Tube Rolling w/Crack

[Doc B.]

I'd say it's safe to assume Josh was being facetious.

[orson]

Thanks for the Infos. I will test it this evening.

[Paul Birkeland]

It has a metallic area on the glass that no other of my 12AU7s has.

All of your 12AU7's should have this, but it's usually at the top of the glass.

If they don't have this, or if its white, then the tube is suspect.

[orson]

Noob as I am it took a time to understand.
Quite embarassing.
But now I know for life what a "topgetter" and a "sidegetter" is.
Hope I entertained you a bit with that question.

[orson]

And to add something useful: I listened the whole evening to the Brimar and must say I like it even a tad more than the Mullard in my setup (non-speedballed Crack with JAN CAHG 5998). Sounds a tiny little bit softer and therefore more organic and alive.

[pnooud]

Hi,

Ive just bough a new tube to replace the tube which came with my amp which had a fault.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi76.photobucket.com%2Falbums%2Fj23%2Fpnooud%2F74F43C88-9D47-4BAA-95C0-47FB613893E4_zpsstx7s9sa.jpg&hash=82366aff0d288e9cb3a5f53cf8dd77de7fbf4528)

I just wanted a cheap tube to check if mine was faulty, so ordered one cheap off eBay that was in the uk, so would be delivered quick, The I ordered a brimar 12au7, but I got a tube that has the brand ZaeuX (or maybe ZaeriX) on it, the guy also gave me a second tube as a free gift which is just labeled 12AU7A, with no other branding.

With the Zaeux tube, there is a little more treble and you notice listening to a track with a busy drum section, the drums seem to have a bit more texture.

The non branded tube was a bit smoother sounding and sounded a bit cleaner, but its not got the same energy.

I prefer the sound of the Zaeux personally.

It would be good to know if it sounds better or worse than the original tube that came with the crack; I seem to remember the original sounding better, but that could have been the glass of single malt I had

Where should I go from here do you think, I am wondering will I get much more detailed sound etc spending a bit more?

[Paul Birkeland]

The Zaerix looks to be of European manufacture, it's probably not a Brimar, but rather an Amperex or something of the like.  It's a very nice tube!

[pnooud]

The Zaerix looks to be of European manufacture, it's probably not a Brimar, but rather an Amperex or something of the like.  It's a very nice tube!

Thanks Caucasian, Thats good to hear.

[Maxhawk]

the guy also gave me a second tube as a free gift which is just labeled 12AU7A, with no other branding.

Several of my Westinghouse tubes have the part number printed at the top like that with the rectangular octagon around it and they also have the flat sides on the spacer too, so my guess is Westinghouse.

[Paul Birkeland]

(The octagon means RCA)

[Maxhawk]

(The octagon means RCA)

Does that mean my Westinghouse tubes with the octagon around the tube number are actually made by RCA? They do have the 337 printed on them which I read somewhere is code for Westinghouse. *shrug*

[Paul Birkeland]

Yes, if there's an octagon around the label, it's an RCA.

If there are a bunch of dots under the label, it's a GE.

[blackeyeliner]

Any recommendations on tube rolling with my crack? I run kit tubes at the moment, and I have a couple of tubes in stock ready to roll: Tung-Sol 5998 which microphones a lot, RCA 6AS7 with a broken getter as power tubes, and a Mullard Box Plate as an input one.

Currently with stock tubes the amp is REALLY bassy, and as much as I appreciate dark sound, it's really darkest thing I've heard. The bass can be tiresome. So what I'd want to do is achieve a more mellow, sweet sound with less accent on the bass.

Where do I go?

[Hornet900]

Hello 
I took a gamble on ebay with two old worn looking  mullard 12au7 tubes and won them  for  £11 delieved.... work really good and sound  nice ... good tubes ...I'm happy   

still haven't heard the gec tube yet

[Maxhawk]

Any recommendations on tube rolling with my crack? I run kit tubes at the moment, and I have a couple of tubes in stock ready to roll: Tung-Sol 5998 which microphones a lot, RCA 6AS7 with a broken getter as power tubes, and a Mullard Box Plate as an input one.

Currently with stock tubes the amp is REALLY bassy, and as much as I appreciate dark sound, it's really darkest thing I've heard. The bass can be tiresome. So what I'd want to do is achieve a more mellow, sweet sound with less accent on the bass.

Where do I go?

I've purchased a ridiculous amount of tubes in a short time. Depending on how the rest of the spectrum sounds, you could try an RCA 12AU7 clear top to bring up the top end, which may subjectively lessen the bass peak.

Or, use your 5998. I understand yours is microphonic, but it should be fine as long as it's quiet if you don't bump your amp or table? For me, the 5998 tightens up the bass and leans it out a little. My CV2984 output tube also tames the bass compared to my stock GE 6080.

What's interesting is the more I listened to the Crack, the more I liked the warm low end. The GE output tube doesn't sound as bloaty as it did before, but of course that's also with different input tubes. Latest iteration is 5687 which requires the Speedball upgrade as well as wiring mods since the pin-out is different. (See other thread about modifications for different tubes).