my advice: listen to it and be positively surprised
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Fosi Audio Box X5 Phono Preamp Review
- Thread starter amirm
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morillon
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if you are not in a hurry...maybe just wait for a richer and improved fosi.... fosi x5 and wiim ultra share a fairly limited approach in terms of adjustment characteristics..moreover, more than 6 months after its release it seems to me that the impedance and capacitance of the ultra has still not been specified... but do not be fooled, the ADC through which the ultra passes in analog, will remain very limited in analog input participates in the limits of the phono part of the ultra without much doubt
Newly made scan attached here.
So I received my X5 this morning and have been listening for a few hours today. It's definitely an improvement over the WiiM phono stage, purely from a noise / hiss perspective. When I first bought the Ultra I had a nightmare trying to eliminate electrical interference from its overly sensitive phono stage, but eventually was able to track it down to an Aiyima power supply that it didn't like. Since eliminating the Aiyima I've been pleased with the performance of the Ultra's phono stage, but it still does have some hiss at mid to high volume, which is noticeable with tracks where there are quiet moments or pauses.
The Fosi X5 is totally silent, with no audible noise / hiss all the way up to the max volume. It's well put together and a big step up in quality from their X2 tube phono preamp that I also own. I find the compact and understated design of the X5 quite attractive, although the orange led power light is a little too bright for my liking (very minor issue). My setup is Project Debut Carbon turntable with Ortofon 2M Red cartridge. The X5 is connected via RCA to the Ultra, then RCA out from the Ultra to my cheapo Musical Fidelity A1 clone, and finally on to the Wharfedale Diamond 9.1 bookshelf speakers. I'm using the lowest gain setting of 38dB as per recommendation in the X5's instruction manual, although I also had no audible noise when using 48dB setting.
It's quite difficult to be certain about differences in sound quality / signature because I can't easily switch back and forth to compare the Ultra to the X5, but I did feel like I noticed one clear difference. I'm particularly sensitive to trebles and found myself having to turn down the X5 due to harshness in that region at higher volumes, which is something I never had to do on the Ultra. Other possible perceived differences were that the vocals / mids on the X5 seemed a little quieter / further away, and the bass seemed a little louder / fuller but these could also just be my imagination.
Overall, the Fosi X5 is definitely a big improvement over the Ultra's phono stage from a noise perspective, and it's well built and looks good on the shelf. Thanks to WiiM it'll no hassle to EQ out the treble harshness to get to my own taste, so I'll definitely be keeping it.
The Fosi X5 is totally silent, with no audible noise / hiss all the way up to the max volume. It's well put together and a big step up in quality from their X2 tube phono preamp that I also own. I find the compact and understated design of the X5 quite attractive, although the orange led power light is a little too bright for my liking (very minor issue). My setup is Project Debut Carbon turntable with Ortofon 2M Red cartridge. The X5 is connected via RCA to the Ultra, then RCA out from the Ultra to my cheapo Musical Fidelity A1 clone, and finally on to the Wharfedale Diamond 9.1 bookshelf speakers. I'm using the lowest gain setting of 38dB as per recommendation in the X5's instruction manual, although I also had no audible noise when using 48dB setting.
It's quite difficult to be certain about differences in sound quality / signature because I can't easily switch back and forth to compare the Ultra to the X5, but I did feel like I noticed one clear difference. I'm particularly sensitive to trebles and found myself having to turn down the X5 due to harshness in that region at higher volumes, which is something I never had to do on the Ultra. Other possible perceived differences were that the vocals / mids on the X5 seemed a little quieter / further away, and the bass seemed a little louder / fuller but these could also just be my imagination.
Overall, the Fosi X5 is definitely a big improvement over the Ultra's phono stage from a noise perspective, and it's well built and looks good on the shelf. Thanks to WiiM it'll no hassle to EQ out the treble harshness to get to my own taste, so I'll definitely be keeping it.
Maybe it is the recommended minimum load. Won‘t do no harm in either case.
Additionally I found the op amp used to be opa1612, with noise parameters of vn about 1nV, but in 2pA. When connected to a high impedance mm pickup, the X5 may be noisier than something equipped with ol’ trusty ne5532. Don‘t they, again, offer obamp rolling …
But anyway, phono stages are way overrated. The mechanics of vinyl, pickup, tonearm etc is so much limited, to „hear“ a difference appears to me as a fantasy ;-)
Switchable gain, very good! Clean enclosure, nice format. Rolling the opamp with benefit.
Doesn't seem likely. I'm guessing that is a typo/misprint.
Similar positive experience here.
I bought the X5 to replace an old Clearaudio SmartPhono-1.
My goal was to have the possibility to set Gain, because I had to turn volume at least a quarter more up. (Result was at 66dB)
And at least the same quality for this setup: Pro-ject Xperience/Ortofon-RondoRed(MC) - Benchmark DAC2 - Audiophonics NCX500 - AudioPhysic Scorpio II.
After a few hours listening it sounds with a tad more clarity and openess. Full control overall.
Not any of the mentioned problems.
I bought the X5 to replace an old Clearaudio SmartPhono-1.
My goal was to have the possibility to set Gain, because I had to turn volume at least a quarter more up. (Result was at 66dB)
And at least the same quality for this setup: Pro-ject Xperience/Ortofon-RondoRed(MC) - Benchmark DAC2 - Audiophonics NCX500 - AudioPhysic Scorpio II.
After a few hours listening it sounds with a tad more clarity and openess. Full control overall.
