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
Most people who have rolled tubes know there's certainly different and possibly better sounds. I've had such bad luck with NOS that I gave up and then my favorite was the current Ei Elite 6dj8's til after a couple of weeks a tube shorted out so I stick with EH 6922's. Be aware many NOS tubes can have a shorter lifespan and/or become microphonic but indeed the sound can be much better.
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.
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.
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.
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.
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.
Has anyone tried replacing the 6922's in the Steelhead with NOS (1960's) Siemens CCa's?
Some more try-outs.

I tried some raytheon triple mica 7044 and rca triple mica 7044. These are also excellent, great drive, body and clarity. I would call these "siemens-like", and seem to show off the Steelhead best as a "sound microscope" but with reasonable warmth. They seem to have the biggest soundstage and the most immediate imaging.

GE five star 5687 are the smoothest and warmest sounding. A little less drive and punch, but possibly ideal for solid state amps. I did not prefer them to the Tung Sol 5687 or the Raytheon/RCA triple mica 7044 in my system.

I still prefer the Tung Sol 5687 overall in my system. They don't deliver the extreme clarity of the raytheons/RCAs, but they have a response characteristic that I crave in tubed sound. They are punchy and sumptuous. Silky highs cascading down into a limpid pool of midrange and bass transitions.

The only other tubes that might be useful to try in the 7044 slots would probably be the Bendix 6900 (expensive and overkill?) or the Amperex 7119 ( too much mu compared to transconductance?) but I am satisfied with the great improved sound from these other inexpensive tubes, so somebody else can try those.

Just as a caveat, I have the Steelhead hooked up as a line stage now feeding a tubed vintage Luxman crossover feeding VTL 450 sig's in triode to the MRT of Apogee speakers and Bel Canto 2002's to the Low Panel of the Apogees. The crossover uses the somewhat cool sounding telefunken 12au7's, which might be the final arbiter of sound before the amplification stage.
However, when I hook up the Yamaha RX-Z9 with it's solid state amplification and using passive crossovers to the Apogee's, the sound dries out a little but the general impressions remain quite similar.
I also tried putting Ediswan CV2492's back into the 6922 slot in place of the orange globe amperex 6dj8. I would just call that a different variation of wonderful sound, the Ediswan having the edge in body and balance, the amperex the edge in warmth and sweetness.
What ever happened to the days when you could just walk into a store and buy a stereo?

I've purchased 2 1962 S/H CCa's and 4 Bendix 6900's for the Steelhead. I'll post my impressions when they get here. I'm also going to try the TungSol's - it'll be neat if they actually sound as good or better than the Bendix's, for way less money.
My friend would be very interested to hear your results, he's trying a quad of TungSols and a pair of Orange Globes soon after his Steelhead breaks in.
Well, I believe I'm finally nearing the end of the road in tube rolling everything I own.

ARC Ref 2 Mk II:
1 Gold Lion 5AR4
1 RCA black plate 6L6GC

ARC Ref 300 monoblocks:
8 Gold Lion KT-88's per side
original 3 Sovtek 6AS7G's per side (actually sound much better than NOS RCA's which I tried)

Manley Steelhead:
2 Siemens old version CCa's
4 Bendix 6900's

I tried Tung-Sol 5687's first in the Manley - the Bendix seem less "punchy" than the Tung Sols, but a little more accurate and extended. I'm still not sure if I prefer the CCa's over Mullard E88CC in the 6922 position - CCa's seem more accurate, but I think the Mullard is "sweeter." It's going to take some dedicated listening to get this sorted out.

