Parasound Zphono Phono Preamplifier Review

[Skeeter]

This is a review and detailed measurements of the Parasound Zphono phono stage. It is on kind loan from a member and costs US $200. There are also versions with USB and ADC (for ripping Vinyl) and higher-end version with more control.

The look is unmistakably Parasound which is to say somewhat industrial and plain:

View attachment 81925

The back panel shows the included, voltage selectable AC mains which I appreciate:

View attachment 81926

As you see the input gain can be changed from moving magnet (MM) to moving coil (MC).

Interesting to see an AC mains polarity switch. Not sure of the safety of that but I guess if you have a hum, it is worth having a switch like this to at least troubleshoot the problem.

Overall, the Zphono is a business-line phono amplifier with solid construction.

Phono Stage Audio Measurements
Let's start with our usual 1 kHz dashboard view with moving magnet setting:

View attachment 81927

As with all good phono stages, there is no visible distortion. So what sets SINAD is simply noise which in this case rises enough to set it to 75 dB. This puts the Zphono in the middle of the pack:

View attachment 81928

Moving Coil setting with input changed to 0.8 millivolts naturally degrades performance due to increased noise that goes with increased gain:

View attachment 81930

Since LP grove noise is likely to be higher than the preamp, the next test becomes more important which is the RIAA equalization:
View attachment 81931

We see nearly flat response which is what we want to have (i.e. no tonality imparted on behalf of the phono stage). A rumble filter would be nice but that is reserved for their higher end unit.

Let's sweep the input voltage and see where hard clipping occurs as this will impact how bad LP pops and clicks will sound:

View attachment 81932

This is better than a lot of budget phono preamps. But let's see if that is frequency dependend:

View attachment 81933

So no concern there.

We can see the same when we sweep the frequency fully:

View attachment 81934


Conclusions
The Parasound Zphono is not sexy but solidly delivers on basic functionality of a budget phono stage. Not much fault can be found in the measurements other than perhaps level of noise.

Overall I am happy to recommend the Parasound Zphono.


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As always, questions, comments, recommendations, etc. are welcome.

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[infinitesymphony]

First, very few mics do above 20k, there designed that way fior a reason, theres nothing audible to record up there. Since thats the only reason people say vinyl is better than CD, its not.

There's quite a bit of natural high-frequency information above 20 KHz, mostly from metal objects and instruments. Jangling keys have 68% of their power above 20 KHz:

https://www.cco.caltech.edu/~boyk/spectra/spectra.htm

A number of small-diaphragm condenser microphones are flat to 40 KHz and taper beyond (DPA, Earthworks, Schoeps, et al).

As far as lodness wars, Compressors have been used in recording for 70 years and tape has been used for limitting for longer. You cant record without limiting the dynamic range.

With quality ADCs and 24-bit or higher resolution, compression and limiting on the way in are no longer necessary.

 

[restorer-john]

There's quite a bit of natural high-frequency information above 20 KHz, mostly from metal objects and instruments. Jangling keys have 68% of their power above 20 KHz:

I wear two set of earplugs/muffs when using my air compressor for cleaning out dust or attching/detaching the hose under pressure. It can make your ears ring instantly otherwise. A significant proportion of the overall level is well into the ultrasonic range.

here's a interesting little toy, maybe get an anti gravity device while you are at it? https://www.amazing1.com/ultrasonics.html

 

[PuX]

As far as lodness wars, Compressors have been used in recording for 70 years and tape has been used for limitting for longer. You cant record without limiting the dynamic range. Your statement aboy compressing vinyl is just plane wrong.

it's all about how much you can compress the sound.
you absolutely can not do the same level on compression on vinyl that is being done on current CDs/digital/radio versions of the same tracks. don't believe me? compare a digital recording of vinyl version of Metallica's latest album with the CD version. vinyl has some breathing room. most likely it has something to do with how vinyl works - you can't record all the sounds at max loudness all the time. sure you can compress the dynamic range, but not as much as on digital versions.