Not any of the mentioned problems.
unknown_analoq
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I certainly wouldn't buy it, it's just cheap chines. HiFi quality is only being built.
In my opinion, there are a lot of flaws here from a design point of view. OPA1612 is not suitable for analog sound, I would rather choose older and higher quality components (LT1115, LT1128, LT1028). The RIAA correction will probably be in feedback, a better solution is passive correction in multiple stages. Poor quality PET capacitors with 2% tolerance are used. Personally, I would prefer to select capacitors with multiple pieces and select some below 1% and use high quality polypropylene. I also miss the input capacitance switch in MM mode and the input impedance switch in MC mode. The only positive is that the power supply is out of the box
Actidamp MK3 or Pearl3 is definitely a better choice....
In my opinion, there are a lot of flaws here from a design point of view. OPA1612 is not suitable for analog sound, I would rather choose older and higher quality components (LT1115, LT1128, LT1028). The RIAA correction will probably be in feedback, a better solution is passive correction in multiple stages. Poor quality PET capacitors with 2% tolerance are used. Personally, I would prefer to select capacitors with multiple pieces and select some below 1% and use high quality polypropylene. I also miss the input capacitance switch in MM mode and the input impedance switch in MC mode. The only positive is that the power supply is out of the box
Actidamp MK3 or Pearl3 is definitely a better choice....
Nope. Read Douglas Self book to know why.
The LT1028 would only be suitable for MC, not for MM due to its high current noise. Still the AD797 would be the better choice for MC.
This is just plain wrong. It leads to higher distortion and lower headroom.
Do you have the measurements of that products?
As I said, there is so much weight put on phono stages—because they are so easy and cheap? Technical excellence costs effectively nothing with that tiny signals, noiseless-ness is a matter of a few bucks extra, capers are fully risk free, a show piece. But 10% of harmonic distortion 3rd order from the cutting / pickup process are neglected, let alone tear and wear plus tolerances for tracking angles and what not.
Finally we hear lament on insufficient capacitor costs. Yeah, it is about precision, but it only gets so far
True, one should keep the record and needle clean. The more the better. Result will always be lacking, though—that‘s life
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Stock, it does include an NE5532; plus two OPA1612 elsewhere. I haven't opened mine; marked-up screen-grab here from JohnAudioTech video I posted back on page 7 of the thread.
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Excellent review!
I think I'll wait for the inevitable YouTube videos showing how to modify this to use a linear PSU, and how to install push-in sockets for the user to swap in desired cartridge loading components. That will eliminate what I'm seeing are the two biggest complaints.
I think I'll wait for the inevitable YouTube videos showing how to modify this to use a linear PSU, and how to install push-in sockets for the user to swap in desired cartridge loading components. That will eliminate what I'm seeing are the two biggest complaints.
OP
- Thread Starter
- #236
This *is* using a linear PSU. AC transformer is external which reduces magnetic coupling. The AC waveform is then internally rectified and regulated to DC.
I'm hung up on the lack of a HP filter too.
JSmith
Master Contributor
Sure, but there was nothing wrong with @Labjr's post here though... it's just a teardown video, in the correct thread, with a short explanation on how the video relates to the thread. Not sure what other summary could be given... I just skipped to the part when he opened it up, then was annoyed he didn't hold the board closer to the camera, as could barely see any of it clearly. The rest is just waffle really anyway... well to me.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.
Not like it was just an unrelated video dump in this case. Good to point out to other members anyway who may not have seen the rule, so not all is lost.
JSmith
KSTR
Major Contributor
The socketed 5532 DIP is sort of a dummy opamp, actually not needed (other than for part of switchable gains maybe) but designed in to appeal to the opamp-rollers, IMHO.
The 1612 are on the input and fiter, and not the best choice for MM.
Skeeter
Member
I would say the exact opposite. Some of the devices you have proposed don’t work well in MM phono preamps. I don’t know how you can say feedback RIAA is inferior to passive EQ. There’s always a noise or overload trade off to make with passive EQ. You don’t have those trade offs to make with all active EQ. The reason why a lot of these phono preamps have low overload margins (and ones that vary with frequency) is because they use passive EQ. On +-15 V rails, all active will give >20 dB O/L across the whole audio band. This BTW means you have to drive the phono preamp with an inverse RIAA signal so the stimulus follows the same frequency response profile coming off the vinyl. There’s just far too much nonsense around passive EQ.I certainly wouldn't buy it, it's just cheap chines. HiFi quality is only being built.
In my opinion, there are a lot of flaws here from a design point of view. OPA1612 is not suitable for analog sound, I would rather choose older and higher quality components (LT1115, LT1128, LT1028). The RIAA correction will probably be in feedback, a better solution is passive correction in multiple stages. Poor quality PET capacitors with 2% tolerance are used. Personally, I would prefer to select capacitors with multiple pieces and select some below 1% and use high quality polypropylene. I also miss the input capacitance switch in MM mode and the input impedance switch in MC mode. The only positive is that the power supply is out of the box
Actidamp MK3 or Pearl3 is definitely a better choice....
For a low cost phono amp like the Fosi, I would use the OPA1612 for MC head amp duty and the NE553x devices for MM and EQ duty. The 1612 has very low input noise voltage (about 1nV/rt Hz) but high noise current making it unsuitable for MM duty. The 5532 is well suited to MM duty.
Selecting capacitors for a product that sells for $109 isn’t economically feasible. Easier to use NP0/COG 1% types. On larger values, you can have 1 or 2 devices at 2% and still get good RIAA conformance. That said, the Fosi RIAA response looks pretty damn good to me.
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