Fosi Audio Box X5 Phono Preamp Review

[EJ3]

This is why I don't have any car. Life is simpler and I don't waste my time this way.

Do you think it's doable more posts about the X5 and less posts about the art of commercial war.

Well, so far, I haven't had the X5 do anything to discuss.
It just seems to do what it is supposed to.
If it does something else, I'll post about it.
As to "commercial war", never heard of it.
I did not start a conversation about anything called that.
Nor did anyone else.

 

[guy48065]

It says he halts plan to put tariffs on low-value packages.

I'm sorry--I missed "duties". I thought you were commenting on halted shipping.

 

[steve f]

I finally plugged in the little Fosi X5, bought because of Amir’s review and all of your posts. Nothing happened. I checked my connections, still nothing. Then a revelation. That little orange thingy on the front is a power switch, not an indicator light. I pressed it and my Grateful Dead record played through my system. Amazing how stuff works when you actually turn it on. LOL.

My review is that it’s a damn good unit. It is exceptionally quiet and EQ appears to be spot on. (The rest of the system is a B&O linear tracking table with a Soundsmith cartridge, Morrison preamp, ATI amps, and Linkwitz LX521.4 speakers with ASP. Not shabby stuff.)

 

[Northa40]

Hello ASR community !

My friends gift me a audio-technica at-lp60x, my first turntable ! Is this pre-amplifier a good investiment from the internal pre-amp from my turntable ?

Sorry my english is not perfect .

Hi ZEeD I have had a FOSI BOX 4 and thought is was great I would certainly add it to the AT-LP60. My thoughts on the LP60 are that it is better than a Crosley and any other suitcase type record player and a great way to get into the hoby. If you purchase the X5 you can always use it for another turntable down the road. There are people in the comments that will say that its not worth it but for $110 USD I think it is worth a shot. If you were going to use it for a moving coil cartridge than there a better choices. Cheers!

 

[cfwotzka]

people are speechless now it seems....

 

[StevenSGT98]

people are speechless now it seems....

Nothing to complain about.

 

[Laika2]

One thing I am seeing on Amazon US reviews, two so far and these are clearly real reviews, very detailed. Both loved the unit but both units lost a channel within a week or two. In my experience most HT electronics go out fast due to a defect or last their reasonable lifetime. My advice if this worries you and you can still return it is to run the heck out of it for a few weeks. Can't speak for you good people but if it ran solid for a few weeks of heavy use I would be in my comfort zone. I have 3, 1 has about 60 hours on it at reference. The 2nd has about 30 hours and the third is in the FS section. (Not a plug, I must be honest it's got very little playtime, could be in the premature channel loss ticking bomb just waiting to happen)

 

[pma]

Relays, relay contact material and quality ….

 

[EJ3]

Hi ZEeD I have had a FOSI BOX 4 and thought is was great I would certainly add it to the AT-LP60. My thoughts on the LP60 are that it is better than a Crosley and any other suitcase type record player and a great way to get into the hoby. If you purchase the X5 you can always use it for another turntable down the road. There are people in the comments that will say that its not worth it but for $110 USD I think it is worth a shot. If you were going to use it for a moving coil cartridge than there a better choices. Cheers!

I think that the record player (nicer. larger, all in one with internal speakers) that I had in 1964 when I was 5 was better sounding than anything in that video.
It might have tracked in the 3 gram range,
Since I started buying my own stereo gear in 1974 (at 17) I have had nothing that sounded that bad or that used more than 1.5 grams of tracking force.
I also have ZERO experience with 7" records, so I do not know their requirements.
But based on what I heard, they would have never had one of my styli touching them (scratches, etc).
As to warped records, placing them between 2 appropriate sized pieces of glass, let them warm gently in the sun, flip over & do the same for half that time & then leave them between the glass to cool down to room temp MAY help.
If not, it goes into a display window to the sun with the curled record collection.
To each there own, I guess.

 

[dymax]

Regarding the input capacitance -- I emailed them about it a few days ago. Per their response, it's 150pF, which aligns with nagsters measurements .

 

[morillon]

Regarding the input capacitance -- I emailed them about it a few days ago. Per their response, it's 150pF, which aligns with nagsters measurements .

hoping that on their next products, the basic value will not exceed 100pf (see we will propose an even lower value before adjustments...)

 

[EJ3]

hoping that on their next products, the basic value will not exceed 100pf (see we will propose an even lower value before adjustments...)

Why that particular value (just curious, not because I have a different idea of what the value should be [because I don't have any idea of what the value should be or why it should be any particular value])?

 

[morillon]

Why that particular value (just curious, not because I have a different idea of what the value should be [because I don't have any idea of what the value should be or why it should be any particular value])?

