Which preamp for a pass labs?

My OPINION....  Even if electronics are fully balanced from end-to-end,
it doesn't matter.

Is this your scientific OPINION or from PERSONAL experience?
Because EVERY time I moved from single ended to balanced connection on equipment that has both, the sound improved in a number of ways.

My OPINION.... Even if electronics are fully balanced from end-to-end, it doesn't matter. The "balanced" effect is all myth and hype. Noise is NOT appreciably reduced since it is in the system REGARDLESS of the design of the interconnects. It is just there. Shielding is the only way to help reduce noice, but it will not STOP noise. So the bottom line is balanced is a complete myth and waste of money. Better to spend money on good single-ended components with top performance rather than wasting it on balanced components.

Opinion yes, fact- no.
Fact: a differential gain stage has up to 6db less noise than its single-ended counterpart. If you have more than one stage of gain, how many db less noise is possible then?
Fact: a differential gain stage has a spec called Common Mode Rejection Ratio (CMRR); if there is a noise common to both the inverted and non-inverted inputs, a differential amplifier with a high CMRR value will be shown to have far less of the noise signal (down by the value of the CMRR) while a single ended circuit will not. Our input circuits tend to be in the high 90s to low 100s in this regard.

Historically, the balanced line system is what made long distance telephone possible. It also ushered in the era of high fidelity, as for the first time the recording gear could be remote (not within 10 feet) from the performance being recording, without degradation. All of music is recorded with balanced line; its not hype.

In the end I bought an Audio Research Ls 26. I've been listening to it for some days but it seems to me that the result is a music that is too soft and with little dynamics. In your opinion, with a solid-stage preamplifier, is it more suitable for greater liveliness and dynamics?
Thank you

In your opinion, with a solid-stage preamplifier, is it more suitable for greater liveliness and dynamics?

No. Its not about tube or transistor, its about execution.

This is my opinion, but ARC is merely competent but never state of the art. Their circuits tend to be overly complex and have often left me scratching my head wondering why in the heck they did something the way they did as usually its pretty easy to spot areas in their schematics where performance has been left on the table, apparently with intention.

For example most of the ARC preamps now include differential input circuits, but every one I've seen has parts installed that actually reduce CMRR (Common Mode Rejection Ratio) because they limit the differential effect in the circuit! The more differential effect you have, the lower distortion, wider bandwidth and more gain you get.

This is part of why I asked earlier why the choice was limited to ARC or Pass. There are other tube preamps out there that are more suitable for driving a Pass Labs amp IMO/IME.