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Tube rolling ARC amps & Steelhead

A while back I decided to try tubes. I have had an ARC Ref 2 Mk II preamp for about 2 years, a pair of ARC Ref 300 Mk II monoblocks for about 1 year, and a Manley Steelhead for 3 months. They sounded great, but it never occurred to me until recently that they could sound better - I always assumed that the manufacturers knew best when they put the stock tubes in.

My speakers are Acoustat Spectra 66 full-range electrostats, and, of course, I wanted more bass. After some investigation, I replaced the stock Sovtek 6550's in the monoblocks (8 per channel) with CryoValve 6550C's (from TubeDepot). The improvement in bass was nothing short of dramatic, and I much preferred them to the stock tubes. Nonetheless, the midrange and treble seemed to be lagging behind. After some more investigation into tube replacement options, I replaced the stock 5AR4 rectifier in the Ref 2 Mk II with a Genalex Gold Lion 5AR4, let the amps warm up a couple of hours, and then listened. I was dumbfounded at the change in sound. There was no "good bass" or "good midrange", everything just fell together with remarkable imaging and coherence, and that was with CD's and the tuner! All from changing ONE tube! I then replaced the stock 6922's in the Manly Steelhead with Mullard E88C's (following the advice of another A-gon member), put on an album, and and watched the bar further raised beyond my wildest expectations. All the sound was in beautiful coherence, rock-stable imaging, perfect balance of frequencies, not a touch of harshness, enjoyable at every volume level, like Neil Young was sitting there in the room pouring out his heart to anyone who would listen. I had a friend with me who has heard my system many times before, and he independently remarked "I can't believe it, everything sounds PERFECT!"

My question is - is this a unique experience, or have others found NOS or other tubes to make such an significant difference? I can certainly see why manufacturers don't include scarce tubes with their products, but it still amazes me that the choice of tube can affect the sound so profoundly. I would be interested to hear if others have had similar experiences.

Other equipment:
VPI Scout / Benz Ruby
Levinson 390S
Luxman T12
klinerm
cjfrbw
148 posts
 
I have tried rolling several different brands of 6dj8 and 6922 variants. The Steelhead can be improved a lot with a good NOS tube. My current favorite is the Amperex orange globe 6dj8 (with splatter shield).
Because the 7044 tubes are cathode follower buffer, I didn't think that they would make much difference. I was disturbed by reports on Audio Asylum that the GE 7044 were extremely microphonic. I tried some D getter 5867 black plate tung sol tubes. Wonder of wonders, it did improve things even more. Better drive, slam and detail, better audibility of lyrics. The steelhead went from being very quiet to dead quiet. I don't like to gush because that gets old, the same old terminology used to death, but it is surprising to hear improvements like this in something that is already so darned good.
Makes me wonder what the Bendix 6900's might sound like, but I don't know if I want to spend $400 or $500 to find out. Some opinions think the tung sol's sound better than the expensive Bendix tubes.
klinerm OP
80 posts
 
Thanks for your post, Cjfrbw.

I'm going to try upgrading the 7044's, per your suggestion. The Steelhead is a wonderful piece of equipment, as you point out, and it deserves to be "maxed out."

With my ARC gear, I've also replaced the Russian 6L6GC in the Ref 2 Mk II preamp with an RCA Black Plate, with overall improved "liquidity" and "listenability." I'm still a novice at this, but I think this is about as far as I can go with this piece.

I have purchased, but not yet installed, RCA Black Plate 6AS7G's to replace the Russian equivalents in my Ref 300 Mk II mono amps, and have purchased GE 6550A's to replace the the Cryo-Valved Svetlana's in the same amps. From what I read, TungSol 6550's may be better, and Gold Lion KT88's would almost certainly be better, but it could take many months and a big wad of cash to try that experiment.

The only saving grace to this madness is that this seems to me to be a sort of "final frontier" in upgrading. There appears often to be fairly good agreement on what constitutes the best tubes of a given type ever made, so there's (thankfully) nowhere to go after that.
cjfrbw
148 posts
 
Yes, the Steelhead is good stuff. Using the tung sol 5687s is like giving it a steroid boost. If the stock Steelhead with the sovteks and the GE 7044s is like a breath of pure mountain air, then the Steelhead with orange globe 6dj8 and tung sol 5687 d getter is the sonic equivalent of a double fudge sundae. No more solid state pretense, just exotic and refined tube sound like a do-no-wrong SET amp.
The tubes are not that expensive, either.
rx8man's avatar
rx8man
1,481 posts
 
Cjfrbw,
Don't mean to side-track this thread but I took your advice for a friend of mine ordering a new Steelhead.
He's getting the 5687 Tung Sol's before the preamp !!
I was also told the Cryo'd Russian 6922's or 6H23N-EB's are a good alternative for replacing the pair of 6DJ8's.
Have you had any experience with those or what are the characteristics of the Amperex Orange Globes ?
Walker T.T./Koetsu Urushi/Cary 805C's reside.
cjfrbw
148 posts
 
Hi, Rx8man,

I don't know about those tubes, no experience. I have heard that some older sovteks are much better than the current kind used in a lot of componenets. If they are not expensive, it is always worth a roll.
I like the Amperexes best. Orange Globe Amperex 6dj8's (the kind with a splatter shield, some variants don't have splatter shields) have a very nice earthy midrange that I really like combined with sweet highs. Orange Globes are excellent in that transition zone from the lower midrange to bass in dynamic material. Amperex white labels (bugle boy types) have very spacious imaging and nice highs, but they tend to have less overall body than the orange globes. White Label A getters and orange label A getter Amperexes are about half way between the standard orange label and the white labels in sound, a nice mix.. Mullards that I have heard have nice midrange, but not as sweet on the highs as the Amperex tubes.
Ediswan tubes are very clear and balanced, but are rare and expensive, they are more like Siemens and Telefunken types.
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