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

@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.

I've had tube phonos in the past, and moved on. Now I use a solid state phono-stage with dual inputs, the Boulder 1108. It is far and away the best sounding phono-stage I've ever had in every detail. There is nothing about my prior tube phonos (Fosgate Signature v2, Herron VTPH-2a) I would say is better, or even close.