ifi Zen Phono Review (phono stage)

[WDeranged]

@Thorsten Loesch I heard you designed this pre-amp. I love the Zen Phono, I tried three or four similarly priced units and nothing sounded as good to me. Have you any opinion on whether the low headroom really does accentuate pops and clicks? No one seems to agree on this.

 

[Thorsten Loesch]

@Thorsten Loesch I heard you designed this pre-amp.

I did.

Have you any opinion on whether the low headroom really does accentuate pops and clicks? No one seems to agree on this.

It doesn't have "low headroom".

For LP the 0dB cutting velocity is 5cm/s and "absolute max" (what we call 0dBFS) is 25cm/s.

It is hard to cut 25cm/s, there are very few exceptions. If you have dust or a scratch that equals or exceeds 25cm/s there is a good chance it will make the needle jump. I would not worry about audibility at that point, it will be very audible no matter what phono stage is used

If the gain is set correctly to match a modern line source we expect thus -8dBV @ 5cm/S and +6dBV @ 25cm/s, overload is at +20dBV (SE) and so we have 14dB headroom over what is necessary.

The corresponding nominal cartridge outputs are -80dBV (0.1mV @ 72dB gain) -68dBV (0.4mV @ 60dB gain, -56dBV (1.6mV @ 48dB gain) and -44dBV (6.2mV @36dB gain) all with 14dB Headroom relative to 25cm/s and 28dB over 5cm/s.

I think these are generally very practical "design center" levels with good overload margins even for outlier cartridges and excellent ones for cartridges in the "design centre".

Unless your ticks or pops are much louder than the loudest signals that can be cut onto LP headroom is not going be an issue, if they are louder, well, I would not worry about the phono stage.

Thor

 

[thyristor]

I did.

Why did you choose Input impedance of 1K Ohms for MC Low (60dB gain)? Recommended load impedance for most Low MC cartridges is 100 Ohms.

 

[Thorsten Loesch]

Why did you choose Input impedance of 1K Ohms for MC Low (60dB gain)? Recommended load impedance for most Low MC cartridges is 100 Ohms.

What is recommended varies widely. I have seen > 10 Ohm, > 20 Ohm all the way to very precise Resistance and Capacitance values.

The Zen Phono is designed originally as 99 USD entry level phono stage, which impedance based cartridge detection and automatic configuration of gain and load.

In other words a "phono stage for dummies".

The automatic configuration (with manual override if auto goes off wrong) was fully developed and tested, but deleted before release as "too advanced" for an entry level product, totally ignoring that the likely purchaser will be buying his first real turntable, cartridge and phono stage (after an all plastic bluetooth turntable) who has no clue how to set up a phono system.

Incidentally this is the "AI" that was somehow misapplied to the so called "elliptic filter" subsonic filter. That operates on the principle that the big subsonic noise is vertical from not completely flat (warped) records. Now for a number of reasons, vertical signals on the LP are in opposite polarity, to if you switch to mono the warped record related subsonic content disappears.

When cutting records, a so-called elliptical filter is used to blend low bass to mono. This is needed to allow the record to be cut. The "elliptical" comes from the oscilloscope picture of a stereo signal on X & Y. Mono shows a straight line, perfect channel separation and 100% pan shows a circle, which is not possible to cut at low frequencies. The "elliptical filter" keeps the oscilloscope picture "elliptical".

By selecting a blend frequency lower than the lowest setting of the "elliptical filter" for playback and blending ultra-low frequencies to Mono allows to preserve both the LF information cut into the record (in other words a warp/rumble filter that does not emasculates the bass response) AND the spatial information remaining after cutting the LP Masters.

Anyway, back to 1k loading at 60dB Gain.

The number of MC Pickups you might use with a 99 USD Phono Stage, even one that punches well above it's weight, is limited.

Basically the most likely MC's are Ortofon Quintet, Denon DL-103/103R and especially the Denon's; which in my view are among the absolutely best MC Pickup's ANY money can buy (if matched with the correct arm and installed correctly); work better with a 1k load than 100 Ohm.