vinyl, whole album:

https://imgur.com/yUttOuJ

CD, 1st track: https://mikeladano.files.wordpress.com/2016/11/hardwired.jpg


by the way, there is something way above 20k on vinyl:

https://imgur.com/X7vYVP0

 

[Frank Dernie]

it's all about how much you can compress the sound.
you absolutely can not do the same level on compression on vinyl that is being done on current CDs/digital/radio versions of the same tracks. don't believe me? compare a digital recording of vinyl version of Metallica's latest album with the CD version. vinyl has some breathing room. most likely it has something to do with how vinyl works - you can't record all the sounds at max loudness all the time. sure you can compress the dynamic range, but not as much as on digital versions.

vinyl, whole album:

https://imgur.com/yUttOuJ

CD, 1st track: https://mikeladano.files.wordpress.com/2016/11/hardwired.jpg


by the way, there is something way above 20k on vinyl:

https://imgur.com/X7vYVP0

It is actually necessary to compress certain music before cutting an LP, it is also often (almost always) necessary to mono the bass and, sometimes to reduce treble energy in order to actually cut the groove. Loud stereo bass would result in the groove not being continuous and high levels at high frequencies can saturate the cutter and are limited by the cutter shape fitting the groove.
CD on the other hand needs no compression to entirely contain all the audible part of the music. In the early days this benefit was exploited but latterly the fact that louder sounds more dynamic and most people listen to digital files on ear buds or in cars digital files are often compressed to hell.
Ironic really because CD can record much more dynamic range than LP can but record comtanies know LPs aren't going to be listened to in a car or ear buds so they don't adulterate the sound so much for the LP release.
Sad.

Most of the ultra HF coming off an lp is likely to be cartridge distortion with most cartridges btw and anyway the just audible line more or less meets the pain threshold for those people that can hear it at around 20kHz anyway, so whether we can measure its presence or not is moot IMHO.

 

[sergeauckland]

On pretty much any recording, anything above 20kHz is just noise, with zero (or less than zero) musical value.

High quality condenser microphones, such as those from Schoeps, Neumann, AKG etc etc are pretty much dead by 18kHz, a very few go higher, but as they tend to have rather more self-noise, they aren't often used.

Anything above 20kHz, if picked up by the microphones at all, is likely to be air-conditioning noise, line whistle from any screens (although now that CRTs are hardly ever seen, this has mostly gone away), equipment fan noise and noise from wall-wart SMPS in the studio. None of those are of musical value, so better not captured.

Similarly, any so called his-res version of classic albums will have been originally recorded on analogue tape which itself rarely did much over 20kHz, and the combination of condenser microphones and tape means that the frequency response of classic albums is unlikely to be flat at anything over 15khz. Converting those tapes to 96kHz sampling is just an exercise in getting money from the gullible by lighting the 96k light on their DACs.

As to compression on LPs, Frank is absolutely right, anything above 20k is distortion and noise, and bass is mono to stop the L-R signal, which creates vertical stylus movement and therefore shallow grooves from making the LP unplayable. Also, with anything other than acoustic music, which has its own natural spectrum distribution, treble energy has to be limited (and cutting lathes have very fast-acting HF limiters) to avoid overheating the (very expensive) cutting head. It's a very sheepish cutting engineer that has to ask Management for a replacement cutting head as they burnt one out.

Cutting LPs is a real art, where experience allows the cutting engineer to get the best out the medium's conflicting limitations. Linear it ain't!

S.

 

[PuX]

CD on the other hand needs no compression to entirely contain all the audible part of the music. In the early days this benefit was exploited but latterly the fact that louder sounds more dynamic and most people listen to digital files on ear buds or in cars digital files are often compressed to hell.

why "early days"? In fact CDs from the 80s did not suffer from this, while same albums were rereleased in 90s and 00s with much higher loudness/compression.
here's an example:
https://en.wikipedia.org/wiki/Loudness_war#/media/File:Masvis-zz_top-sharp_dressed_man.gif


producers really started exploiting this in the 90s, most notably Rick Rubin on Californication, but there are plenty of earlier cases. CDs from the 80s are mostly unaffected.

pick any modern days mainstream release - the practice of compressing everything to max loudness is definitely in use today.

digital allows this, while it's not possible to do to the same degree in analog.

