Tube Rolling w/Crack

[Sh7eleven]

I only have an hour or two on it at this point but I did like what I heard. I immediately noticed the increased clarity that an acoustic guitar came through and the bass seemed very focused.  I had a cv4003 arrive yesterday. I'm eager to listen to the pair, but I don't want to make too many changes too fast. Otherwise I have a tough time sorting through how a new piece changes the sound.   

[Laudanum]

I only have an hour or two on it at this point but I did like what I heard. I immediately noticed the increased clarity that an acoustic guitar came through and the bass seemed very focused.  I had a cv4003 arrive yesterday. I'm eager to listen to the pair, but I don't want to make too many changes too fast. Otherwise I have a tough time sorting through how a new piece changes the sound.   

Agreed, spend some time with the 5998 then add the CV4003.   I dont have great ears but the differences between 5998 and 6AS7 or 6080 are pretty easy to distingush.  For me, the differences between 12AU7's are more subtle.   I really have to spend a good amount of listening time with a particular 12AU7 before trying another one.  So you are definitely on the right track making slower changes.  Glad you like the 5998 so far.  Really nice tubes.

[Lar]

I also enjoy the 5998 and found it better sounding then the 6080. But the CV4003 was a disappointment for me, sounds rather flat and lifeless. So went back to the 5998/6SN7EH and am happy as a clam.

[Dr. Toobz]

Interesting observation to report.....tried out a 6922 with about 400 hours on it, and the sound is very different than the burnt-in 6CG7! I can't decide which one to keep. The 6922 apparently has extremely low distortion at that operating point, or at least compared to other tubes I've tried as drivers. The sound is very modern, crisp, clean, and has great decay and space around the notes. The only downside is a more forward soundstage. On the other hand, the 6CG7 sounds more like the "tube" stereotype. It has richer harmonics and is noticeably less clean and detailed, but wins in the depth department with a slightly larger soundstage.

[Paul Birkeland]

What is the operating point for the 6922 that you're using?

Running properly, the 6H30Pi would be a fun one to try.  With a second speedball PCB, the 6BX7 is an interesting choice also, though you'd need to shove 20ma of current through it with 5v on the cathodes for it to work well. 

[Dr. Toobz]

I'm using the regular operating point, wired for the different pinout. This seems to be the same one as used by the Seduction, or at least the plate voltage (75V) and use of LED bias (via Agilent HLMP-6000) are similar. I'm also using the Speedball C4S to load the driver tube.

Going back and forth, I still can't decide which to chose, as the sound is almost as different as solid state versus tube. One is clean and unveiled, the other is warm and lush. A happy medium may be keep the 6922 and slip the 6080 out of the cathode follower position in favor of a warmer-sounding tube, like the Russian 6N13S.

[fipple8]

I'm another Crack/Speedball user firmly in the Tung Sol 5998/WE 421A camp. As Laudanum pointed out, they are not the same tube. If the data sheets can be believed, the WE 421A's amplification factor is a bit higher than the Tung Sol 5998's, and so is its transconductance. They are close, however, and for many listeners both sound better than the 6AS7G/6080, no matter who manufactured the latter. These tubes' basic electrical and operating characteristics genuinely make a significant difference in the Crack's sound. I have Tung Sol and Cetron 7236s as well, and they fall pretty much in the middle: Better than the 6AS7/6080, not as good as the 5998 or 421A. And looking at the 7236's data sheet, its MU and transconductance are lower than the 5998/421A, but significantly higher than the 6AS7/6080. The 5998 and 421A definitely impress me as bringing out the most detail in a musically necessary, not analytical or dry, way. From what I've picked up in this forum and elsewhere, I believe it's probably the effect the 5998 and the 421A have on the Crack's output impedance. These tubes lower the circuit's stated 120 ohms enough to reap damping benefits, especially with the 600 ohm DT 880 phones that I use with my amp. It's a shame that a kind of modern "tulip mania" has made so many NOS tubes--the WE 421A, the Tung Sol 5998, and now even the 7236--so expensive.

