NOS tubes new production

I was wondering why some tube manufacturer or small niche manufacturer doesn't make tubes that are exactly the same as the rare type of NOS that are in such high demand and sound the best. The manufacturers of the old Seimens, Telefunken, Mullard etc made the best tubes. The new production of these models from other manufacturers don't always sound as good as the old stock. Would the demand be too small to make it worth while? Are the patents a roadblock to this problem? A good example of this is the EL34 where the old stock sounds the best and the prices are skyrocketing, or the 7308-nothing new sounds as good as the NOS. I know that it can be done technically. Would this be too expensive? We need to pick the brains of these old guys that manufactured them before they are all gone. I know that there are supplies of new old stock available from ebay etc, but this is not the same as going to a dealer to buy new tubes that have a guarantee and that you can have confidence in. I have bought tubes from ebay that are NOS, but with my experience I wonder are these used, or is the production date code the ones that are not as good or are these fakes or relabeled? Just the hazards of NOS. This problem will only get worse as they get harder to find.
The knowledge is long gone. The market would be tiny and manufacturer would never make a profit. The technology may not be an issue but knowing how to use it certainly is. The days of great NOS-quality tubes is gone forever, IMHO. Buy them now, they are only going to get more expensive. I've already got my stash pretty complete.
Three reason for not remanufacturing NOS: 1) extremely limited market! Don't forget, in the tube heyday, EVERY device could only use tubes, there were no such "animals" as transistors. Now, with solid state devices, especially I.C.'s, (which can be programmed for multiple or different (applications) it would be insane for a manufacturer to design and use tube circuits for most "garbage" commercial electronics. And let's not forget about weight, bulk, lethal voltages, and power consumption when compared to solid state circuits! 2) Some of the precision manufacturing jigs do not exist anymore. Others are probably damaged. When manufacturing, one of the greatest costs can be retooling for manufacturing. 3) Rare elements necessary for the manufacture of tubes have probably become cost prohibitive when compared to prices in the '30's, '40's & '50's. Some probably are not available at the extreme purity of bygone years. Due to new workers' safety regulations, hazardous materials and manufacturing procedures used in the production of tubes cannot be approached with the same cavalier attitude as in the past. Furthermore, not every NOS tube is created equally! A good supplier of NOS tubes will have to do checking and matching (for multiple tube sets). A reputable vendor will have to trash many otherwise good tubes that are unacceptable for the high demands of audiophiles. A particularly tough tube (noisy) is the 6922 family. Personally, I would NEVER buy raw or graded tubes from an unknown Ebay source. Too much fraud & ignorance of the complexities of measuring & grading tubes. Do you really think that "Teddy Tube" who sells as a part time hobby and has a $600- worth of testing electronics can give you a quality NOS tube or matched pairs/quads/octets? Would you use a surgeon that went to a correspondence school and used a butter knife instead of a scalpel? Sometimes the least expensive turns out to be the most expensive! I HIGHLY RECOMMEND Vintage Tube Services as far and away the best supplier of quality NOS tubes. [ Tel # 616-454-3467. Andy does tubes, AND ONLY TUBES! Call him, and you will be impressed!] Tubes still have a place for radio frequencies (transistors are useless here!) and in special heating applications, where the sole purpose of the tube uses the plate (graphite) to serve as a heating element! Happy Tunes!
Richardson Electronics has been making some, I believe copies of the MO Valve KT88s and the WE 300Bs, and the Chinese Golden Dragons were supposed to be exact copies of the MO Valve KT88s. Richardson's are or were exorbitantly priced, due to the excessive tooling costs and limited demand, and the reliability of the Chinese tubes has been questionable, to say the least. In addition, I believe that EI of Yugoslavia had the old Telefunken equipment, and produced a number of 12AX7 and 12AU7 type tubes, among others, until the war there apparently destroyed their factory. Those tubes had some, but not all, of the Teles' magic; I have some in reserve if I run out of Teles. I think Ed is right, unfortunately; it's principally economics, as well as part execution and part materials. On the bright side, a lot of the new tube equipment has been designed around currently available tubes, and often "voiced" with those tubes in mind, so that you can still get excellent sound from current production tubes.
You simply cannot avoid Kevin Deal at upscale audio when discussing NOS. I have dealt with him on my CJ preamp/amp and found him wonderful to do business with and I am extemely happy with his recommendations on CJ gear. He stands behind his tubes and he is going to be there for the long haul. Regards, Steelhead