Phono preamps quality and how to judge

[ExPerfectionist]

I posted this on the Rega Fono MM Mk3 review thread as well..

I'm considering the Rega Fono MM Mk 5. This line seems to get a lot of recognition and awards, but doesn't necessarily "rate" well here. I'm wondering what parameters make a "good" phono pre-amp besides just the SINAD? Is it the frequency response linearity? What is the difference and why would some phono pre-amps cost thousands of dollars? Are there other things that make them better and better-sounding besides better SINAD and flatter RIAA equalization?

This is from a Whathifi "best phono preamps" article

Best phono preamps 2024: budget to high-end, tried and tested

A turntable's best friend

www.whathifi.com

"The Rega Fono MM MK2 was one of the finest phono stages available, so to say expectations were high for its successor is a bit of an understatement. Thankfully, it meets them and then some. The MM MK3's basic design has been fine-tuned within an inch of its life, making for a much sleeker product that retains the winning simplicity of its predecessor.

The Award-winning sound of the MK3 now has a greater dynamic range, tauter bass and greater clarity, making an already fantastic performance even better. A wide-open soundstage, masterful handling of timing and dynamics (no surprise given Rega's enviable track record with amplifiers and turntables) and reduced noise levels elevate the performance even further.

Easily one of the best sound-for-pound phono preamps around."


I currently have a Rega Fono Mini A2D paired with a U-Turn Orbit Plus with an AT VM540ML cartridge. Considering a phono pre-amp upgrade and am looking at the Rega Fono MM Mk 5, and the Schiit Mani 2.

Thanks for the input!

 

[DVDdoug]

Are there other things that make them better and better-sounding besides better SINAD and flatter RIAA equalization?

That's pretty much it. You could add gain, headroom, channel matching, and "features" like variable load capacitance, etc. You might also see a spec or measurement for crosstalk/channel separation but in reality that's limited by the record & cartridge.

greater dynamic range, tauter bass and greater clarity, making an already fantastic performance even better. A wide-open soundstage, masterful handling of timing and dynamics

Dynamic range is defined by SINAD and headroom. Otherwise, just typical non-scientific "audiophile nonsense".

Audiophoolery

Of course, the real limitation is usually the analog record. IMO it's silly to spend a lot of money on something that can never match the sound quality of a cheap digital player.

 

[Rja4000]

This is from a Whathifi

WhatHiFi is not exactly considered as a reference for rigorous testing and evaluation.
I consider their recommendations value as just below marketing adds - since they have likely the same objectivity, but without saying.

As per your question:
Noise, load tolerance or adaptability, frequency response, distortion, gain, headroom (to an extent) or, rather, short peaks tolerance.

 

[ExPerfectionist]

That's pretty much it. You could add gain, headroom, channel matching, and "features" like variable load capacitance, etc. You might also see a spec or measurement for crosstalk/channel separation but in reality that's limited by the record & cartridge.

Dynamic range is defined by SINAD and headroom. Otherwise, just typical non-scientific "audiophile nonsense".

Audiophoolery

Of course, the real limitation is usually the analog record. IMO it's silly to spend a lot of money on something that can never match the sound quality of a cheap digital player.

Thank you, makes sense!

 

[ExPerfectionist]

WhatHiFi is not exactly considered as a reference for rigorous testing and evaluation.
I consider their recommendations value as just below marketing adds - since they have likely the same objectivity, but without saying.

As per your question:
Noise, load tolerance or adaptability, frequency response, distortion, gain, headroom (to an extent) or, rather, short peaks tolerance.

Thank you!

 

[MaxwellsEq]

I currently have a Rega Fono Mini A2D paired with a U-Turn Orbit Plus with an AT VM540ML cartridge. Considering a phono pre-amp upgrade and am looking at the Rega Fono MM Mk 5, and the Schiit Mani 2

The phono stage on my quite old amplifier became unreliable, so as a stopgap I bought a Rega Fono Mini A2D. I also thought it might help with vinyl digitisation. I recently bought the Cambridge Alva Duo to replace it full time.

