Tube Rolling w/Crack

[attmci]

When you put new caps in the signal path, I would run the amp for a few hundred hours before altering any other parameters/making additional judgements.

Why it took so long for caps to settle? Thx.

 

[Paul Birkeland]

I'm not sure that there's any agreement as to what's going on with cap break in, this is just a part of the collective experience of the hobby.

 

[Kitchener]

I wanted to get for a Mullard for my Crack, so I went to eBay and searched for Mullard 12AU7.
But which one!? There are a million different “Mullards” it seems.

Long Plates.
Grey Plates.
Black Plates.
Clear Tops.
Reissue.

Help cheapskate out!

-not that I need new tubes, I just want a small selection of replacements for posterity.

 

[Chris65]

You can eliminate two from your list. Mullard never made clear tops & the re-issues are Russian not genuine Mullard.

 

[JamieMcC]

I wanted to get for a Mullard for my Crack, so I went to eBay and searched for Mullard 12AU7.
But which one!? There are a million different “Mullards” it seems.

Long Plates.
Grey Plates.
Black Plates.
Clear Tops.
Reissue.

Help cheapskate out!

-not that I need new tubes, I just want a small selection of replacements for posterity.

You are probably looking for the mullard 12au7 box plate (CV4003) its probably the best of the bunch without getting into silly money. Do a bit of googling on it.

 

[Paul Birkeland]

Help cheapskate out!

As a fellow cheapskate, you can find a lot of tubes with printing on them that's pretty generic, but that are genuine Mullard tubes.  This is the kind of auction I'd look for:

https://www.ebay.com/itm/3-WEBCOR-IEC-MULLARD-BRITAIN-12AU7A-ECC82-VTG-Vacuum-Tube-RADIO-GUARANTEED/263488316290?hash=item3d5920a382:gn4AAOSwogpaXkHV

The one with the red printing looks to be American, but the other two are certainly Mullards. 

 

[JamieMcC]

As a fellow cheap skate finding premium tubes on ebay at low/reasonable prices due to slightly strange listing headers was always a buzz when I was running my Crack.

I spotted this listing today that might be of interest.

https://www.ebay.co.uk/itm/2-6080-valves-tubes-1-GEC-1-GE-avo-tested-Free-worldwide-ship/232669681200?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

 

[Kitchener]

As a fellow cheapskate...

The one with the red printing looks to be American, but the other two are certainly Mullards. 

As a fellow cheap skate...

Cheapskates unite!

I assume it takes half a lifetime's worth of experience to tell one type of tube from another like that, Paul.
But are there some pointers you can share or online sources you can recommend that can teach an absolute neophyte like me how to tell what's what?

You are probably looking for the mullard 12au7 box plate (CV4003)

I'll give those a look, thanks!

You can eliminate two from your list.

Good!
I've mostly heard Reissued tubes muttered in the same breath as Sauron and Voldemort, so I tend to give those a long look down the nose.
Though this snobishnes has not been earned through experience, just reading forum posts, I'm worse than a hipster!  :
Are all reissues shit?

 

[Kitchener]

I don't know if this is strictly adherent to the rules of this thread, but I'm dying to tell someone and I didn't know where else to post this.

So I built by Crack over the weekend.
Such a fun project! (apart from mouting that god damned transformer and those sodding 6-lug terminals!)
And I just have to share my first experience with tube rolling!

Anyway, I'd already ordered a set of Clear Tops and a set of 6H13Cs (Svetlana, I think), and my Crack came with a Clear Top and a 6080 Philips tube.
I'm aware tubes and components need a substantial burn-in period before you get their best performance, but I could stop myself from switching between the 6080 and 6H13C.

And today at the office I was first listening with the 6H13C (I just really like the massive bottle look of these!) but after a while I started finding the high notes (symbals and such) a little too sharp.
So I swapped in the 6080 and the sharp edges were gone!

Of course you men-of-the-world know this, but for a simpleton like me this excited me greatly!

 

[Paul Birkeland]

I assume it takes half a lifetime's worth of experience to tell one type of tube from another like that

The seams in the top glass can tell you a fair bit about where the tube may be from (and isn't from for that matter).

 

[attmci]

Cheapskates unite!

I assume it takes half a lifetime's worth of experience to tell one type of tube from another like that, Paul.


http://www.tubemaze.info/deciphering-european-tube-date-codes/

But are there some pointers you can share or online sources you can recommend that can teach an absolute neophyte like me how to tell what's what?


I'll give those a look, thanks!

Good!
I've mostly heard Reissued tubes muttered in the same breath as Sauron and Voldemort, so I tend to give those a long look down the nose.
Though this snobishnes has not been earned through experience, just reading forum posts, I'm worse than a hipster!  :
Are all reissues shit?

 

[Doc B]

It's the same as wine. The tube you like the sound of is a good one. The tube you don't like the sound of is a bad one. Take every opinion with a grain of salt and attempt to hear the tube for yourself, in the gear you want to use it in. If you are stressed that you are going to be paying too much for a tube because you may not like it, that is not a good tube for you. If you can afford to buy a tube even if it may not float your boat, it is worth trying.

