signal be amplified by the built-in Amp, then brought back down to Line level via the adapter, then once again amplified to Speaker level by the Fosi, sounds extremely inefficient.

Instead, I'd try to modify the Yamaha by adding RCA Line outputs myself.

There's a service manual available online which guides you through the disassembly process and contains detailed block diagrams and PCB schematics.

I ended up getting a denon x3300w for 200 CAD that has a full set of preouts so problem solved. Thanks!

 

[SMen]

I just meant mine are running more than warmer (more like a bit hot) as so much that I do want to put them in proper ventilated place.
Can this be an issue- I don’t know but probably not. (*** My AVRs have been running hot but still work even after 2 years ***).

But they, Fosi v3 mono, do their job very well that running a bit hot doesn’t bother me much, but doesn’t mean it won’t others.
While saying warm or a bit hot are subjective, a quick comparison for me is Fosi ZA3 which runs just warm in comparison.

Thank you. They do 'heat sink' into the case I guess, and ZA3 has more space in the case.

 

[V.b.]

If you are worried about thermal performance, just place it on its side, raised a little to keep the ventilation holes open, and, maybe, stuck a low profile heatsink on the former underside.

Maybe you have around an old external 3.5 hdd or router accesory.