Tube Rolling w/Crack

[nick-seattle]

Hmm. I discovered in my collection something that I didn't know exists Tung-sol 12au7 with Black Glass & Black Plates. So I compered the gray plates version with black plates - both black glass. I honestly like black plates more, could be just psychological It has more body and warmer sounding, but details remained the same! Very cool tube.

Ok, so I'm wondering how you know its a black plate if its black glass!  ???please post a pic!! 
gotta see this!

Here you go, it's hard to see because of the black glass, but the difference is big - one is mate gray plates - the usual ones; second is SHINY black plates. Kind of cool. The 12ax7 Tung-sol with black plates has mate black plates. Anybody has any more info about the tube? I couldn't find anything.

http://tubemaze.info/tung-sol-12au7-black-plates-black-glass/dsc04220/

[Doc B.]

Your picture shows a couple of tubes with either flashed barium gettering or aquadag interior coating, both of which Tung-Sol used. Too much of the tubes is cropped out of the picture to say for sure. There is no black glass in the picture.

[nick-seattle]

Your picture shows a couple of tubes with either flashed barium gettering or aquadag interior coating, both of which Tung-Sol used. Too much of the tubes is cropped out of the picture to say for sure. There is no black glass in the picture.

I tried to focus on the area that shows plates Here is the full picture
http://tubemaze.info/tung-sol-12au7-black-plates-black-glass/tung-sol-12au7-black-plates-black-glass/

Both have []-getter and otherwise are indistinguishable from one another, except for the plates.

[Doc B.]

That is an internal coating. Tung Sol used it quite a bit, and you will see it on other brands as well, for example a lot of early 6V6s, 6SL7s etc have it. Appears to be Aquadag, though that was generally used as a screen rather than a getter AFAIK so I'm not sure if that's what it is.
.

[dwilli852]

Picked up some Tung Sol 5998's today. What a great sounding tube. They have a more open and detailed sound over the RCA black plates I've been using. Been swapping out 12au7 and 12BH7's to find the best sound. Hell, they all sound good. Haven't found a favorite yet.

[williaty]

Where were you able to find some 5998s? I've been half-heartedly trying to find more of them as backups.

[dwilli852]

Where were you able to find some 5998s? I've been half-heartedly trying to find more of them as backups.

Picked up 3 from a seller on Ebay.

Took awhile to find some at the right price.

Still looking for a deal on some WE 421a's.

[nick-seattle]

Another interesting find - GE 5963 Black Plates - I usually don't expect much from GE, but this was a very nice surprise. Great tube! Check out the review:
http://tubemaze.info/ge-5963-black-plates/

[nick-seattle]

Today I received two tubes that I've been hunting for a very long time. Mullard CV491 Long Plates and Tung-Sol 7236. WOW! The Mullard is the most dynamic and punchy tube that I've ever heard - the music is warm but is superbly fast an that is assisted by the speed of Tung-Sol... absolutely to die for combo.

[wullymc]

A novice question,

when tube rolling is there a need or would it be good practice to verify the voltages again?....or just insert tube and listen?

I have a CV4003 and RCA 6AS7G on the way and am anxious to hear.


Thanks!

[Sh7eleven]

ditto, I have the same combo on the way, Great choice Wullymc! (well, i guess i don't know if its a great choice just yet, find out early next week.)

First tube rolling experience - so I'm pretty curious! In addition, would it be wise to substitute in one and spend some time with it? I want to avoid making too many changes at once so I understand how the sound is affected. Any opinion on which one I should I roll first, power or driver?

[jrihs]

HI!
Is the 2399 = to the 5998/421a?

[grufti]

Correct, Chatham [and possibly some others] seem to have used 2399 instead of 5998, not sure why.

You can sometimes get a good deal on those ... and that could just be the reason why you ask. Good luck.

HI!
Is the 2399 = to the 5998/421a?

[Noskipallwd]

A novice question,

when tube rolling is there a need or would it be good practice to verify the voltages again?....or just insert tube and listen?

I have a CV4003 and RCA 6AS7G on the way and am anxious to hear.


Thanks!

I haven't worried too much about checking voltage levels after a tube substitution. The voltage readings will vary some from one tube type to another. I did look at the voltage readings after dropping in the 5998, just curious, and the levels were higher across the board. If you were to attempt to roll in a tube that is not considered a direct replacement for each tube type, it might be wise to check your operating points. I have found the CV4003 to be an excellent choice for the Crack, have not tried the 6AS7G so I can't comment on that one.

Cheers,
Shawn

[Laudanum]

HI!
Is the 2399 = to the 5998/421a?

I have one.  2399 was supposedly an internal part number for the 5998.  It is the same, Tungsol tube despite there being a little bit of debate about it around the web.
The 5998 is probably not the exact same tube as the WE 421a based on web concensus.  There is more debate about that than 2399 = 5998