I'm also playing with subbing power tubes (one per side at a time)in the monoblocks. Have just replaced one Gold Lion with a GE 6550A - noticeably brighter and more forward, which is kind of nice, but I already miss that MOV "ultimate smoothness." I'm ready to try subbing a Tung Sol 6550, a Svetlana Cryo-Valve, and maybe some others, to see what kind of effects they produce.
More updates please on the tube rolling for the Steelhead. I just replaced Manley 250's amps with 10 year Jeff rowland Model 6 driving the new Von Schweikert VR-7SE. The change was dramatically better. Manley couldn't produce enough bass or highs. It opened up more possibilites with the steelhead. Leaning toward the above post suggestions on the siemens and bendix. Any thoughts?
I currently use the tung sol 5687's and like them for their warmth and punch. I think tube rolling is going to depend on your system. I have tried the raytheon triple mica 7044's, and they are also better than the stock GE 7044, which can sound soft and bland. You should try some of these, they don't cost that much, and for the 6922
I don't think there are any bad or best choices, but most decent NOS tubes will sound better than the stock soviet 6922's and some improvement is also possible by changing the 7044's. I would like to try the bendix tubes, but have generally heard that they do better in circuits that bring them closer to their higher 600v rating than in circuits that keep them at 250v or 300v, and they are very expensive. Amperex, Mullard and Ediswan tubes are all good choices for the 6922 slot.
More updates - keep in mind Cjfrbw's admonition that most of this is probably system dependent, so it may not work for you.


1) I've decided I prefer Mullard E88cc's in the 6922 position over grey-plate Siemens CCa's. A little less accurate, perhaps, but more "musical". Go figure.

2) The jury is still out in my mind on whether Bendix 6900's are better (in absolute terms) in the 7044 position than the TungSol 5687's. For the money, it's a "no-brainer"; the TungSols blow them away.


1) I have decided Tung Sol 6550's have far too much bass, relative to Gold Lions, for my taste. I have gone back to all Gold Lions.

On another note, I have amassed quite a collection of Gold Lion KT88's, ranging from the older "large lion" brown-based ones complete with rotting boxes (which I think are unequivocally real), to slightly smaller "small lion" tubes with black bases and newer-style boxes. Some of the latter have solid plates, and some have holes. I recently saw a thread on Tube Asylum in which the latter, newer style were described as "unequivocal Chinese fakes", identical to current "Shuagang" (or something like that) tubes.

I don't pretend to know much about this, but I understand that MOV did begin manufacturing in China towards the end of their production. I have been conducting A/B tests (not blinded) between the older "unequivocally real" Gold Lions, and the newer "maybe fake" ones. Guess what? If anything, the newer ones sound BETTER, at least in the above system. If the newer-looking Gold Lions are actually current "Shuagangs", then I think there is a real bargain to be had. I have also wondered that if the Chinese companies kept making tubes after MOV went under, then it may not be so surprising if their current tubes look like later Gold Lions. I'm pretty much content to believe what my own ears tell me, but if anyone is really an "expert" in this area, I'd like to hear their 2 cents' worth.
Just got my Manley Steelhead with Telefunken 6922 and Phillips 5687, it sounds beautiful.

1. Did you discover the differences between tubes in blind testing?
2. Do you have a background in electrical engineering?
I agree with the above post - for my own ARC Ref 2 Mk II preamp, I let the engineers at ARC carefully select individual tubes from their already carefully spec'd lots.


1) no, and

2) no.

The topic of this (ancient) thread is the sound of different tubes, and respondents' enjoyment or lack thereof of various tubes in the specified equipment. The topic is not about objectively measuring anything. (Almost) everyone posting here clearly believes that they hear very significant differences in different tubes (I know I do), and I doubt that all of us are wrong. We enjoy sharing our impressions with other enthusiasts who feel similarly. No one posting here except you cares one whit about objectively measuring parameters that some people may or may not think are important. We have our systems because we enjoy them, not because we want to measure them.

The human auditory system has evolved over hundreds of millions of years, and it's pretty much a sure thing we will never completely understand it. Who knows what makes music sound "good" or "real?" We'll be asking and attempting to answer those questions for many years to come.

So please mmrkaic, and I say this sincerely. Sit back, chill, maybe get a drink, and just enjoy the music.