While some advocate "no loading" and others advocate to impedance match the cartridge or even to use a virtual short circuit ("current mode"), I find modest loading is most likely to work universally.

Thor

 

[thyristor]

Basically the most likely MC's are Ortofon Quintet, Denon DL-103/103R and especially the Denon's; which in my view are among the absolutely best MC Pickup's ANY money can buy (if matched with the correct arm and installed correctly); work better with a 1k load than 100 Ohm.

Denon DL-103 has very low 0,25 mV output so most people would probably use MC V Low that's 72dB and 110 Ohm. Why 1K for 60dB and 110 Ohm for 72dB?

I use Zen Phono with Technics SL-1500C and AT-OC9XML. Cartridge has 0,4mV output and I use 60dB gain for it. The sound is excellent and Zen Phono is very quiet. I haven't bought a more expensive preamp because it's very hard to justify the price. Diminishing returns.

I'm a bit confused about your explanation of AI Sub-sonic filter. When it's on does the production version of Zen Phono have this "impedance based cartridge detection and automatic configuration of gain and load?"

I haven't used the Sub-sonic filter as I don't have warped records.

 

[Bob from Florida]

Denon DL-103 has very low 0,25 mV output so most people would probably use MC V Low that's 72dB and 110 Ohm. Why 1K for 60dB and 110 Ohm for 72dB?

I use Zen Phono with Technics SL-1500C and AT-OC9XML. Cartridge has 0,4mV output and I use 60dB gain for it. The sound is excellent and Zen Phono is very quiet. I haven't bought a more expensive preamp because it's very hard to justify the price. Diminishing returns.

I'm a bit confused about your explanation of AI Sub-sonic filter. When it's on does the production version of Zen Phono have this "impedance based cartridge detection and automatic configuration of gain and load?"

I haven't used the Sub-sonic filter as I don't have warped records.

The Denon 103 I have says .39 MV on its paperwork. The resistance of the coils is 40 ohms. The rule of thumb is at least 10 times the coil resistance for the load. So you want at least 400 ohms load for a 103 and with 60 db of gain - my 103 gives .39 volts at the output of the Zen. Going too low a load resistance tilts your tonal balance towards emphasized bass with little treble response. Too high a resistive load causes the opposite - no bass and lots of treble detail. You see a lot of phono stages with 100 ohm MC inputs and you need to pick the appropriate cartridge with coil resistance under 10 ohms. The choices for the Zen are brilliant and you have additional flexibility if you can use the balanced output - it adds 6 db of gain for each setting - ie 60 db becomes 66 which helps the 103 for example.

 

[Thorsten Loesch]

Denon DL-103 has very low 0,25 mV output so most people would probably use MC V Low that's 72dB and 110 Ohm. Why 1K for 60dB and 110 Ohm for 72dB?

The 103 is nearly 0.4mV @ 5cm/S. At 25cm/S (the vinyl equivalent of "0dBFs") it will be 2mV and thus 2V out from the phono. So a loud cut LP will be comparable in loudness to a CD with some decent dynamic range.

I'm a bit confused about your explanation of AI Sub-sonic filter.

There is no "AI". The actual AI tech was deleted before releasing the product. The positions for the components forming the hardware still exist on the PCB but the components are not fitted and I suspect the MCU software doesn't support it.

When it's on does the production version of Zen Phono have this "impedance based cartridge detection and automatic configuration of gain and load?"

No, this function was deleted.

I haven't used the Sub-sonic filter as I don't have warped records.

If you do get one, try, it works great. And totally without artificial intelligence, just with common sense.