 

[scott wurcer]

No. It hides potential differences. See #17 and #18. For MM inputs these low Rs measurements are meaningless.

To make things (hopefully …) a bit clearer I made a quick and dirty noise simulation with LTSpice and the two OP amps I mentioned earlier (AD797 and NE5534). AD797 has very low voltage noise (~1nV/sqrt(Hz) and relatively high (2pA/sqrt(Hz) current noise. NE5534 (which, by the way, is used in the Parasound Zphono if I read the photos on the net correctly) has reasonably low voltage noise (~3.5nV/sqrt(Hz) and reasonably low current noise (0.4pA/sqrt(Hz)). For the sake of simplicity I simulated a linear amplifier with a gain of +40dB (100) and 5mV input voltage.

In the image attached you see (from left to right):


View attachment 82096

Summary:
In this test AD797 is much better than the NE5534 a low source impedance.
With a real world (MM-like) source impedance the result is reversed and the NE5534 is better than the AD797.

You can do the same test with the standard 47k input resistor of MM inputs:

View attachment 82098

Here the results are:

(1) AD797 with a source resistance of 20 ohms. SNR (unweighted, 20Hz … 20kHz) is excellent at 88dB.
(2) AD797 with a typical MM as source impedance (500 ohms, 0.5H): SNR is low at 53.3dB.
(3) NE5534 with a source resistance of 20 ohms. SNR is very good at 74.7dB.
(4) NE5534 with a typical MM as source impedance: SNR is good at 62.1dB. That's more than 4dB worse than without the 47k resistor!

Again the MM source impedance reverses the result obtained with the 20 ohms source.

Where's the recommended input capacitance and RIAA & A weighting? There are numerous MM phono projects (and products BTW) on the web using LT1115's or AD797's or any number of other low noise bi-polar op-amps.

 

[Frank Dernie]

why "early days"? In fact CDs from the 80s did not suffer from this, while same albums were rereleased in 90s and 00s with much higher loudness/compression.
here's an example:
https://en.wikipedia.org/wiki/Loudness_war#/media/File:Masvis-zz_top-sharp_dressed_man.gif


producers really started exploiting this in the 90s, most notably Rick Rubin on Californication, but there are plenty of earlier cases. CDs from the 80s are mostly unaffected.

pick any modern days mainstream release - the practice of compressing everything to max loudness is definitely in use today.

digital allows this, while it's not possible to do to the same degree in analog.

The fact that it can be done in digital doesn't make it good.
Most modern compressed recordings sound absolutely rubbish on a good system.
It would be possible to compress analogue just as much but why would anybody? It is complete crap (Edit, compression, I mean).
I find the early CDs sound much, much better than the compressed reissues.

 

[infinitesymphony]

Anything above 20kHz, if picked up by the microphones at all, is likely to be air-conditioning noise, line whistle from any screens (although now that CRTs are hardly ever seen, this has mostly gone away)...

Oh, I know this one well, and I'm so thankful the era of CRTs is over. I hear the horizontal scan rate frequency (15.625 - 15.750 KHz) in a lot of recordings at what I consider to be distracting levels.

Here's a portion of Porcupine Tree's "Lips of Ashes" from 'In Absentia' (2002):

 

[PuX]

The fact that it can be done in digital doesn't make it good.

that's exactly why I was pointing out it was a potential benefit of vinyl - less compression than modern digital releases.

 

[infinitesymphony]

that's exactly why I was pointing out it was a potential benefit of vinyl - less compression than modern digital releases.

