If NOS pre or power tubes became unavailable altogether, what new tubes would you buy?

@almarg , thanks for the additional info. It’s good to know that heater-to-cathode leakage is not influenced by voltage, since I’m considering trying the Sophia’s in my preamp.

Al, although the high sensitivity of your speakers reveal the issue with hum, the specs of these tubes don’t lie.

Specs is the wrong term; I should have stated "measurements" since you knew about Ralph’s criteria in this area. I did look at the GE datasheet and saw that Sophia was comparing their tube to a well known NOS tube’s specs. To be honest, I never heard of heater-to-cathode leakage until your findings.

Thanks, Lowrider.  Speaking of terminology, I should be more precise with my own.  The number of megohms (millions of ohms) that I referred to as heater-to-cathode leakage is more properly referred to as heater-to-cathode resistance.  "Leakage" would more properly refer to the amount of current that would be conducted by that resistance under a given voltage condition.

Best regards,
-- Al
   

If the sun went into super nova, and wiped out all life on earth, what music would you listen to?

Similar STUPID question!

@don_c55 ,  No, the question is not trying to get at hypotheticals.  It was asking folks who prefer NOS tubes what they would buy from the selection of new tubes.  Perhaps, I could've phrased it differently (i.e. What new, non-NOS, tubes do you like the best next to NOS?)  

What gives with all of the hostility and argumentativeness?  Why take the time to tell people their question is "stupid"?  Why try to change the subject of the forum thread?  I just don't get it.  

For those of us in the hobby who want and enjoy the exchange of information, these types of responses do not do anything meaningful to advance the discussion or create/propel curiosity.  

Al you are not alone concerning the hum problem using the Sophia 6sn7 tube and thank you for bringing it up, I should have mentioned my experiences as well. It also happened to me several months after purchase of my first pair. Lowrider this was at the time purchased for a Supratek Syrah pre-amp. The modwright oppo cd player had the Sophias in place when I purchased and I have not had any issues as you note. After I determined it was one of the tubes causing the problem in the pre-amp, I checked on my Hickok tube tester but couldn’t determine what might be the cause. This was about 3 months after initial purchase. I called Sophia but since I didn’t purchase the 18.00 year warranty they initially said there was nothing they could do. After I balked about the price paid and the longevity Sue finally agreed to send out another pair. I subsequently had a similar hum problem with one of those tubes but after a longer period. The third pair was the charm and no problems. By that point I purchased the warranty.

Lowrider make sure you purchase the warranty and enjoy! They are quite nice tubes sonically at least.