Thor

 

[Bernard23]

I've just tried one in my system: Technics SL-1800 with an AT MV95ML and a Technics 270C with a black diamond eliiptical stylus. I'm comparing it to the onboard phono of my Yamaha A-S501 and an old Cambridge Audio 540p amp. I think it sounds better than the CA, and pretty sure they both sound a little better than the Yamaha; but I can't be completely certain as it takes too long to disconnect and reconnect them quickly. I get a little hum with the AT, and less using the 270C, in both case it's below the noise floor of vinyl. I like the sub filter (main reason I got it tbh) as I have a very bouncy suspended wooden floor, and tiptoeing across the room sends my speakers into a flapping frenzy.

 

[Thorsten Loesch]

I've just tried one in my system: Technics SL-1800 with an AT MV95ML and a Technics 270C with a black diamond eliiptical stylus. I'm comparing it to the onboard phono of my Yamaha A-S501 and an old Cambridge Audio 540p amp. I think it sounds better than the CA, and pretty sure they both sound a little better than the Yamaha; but I can't be completely certain as it takes too long to disconnect and reconnect them quickly. I get a little hum with the AT, and less using the 270C, in both case it's below the noise floor of vinyl. I like the sub filter (main reason I got it tbh) as I have a very bouncy suspended wooden floor, and tiptoeing across the room sends my speakers into a flapping frenzy.

If you get hum, make sure the ground wire from the turntable is connected and if hum persists, connect the ground post on the Zen Phono to mains earth.

Thor

 

[Bernard23]

If you get hum, make sure the ground wire from the turntable is connected and if hum persists, connect the ground post on the Zen Phono to mains earth.

Thor

TT is grounded, tbh its a very low level.

 

[Thorsten Loesch]

TT is grounded, tbh its a very low level.

There should be no hum whatsoever.

Is your Audio System Earthed anywhere? Or are all Plug's 2-Pin?

Thor

 

[Bernard23]

There should be no hum whatsoever.

Is your Audio System Earthed anywhere? Or are all Plug's 2-Pin?

Thor

All units are earthed - UK plugs.

 

[Bernard23]

I'm looking at upgrading my cart, and in keeping with the vintage technics vibe, considering a technics 205C II L from the 70s, which is described as a low Z version, and would be combined with a Jico SAS stylus - estimated o/p of 1.0 - 1.5mv. Presumably one of the higher gain settings should cope with that?

 

[LtMandella]

My IFI Zen Phono is one of the best value for $$ purchases I have made in HIFI in 50 years of buying. Right up there with the original Boston Acoustics A40 speakers, original NAD 3020 amp, and Grado SR headphones.
It sounds great in my Music Hall MF7.1 TT, and the various gain options allowed me to buy my first Audio Technica MC cartridge. My gear is fairly high end, and revealing but sweet (Grounded Grid preamp, Tube OTL or Class A power amp, Ref 3A DeCapo I speakers) and I can listen for many hours in the day with no listener fatigue. The IFI Zen fits right in! The sound is perfectly balanced, excellent bass and highs, very little sibilance, rumble filter, and perfectly quiet. One of the best purchases I have made.

Regarding clicks and pops: In my 500+ LP collection (about 1/2 purchased used) I have eliminated all audible surface noise _except_ for the rare scratch. How? I bought a generic ultrasonic tub bath cleaner that was bundled with a small motorized LP holder/rotator that mounts on the sidewall of the cleaner tub. It works FANTASTICALLY. Unbelievable how much junk it removes from the grooves for even brand new records. You won't believe how quiet your LPs are after you ultrasonic clean them...

 

[Bernard23]

A week in or so and I've no complaints about it. Does the job for me.

 

[vsrrr]

What is recommended varies widely. I have seen > 10 Ohm, > 20 Ohm all the way to very precise Resistance and Capacitance values.

The Zen Phono is designed originally as 99 USD entry level phono stage, which impedance based cartridge detection and automatic configuration of gain and load.

In other words a "phono stage for dummies".

The automatic configuration (with manual override if auto goes off wrong) was fully developed and tested, but deleted before release as "too advanced" for an entry level product, totally ignoring that the likely purchaser will be buying his first real turntable, cartridge and phono stage (after an all plastic bluetooth turntable) who has no clue how to set up a phono system.

