How hard is this on a tube pre amp?

It's a live show from PBS... The levels are just crazy low. The funny part is the interviews shown between the live set are Normal, which is loud as heck at the volume needed for the music.

And speakers are martin logan ascents. Not the most efficient speaker around, but not terrible.

Czarivey, oppo list the output at 2.1 SE and 4.2 balanced.

Analog Audio Characteristics** Frequency Response: (RCA) 20Hz – 20kHz: ± 0.2dB, 20Hz – 96kHz: -1.5dB. (XLR) 20Hz –
20kHz: ± 0.3dB, 20Hz 96kHz: -1.5dB
Signal-to-Noise Ratio: >130dB (A-weighted, auto-mute), >115dB (A-weighted, no auto-mute)
THD+N: <0.0003% or -110dB (1kHz at 48k/24b, 0dBFS, 20kHz LPF), <0.0017% or -96dB
(1kHz at 44.1k/16b, 0dBFS, 20kHz LPF)
Output Level: 2.1 Vrms (RCA) or 4.2 Vrms (XLR) at 0dBFS
Dynamic Range: >110dBV
Channel Separation: >110dB

It seems to me that you have a lack of input level and using player with weak signal.
There are players that have 2v output and perhaps you should look for the one instead of what you have.
Your volume settings past 12:00 should realy shake the house while moderate volumes should between 9:00 -- 10:00 or 10:00 -- 11:00
Your tubes in preamp pretty much 'don't care' about your volume settings. Oppo players have only 1v output.

It's not really that loud since the recorded signal is low. It's about as loud as 11:00 on most standard CDs. (Rock)

wow how loud do you need??
ref2 already seems to be a high gain pre, but turning it to 3:00 -- chances you're hard either on speakers or amp.

Dial it up. No problems. I believe most, if not all, volume controls are actually attenuators and are more linear for stereo tracking (unless they are really fairly extravagantly designed and built) in the upper reaches.

I "slingshotted" pres together from a line stage to a TacT for years and unless you drive it into distortion, so what?
You can do the same thing from a tape deck with volume controls or by setting a phono pre a bit hot.

FWIW, I sometimes push my Ref 5 SE to 80+ clicks out of 104 total clicks when playing some records. Kal said I won't hurt the Ref 5. If you want to be certain, e mail Kal. He's very responsive.

BTW you are better off with the volume control in the upper area on the dial because it is more flexible that way.

It's no big deal.preamp tubes last for years. I have my volume control almost at full gain and the tubes are over 6 years old . Preamp tubes are not expensive to replace.

The volumn control is really an attenuator. You are not hurting anything by turning it up louder. This also will have no bearing on tube life. Enjoy