What's A Good Upgrade From A Manley Steelhead?

@drbond Thanks - I just sent an email to Brent to see what he has. I've bought from him in the past and his suggestions are usually spot on.

I just don’t feel like I get as much mileage (as in, a wide variance in resultant SQ) from rolling 6DJ8 / 6922, as opposed to say 12AX7 / 12AU7 / 6SN7 or even KT / EL power tubes. Maybe that will change in the future. I’ve tried a lot of them, but no CCA’s or pinched-waists yet. You do have to be careful of "duds", but Brent Jesse will get you good ones.

Certainly, some phono stages are more friendly to tube rolling than others. The VAC’s are beautifully voiced with stock tubes, so you have to be careful not to stray from that balance, which is tricky. I had put in some RCA blue-tips (from VTS) in there that sounded just AWFUL (bright, harsh mess) and didn’t "figure out" that I should blame that tube for way too long. I was so sure it would be a good tube.

Like @tomic601 I find the Herron a bit tricky to roll - funny, I currently have the EXACT same Mazda silver plate 12AX7 (best of this type, IMO) in it that he mentioned! I like generally warmer stages, but the Herron is just not going to be swayed there and so I found it best rather to maximize its strengths with the Mazdas. I don’t have a lot of 12AT7 to roll for those 3 slots. I tried British Mullards from Upscale (usually very warm) and didn’t find much improvement over the stock tubes.

The ARC Ref 3 doesn’t have as many options as most tube stages. There are a couple options that I didn’t explore: 6H30 "DR" (very expensive, hard to find matched) and 6N6 (supposedly these will wear out faster in this application). You can roll the single 6550 regulator tube, to some positive effect. Anyways, this is a great stage that’s voiced right so you "shouldn’t" really feel the need to roll. It you want to hack its sound, then using an outboard SUT (like I did) has far greater impact.

The Hagerman Trumpet MC ships with Russian Mullards that are too warm and you can literally only go up from there lol. At this price point ($1289), it’s impressive to get even the 6 Russian tubes included.

In general, phono stage rolling is a lot harder - you will run into noisy, microphonic tubes. Just listen and move on as needed. Also - perhaps this should be obvious - the choice of phono stage is going to make far more impact on the resultant sound than your choice in tubes. You're not going to make one of these phonos sound "just like" the other with rolling. 

Keep it or sell it and buy a 1000 dollar solid state unit and invest the money to upgrade speakers or other amplification.   Despite claims of RIAA accuracy and precise amplification the phono stage is a simple process made over complicated.  An electrical engineer I was mentoring was amused when I was looking at a 12,000 dollar audio research model.  He came back with a RadioShack plastic board powered by an eveready 9 cold dry cell and parts from the drawers at RadioShack.
Only upgraded when I went to lomc.  Still have it and laugh 

@mulveling Thanks for the info and suggestions. I'd emailed Brent and he came back with a recommendation that I just purchased - 

Amperex green and orange industrial type 6922 gold pin and NOS RCA Bronzeplate 5687.

I doubt this will take me to a place where I no longer feel an urge to upgrade, in fact I think I've just had an "Oh look a squirrel" moment, as previous rolling with the Manley has had a minimal impact (as you stated in your post, rolling won't change its spots). But it will keep me amused for another couple of weeks while I concentrate on a tonearm and cartridge upgrade. 

People used to buy used Techtronix oscilloscopes just in order to harvest the TFK 6922s inside. (Perhaps also Siemens brand.)