Tube Rolling w/Crack

[InnerTube]

1.  I would remove the 6080 and replace it with a good 5998 or 6SN7g tube.  Perhaps a Tung-sol or even a RCA.

2.  There are good old tubes (NOS = New Old Stock and JAN = Joint Army Navy) and good new tubes.  Most people tend to prefer the older tubes if they test well.

3.  The test value depends on the scale, brand and quality of the tester.  You would need to know the GOOD/BAD parameters before making a decision based on the tube results alone.

4.  Except for super exotic tubes, the Tung-sol seems to be at the top of the heap.

5.  I would place the brand and the condition of the tube before seeking out a mil-spec tube.

6.  By far my favorite 12au7 replacement is the 6F8G or the 6C8G.  You will need an adapter for both found on eBay.  (see my post about these tubes above)

Hope this is helpful, JS

[Paul Birkeland]

1.  I would remove the 6080 and replace it with a good 5998 or 6SN7g tube.

We have mentioned elsewhere on this forum that plugging a 6SN7 in place of the 6080 will destroy the 6SN7 and perhaps even the amp.

[Rossputin]

thanks CB/PB. If I were only going to roll one tube to start, would you recommend it being the 12AU7 or the 6080?

Also what do you think of the suggestions re subs for 12AU7 that involve using an adapter because the other tube has a different number of pins? (And what does the adapter wire connect to?)

[JLDub]

Hey Ross,

Here's where I got a great basis for power tubes at least.
https://www.superbestaudiofriends.org/index.php?threads/bottlehead-crack.120/page-3
It's older and prices are not US but still very helpful.

Also, check this out from this forum:
https://bottlehead.com/smf/index.php?topic=663.msg30393#msg30393
Bottom post.

I have found most of the answers to your questions in some form or another through research on Google. But then again, I'm obsessive and may be more persistent about reading up on this stuff than most people

For the preamp tube, check out new production Genalex Gold Lion 12UA7. They seem to be pretty popular. Any decent vintage preamp tube I've seen like the Mullard CV4003 https://www.upscaleaudio.com/products/mullard-cv4003-12au7-vintage-new-old-stock usually costs about $80 - $100 and up and just isn't worth it to me. I wouldn't spend more than $50 on a tube personally and that's a stretch.

Hope this helps.

[Rossputin]

Thanks much!  I'm thinking about this: http://www.tubemonger.com/La_Radiotechnique_12AU7_NOS_NIB_FranceECC82_MIL65L_p/1215.htm

[InnerTube]

Sorry.  I meant 6SA7.  Bad mistake, js

[InnerTube]

Sorry.  I meant 6AS7.  I am too old to be giving advice from memory.  Bad mistake, js

[JLDub]

Ross,
Forgot to mention, scroll through that first link for 6AS7G and 12AU7 tubes. Also, you may want to check this out http://www.nostubestore.com/2018/02/brimar-cv4003-12au7-ecc82.html
Upscale has a stock at about $20 more. They're generally more expensive.

[attmci]

Hello folks,

A couple of quick questions for you...or maybe not so quick:

1.  If I'm going to mess around with tube rolling for my Crack (with Speedball), would the 12AU7 be a higher priority than the 6080?

2. What's the deal with "vintage" tubes? Is a tube from the 1950s or '60s likely to sound different than a new tube, and if so is that because of difference in manufacturing, or difference that occur with age? I kinda like the idea of a tube made in the same year I was born (mid-'60s)...

3. On eBay plenty of sellers note test values for tubes.  What exactly are those and how should I think about them?

4. Are there any brands of tubes out there for which there is a consensus (something which seems generally to be absent in almost every part of the fascinating discussions on these topics) that they are either A) among the best and should be sought out or B) to be avoided? Related: Are there particular countries of tube manufacture that are thought to be uniformly superior or inferior as far as tube quality?  (For example, I've seen plenty of positive mention of Tung Sol.)

5. I see that some substitutes for the 12AU7 are tubes that are "military spec", which seem particularly to be designed to handle frequent power on/off cycles and maybe have some other tighter tolerances. I like that idea, because I do tend to turn the Crack on and off at least once most days of the week. But is that "mil spec" really something worth seeking out?

