restorer-john
Grand Contributor
It's more important to have a correct load on the front end for MM, not a 20R AP generator source impedance.
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Fosi Audio Box X5 Phono Preamp Review
- Thread starter amirm
- Start date
It's more important to have a correct load on the front end for MM, not a 20R AP generator source impedance.
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Who knows, maybe Fosi will come out with an upmarket model with capacitance and loading controls and a subsonic filter? Maybe a mono button to decrease surface noise when playing mono records too. Their design has great bones and they can differentiate future models by piling on features.
AudioSceptic
Major Contributor
I suspect it will be worse than most of us imagine...
Is that documented anywhere?
Even after repeated requests, I don't see a reply from Fosi about this, and the Fosi site only has this for specs:
Specifications
- Input Mode: MM+MC RCA
- Output Mode: RCA
- THD: ≤0.009%
- SNR: ≥ 92dB
- Device Dimension: 4.1 x 6.5 x 1.4 inches
- Power Supply: 16V/1A
No user manual to read either. (Hmmm....)
Also,
Multiple Gain Settings: With 4-Level gain adjustment settings of 38/48/56/66dB, the preamplifier accommodates both MM & MC cartridge types
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Introducing the Phono Cartridge Measurement Library
Skip to the index. After years of development we are finally launching our phono cartridge measurement library. These measurements were created using the brilliant cartridge response python script written by @scott wurcer and @JP. Information about its origins can be found in the following...
www.audiosciencereview.com
If we look at this.
50 dB H2 distortion for a Shure V15 VMR with a Wayne Kirkwood Flat MM using a clearaudio test disc.
The CBS test disc was just 30 dB distortion
Introducing the Phono Cartridge Measurement Library
That’s a boron pipe cantilever?
www.audiosciencereview.com
Tonton_ZEeD
Member
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
.
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
.
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There is a manual - No data for C, Z.
Thermionics
Member
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Loading can be easily accommodated via 2-way RCA splitters and loading plugs (as long as you are comfortable in doing a little DIY), but, yes, capacitance loading would be a nice-to-have (if FOSI Audio is listening). Maybe via sliders or jumpers on the underside?
It's a simple 'how to'. Not really documentation.
You know, I think it's funny that we have a phono stage being judged on its superior SINAD, which you're extremely unlikely to get to hear because the surface noise from any record is going to absolutely bury the noise from the preamp. This preamp has really really low noise, which is great, but it lacks important features such as variable loading for MC cartridges and any useful documentation that would be helpful for cartidge-tonearm-cable matching.
Phonograph playback is an electro-mechanical system. The final quality of that playback system is going to be far more dependent on the cartridge-tonearm-turntable performance than on the performance of the phono correction/preamplifier stage. Unless there is something horribly wrong with the phono stage in use, I seriously doubt anyone with a U-Turn Orbit turntable is going to hear the difference between its built in phono stage and this Fosi Audio wonder preamp.
Had Fosi included capacitance and impedance loading options, I would think differently. Since phono cartridges definitely sound different into different C and Z loads, that would have made the product more useful and widely compatible.
Grado carts sound very good into 10k ohm load.
AT carts do not like high capacitance loads. 250pF max, I'd say, and that would include the roughly 150pF to 200pF from the tonearm wiring and turntable to preamp interconnect cable.
Vintage Shure, Stanton and Pickering MM cartridges tend to be higher in coil inductance (L) and internal series resistance (Rseries) and are supposed to work better into higher C loading. Some say they sound better into a higher than 47k load at the preamp input.
The Denon DL110 HOMC cartridge works well into as low as 1.5k ohms (its Zout is only 150R or so). It sounds more harsh and brittle into the standard 47k ohm load. More pleasant (to my ears, at least) into 1500 ohms.
The Denon DL103 MC cart works best into about 400 ohms (its Zout is about 40 ohms). However, many more expensive MC carts have Zout of 10 ohms or less, and those work well into a smaller 100 ohm load.
Unlike digital sources, there is no standard for C, L or Z in phono preamps, other than the 47k ohm input loading for MM carts. There's no standard at all for MC carts.
Anyway, it's fun to kibbitz about audio gear.
OP
- Thread Starter
- #111
You best get out of audio market as this is by far the norm, than the exception. PDF? you must be kidding me...
KSTR
Major Contributor
There is absolutely no excuse to not provide the data as it is available anyway and making a PDF document takes no more than maybe one hour of work (less if you have templates to build on). If the data isn't available in house, all bets are off.
Most competitors offer complete data and manuals and those are easly accessible and there are downloadable versions, for example for the $100 Pro-Ject Phono Box.
Won't most of the result there be dependent on the quality of the test record, on the deck, and on the cartridge. Far more so than the phono pre.
Pro devices come with good documentation, e.g. RME's ADI2/4 pro that has a phono (MM) input
Also, Park Audio's documentation is decent
Of course, they are not in the same category (price/functionality)..
Edit (device with comparable price): the ART Phono Plus Phono Preamp & Audio Interface
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I’ve been playing LP records for 48 years. The only seriously warped records I’ve seen were that way from day one. None of the flat ones ever warped themselves.
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That’s what most people say. The test sheet from the factory packaged in mine spec’ed the test condition as 1k ohms. I listened at 1k and 400 and all I could hear was the reduced volume. Output into 1k ohms , according to the test sheet .39mv. I set it at 1k.
Interesting phenomenon on these threads. A test of a phono stage followed by a discussion by people that like to listen to their vinyl records, interrupted by folks telling us how foolish we are. If you don’t play with vinyl, don’t ever want to play a vinyl record again, and think anyone that does so is a fool, why did you even read the review? I ride motorcycles. I own 4 of them. There are types and brands of motorcycles and riders that I think are foolish. I don’t feel compelled to monitor their discussions and occasionally jump in to tell them how ridiculous they are.
renaudrenaud
Major Contributor
It is certainly the most hated Hanpin turntable.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
You can inform yourself reading about the subject here
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I would agree. What can be inserted between the AP generator and the input to simulate a MM and MC generators?
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