Can I both love and hate you guys?  The information regarding the SV83 output tubes and the 5Z3 rectifier tube was spot on and my system has never sounded better.  Which is why I love you guys.

The thread about the 6NS7 as an input tube has got me thinking what can be gained so … well you know.  

So here’s the scoop.  I have a MHDT Orchid DAC which uses the 5670 tube.  It has been reported that I can improve the sound by using the 6922 with adapter or the 6SN7 with an adapter with the caveat that while the 6SN7 works great it’s too fat to fit thru the hole in the top of the case so you have to modify the case or leave the top off.  

I’m currently using a Sylvania JAN 6922 in the SE84UFO and it sounds really good but in my mind it’s a little microphonic which is causing vocals to distort as they belt out in the higher registers at higher volumes.  (That may not really be the problem so I would LOVE some input on that but my mind process I also believe that is why manufactures tried a pinched waist tube)  The band tube dampener helps but it also dampens out some of the air.  I’ve tried 4 or 5 different input tubes and to my ears the Sylvania sounds the best of those I’ve tried.  

The other thing is I’m having problems justifying spending over $100 for a tube in a $1000 amp.  Sure there is the chance that a $300 Amperex pinched waist input tube  could make it sound better than a $2000 dollar amp but it’s probably not going to sound as good as the SE84UFO25 and should I just be saving for that instead.

Here’s where I’m at.  I have various 6N1P / 6H1N  6n1N-EV( NOS ) Russian Rockets… They all sounded flat to me
                 Siemens 6922 didn’t like very bright almost screechy and really microphonic
                 Stock Russian tube that came with the amp second favorite
                 Sylvania JAN 6922 my favorite so far with about $100 total for all of them

Replaced the Valve Art Rectifier (that was sparking) with an old National Union 5z3 tube with adapter that sounds great for $17 with the adapter

                 A mixture of Russian EL84, stock 6N15Ps and some  “lightly used”
                 615Ps that all sound good about $40

                      I have about $180 in 5670 tubes

To cut down on all the different kind of tubes and adapters I’d like to standardize on an input tube type.  My choices are the 5670 which I have but aren’t rated as good as the 6922 in the DAC and didn’t seem to be preferred in the Decware amps

Find some more Sylvania JAN 6922 with adapter see how I like it in my DAC.

Go down the 6922 trail amperex seems to be the ones to beat but the prices limit me to the newer less desirable ones.

Go 6S7N with adapter route which (again in my mind) seem to have thicker glass and build and should be less microphonic if that’s what I’m hearing and early 50s tubes are in my price range and 40s version can be found for not HUGE bucks.

Any alternative input or what I can expect sound wise would be greatly appreciated and why I love you guys.

Cheers

I'll second the Synergistic Research Orange fuse. In my case I wouldn't say it was transformational, but it is a nice upgrade. In the summer (maybe at other times too) they have a buy 2 get 1 free sale that makes the cost a little easier to swallow if you need more than one. But for a couple dollars you can get a ceramic fuse that will probably sound better than the stock glass one, and you can decide if you want to go any further.

As for your specific questions, I'm not going to answer them .  Instead I'll give you some ideas that might be an alternative to a high dollar "heritage" 6922/7308 like the Amperex. There are 3 types of compatible input tubes that I've found can sound really good and are (relatively) affordable. The PCC88/7DJ8 , ECC189/6ES8 and the PCC189/7ES8. For me personally, I like all the following tubes that I've found for less than 15 bucks each: Mullard (lightly used) and Tesla PCC88, ECC189 various US brands but either Mullard UK or Philips Holland made. Mullard and Toshiba PCC189. I also really like Tesla "silver pin" E88CC/6922s that I got for 15 bucks each and in general are much less expensive than the gold pin tubes but sound really good. Also, don't underestimate how much difference another rectifier can make. A lot of people, and I guess I'm one of them, think they are the tube with the biggest impact on the sound, the other tubes sort of tweak that sound around the edges.

You say you want to "standardize" on an input tube, but to me that sounds better in theory than practice. I don't think you're going to be happy if your "standard" tube doesn't sound as good as something non-standard. IMO if you want to do much better than stock Decware tubes (input and power tubes, plus a NOS rectifier) you're going to have to experiment, because everyone has different rooms/speakers/systems/expectations and what works great for one of us may be terrible for you, and vice versa. You don't have to spend a bunch of money, and for me at least tracking down bargains is part of the fun.

One last question, did you get the "Anniversary Mods" aka the bypass caps with your UFO? If not that would also be money very well spent IMO. Nothing wrong with saving for a UFO25 either, but the bypass caps get you part way there at a fraction of the cost (and wait).

I purchased the amp the end of 2019 and at that time the only option was Capacitors: Copper Beeswax $130  which I included.  Whether this was like the anniversary mod I don't know.

This doesn't sound like the anniversary mod. My (strong) advice would be to contact Decware about getting the mod installed. I think this will give you the biggest improvement and the best bang for the back.

In the meantime you hoard investigate other tube options