Vincent PHO-8 Phono Stage Review

[acmn]

This is a review and detailed measurements of the Vincent PHO-8 Phono stage/preamplifier. It is on kind loan from a member. The PHO-8 costs US $249 on Amazon with free shipping.

The PHO-8 comes in a two-box configuration with separate linear power supply which I did not expect to see in this price range:

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The package has an elegant, albeit small, presence that you don't usually find in budget audio components.

There is only one control for moving magnet and moving coil gain setting.

The back panel is as you would expect:

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There is even a timed delay turn on in the phono stage with a relay activation after which the LED lights.

Everything here feels like a $500 device. That is with the exception of that likely phony "QC Passed" sticker.

Phono Stage Audio Measurements
Let's start with 5 millivolt, 1 kHz signal fed to the unit with RIAA reverse equalization in moving magnet setting:

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Performance is dominated by the 60 Hz mains hum which is typical of phono stages. Ignoring that, distortion is buried below noise level. We can tease it out using signal processing however:

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This is excellent and essentially distortion-less compared to the source (cartridge/LP).

Here is our dashboard using moving coil setting:

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Don't go by SINAD as that is determined entirely by the mains hum which can be higher or lower in your system (I managed to reduce it a bit in my setting with playing with grounding).

So far so good until we get to frequency response:

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Ah, this is a shame. We have a built-in EQ with slight boost in bass and more so in high frequencies. I upped the source impedance from 20 to 600 ohm and that made it slightly worse but the variation is still there. There is also slight channel mismatch.

Clipping point and hence overload is quite high:

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This is twice as high as some other phono stages I have tested.

Finally, changing the frequency and level shows no frequency dependent distortion source in audible band:
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You just lose some headroom but given how much you have to start with, it is not an issue.

Conclusions
The Vincent PHO-8 comes dangerously close to nailing objective measurements. Unfortunately it doesn't correctly implement RIAA equalization. Since that is critically audible, I can't look past it. Specification is for +--0.5 dB so maybe this is an outlier. But maybe there are some worse than this.

As it is, I can't recommend it but you have the data to decide if it fits your needs.

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

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The Cambridge Duo has a flat frequency response which makes it superior:

DJPre was also good in this regard but doesn't nearly have the same headroom. This means pops and clicks may be more audible.

The boost in the frequencies in Vincent phono comes from the fact that it uses Neumann compensation.

 

[Zackthedog]

Well after the fact, I just wanted to chime in to say that I ordered a Vincent PHO-500, which supposedly is the the PHO-8 with a USB output. I know subjective opinions are to be taken with a grain of salt here. But I read this review and thought, well, how bad could it be? IMO this phono pre is waaaaaaaaaaay too bright, as reflected in the measurements. I have a Rega Planar 3 with a Benz Micro MC20E2 high output moving coil cart. I have *always* like this combo--lively but never overly bright. My other phono pre is an old Creek. Not the ultimate in detail but pretty darn good for the price. I have an all-tube system driving old ProAc Response 2s that could never be accused of brightness. Comparing digital remasters and the Creek preamp to the Vincent, I must send the Vincent back. It's unacceptable.

 

[Jim Hagerman]

Would it help to move the power supply further from the preamplifier (as far as power cable allows)?

That's exactly what I wanted to ask! I'll bet testing was done with units stacked. My guess is that leaked magnetic fields from power transformer go into front end of phono circuit. Can this be re-tested with boxes separated a bit? It'll only take a few inches...

 

[Jim Hagerman]

Unfortunately it doesn't correctly implement RIAA equalization.

This is a matter for debate. Clearly the circuit implements a 3.18us zero, aka the Neumann turn. The idea is to offer up a partial correction of the two poles at 50kHz found in the cutting head amplifier, which restores some of the lost airiness in upper treble. Mostly what it does is to unravel an exceeding phase shift, which makes the harmonic texture of something like a violin or piano sound off (as upper harmonics get delayed too much in time).

I wrote a paper on this subject almost 30 years ago...

RIAA Equalization

 

[amirm]

That's exactly what I wanted to ask! I'll bet testing was done with units stacked. My guess is that leaked magnetic fields from power transformer go into front end of phono circuit. Can this be re-tested with boxes separated a bit? It'll only take a few inches...

It would only take that if we had a time machine! The unit was loaned to me three years ago and returned to its owner. There is no possibility of retesting it. Also note that the pictures you see in the review are staged in my lightbox. That is not necessarily the configuration I used for testing. This being so long ago I don't remember how I tested it anyway.