Incidentally this is the "AI" that was somehow misapplied to the so called "elliptic filter" subsonic filter. That operates on the principle that the big subsonic noise is vertical from not completely flat (warped) records. Now for a number of reasons, vertical signals on the LP are in opposite polarity, to if you switch to mono the warped record related subsonic content disappears.

When cutting records, a so-called elliptical filter is used to blend low bass to mono. This is needed to allow the record to be cut. The "elliptical" comes from the oscilloscope picture of a stereo signal on X & Y. Mono shows a straight line, perfect channel separation and 100% pan shows a circle, which is not possible to cut at low frequencies. The "elliptical filter" keeps the oscilloscope picture "elliptical".

By selecting a blend frequency lower than the lowest setting of the "elliptical filter" for playback and blending ultra-low frequencies to Mono allows to preserve both the LF information cut into the record (in other words a warp/rumble filter that does not emasculates the bass response) AND the spatial information remaining after cutting the LP Masters.

Anyway, back to 1k loading at 60dB Gain.

The number of MC Pickups you might use with a 99 USD Phono Stage, even one that punches well above it's weight, is limited.

Basically the most likely MC's are Ortofon Quintet, Denon DL-103/103R and especially the Denon's; which in my view are among the absolutely best MC Pickup's ANY money can buy (if matched with the correct arm and installed correctly); work better with a 1k load than 100 Ohm.

While some advocate "no loading" and others advocate to impedance match the cartridge or even to use a virtual short circuit ("current mode"), I find modest loading is most likely to work universally.

Thor

As someone who's been looking for a cartridge upgrade for my SL-1200 and iFi Zen Phono (with balanced cable upgrade), it sounds* like you're recommending the Denon 103/r as a great match? Has anyone else tried this specific combination?

I'm not nearly as technically savvy as most ASR members as it relates to cartridge/loading/etc. (a subject I've always been confused by), which has made me hesitant to upgrade cartridges. I'd greatly appreciate it anyone could point me in the right direction to self-educate so I can find the perfect match for the Zen Phono!

 

[AaronJ]

As someone who's been looking for a cartridge upgrade for my SL-1200 and iFi Zen Phono (with balanced cable upgrade), it sounds* like you're recommending the Denon 103/r as a great match? Has anyone else tried this specific combination?

I'm not nearly as technically savvy as most ASR members as it relates to cartridge/loading/etc. (a subject I've always been confused by), which has made me hesitant to upgrade cartridges. I'd greatly appreciate it anyone could point me in the right direction to self-educate so I can find the perfect match for the Zen Phono!

I've not used a DL-103 on my Technics, but I've read all over the place that it is not a good match for the Technics tonearm without a bunch of modification. Careful there if you decide to go that route. The performance will probably not be limited by the iFi Zen Phono.

 

[MaxwellsEq]

I'd greatly appreciate it anyone could point me in the right direction to self-educate so I can find the perfect match for the Zen Phono

Cartridge matching has a some mechanical aspects and some electrical aspects.
Mechanical: obviously if the cartridge is too tall or short for your arm, the vertical alignment of the stylus in the groove may be suboptimal. Some arms let you adjust this. More importantly, if the cartridge compliance doesn't match the mass of your arm, there can be problems, which you can't adjust for.
Electrical: moving magnet and moving iron are usually high output, moving coil is usually low output. You need a lot more gain for a moving coil cartridge. Impedance matching has a less significant impact. MM standard is usually 47kOhms and 100 to 200pF. MCs prefer to see about 100Ohms.

 

[Bernard23]

Does the load impedance change with gain settings, or is it fixed across mm through to ultra low MC?

 

[Bob from Florida]

MCs prefer to see about 100Ohms.

The loading depends on the moving coil resistance - greater than or equal to 10 times the coil resistance. Many moving coils are 30,40, or 50 ohms and work better at higher load resistances than 100 ohms.