Agree with those that have said you don't need to spend a lot of money for tubes that give high level performance. And note, all of these comments are IMHO/YMMV.
Can't help with the JJ's, I have some of the other current production but none that I would recommend before the NOS options. Don't know what your reference to the '75 HG is, if it is the '75 Voskhod 6N23P then I would say it's a good tube not a great tube.
TL;DR version: The Reflector 6N3P-E is an excellent high quality/low cost choice.
The Telefunken you mention, assuming you are referring to the E88CC, is one of the very good tubes, certainly one that would put you into high level SQ. Nice tube to have in your collection as a benchmark comparison, but you can do better for less. They can be found for less than $400 on eBay but you do take your chances. Unless it's Langrex (UK), they have an eBay store. They are one of the reliable, high quality sources for the Tele E88CC. About a year ago you would have paid over $300, still a good price for the quality, but at the moment they have them listed at 190GBP or $248 USD. They show only 1 pair available, but their stock list actually shows more than that, may be that the offer page refers to already matched sets. Compare this with the Upscale price at $418 for top grade.
However, back to best sound at best price. For me this would be the Reflector 6N3P-E (adapter required). I have heard these from the years '74 through '88, and they are consistent in SQ, although the '80s are easier to find. I prefer these above every small format 9 pin tube I have purchased and compared. Comparisons include several $$$K worth of the usual top tier Euro/USA from the '60s.
These use the same adapter as the 396A and 5670, both very good tubes but not at the level of the REFL 6N3P-E. Cost is the most reasonable you will find for tubes, matched pairs for ~$20, singles at just a few dollars in small batches of 4 or 8. Do not take this ridiculous low price as a measure of quality, they have been ignored and are still selling at surplus levels.
If this tube interests you and you want additional information and/or sound comparisons, you can search my post history. I started experimenting with these tubes in early 2016 and did post in several different threads. I discovered these while I was doing an extensive comparison of the REFL 6N23PS, which would be my second favorite tube.
The Reflector 6N23P is a great tube, but not quite up to the SQ of the REFL 6N3P-E. The REFL 6N23P has a slightly increased mid bass which may be favored in a headphone like the HD800, or not so favored in something like the HD650, although it does also have very good sub bass. The extra dimension at the low end, while maintaining good performance through the rest of the range, is the reason that this tube, for me, surpasses tubes like the Telefunken E88CC and others in that high cost library. There was considerable interest in these in recent years, especially the '74 and '75. My exploration of the years '68 through '73 easily matched the expensive '74s and '75s I had purchased. Easiest years to find are the early '70s at ~$50 for a matched pair. Note: my sample set on these tubes was considerable, not just a few pairs.
Quick note: my early impression was that if you took the best quality of the Telefunken E88CC and the Reflector 6N23P and combined them, that would be a good starting description of the Reflector 6N3P-E. Remember to SPL match if you do comparisons, the 6N3P-E require just a slight bit more power, about an 1/8" to 1/4" turn on the volume.
BTW, this would be on the Valhalla but also the Mjolnir2, Lyr1/2, and Vali2. For a DAC I'm using the GungnirMB.
A few other points on moving toward the goal of best clarity and 3D experience in complex orchestral passages: At some point you will need to go beyond the HD650. Of course, the HD800/s is a great choice, in a lower price range you can consider the Aeon ($799). You will also want to consider the DAC built into your Marantz. The power tube design for the Valhalla doesn't offer much in the way of tube rolling for the power tubes, but there is the FOTON from the '60s that you can consider at ~$40 a pair. Then there is the amp, if want to move up from there, one easy choice would be the MJ2, or for all-tube options you could look at the larger and more expensive offerings.
Again IMHO. Hope it was helpful. Enjoy!
