Fosi Audio Box X5 Phono Preamp Review

[davmol]

Great review. I suppose the question is do you think I would hear an audible improvement over the phono stage built into the wiim ultra? Since I eliminated the electrical interference, the phono on the wiim has been clear, minimal hiss etc so not sure if I should take a punt on this fosi or not

 

[Labjr]

Great review. I suppose the question is do you think I would hear an audible improvement over the phono stage built into the wiim ultra? Since I eliminated the electrical interference, the phono on the wiim has been clear, minimal hiss etc so not sure if I should take a punt on this fosi or not

I'd certainly want to hear what -20db SINAD difference sounds like.

 

[Brycycle]

Very nice. Are there chances to have a look inside?

Here's a breakdown on the internals:

 

[davmol]

I just sold some headphones on ebay so I've got a bit of cash in the audio jar, and this X5 is £98.99 on Amazon UK at moment....

I was on the fence for a few minutes but then Jeff told me if I ordered it asap he would deliver it to my door in under 14 hours, so I've pulled the trigger. Will report back after a few hours / days of listening.

 

[restorer-john]

Here's a breakdown on the internals:

Life is too short to sit through 20 minutes of borefest that. This is exactly why youtube links with no supporting summary or details are banned now on ASR.

 

[Labjr]

The reviewer mentions a low level noise/hiss in the Fosi X5 but nothing about noise in the Project Phono Box which has worse performance. Like the Fosi X5, the Project Phono Box has AC line noise but uses a switching supply?

 

[restorer-john]

The reviewer mentions a low level noise/hiss in the Fosi X5 but nothing about noise in the Project Phono Box which has worse performance. Like the Fosi X5, the Project Phono Box has AC line noise but uses a switching supply?

Where in the video? I can't seem to find how to search the closed captions on a youtube video anymore.

 

[Labjr]

Where in the video? I can't seem to find how to search the closed captions on a youtube video anymore.

At about at the 18 minute mark.

 

[Endibol]

Fosi Audio Box X5 Phono Preamp for Turntable

Fosi Audio MM Turntable Phono Preamplifier. Compact design with 3.5MM AUX and RCA output.

fosiaudio.com

From that I get said US$ 131, rounded off. Maybe there’s a geolocator at work (Spain here). The „google“ result, embedded in the headline it tells it to be 110, though. Amazon listing, Europe again is 134, currency conversion considered.

Probably Amir's price is for the USA. For Europe they include approx 20% VAT, depending on the country.

 

[taleoffice]

Probably Amir's price is for the USA. For Europe they include approx 20% VAT, depending on the country.

Thats correct. In Europe, usualy we see the prices with VAT, so every news about new tech and its price on USA webs site I almost every time get excited, but then I always realise that I have to do the math. USA price ×1.2. And im on the ground again.

 

[Skeeter]

This is a very common approach in these products.

It has to do with safety I believe. It means they can leave the HV isolation safety certification to the PSU manufacturer and they’ve then only got to do deal with the low voltage stuff. Common practice as you say.

 

[GXAlan]

There was a guy who used to frequent another forum that tried to get away with a commercial product wherein he quoted the SnR at the maximum output of the preamp which was about 10V. So he had these outrageous SnR figures on MM phono inputs of 120 or 130 dB which of course was absolute nonsense.

Caveat Emptor.

Even TEAC makes claims like that where the residual noise published doesn’t make sense how they got the dynamic range value.

 

[Skeeter]

Interesting way to frig the numbers, but absolute bs on the part of the vendor.

 

[morillon]

Updated!
Amazon AU: https://www.amazon.com.au/dp/B0DLWM2YPD

I don't understand... sir fosi... you were quick to intervene in this post... but the two or three simple and basic but important questions about this phono are still unanswered...
Post in thread 'Fosi Audio Box X5 Phono Preamp Review' https://audiosciencereview.com/foru...box-x5-phono-preamp-review.59982/post-2198182


;-)

 

[Hamrin]

Mine goes back to Fosi...

Poor power supply... Noisy with audible hissing and whistling.
Also a perceivable hissing is audible from speakers when gain goes above 38dB, no matter which cart is connected.
Most important all these issues are there without any spinning vinyl.

I've used from a simple stupid Shure M75EB up to my Hana SH.
All these carts are well managed by my old Tisbury Domino and the Aiyima T3 Pro without any sort of noise.

Soundwise... Engaging, well defined, more focused than the T3 but less midrange weight compared to Tisbury.
A keeper on this side, but all this noise is not acceptable.

Bad unit?
Maybe...

 

[KSTR]

Even TEAC makes claims like that where the residual noise published doesn’t make sense how they got the dynamic range value.

View attachment 421462

Please read the provided specs in the manual, all relevant conditions are properly stated:

SNR is for rated output (not ref. 5mV@1kHz at input), shorted input, and A-weighted noise measurement (IHF-A / IEC 61672-1) .

 

[Heinrich]

I don't understand... sir fosi... you were quick to intervene in this post... but the two or three simple and basic but important questions about this phono are still unanswered...
Post in thread 'Fosi Audio Box X5 Phono Preamp Review' https://audiosciencereview.com/foru...box-x5-phono-preamp-review.59982/post-2198182


;-)

I accused fosi for an error on my side. Now I‘m tempted to defend this product.

First of all, the vinyl technology itself is a limiting factor so that everything less noisy beyond -60dB is wasted. One might argue that the technology involves silence when changing the disc, and you don‘t want noise to be heard then. A pretty weak argument, if evaluated in its details, me thinks.

Something similar shall be said regarding distortion. I had to learn that 10% HD3 in treble is just normal, while in the mids a minimum of 0,5% is considered excellent, but after meticulous optimization, mind you. Cost no object; you can‘t buy yourself out of these common boundaries.

I came to conclude that especially HD of the needle/pickup/disk aggregate is such bad, that we cannot evaluate quality by numbers anymore. It‘s not a quantifiable thing, but a sort of ‚character‘ who one may like or not, simply.

The X5 is lightyears away from interfering with that personal experience.

Add.: I‘ve not seen any MM pre specified regarding input noise current (current), which would resolve the raised issue here entirely. Btw, you‘re sure that the reactive part of the inductance has to be taken into the equation?

 

[Wesseling Audio Lab]

Mine goes back to Fosi...

Poor power supply... Noisy with audible hissing and whistling.
Also a perceivable hissing is audible from speakers when gain goes above 38dB, no matter which cart is connected.
Most important all these issues are there without any spinning vinyl.

I've used from a simple stupid Shure M75EB up to my Hana SH.
All these carts are well managed by my old Tisbury Domino and the Aiyima T3 Pro without any sort of noise.

Soundwise... Engaging, well defined, more focused than the T3 but less midrange weight compared to Tisbury.
A keeper on this side, but all this noise is not acceptable.

Bad unit?
Maybe...

Thanks! I'm guessing not a bad unit!
Check out Hifisonix XAltra phono pre - There is a well respected builder on DiyAudio that was selling 2 of them at a crazy low price

 

[cgallery]

I'm surprised that so many phono stages continue to use internal and external AC adapters instead of using DC adapters and additional rectification internally (if desired).

In other words, I'd just keep AC out of the phono stage's enclosure altogether.

 

[Hamrin]

Costs maybe?
Anyway if they pair fair ones there are no great issues, the Ayiyma's one is dead silent.
In the past I owned Rega and Schiit stages, with good AC adapters too.

The one I've found with Fosi is crap, buzzes like a nest of mosquitos just plugging it.