6. I realize this is a "Coke vs Pepsi vs RC" question, meaning there isn't a "right answer" but what's YOUR favorite replacement for a 12AU7 in a Crack and why? (Feel free to answer for the 6080 as well!)

Thanks in advance for your insights and advice!

Ross in Colorado

I found it's kind of dangerous to ask this kind of questions here instead of reading and investigation by yourself. There are many forums. Just google it.

[Rossputin]

I've read dozens...actually probably hundreds...of posts across the web. Didn't think it would hurt to consolidate a few questions in one reply here. Still don't think it's a problem.

[Tom-s]

I've rolled 100's of tubes in my Crack. I can only recommend the "Russian combination" for a reasonable price.
6H13C (Svetlana winged C, OTK)old stock for the power tube.
ECC82 Gold Lion new production for the input tube.

On the other end of the spectrum, for just marginal gains over the above mentioned combination (but have heard none better to date), there's the not so reasonably priced/unobtanium "English combination".
A1834 GEC power tube.
ECC32 Mullard input tube.

[JamieMcC]

Far to many variables in tube rolling for definitive views on tube combinations imho.

Much also depends on the rest of your source and headphones used, Crack upgrades and of course personal tastes. Also worth a mention some of the popular tubes were produced for 20 or so years the formula and components inside may have had several design reconfigurations over that time and as such reviews on a certain tube can be a little misleading as they might be referring to a tube manufactured with a specific date

I would suggest you become familiar with how the Russian 6N13S & 6Н13С tubes look, these are available new old stock for around $10 they are also widely rebranded and you will see the same $10 tube being offered as fake premium tube for as much as $100 *don't be fooled* the distinctive silver getter marking at the base of the tube is easy to spot.

While the pictures no longer work this is a great resource for Crack tube rollers

http://the-key.enix.org/~krystal/review-tube-bottlehead.html

ps I think using a tube from the year you were born is a neat idea best of luck with your search

.

[Doc B.]

Jamie is making some very salient comments here. There are current production and readily available tubes that very good sounding tubes and they don't cost a lot. And a lot of judgments seem to be made based upon a single sample - not particularly scientific.

When I started in this business in the 90s one could buy a Fisher 400 for $75 at a swap meet, pull the Telefunken 12AU7s and run them in a Foreplay. Extra ones I could sell for maybe $15 a piece. Now a good Telefunken 12AU7 costs more than a Foreplay did. And of course the Fisher goes for what, $1000 restored? I get it - I'm old, that was a long time ago, they are supposedly more rare now and everyone wants to make money on their investment (Doc says buy CDs and CD players).

Because I got into this when Teles were $25 and 5998s were $15 I do have those tubes around, along with Tele E88CCs and EF806s for my Eros, Amperex 845s in my Neothoriator, etc.  And I run them. I even have a mesh plate 10, a Pliotron, stuff that actually is quite rare and exotic.

However the difference between these tubes and something bang for the buck like a clear top 12AU7 or a Russian 6H32p or a Chinese 845 is not actually something of mythical proportions. If you have the budget and want to try $300 tubes in your $300 amp, go for it. And burn those bitches up. They sound nice and were meant to be used! But if you don't have the budget, don't feel like you're missing something critical to improving your karma or advancing the entire species. Yes, they are nice but probably not as much an improvement as the same money spent on carefully employed room treatment or a better sounding source component than what you currently have.

[Paul Birkeland]

the Fisher goes for what, $1000 restored?

I had to up my homeowner's insurance a bit.

[Doc B.]

Because FM radio sounds soooo good these days. I was chuckling with my motorcycle buddies about the same thing regarding bikes yesterday. Kind of astounding what a mundane thing like a CT90 goes for these days. I could buy an Aprilia Futura for what some guys are asking.

If anyone is interested my Nagra T is for sale for $28,000 and my Altec 250SU console is available for $40,000. I will sell my Amperex 845s for $6500. And the original S.E.X. kit is available for $1.5 million for the pair. Daddy needs to get to Bonneville.