For objective measurements of the Cambridge, search ASR. My subjective observations are that, compared to the Fono Mini, with the Cambridge background noise is quieter both when playing discs and when not. It's also less susceptible to record faults, such as clicks and scratches. The tonality seems pretty accurate and neutral and the bandwidth is wider than the Fono Mini, with low frequencies apparently properly extended and higher frequencies also better extended.

 

[pma]

In case you intend to be serious, you have to test the phono preamp with the record player + cartridge used. “Clinical“ lab test does not reveal enough about the system immunity to hum voltages, that depend on preamp power supply, internal wiring and grounding. So you have to do the test in your real system, do not rely on tests posted in the forum or magazines.

 

[80smusicsean]

That's pretty much it. You could add gain, headroom, channel matching, and "features" like variable load capacitance, etc. You might also see a spec or measurement for crosstalk/channel separation but in reality that's limited by the record & cartridge.

Dynamic range is defined by SINAD and headroom. Otherwise, just typical non-scientific "audiophile nonsense".

Audiophoolery

Of course, the real limitation is usually the analog record. IMO it's silly to spend a lot of money on something that can never match the sound quality of a cheap digital player.

I have given up calling my goal HiFi because I enjoy the vinyl experience too much. I love the act of participating with my albums and flipping them and dropping the needle and appreciating the aesthetics of colored vinyl, etc. I want the best sound I can get given that I can accept some limitations (e.g., vinyl records).

But I also take issue with some of what I read in that Audiophoolery article. When I had a Yamaha 7 channel receiver and I upgraded my speakers to Klipsch 600mII, I could hear an audible hum during the quiet parts of songs (e.g., listening to Kind of Blue by Miles Davis has many quiet moments). I hated that hum sound and it distracted from any enjoyment I could experience. It was a cheap $375 receiver I bought before I knew I was getting into the audiophile world. I upgraded to an Emotiva BasX TA2 and the hum is gone. To me, that's a huge upgrade that improved my sound more than any room treatment could possibly do. The speakers I had before these Klipsch were Polk Audio bookshelves that were as entry level as possible and costs $60 for the pair. They sounded horrible (e.g., my sound bar for my computer sounds better for that matter), so that upgrade was even bigger than the amp upgrade. I scoff at the article suggesting that spending more money is fool's gold. I am sure there are budget items that could do better than the speakers I had or the receiver/amp I had, sure. But I had to spend money to improve on those poor quality items.

I have also found that I like the sound of the Project Tube Box S2. It's a tube-based phono preamp. We know that with these tubes and playing vinyl automatically introduces subtle distortion but what I think your equation fails to understand is that some of us enjoy that subtle distortion as a part of the experience when it comes to tubes and vinyl. Though, I am open to the fact that I like the Tube Box S2 more because it possibly provides loudness or brightness over the internal phono preamps in my amp or my turntable and that I am being fooled. TBD. ;-)

 

[JeffS7444]

I'm wondering what parameters make a "good" phono pre-amp besides just the SINAD? Is it the frequency response linearity? What is the difference and why would some phono pre-amps cost thousands of dollars? Are there other things that make them better and better-sounding besides better SINAD and flatter RIAA equalization?

Dynamic range, in the sense of offering better immunity from overload, which might make clicks and pops harsher than they need to be.

Ideally, I might like to see provisions made for resistive and capacitive loading adjustment, but I admit that for me, it's mostly about maximizing measured performance, rather than something I can readily discern by hearing alone, as in my Ortofon 2M tweaking, where I was fussing over a high frequency peak somewhere over 17 kHz.

And since learning to do some vinyl measurements, I now like to see low frequency noise addressed, such as via 30 Hz filter.