To do this properly, you would need to have at least 150 pico to then modulate by adding upwards...but with the preamp cumulation plus all the wiring...so it is too high as a minimum...

 

[EJ3]

To do this properly, you would need to have at least 150 pico to then modulate by adding upwards...but with the preamp cumulation plus all the wiring...so it is too high as a minimum...

Thanks.
I have this Fosi for one of my systems (For my main system I use an Apt/Holman preamp that has adjustable capacitance).
I have heard that this spec may be differently optimal for different carts? (I have never experimented with this idea).
But I have heard that for my carts that it should be higher (so I would likely have to somehow add capacitance? [n)
My carts are in this family of carts (I have NOS & JICO styli):

• V15 Type IV 1978-1982
• V15 Type V 1982-1983
• V15 Type V-MR 1983-1993

 

[JP]

Depends on the cart - I’ve some where around 50pF total is ideal. Easy to add, but you can’t take away, so I’d want the lowest possible. My current phono stage is about 10pF.

 

[Muddywaters]

Why that particular value (just curious, not because I have a different idea of what the value should be [because I don't have any idea of what the value should be or why it should be any particular value])?

Moving magnet cartridges are particularly sensitive to capacitance loading. It impacts their upper end frequency response. Thus the total capacitance the cartridge sees including the tonearm wiring, tonearm cable and the phonostage input combined is important if you desire the flattest response possible. Using good low pf cables you’re stuck with what your phonostage has.

If you look at the thread on cartridge fr database all the posts should indicate the capacitance used generating the data.

As JP notes above lower is better because you can add it for carts that need higher but difficult to impossible to lower.

 

[dymax]

To do this properly, you would need to have at least 150 pico to then modulate by adding upwards...but with the preamp cumulation plus all the wiring...so it is too high as a minimum...

It's a little high but I think with some decent (not necessarily expensive) low pF cables (BJC LC-2 are ~11pF/ft, FosPower 2 (really cheap, dual shielding) are ~15pF/ft per another forum) + tonearm wiring, you could still be in spec for AT-VM95X carts: 100 - 200 pf, if that were someones goal. I understand cart specs vary; used the AT-VM95X because they're so common.

 

[JP]

Thanks.
I have this Fosi for one of my systems (For my main system I use an Apt/Holman preamp that has adjustable capacitance).
I have heard that this spec may be differently optimal for different carts? (I have never experimented with this idea).
But I have heard that for my carts that it should be higher (so I would likely have to somehow add capacitance? [n)
My carts are in this family of carts (I have NOS & JICO styli):

• V15 Type IV 1978-1982
• V15 Type V 1982-1983
• V15 Type V-MR 1983-1993

With MM you’re mostly dealing with an electrical resonance where lower C will reduce the resonance, however too much can form a low-pass that rolls-off the response. This load plot shows both:

However you also have the mechanical properties that are set, so the electrical can compensate for that. With your VMR the electrical resonance is use to raise he response to be flatter. That cart wants to see around 300pF or a bit more. AT-150MLX is the opposite - as low as you can go for the one. No more than 150pF, but 50pF gives a flatter response.

Resistive loading can also be changed to tailor the response. Example here.

 

[EJ3]

With MM you’re mostly dealing with an electrical resonance where lower C will reduce the resonance, however too much can form a low-pass that rolls-off the response. This load plot shows both:

However you also have the mechanical properties that are set, so the electrical can compensate for that. With your VMR the electrical resonance is use to raise he response to be flatter. That cart wants to see around 300pF or a bit more. AT-150MLX is the opposite - as low as you can go for the one. No more than 150pF, but 50pF gives a flatter response.

Resistive loading can also be changed to tailor the response. Example here.

When I went to the forum, I remembered being there before (I have some memory fog from 2 X having Covid & a really, really bad car accident that has taken me 18 months to be walking some again). It looks like I need to be somewhere around 325-400 depending on the SHURE cart that I am using (all T4P's for my Technics SL-M3). The other TT is my mother's a DUAL 1229 with a V15 IV on it (she's 91 & managed to break the stylus, I told her to let me clean it from now on). But I have to get her another one.
Anyway, thanks for getting me back to forum where I need to be for this.

 

[morillon]

Depends on the cart - I’ve some where around 50pF total is ideal. Easy to add, but you can’t take away, so I’d want the lowest possible. My current phono stage is about 10pF.

it's not a common value...what cartdrige?
very low capacitance cable very short?...

certainly the lower the better, if offered on this basis of the adjustments...
but a 50, (at a pinch 100 if low capacitance cables) would already be not bad...