Good 61NP replacement tube for NovaPre?

My Peachtree NovaPre (pre amp not integrated) will be returning this week from Signal Path from warranty repair. I though while I have it out of shelf, maybe a new tube would be fun to try. To be honest, I cannot tell much of a difference between tube and SS when switching (remote has tube off button). According to specs, the unit ships with a 61NP tube. So with that info, I am always looking looking to warm up and extend low end if possible (I know it may not make a huge difference). My current system NovaPre, B&K ST140 (last version), ZU Omen speakers (latest version), Oppo 103, Apple TV, and Canare 11 gage speaker wire.

Don't get me wrong, I love the way my system sounds. Just getting the urge to tinker. Also I wrote upscale audio...but no reply (afetr a couple of weeks).
I believe you mean 6N1P. As far as I know, no one else is making that tube unless you can find a cross for a 6N1P.
Yes 6N1p. Hopefully I'm not stuck with a single manufacturer for a tube
One of my amps uses the 6n1p as driver for a 300b. I found the NOS ones to sound better. Do a search for one that has 6n1p-eb, Voshkod or has the "rocket logo" on it.
Don't waste your time...I tried rolling some NOS tubes in mine and the difference was too minimal to even describe. The tube is a buffer and EVERYONE I have talked to has said the tube sound is virtually identical to the SS sound.
You may wish to try using 2 tube dampening rings on each tube if you wish to change it's sonic character, i.e. too bright.
I don't think it's too bright...I'm always up for warming things up. If the tube change will not make a difference, then to me it sounds a little gimmicky on why Peachtree does include a tube. Maybe on a test bench the difference is there.
The 6N1P datasheet states that it is similar to the 6Dj8/6922/E88CC (which are equivalents) - except for the higher heater current (2x higher for the 6N1P). A look at the data sheets shows other differences, so I'd stick with the 6N1P if that's what was specified.
All these tubes were designed to be low distortion and linear from the outset - which is not always the case with tube design. Perhaps this is why people refer to them as SS like? Those who prefer euphony to accuracy probably won't 'like' this tube - which is ok.
Looks like the 6N1P's are all made by same manufacturer (as said by HiFigeek). So an advertised upgraded tube is probably no more than a re-label. Thanks for info.