[pataburd]

If this thread already exists elsewhere, please point me in the proper direction (and I'll close this one). Otherwise, I thought it might be worthwhile to consolidate tube-rolling related discussion(s) on one, dedicated thread. : )

The 337 arrived for me just yesterday, having been shipped with NOS tubes. I've initially tubed up w/2x JAN Philips 6SJ7WGT and 2x RCA 6AS7G black plates. What immediately struck me was the neutrality of the 337, although with the tubes currently on board, and especially with the K501 plugged into the amp, it can come across as a bit overly frank for my liking. (Gordon Lightfoot's "Sit Down Young Stranger" does sound exceptional, though, with the K501. That recording and the K501 seem to have been made for each other--almost independent of source/amp.)

Based on my historical usage of the Darkvoice 336i, I'm led to think that the RCA 6AS7G black plates are making the 337 almost tactless on all but the best of recordings. With the 336i I found that these tubes could err on the sharp and edgy side, and land at a far cry from what I would normally expect from an RCA tube (biased by my exposure to the RCA 6SN7GT, for example). From my experience with the JAN Philips 6922/ECC88/6DJ8, I recall a rather astringent, brightish-sounding presentation as well. So the tandem effect(s) of these two particular tubes might be making the sharp even sharper and the edge edgier still.

The RCA 6AS7G gray plate, well now, that's a different animal: lush, expansive and enveloping when powering the 336i. And I am assuming that fitting two of the gray plates to the Darkvoice 337 would provide more tact and less edge compared to what I'm experiencing now (primarily with the K501; the D2000 and the HD600 sound more at home with the black plates, though edgy from time-to-time, too).

Anyway, I'm currently on the lookout for a pair of the RCA 6AS7G gray plates. In addition, I've just ordered a pair of the Svetlana 6N13S and--yes, "tube venom" has taken effect rapidly (I'm afraid it's even too late to apply a tourniquet)--a pair of the Mullard 6080. Again, I am basing these choices on my tube-rolling experimentation with the 336i. The RCA 6AS7G, Svetlana 6N13S and Mullard 6080 were among my most favorite for the 336i and I am expecting comparable compatibility with the 337. Realizing that there are further synergistic considerations, since the 336i employs the 6SN7 driver and the 337 the 6SJ7, are these reasonable expectations nonetheless?

This is my first experience with the 6SJ7 tube, so I'm not sure how accurately my 6SN7 and/or 6922-tinged analogies based on brand name (and related "house sound") will carry over. I must forewarn the reader, too, that of all the tubes I've tried to date, I heavily favor the 6SN7. : )

 

[Mazuki]

The input pentode in the 337 is triode-strapped, so you could actually roll a rather large number of sharp cutoff pentodes.

I personally prefer to use EF80s.

 

[pataburd]

Mazuki,
Would you happen to have a representative list of permissible sharp cut-off pentodes? : )
PAB

 

[pataburd]

Question:
Has anyone tried the Amperex 6SJ7 in the Darkvoice 337? If so, would you please share your experience?
: )

 

[pataburd]

Re-tubed with the JAN Tung-Sol 5998 and RCA 5693. Why not just "cut to the chase"? : )

This combination is the only one I've tried so far that seems to get something more than mediocre from the K501.

The GE 6080 and RCA 6AS7G black plate are simply too edgy, hard and grainy, IMHO (admittedly, the K501 can be extremely finicky; the D2000 and HD600 are much more tube-inclusive with the 337--the D2000 more so than the HD600).

Anyway, I barely tolerated these power tubes on the 336i with the 6SN7 driver, but with the 6SJ7 I don't think they're a good match at all. Until the Svetlana 6H13Cs and Mullard 6080s come, the Tung-Sols stay right where they are! : )

 

[Mazuki]

Quote:

Would you happen to have a representative list of permissible sharp cut-off pentodes?

So far I have tried 6SJ7, 7C7, EF80, 6EJ7.

In my experience, 7C7s have the lowest noise and the lower gain is useful for an amp with this much power.

