Fosi Audio V3 Mono Amplifier Review

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 It is outdated, has a short working life and is conductive.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EDIT: Arctic Silver Ceramique is very outdated and is not conductive but has a short life and not very good thermal conductivity.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

 

[antcollinet]

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.View attachment 368773View attachment 368774

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

Agreed. Messing about with thermal paste is pointless. You are more likely (IME) to make things worse, than better.

 

[Doodski]

Agreed. Messing about with thermal paste is pointless. You are more likely (IMO) to make things worse, than better.

A thermal paste MOD is pretty much 100% guaranteed to be a waste of time but these are a MODers paradise machine.

 

[somebodyelse]

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?

Personally I wouldn't, just as I wouldn't change the opamps, but if people insist on doing it they should put the aftermarket paste in the place where it has a chance of making an improvement. People who have paste left over from a PC build probably have the skill to do the job without much risk. Turning it on its side and/or using a fan would probably be more effective in improving cooling if you really need it.

 

[mgbpuff]

Just because it feels warm does not mean it has a problem. It was designed with the temperature rise in mind. This reminds me of my motor days with Reliance Electric when customers would say they wanted smaller frame sizes and then would complain that they run so hot that you could not even touch them. Well, they were designed for that and had high temp insulation and eddy current dissipating frame designs just so they could put more hp in smaller frames.

 

[antcollinet]

People who have paste left over from a PC build probably have the skill to do the job without much risk.

This might be an assumption too far. PC motherboards/CPU sockets are designed to make this pretty foolproof, with standardised, well engineered, robust, and tightly toleranced fixing methods for the heatsink down to the CPU.

The same does not apply to TPAchip amp based designs. The clamping force between chip and heatsink/spreader is highly dependent on the mechanical design, and fixing methods. Consistency of this may be highly dependent on the assembly process. It will also depend on the designed for viscosity of whatever paste is specified, and the designed for quantity and application method. None of which is known by the modder.

I have a number of unhappy experiences of heatsink paste incorrectly selected or applied causing problems in a high volume power electronic manufacturing environment.

 

[Doodski]

It will also depend on the designed for viscosity of whatever paste is specified, and the designed for quantity and application method. None of which is known by the modder.

I have a number of unhappy experiences of heatsink paste incorrectly selected or applied causing problems in a high volume power electronic manufacturing environment.

If one delves a little deeper into the MX-4, MX-5 and MX-6 thermal compounds that are so popular these days due to their 8 year service warranty they will find that there are tiny improvements in thermal conductivity but the major differences are viscosity like you say that is so important.

 

[Toroid]

Do we know if these could drive a 2 ohm speaker but highly efficient 95db at not insane volume? (One that only dips to 2.3 ohm, but never goes over 2.8 ohm)

 

[motorstereo]

^^^^^Mine has been running 2 pair of IMF supercompacts wired in parallel since it arrived here last week. It does get warm from the 4 ohm load but I'm thinking it would handle a 2 ohm load as long as it's not driven too hard.

 

[antcollinet]

Do we know if these could drive a 2 ohm speaker but highly efficient 95db at not insane volume? (One that only dips to 2.3 ohm, but never goes over 2.8 ohm)

Yes. You are only going to need to average 1 or 2 watts with such speakers.:

 

[Sokel]

Yes. You are only going to need to average 1 or 2 watts with such speakers.:

View attachment 369121

Assuming that this 2 Ohm speaker must be subs (what else is a constant 2 Ohm load?) and for proper integration there's surely some EQ involved it may need a little more than a watt or two to balance the loss.
If filling dips too (not advisable but people do it anyway) can go way-way higher.
But yes,test showed that can do it (in it's time constraints) .

 

[staticV3]

Assuming that this 2 Ohm speaker must be subs

What sub has a 95dB efficiency?

I'd imagine that @Toroid is talking about a fancy horn system or CBT speaker, or perhaps a panel-type speaker.

 

[Sokel]

What sub has a 95dB efficiency?

I'd imagine it's a fancy horn system or CBT speaker.

These are usually 8 or even 16 Ohm.
I'm really curious!

 

[staticV3]

These are usually 8 or even 16 Ohm.
I'm really curious!

I bet it's a dipole panel speaker

 

[Sokel]

I bet it's a dipole panel speaker

On the other hand I found this:

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