This is backwards though, because as others have said, with vinyl compression is sometimes required to prevent the stylus from hopping or skating off the record. A classic example of almost too much dynamic range is the final cannon section of Telarc's 1812 Overture release:

That said, these days it is not uncommon for vinyl releases to have a different master with more dynamic range than the digital releases simply because that's what the vinyl audience wants. That makes it a record label decision rather than something inherent to the format.

 

[PuX]

This is backwards though, because as others have said, with vinyl compression is sometimes required to prevent the stylus from hopping or skating off the record. A classic example of almost too much dynamic range is the final cannon section of Telarc's 1812 Overture release:

ok, I get the point about "too much dynamic range", that's a technical limitation - but generally was there any moment in time when vinyl releases were more compressed than CDs on average? Maybe 80s, but I don't think so. Because today loudness is exploited way too much on every mainstream digital release. In many cases to the point of being unlistenable, I'd say.
It was definitely not the norm to have clipping on any release. Now nobody bats an eye at that.

 

[Cbdb2]

that's exactly why I was pointing out it was a potential benefit of vinyl - less compression than modern digital releases.

You make it sound like vinyl is naturally uncompressed. compression has nothing to do with the format, its a production decision. And theres probably CD releases that have less compression than there newer vinyl release. And actually if you wanted full dynamics, which nobody does, a CD is abetter way to go because it has more dynamic range. Why do these vinyl MYTHs persist? Are we heading into a new dark age where science is seen as optional?

 

[Frank Dernie]

That makes it a record label decision rather than something inherent to the format.

That was the point I was making.
Sorry but the way you wrote your original point made me think you believed it was the format.
In the early days of CD the record labels were delighted by the extra dynamic range and the ability to put everything recorded into the release unadulterated. It was much later that the compression and loudness wars set in. That is why I put early days and why the best version of any non-classical music release is the first one, before "remastered" meant "compressed and ruined"!
Classical releases still mainly maintain the full dynamic range of the recording afaik.

 

[Frank Dernie]

ok, I get the point about "too much dynamic range", that's a technical limitation - but generally was there any moment in time when vinyl releases were more compressed than CDs on average? Maybe 80s, but I don't think so. Because today loudness is exploited way too much on every mainstream digital release. In many cases to the point of being unlistenable, I'd say.
It was definitely not the norm to have clipping on any release. Now nobody bats an eye at that.

Definitely yes. At the beginning of CD the record companies were delighted to have a format that didn't need compression, bass mono and treble roll off in order to be manufactured.
I am not sure when it started but the CD worse dynamic range than LP probably got perpetrated around 15 to 20 years ago???
My best sounding non-classical CDs are all from the last century

 

[Frank Dernie]

And actually if you wanted full dynamics, which nobody does,

I do.
I have a quiet room and a good system.
I understand you are right for people listening on headphones on a train or via a car stereo (I feel the same way when listening like this) but for "high-fidelity" home listening full dynamics is a must IME.
All the digital recordings I have ever made retain their full dynamics and sound best to me that way.

 

[PuX]

You make it sound like vinyl is naturally uncompressed. compression has nothing to do with the format, its a production decision.

I feel like it is technical limitation of vinyl that is a blessing in disguise. On digital you can make a record that clips all the time, while if you do the same on vinyl the needle will skip as demonstrated in the video a few posts above. There has to be some dynamic range for vinyl to work, while on digital everything can be loud all the time.

if you wanted full dynamics, which nobody does

Of course there is plenty of people who do!
I am not limited by my amp so I would rather have the full dynamic range and control the loudness by myself.


Who else wants it? People with ears who don't like listening to a clipping mess. They are even paying extra for hi-res versions. Not all hi-res releases deliver of course, but usually they are better than the regular CD and streaming versions.

 

[murraycamp]

demonstrable truth seems to have lost it's value these days

Word.

 

[Angsty]

I used to find it amusing that people would claim that their digitized needledrops of LPs sounded better than their CDs of the same music.

I’m no longer amused, just shaking my head that it’s come to this.