 

[pataburd]

Thank you for the list of admissible pentodes, Mazuki. Do the EF80 and/or 6EJ7 need adapters? (I'm dumb as a fencepost here.)

I tried two Philco 7C7 the other day (using loctal adapters that Skylab graciously sold me), but didn't care too much for them. Sure, they were quiet and spacious, but at the same time "too" smooth, I felt, at the expense of failing to resolve essential details and textures. It was like scooping smooth peanut butter from a jar clearly marked "extra chunky." The Philco 7C7 also had the tendency to sound billow-ous and even edgy/glary on certain recordings; things sounded as though they were circumscribed with an "aura" of whitish noise. Curiously, though, vocals seemed very well resolved in their sandy/throaty/white noisy aspect.

Just got in a pair of NOS JAN Sylvania 7C7 this morning. God willing, I'll roll them this afternoon or tomorrow morning and report back.

Meanwhile, the Tung-Sol 5998/RCA 5963 sound absolutely sweet with the K501! : )
PAB

 

[Skylab]

My experiences:

Power Tubes:

I too have settled on the Tung-Sol 5998 as the best power tubes for the Darkvoice 337.

I also tried the following 6AS7-type tubes:

> RCA Grey Plate 6AS7G
> RCA Black Plate 6AS7G
> Tung Sol black plate bottom getter 6AS7G
> Tung Sol 7236
> Raytheon 6AS7G
> G.E.C. A1834 (6AS7G)
> Amperex (Holland) 6AS7G
> Raytheon 6080

I disliked the 6080. All the rest sounded quite good. The GEC's are the second best (I actually prefer them over 5998's in my SP Extreme). 7236's were also a little too lean for me. Tung-Sol 5998's are the best (ALL 5998's are made by Tung-Sol regardless of brand, INCLUDING the ridiculously overpriced Western Electric 421A, which are just Tung Sol 5998's rebranded).


Driver Tubes:

A. There are 4 main 6SJ7 construction types, regardless of brand (although the different brands can be and sound a little different):

1. Metal envelope - yuck - microphonic and hard sounding (5693 are decent sounding but still tend to be very microphonic)
2. Glass Envelope ribbed plate - "GT" or "WGT" - can sound excellent, although more prone to hum than the below. The WGT military tubes from Sylvania and Phillps are really nice.
3. Glass Envelope smooth plate - usually but not always VT-116A, always tall-bottle - excellent sounding to be sure. The Raytheon and Sylvania VT-116A's are really nice.
4. Glass Envelope mesh plate - the best sounding of all by far IMO. The Tung-Sol version of these are what I settled on and continue to use.

B. EF80/EM87: these sound very nice to be sure. I tried Amperex Bugle Boy mesh plates, which sound very similar to the Tung-Sol 6SJ7GT mesh plates. Require adapters.

C. 7C7 - also very good sounding, but IMO no better than good 6SJ7GT's. Require adapters.

 

[NoPants]

well for what it's wroth, my impressions are quite old now...

I played with some Jan-Phillips (thanks for checking for me mazuki) 6080s around the beginning of the year, and they sounded alright for what I paid. I agree with Skylab that they're a little lean, but it was because there was an accent on treble, giving that sparkly princess feeling.

Sadly DV337 died before I got a chance to really listen to the RCA 6AS7's. How much would you guys consider paying for the tung-sol 5998s? I think I saw a pair that could be snagged for around 60$ on ebay...

 

[Skylab]

You can currently get Tung-Sols for $22 each, brand new, here: Antique Electronic Supply - a highly reputable seller, much better than buying from EBay. They may not be branded Tung-Sol, but again ALL 5998's were made by Tung-Sol (Do NOT get the GE made straight-bottle 5998A's though, those are basically 6080's at a higher price).

 

[Mazuki]

I've had trouble with Tungsram EF80s. They never stop humming. Be aware.

 

[pataburd]

My experiences:

Power Tubes:

I too have settled on the Tung-Sol 5998 as the best power tubes for the Darkvoice 337.