[grufti]

I am also firmly in the 5998/WE 421A camp and have not used anything else in a long time [Crack & Speedball with DC heated tubes]. I personally really disliked the 7236 in this configuration and with all headphones that I use.

Your mention of "tulip mania" now including the 7236 is great news for me. I have a quite a few and tube prices always seem to be depressed during the summer months. Late fall early winter might bring some windfall resale profits for me on those ... and for that matter make other people happy.

[fipple8]

Supply and demand, I guess, the 7236 gaining more and more attention as 421As disappear, 5998s become ever rarer and more expensive, and amps like the Crack become more popular. Seeing 7226s selling for between $40 and $60 apiece recently really impressed me with how fast tube price acceleration can happen: I bought a beautiful PAIR of NOS 7236s just a year ago for about $30. Five years ago, I bought NOS 421As for about $85 apiece, NOS 5998s for $25. Makes me wonder what's going to happen when the 421A and 5998 supply is effectively exhausted. I don't see anyone ever producing modern versions. Well, maybe SOMEBODY, but they'll cost $500/pr. (The boxes, however, will be really nice.  )

[Paul Joppa]

... Makes me wonder what's going to happen when the 421A and 5998 supply is effectively exhausted....

The demand will die down when they become unavailable or too overpriced; then a few years later the hoarders who missed the bubble will let them go for cheap because nobody wants them anymore. Seen it before. At least with tulip bulbs, you can eat them!

[BNAL]

Paul,

I had no idea you were that old.

[dwilli852]

Picked up a couple Valvo ECC 82's on the cheap.

Great sounding tubes.

Keeps getting harder to find a good deal on tubes.

[Laudanum]

I have a couple Amperex and Philips that sound really nice.  All from the Herleen plant.   Lately Ive had a GE JG 5814 triple mica in there.  I really like this tube as well.  I have a few of them, black and grey plates.  The GE in there now is actually a grey plate.   I had a Sylvania 12BH7 in there for a long time.  Like that tube very much as well.  Done buying 12AU7 types I think (I hope).  I dont have any that are especially rare, super expensive or incredibly hard to find.  But Im very happy with several types that I have and Im probably covered for life where 12AU7's and equivalents are concerned.  Not just for Crack but for everything I own that uses them.   

[dwilli852]

I have a couple Amperex and Philips that sound really nice.  All from the Herleen plant.   Lately Ive had a GE JG 5814 triple mica in there.  I really like this tube as well.  I have a few of them, black and grey plates.  The GE in there now is actually a grey plate.   I had a Sylvania 12BH7 in there for a long time.  Like that tube very much as well.  Done buying 12AU7 types I think (I hope).  I dont have any that are especially rare, super expensive or incredibly hard to find.  But Im very happy with several types that I have and Im probably covered for life where 12AU7's and equivalents are concerned.  Not just for Crack but for everything I own that uses them.   

I'm about the same way on 12AU7's.

Still looking for a Siemens Silver Plate ECC82 and a WE421a just to see how they sound.

I picked up the Valvo's off Ebay for 5 bucks each.

Just threw a low bid out there a won them.

[Laudanum]

Yep, sometimes you get lucky on ebay.  Used to happen often for me, now it's more rare.   I have 2, pretty nice 6922's that I need to find mates for.  A Valvo and an Amperex.  I got them cheap on ebay a dozen years ago as singles with the intent of finding a mate for each at that time.  Never did back then and last I checked, one of them was pretty pricey and I never came close to coming across a "steal" when I was actively looking.  I may just sell them instead and get another pair or two of something else, probably some easier on the wallet Amperex.  Im quite happy with BB's or Orange Globes in two CDP's and also Seduction.  Couple more pairs should take care of me for the long haul.  Those CDP's especially are easy on tubes and a good pair or two will probably outlast both players.