Tube Rolling w/Crack

[drowningcactis]

thanks paul

[w0lfd0g]

I have spent much of the past 48 hours rolling tubes. 

Output tube
Have tried the following:
1. Chatham 5998
2. Bendix 6080WB graphite
3. WE 421A
My favourite is the 421A and least favourite the Bendix

Driver tube
1. Mazda CIFTE 12AU7 1962
2. Brimar CV491 1971
3. Valvo ECC82
4. Tung Sol 12AU7A (1959 from memory) - Laddered grey plate
5. Telefunken ECC82 laddered grey plate
6. RCA 12AU7A clear top
7. Mullard ECC82 1962
8. Siemens laddered grey long plate

I can't hear a difference between the driver tubes, other than something very subtle, that is probably my imagination.

What's going on?  I can think of a few options:

1. My ears are too "unlearned" to hear a difference - I would be surprised if this is the case as I have tube in the Lyr before and was able to hear a vast difference in such aspects as balance, clarity and sound stage as a result of rolling.

2. The way I have modified my Crack removes any effect from rolling driver tube - I don't know enough about circuit design to determine with this is correct or not.  For what it's worth, i have the Speedball installed, Have 100 uF ES Clarity caps bypassed with 10 uF Mundorf Supreme as output caps, have replaced the final power cap with a 220 uF TC Clarity cap and have an Alps blue pot.

3. There is no difference in sound in this family of tubes in the Crack and the tube marketers have brainwashed us all

4. I didn't give the tubes enough time to burn in  (which would suggest that in their embryonic state, all of the driver tubes sound the same until having reached adolescence)

Can someone please help?  Do I persevere?  Do I sell all my expensive driver tubes and keep a couple of RCA cleartops? Do i try other families?  BTW - The amp sounds equally terrific with the various drivers.

FWIW - My tube rolling playlist consisted of Bach (portion of St Matthew Passion), Bjork, Mahler (portion of Kindertoten Lieder), Sarah McLachlan, Dire Straits, Rage Against the Machine and William Cornysh sung by the Tallis scholars (early sixteenth century sacred choral music).

Cheers!

[Paul Birkeland]

What sources are you feeding your Crack with? 

[w0lfd0g]

FLAC into Meier Audio StageDAC via optical

[Paul Joppa]

For what it's worth ...

The 12AT7 is not a very linear tube, in "normal" applications; the 5670 is actually much more lnear. When we were developing the Paramount upgrade/soft-start/5670 driver, Ed made some detailed distortion measurements - measuring each harmonic individually. With the C4S plate load, the distortion spectrum of the amp was almost the same, apparently dominated by the extremely linear 300B output tube. The C4S plate load (i.e Speedball in this case) appears to linearize both drivers to the extent that the power tube distortion spectrum dominates.

Linearity is of course not the only audible difference between tube, but it's a major part of the difference (IMHO of course). This could possibly explain the difficulty of identifying a difference between drivers with the Speedball installed.

[w0lfd0g]

Thanks Paul - Very helpful.

What other objective variables in the tube's physical makeup effect the listener's subjective audible perception apart from linearity?  Interested to know - All part of the learning experience for me (am relatively new to audiophile pursuits).

Many thanks

Nathan

[dwilli852]

Picked up a early 60's Siemens ECC82 silver plate.

Great sounding tube with the 5998.

Lot's of detail.

Can't complain about anything with this one.

 Keb' Mo' never sounded better.

[STURMJ]

keb' mo' fan here too.

[audiophileboss]

What are the best most Hi fi 6080 and 12au7 tubes on the market and the cost?

[adamct]

What is the best beer, wine, painting, movie, book on the planet, and what does each of them cost?




OK, sorry. It's subjective. But you can search the Crack forum for the tube rolling thread to hear various opinions.

[Grainger49]

There is a thread of Tube Rolling In Crack.  The longest thread on the forum.

http://www.bottlehead.com/smf/index.php/topic,663.0.html

[Doc B.]

They don't really exist. But no worries, you can't afford them anyway.

[earwaxxer]

Aaah, common guys... Some good feedback is in order here... I say. and this is my opinion, one should buy as many "flavors" as you can, and sample them, then form an opinion. Come back here, express such opinion and you will then get some "constructive" feedback. No short cuts. Got to do your homework. Its a "give and take". Right?

[Nick Tam]

What are the best most Hi fi 6080 and 12au7 tubes on the market and the cost?

If I told you that the most expensive combination of possible tubes that you could put into the Crack cost as much as the Crack kit itself, would you still want to buy it? Or do you just mean a "6080" tube and a "12AU7" specifically?

The Comprehensive 6080/6AS7 Rolling Guide:
http://www.bottlehead.com/smf/index.php/topic,3453.0.html

[Aeolus Kratos]

If I told you that the most expensive combination of possible tubes that you could put into the Crack cost as much as the Crack kit itself, would you still want to buy it? Or do you just mean a "6080" tube and a "12AU7" specifically?

The Comprehensive 6080/6AS7 Rolling Guide:
http://www.bottlehead.com/smf/index.php/topic,3453.0.html

Hi Nick,

Can you give me some impressions on the G.E.C Brown Base 6AS7G and the Western Electric 421A? I'm using Tung-sol 5998 (actually it's Chatham 2399) and I'm tending to upgrade to the 421A or G.E.C. What are the differences between them? And are they worth the premium between the 5998s and 421A/G.E.Cs?

And of course I'm using Speedballed Crack for this.

Best regards,

Kratos.