I also tried the following 6AS7-type tubes:

> RCA Grey Plate 6AS7G
> RCA Black Plate 6AS7G
> Tung Sol black plate bottom getter 6AS7G
> Tung Sol 7236
> Raytheon 6AS7G
> G.E.C. A1834 (6AS7G)
> Amperex (Holland) 6AS7G
> Raytheon 6080

I disliked the 6080. All the rest sounded quite good. The GEC's are the second best (I actually prefer them over 5998's in my SP Extreme). 7236's were also a little too lean for me. Tung-Sol 5998's are the best (ALL 5998's are made by Tung-Sol regardless of brand, INCLUDING the ridiculously overpriced Western Electric 421A, which are just Tung Sol 5998's rebranded).

. . .
[\QUOTE]

Sky,
The Mullard 6080 were the only 6080 I ever liked with the 336i, and I am expecting even more of their favorable contribution with the 337. They are available through Langrex in Britain for 10 GBP apiece.

The nicest 6AS7 I've tried--again, with the 336i--were the British-made Sylvania (I cannot find any more of these, though) and the Svetlana 6N13S, available for about $10 apiece/shipped from the Ukraine. I liked the RCA 6AS7G gray plates for their spaciousness and open mids and highs, although bass could be a bit wooly.

I wish the 337 had employed 2x 6SN7. That tube imparts a creaminess and musicality to the sound that the 6SJ7 and its variants that I've tried so far can't seem to replicate. The DV337 sounds great, but it's a very straight up signature, more solid-statey than tubish.

I will repeat, though, in agreement with Skylab's declaration, that the Tung-Sol 5998 is the best of the power tubes I've tried so far. But with some Mullard 6080s and Svetlanas en route, that could change. I'd also like to try the JAN Sylvania 7C7 with the 5998s tomorrow, God willing--if I can fight the urge to switch in the Bada first thing in the morning! : )

PAB

 

[Skylab]

I should have added that I tried the Svetlana 6H13C, and I didn't really care for them either. Kind of ho-hum sound.

I have also sometimes wished that the 337 used 6SN7's, since I have a whole bunch of good ones, but Mazuki has theorized that a potential reason for the 337's dynamic, enthralling sound might be due to the use of the 6SJ7 in triode-strapped mode, and this does make some sense...

 

[pataburd]

Sky,
To me the Svetlana 6H13C/6N13S sounded "alert," clean and transparent (w/the 336i) and went well with the RCA 6SN7GT/VT-231.

Tried the JAN Sylvania 7C7 this morning and the 337 sounded almost dead-on neutral, but with some recording-dependent glare and bothersome treble edge. The K501 came across as stark, bordering on sterile w/Eddy Arnold. The HD600 sounded fairly detailed, but a bit lean, with some treble glare here and there, and not-all-that-well-extended in the bass, nor particularly well textured in general.

This last outing with the 337--and the 7C7--has me pining for the 6SN7 and the Bada (I get three--count 'em: THREE!!!-- 6SN7s w/the PH-12). No Mullard or Svetlana tubes in the mail today, so I'll probably retire the Darkvoice for a few days. : )

Lastly, while I do agree that the 337 sounds dynamic, I would use the adjective "arresting" instead of enthralling, due to this amp's more assertive--for tubes--signature. While the music certainly steps right up to greet me with the 337, I don't quite feel swept into it. And while I have felt "captive" to the sound of this amp, I have not yet "gotten lost" in the music as the result. That could simply be a function of eventually finding the "right" driver tube(s) at this point, too, but do I want to invest all that time and effort to maybe find the best one or two?

Finally, my favorite headphones, the K501 (even with the 5998s and 5693s in place) just don't seem to convey as magical a midrange with the 337--so far. The HD600, on the other hand, have scaled up extremely well with the Darkvoice and are probably the best-sounding/responding on the 337 of the three sets of headphones I currently own.

PAB

 

[Skylab]

Yeah, I wasn't wild about the 7C7 either, to be honest. Tung-Sol Mesh plate 6SJ7GT's are where it's at