Two Paths to Musical Truth: The Case for Both Solid-State and Tube Phono Stages

I’ve done it - most of my stages are tubed but now I’ve also got a Pass Xono and XP-17 in the mix. I’ve also had lower-end SS over the years. The Pass are excellent. Far beyond those cheaper SS stages. Very clean sounding and punchy while remaining highly musical. I really enjoy them.

Yes tubes tend to be warmer and "sweeter" but the biggest variable in tube phono stages is what they’re using for MC gain. These can be all over the map in implementation and sound. In my experience, most of these aren’t as good as Pass’ MC stages. With a Pass, you really need to be looking at very low output cartridges 0.2mV and below before you *might* do better with an outboard SUT. With tube stages, for most of them I preferred an outboard SUT no matter the claims of how great their MC stage was. Even those with SUT built in  - often these were not my preferred SUT choice (e.g. Lundahls aren’t my favorite, CineMag 3440 sucks compared to Sky / 1131 / 1254 etc). And the JFET MC stages in tube phonos are quite often disappointing IMO. Have yet to hear one that’s great below 0.3mV. They either sound "sterile" or noisy or both. And finally - a tubed MC stage has always seemed like a horrible, horrible idea to me. 

Between Xono and XP-17, the latter is a little cleaner and more dynamic sounding. Xono a bit warmer and "rounder". I like each at different times, depending on the rest of the system. But you have to be especially careful not to overload XP-17 when using a SUT, as its minimum gain level is 55dB. I even hit obvious distortion on just a 0.3mV Windfeld w/ a 15x SUT, which normally should be ideal. XP-15 and Xono are a more natural partner to SUT. Of course the SUT choice itself changes sound a LOT - probably more than any other one thing. 

I'm enjoying the Pass for a while before I inevitably (or not?) go back to tube w/ SUT. VAC and Hagerman are my "classic" tubey sounding stages. I've also had less tubey-sounding tube stages and they're good but not my preference. 

@lalitk One difference is its a lot easier to design a tube preamp to have a very high overload characteristic. It turns out this is important since the phono cartridge inductance in parallel with the tone arm cable capacitance forms a resonance that can be active.

With MM high output cartridges the inductance is fairly high so the resonant frequency is at the upper end of the audio range or ultrasonic. It can be as much as 20dB higher than the regular signal. Noise at these frequencies can overload the phono section if its not designed with this issue in mind. That can result in ticks and pops. 

With LOMC cartridges the inductance is much lower so the frequency of the resonance is much higher (with the Lyra Titan about 5MHz). In addition, the coils tend to have a high Q factor which is to say they are wider than they are long; this causes the resonant peak to be sharper and higher in amplitude, about 30dB. When this peak goes into ’excitation’ (a radio term) the result is Radio Frequency Interference (RFI) injected directly into the phono stage. 

This is why there are ’cartridge loading resistors’ for LOMC. As you can see they are really for the benefit of the phono section front end and don’t actually affect the cartridge output at all. 

The RFI at the input of the phono section can overload it, again resulting in ticks and pops but also added distortion, which is the source of the brightness many people hear when the cartridge is ’unloaded’. Adding the 'loading resistor' detunes the resonance so it can't go into excitation; no RFI so sounds less bright due to less distortion. 

If the phono section if designed with this in mind its no worries- plug and play and no messing with the ’loading resistor’. 

Again, its much easier to design a tube phono section that has this RFI immunity. 

The result can be more relaxed presentation and far less ticks and pops. 

@mulveling 

Thanks for sharing such a detailed breakdown. It really highlights just how variable MC implementations can be, even among high-end tube stages. I can see your point on MC gain stage often being the limiting factor in many tube designs, and that the choice of SUT can dramatically change the outcome.  I have not ventured into external SUT territory just yet for the reason that I am still working towards obtaining my ultimate cartridge and perhaps another phonostage. 

Another concern which you succinctly pointed out is integration. Fortunately, I have a very high-quality tube phono stage with a well-matched internal MC gain stage allowing me to preserve tonal balance, dynamics and the flow of the music without having to tweak or compensate elsewhere in the chain.

That said, your observations on the Pass Xono and XP-17 are quite compelling. I can imagine how the Xono’s warmth and the XP-17’s cleanliness would complement different musical moods. It reinforces my point that system synergy often matters more than chasing one “perfect” stage. even a legendary SUT won’t solve mismatched integration issues.

BTW, you’re one of the few posters I’ve closely followed over the years. My return to analog was in many ways inspired by contributors like yourself and those with an incredible journey, their willingness to share knowledge and experience so openly, without any hint of bias or agenda. It’s that kind of generosity that keeps this hobby both inspiring and grounded.

Cheers! 

We all know "Tube" is not for everyone, and others love tubes in the signal path. 

A good friend of mine has a mastering and recording studio. He’s also a musician. 

Many would not believe this, or want to, and go as far as stating its absolutely unheard of and "against all best practice standards" to use tubes in mastering and/or recording systems. Many have shared this is ridiculous to do, LOL. :) 

Well check this, he uses a dual tube DAC somewhere within the mastering/recording component stack and loves it. He’s retired now, and still does this for fun and musician friends who seek out his services and prefer his mastering and recording services. 

His reference playback system does not use tubes in the preamp or amplifiers, interestingly enough.  So go figure, to each his own.  

There was a time in recording history when every device in the chain of creating a new LP used tubes for amplification, etc.  Some would say that the LPs of that era are the highest quality best sounding LPs ever made, even including the mono LPs, or at least that those older LPs are certainly not categorically inferior to modern production done with SS.  So all of that proves nothing. All of the greatest RCA, Columbia, Verve, Blue Note, and etc recordings were made using tubes in the recording chain, including record lathes driven by tubes,

Faults often ascribed to tubes by those who dislike tube gear are usually due to subpar circuit topology or the quality of ancillary parts, like especially coupling transformers on amplifiers. A vacuum tube configured for audio is inherently a wide bandwidth, very low distortion device.