 

[JeffS7444]

I have also found that I like the sound of the Project Tube Box S2. It's a tube-based phono preamp. We know that with these tubes and playing vinyl automatically introduces subtle distortion but what I think your equation fails to understand is that some of us enjoy that subtle distortion as a part of the experience when it comes to tubes and vinyl. Though, I am open to the fact that I like the Tube Box S2 more because it possibly provides loudness or brightness over the internal phono preamps in my amp or my turntable and that I am being fooled. TBD. ;-)

Tube circuitry can be pretty linear, so what you often wind up with is about the same sound one would get from integrated circuits, but with a higher cost of operation.

 

[robwpdx]

Phono preamps are preamps with an EQ network. You can build them with low noise discreet gain devices: FET, bipolar transistors, or tubes. Or you can build them with op amps which usually have several gain stages resulting in a lot of gain in one package. For moving coil preamps, you can add a transformer for gain, hopefully a more linear one. Transformers don't add noise but they can be non-linear to a greater or lesser degree. There are a small number of quality production transformer makers in the world. I have a lot of respect for Jensen - https://www.jensen-transformers.com/transformers/moving-coil/. Jensen distribution is specialized, not Newark, Mouser, etc. A packaged connectorized 2 channel MC transformer pair is about $650. You can design a MC preamp without an input transformer.

Because it is a preamp, you also need RF filtering on the input. If you were a designer and not using an input transformer, you could build a balanced differential input, rather than single ended with a phono jack. You would have to be sure that is carried all the way from the cartridge in the turntable wiring.

The resistor-capacitor network defines the RIAA curve. 1% polystyrene capacitors are common and inexpensive.

I built my own long ago. I would stick with the ASR SINAD. The imperfections of vinyl mastering/pressing, the cartridge, and the turntable will have more (bad) sonic effects than a decent ASR-tested preamp.

 

[anmpr1]

1) I have given up calling my goal HiFi because I enjoy the vinyl experience too much. I love the act of participating with my albums and flipping them and dropping the needle and appreciating the aesthetics of colored vinyl, etc. 2) I want the best sound I can get given that I can accept some limitations (e.g., vinyl records).

3) ...I could hear an audible hum during the quiet parts of songs (e.g., listening to Kind of Blue by Miles Davis has many quiet moments). 4) The speakers I had before these...

5) Though, I am open to the fact that I like the Tube Box S2 more because it possibly provides loudness or brightness over the internal phono preamps in my amp or my turntable and that I am being fooled. TBD. ;-)

1) Don't say that. The only thing we do when we switch on our systems is to listen to hi-fi. The idea of the 'absolute sound' (Harry Pearson's thing) of live music in your living room, via your stereo, is ridiculous. What we enjoy in our listening rooms is a recorded sound reproduced via whatever. It is all artificial. We substitute one artifice for another. And then expect that we are reaching some sort of goal or end point? Does anyone really believe that?

2) The 'best' sound would by definition entail minimizing sonic limitations. Yet if we are sincere, and if that is our goal, we will learn to play an instrument, and walk away from our music systems. One gets to a certain 'hi-fi' level, even a very expensive one, and limitations will always manifest. The audiophile (fool) simply trades this for that. So it's not so much about accepting limitations, as deciding which trade-offs you personally think are acceptable.

3) Hum (and other phono related noise) is just a fact of the LP chain. At best one can minimize it to the point that it will be masked by the program, but you can never get rid of it. Not like digits. And, as you hint, during the heyday of analog LP many suggested that it are (!) record's peculiar distortion characteristics, per se, that made/makes LP listening appealing.

4) Loudspeakers will always make the biggest sonic difference in your set up. Whether you like one or the other is a personal matter. IMO

5) The easiest thing audiofools (I'm included) can accomplish, is to fool ourselves. The only way to get around it is to hide the brands and match the levels. Then compare, blind. Practically impossible when we are talking about records, and the gear that is required to play them.

Or go to some of the 'distortion' listening sites. Klippel has one. Test how much (or how little) distortion you can actually hear. Once you've done that, you'll most likely walk away depressed. But you might stop worrying about it, and learn to enjoy what you have, for what it is.