Tube Rolling w/Crack

[Paul Joppa]

6520 is a 6AS7 with matched sections and high reliability.

[InXcesS]

What do you guys think about the Tesla 12AU7?

[John EH]

Still messing around with these Svetlana Winged C 6H13C.  Usually I just give up on a tube when I don't like it's sound.  One thing I noticed was my 12AU7 installed was a clear top. I replaced it with a Mullard Box Plate CV4003 and then just left the amp on for a couple days.

Things are much improved.  Thinking about just leaving this tube in to save my highly overpriced Western Electric 421A. Recently lost a metal base 5AR4 on another amp that would cost a bundle to replace.  I really need to get used to listening to newer production tubes and quit playing around spending money on uber tubes.

This Winged C is good enough with burn in and a good companion 12AU7 tube.

[borism]

That's interesting John. I also put the Svetlana Winged C back in replacing the Chatham 2399. It is paired with a Mullard CV4003 and find it is sounding more mellow but still very pleasing.

[JamieMcC]

If you have the E80cc its a nice pairing with the Svetlana Winged C 6H13C

[borism]

I don't have any E80cc but have some Mazda/Cifte and Radiotechnique 12AU7s. Given the more mellow presentation of the Svetlana Winged C it may be a nice combo since I find those 12AU7s livelier than the Mullard. I'll have to try.

[russell_janab]

I just finished my amp build about week go and recently added Speedball. I am simply blown away by the performance of my 650's

Obviously now I have an appetite to experiment further! my kit originally comes with the 6080

can anyone comment on their experience with replacing the 6080 with any of the ones below:

6AS7G
6H13C
5998
7236
6N13

All comments welcome and thank you in advance!

[Nathan]

I have the stock 6080 plus a 6as7ga and a 5998. I listen mostly via the 5998.

[Nathan]

I am wondering about my tubes. Pre Speedball I ran Tung Sol 5998 and Mullard 12au7. By all accounts fine NOS tubes.

Now with the speedball, the bass is clearly better. Yet I'm also thinking that the overall presentation got a touch brighter too-

I substituted the 5998 with a nos GE 6as7ga I have and in fact the slight brightness I not on the crack/speedball/5998 isn't their. And the 5998 is a lovely tube- maybe it's the Mullard I'm hearing? I have an RCA clear top but that tube is a touch bright to start with so I wasn't going to throw that into the mix.

Pre Speedball, the 5998/12au7 combo was superb. What do people use with the speedball?

By the way, I have perhaps 1 hour of listening time on the speedball, so maybe it's still pretty green.

Thanks all!

[Jimb0]

Hi Nathan,

I'm using the Tung Sol 5998 as well with Amperex Bugle Boys 12au7's and CBS Hytron 5814's. I've been very happy with both so far. I cannot comment no the Mullard's as I have not heard them.

Have you considered retrofitting the input tube so you can use other tubes like the 12BH7/5687/7119's. A few Crack users here say it is a far better sounding tube than the 12au7's. I'm looking into modding mine for those specific tubes.

EDIT: Btw, I've never had any problems with the brightness on both Amperex BB's and the CBS Hytron's.

Jim

[Nathan]

I'm considering a 12bh7, particularly since with the Speedball, it's a straight swap

[Strikkflypilot]

I do not believe it is a straight swap, as the plate voltage would be low(terminals 1 and 5), there is a thread on retrofitting for the 12bh7, E80CC...

[Jimb0]

I'm considering a 12bh7, particularly since with the Speedball, it's a straight swap

Yes, you'll need to do some modding in order for the 12BH7 to run at the proper voltages.

[Rocketman248]

Built the Crack about two weeks ago.  Went shopping in Tokyo today, and picked up a few goodies.  My first foray into tube rolling.

[Jimb0]

Built the Crack about two weeks ago.  Went shopping in Tokyo today, and picked up a few goodies.  My first foray into tube rolling.

Very nice Rocketman! Welcome to the club! Hope you are enjoying your music

Jim