Tube Rolling w/Crack

[Paul Birkeland]

I don't believe anyone has installed a rimlock socket on a Crack, you should give it a shot!  Do be aware that the E80CC works better in the Crack circuit running a little less current than the 12AU7 to bring its plate voltage closer to spec.  These mods are outlined by those who have performed the modification. 

-PB

[Tom-s]

Thank you for the reply. I stumbled upon these tubes when reviewing E80CC options because i liked those best with my crack.
The operating points aren't exactly the same but close enough to use them with the E80CC bias for crack.
Here in Europe they were fairly popular because they were build for low microphonics (compared to their predecessor; 6SN7) and linearity.
Nowadays the prices are very low because of the B8A (Rimlock) socket that is needed.
The reason i asked is because i've been using these for the last few months with most excellent results (especially the Hungarian) compared to other tubes i use in my Crack (12au7's, 6F8G, 6SN7, 6C8G, 6SL7, 6CG7/6FQ7, E80CC, 12BH7 and 5687/7119's).

[Francisco]

Hello all, i'm currently using a Mullard 12AU7 cv4003 and a Mullard 6080 cv2984. I would like to get a Tung-Sol 5998  to pair with cv4003, but these are thought to find.

So i was wondering, what would be a good price for an used 5998 tube nowadays ?

Also what would be a good ma and gm rating for an used tube ?

Thanks

[cddc]

I remember someone on head-fi said that the Crack tubes are Russian NOS tubes. But my Crack came with 2 made in USA tubes.

Don't get me wrong. I prefer made in USA or England tubes. Just curious why they are not Russian NOS tubes as someone said?

[mcandmar]

There are no Russian 6080 and 12AU7 tubes.  You can fit a 6H13C which is a Russian 6AS7G, but there is no equivalent to the 12AU7.

[cddc]

There are no Russian 6080 and 12AU7 tubes.  You can fit a 6H13C which is a Russian 6AS7G, but there is no equivalent to the 12AU7.

Cool, thanks a lot for the reply.

The last time I submerged in the head-fi Crack thread was like at the beginning of this year. So I must have remembered something incorrectly.

I have never dipped my toes in the tube rolling waters. So what are the 2 stock tubes?

[mcandmar]

Its a lottery. Your pretty much guaranteed they will be american made tubes, but the brand will vary.  I have gotten some interesting tubes before, so you never know..

[cddc]

Its a lottery. Your pretty much guaranteed they will be american made tubes, but the brand will vary.  I have gotten some interesting tubes before, so you never know..

Lottery...so what is the jackpot?...lol

Thanks a lot for explaining the tubes

[Chris65]

Though you might get an new made Russian tube like I did..

[Paul Joppa]

Occasionally Bottlehead will acquire some especially good and/or famous and/or just rare tubes at a good price. Sometimes they will be announced, sometimes it's a lucky draw that you will get them, sometimes it becomes part of a promotion. Depends on Doc B's mood  :^)

Tubes are 12AU7 and 6080. Both have many equivalents. The 6080 is used as a cathode follower, which means that a wider variety of tubes are close enough to work.

[Doc B.]

Yes, we guarantee that we won't guarantee what brand tubes you will get. We go through jillions of them and we get what we can get at any given time. Almost all the time, but not absolutely all the time, they are old stock American tubes. We do test every one in a TV-10 tube tester before it goes out. We do not listen to every one.

For what it's worth I can also guarantee you will usually get more accurate information about this kind of thing by asking us directly rather than asking on Head-Fi.

[cddc]

Thanks a lot Chris, Paul, and Doc. B to clear up my confusions. Now I got it.

They are stock American 12AU7 and 6080 tubes instead of the rumoured Russian tubes from head-fi.

I actually prefer American or English tubes. I think they are more reliable, if I am not guessing wrong again this time.

The stock tubes in my just-built Crack are awesome - background is dead silent, no microphonics whatsoever, very engaging

[mcandmar]

I actually prefer American or English tubes. I think they are more reliable, if I am not guessing wrong again this time.

There is absolutely nothing wrong with Russian made tubes, for the crack specifically a 6H13C is up there with the best of them.

[Tom-s]

If a newcomer to Crack asks me what the best readily available / budget tubes would be i'd recommend the Russian combination.
6H13C with Genalex Gold Lion ECC82 new production.

Great starter pack: full bodied bass, large soundstage, musical mids. A combination made for easy listening, hour after hour.

Edit: And i never encountered any problems with these tubes.

[cddc]

Cool, it seems that there are some pretty good Russian made tubes. Thanks a lot for your recommendation, mcandmar and Tom-s!