Fosi Audio P4 Preamplifier Review

[Nopiano]

Sorry I am lost here. Maybe I am being a bit dense but it is Sunday morning and I'm only just starting on my third pint of tea.

The V3 is an integrated amp so to use a separate pre-amp with it would it not need the ability to separate the pre and power stages? I looked at the review of it on here and it doesn't seem to have that function.

It’s better to think of the V3 as a power amp with a gain control. It’s not integrated with anything, least of all a traditional preamp section with input selection, tone controls, etc.

 

[DSJR]

I'd like to know if the P4 performance would be improved further (near maximum output) with a slightly higher voltage power supply? I mean, the opamp used should be easily able to use 15VDC rails.

Maybe it wouldn't make a jot of difference and may tax the electrolytic caps used, so forgive the probably numpty question (the use of the word 'numpty' is currently a kind of hot topic in the UK at this time )

 

[antcollinet]

Sorry I am lost here. Maybe I am being a bit dense but it is Sunday morning and I'm only just starting on my third pint of tea.

The V3 is an integrated amp so to use a separate pre-amp with it would it not need the ability to separate the pre and power stages? I looked at the review of it on here and it doesn't seem to have that function.

It is only integrated in that it has a built in (manual) volume control.

If someone wants remote volume control, or more than one input being selectable, or needs some extra gain (eg for a turntable) or tone controls, then this preamp can provide that functionality. Sources into preamp. Output of preamp into Fosi V3.

 

[NorthernSoul73]

The Naim is from an era where amps really *could* 'sound' different to each other. Maybe the latest models are a bit better?

I've certainly got no complaints with it and as to how it sounds its a difficult one to quantify but seems to have plenty power on tap!

 

[gvl]

I would like to know what the input impedance is.

Me too!

 

[gvl]

Is pre-out just hardwired to the RCA output or there’s more to it, eg it’s taken before tone controls?

 

[Ropeburn]

Is pre-out just hardwired to the RCA output or there’s more to it, eg it’s taken before tone controls?

A good question, especially if you're intending to use it as a subwoofer output, or any other purpose for which EQ would be detrimental to. I hope @Fosi Audio can clarify.

 

[telemike]

I ordered this even though I don’t really need it

 

[Carl-Fosi Audio]

I find it spectacular that the volume control is motorized
Sorry if I'm asking in the wrong place, but I saw that the BT30D Pro now supports 48V. I bought one about 2 months ago, but it says 24-36V. Is it possible to use a 48V power supply on mine?

If it says 24-36V, then you can only use 24-36V power supply, but not 48V.

Hilarious. A virtually transparent straight wire with gain for $80! And to think in the bad old days audiophiles used to pay literally thousands of dollars for this and none of them were nearly as good.

Would be great to see a balanced version, and, while everyone knows you could just buy multiple units to add channels, still would be nice to have 4-8 channels in one case.,

As always great review, Amir.

How do you use the 4-8 channels then?

 

[Carl-Fosi Audio]

When I think about the amount of money spent trying to find a transparent preamp...

Fosi is really building a solid fan base with inexpensive equipment and nice measurements. Don't need this preamp but already have a BT20 Pro, the little portable DAC, the phono preamp... And I see Fosi offering more and more products in the future, so there is a chance I found one again for my use case.

Which preamp are you using now?

 

[Carl-Fosi Audio]

IMHO instead of chasing balanced connections or separate components, Fosi should focus on creating a high-quality, fully integrated device—one that could shake up the entire market, outclassing the Wiim and all those overpriced pseudo-hi-end streamers.

Imagine an all-in-one unit that combines a streamer, DAC, preamp, and power amp, while also offering analog and phono inputs—and most importantly, featuring an internal power supply!

If you think about it, Fosi already has all the building blocks in its catalog:

• An excellent phono preamp
• A variety of DACs with coaxial, optical, USB, and Bluetooth inputs
• A solid analog input stage
• High-quality power amps in class-d and class ab

they need a good streamer module. I hope they will work hard,
I don’t currently own any Fosi devices because I’m not a fan of separate boxes, but I would definitely buy a well-engineered, great-sounding integrated amplifier from them.

Then I am afraid it would be expensive.

 

[longts]

It looks nice

 

[Carl-Fosi Audio]

I’m a big fan of these useful, low cost devices so it’s great to see this one performs well.

If this company made a low cost studio monitor controller in the same vein as something like the Drawmer CMC series, they’d probably sell a tonne of them.

Could you please tell me what is a stadio monitor controller?

 

[dav0043]

So...the title of this site is Audio SCIENCE Review. Products are designed by engineers (science). Prices are set by marketers (not science). And this preamp is 'Great' by the majority of raters? Maybe we need 2 user inputs: a rating for the engineering of the product and 1 for the value of the product. This may punch above its weight but it is far from great when compared to devices that are objectively "great'.

 

[renaudrenaud]

Which preamp are you using now?

I have 2 Topping at home right now, one A90 and one L70. I like these because the price, the performances and the balanced input / output.

I don't usually buy because I need this one or this one. I buy because I like to buy, wait, unpack and listen. I am a bit curious and spending some money in new equipment, this is my way. I am lucky enough to have a lot of children and they receive some equipment time to time. They don't care at all, they just use it and listen to their music.

 

[antcollinet]

but it is far from great

In what way?

 

[Adaboy4z]

A set of Balanced input and out would cover it for a lot of peoples gear. It's small enough to place right beside a dac.

 

[xevman]

Been using this with v3 monos and it works great, had to put the gain on this preamp and the v3monos to minimum aswell as the output voltage of my wiim pro to get good range of adjustment on the volume control.

 

[restorer-john]

Honestly, it is pretty hard to fault anything about this little preamplifier. Especially for the almost giveaway price.

It will turn an old integrated amplifier into a remote volume unit by inserting this into the tape loop. You could use it as a high quality remote source switcher and level controller. You could take a bare bones power amp and use this with confidence as it's nicely made, full of relays for proper switching and looks as cute as a button.

Even I want one.

 

[GianDi]

Then I am afraid it would be expensive.

I don't think so