People spend so much time fiddle farting around with "reviews" and "rolling" because it is easy. That does not mean it is the most influential thing on the sound. If people spent as much time on room treatment as they do rolling ebay tubes there would be a lot more listenable audio systems in the world.

 

[Kitchener]

That link was great, attmci, thanks!

It's the same as wine.

"Tubes and Wine", I smell a new subforum in the making!

If you are stressed that you are going to be paying too much for a tube because you may not like it, that is not a good tube for you.
If you can afford to buy a tube even if it may not float your boat, it is worth trying.

Advice to live by, Doc, thanks!

The seams in the top glass can tell you a fair bit about where the tube may be from (and isn't from for that matter).

I'll make a note of that.

 

[AllanMarcus]

Hi. In general, is there any way to characterize the benefits of changing the input tube vs the driver tube? Does one tube affect the sound more than the other tube?

Update: Found this on page 4:

The general rule of thumb (IMO) is that the more gain, the more influence.

Since the 6080 is wired for unity gain, the 12AU7 should have a vastly greater influence on the sound, though there are some special 6080 variants that may suggest otherwise.

so there's my answer.

 

[adydula]

I was out of a Dac for the past three weeks, a dac i had for several months started acting wierd, sent back twice to get the issues resolved..and now with it back home and working very well...the Crack
with the T1's is soinding soooooo good...yeah most of crack owners with high impedance cans really understand this, but everyonce and awhile we like to share how great this little amp is.....and with HD800's amd T90's
T1's etc...its really well defined marraige.....

Finally stopped chasing nirvana and just enjoy the music and all those cds ripped that I havent listened to...they all sound like "new"!

Alex

 

[BZ58]

I have a tung sol 5998 that has a hole at the end of the plastic center key. The tube sounds fine, except for an occasional quiet sound like someone is sanding wood. When playing music I can't hear the sanding sound. I have another 5998 that has a broken center key. I bought it like that knowing that part was broken. It is very holographic but sounds OK. I got both a while back for a very fair price. None of my other tubes in my small collection have a hole on the bottom.

Is it common for some tubes to be open on the bottom? Doesn't the term vacuum tubes mean they're vacuum sealed?

Does it affect the sound?

Should I attempt to repair it?

 

[buldogge]

I have a tung sol 5998 that has a hole at the end of the plastic center key. The tube sounds fine, except for an occasional quiet sound like someone is sanding wood. When playing music I can't hear the sanding sound. I have another 5998 that has a broken center key. I bought it like that knowing that part was broken. It is very holographic but sounds OK. I got both a while back for a very fair price. None of my other tubes in my small collection have a hole on the bottom.

Is it common for some tubes to be open on the bottom? Doesn't the term vacuum tubes mean they're vacuum sealed?

Does it affect the sound?

Should I attempt to repair it?

The hole in the bottom of the intact guide key isn't an issue...that's just the plastic base.

If you want to repair the one with the broken guide key, you can use these: https://www.ebay.com/itm/6-Pcs-Vacuum-Tube-Octal-Socket-Saver-Missing-Broken-Guide-Key-Fix-Repair-Keyway/152149115670?hash=item236ccb4316:g:QtIAAOSwacdZbjxB

-Mark in St. Louis

 

[InnerTube]

I appreciate very much the list that I have quoted below from Dr. Toobz.  It has been quite helpful in my search for tubes for the Bottlehead Crack without speedball.  I do have the speedball upgrade but after reading that some have had problems when installing speedball, I decided to wait.  Thanks again, Dr. Toobz

At the suggestion of Grainger49, let's compile a list of tubes that can be rolled in the Crack. I'll update this list periodically as more tubes are tested, and have separated the list into drop-in replacements vs. tubes that might need the heaters rewired or some other modification. Please PM me with any additions or corrections! Maybe we can eventually make this thread a sticky? (Last updated: 05/22/2010).

DROP-IN EQUIVALENTS

Input Tubes (Original: 12AU7)

12AU7(A)(WA)
ECC186
ECC82
ECC802(S)
E8025
E82CC
CV4003
CV4122
CV491
5814(A)
6189(W)(WA)
6680 (WL6680)
6067
7489
7316
5963 (computer version of 12AU7)

Sort-of-Drop-In (but not equivalent - for best results, replace plate resistors with Speedball boards)

E80CC
12BH7

Power/Output (Original: 6080)

6AS7G
6080
6H13C
5998
7236
6N13

SUBSTITUTIONS (circuit changes required)

n/a

FWIW, tube rolling can indeed make a difference in your Crack. I've had the chance to try out another power tube - a Russian 6H13C (6AS7). The amp sounds a bit warmer now, with a bigger soundstage, plenty of bass, and maybe a hair less vivid treble. A good investment at about $20 - I bought mine online from the TubeStore. This definitely sounds a little sweeter and more "tubey" than the 6080 in there before. YMMV, of course.

 

[InnerTube]

Equipment:
Amp - Bottlehead Crack - No speedball
Tubes - RCA 6F8G with adaptor and the Genalex Gold Lion B-749
Source Unit - Oppo 205
Headphones - Sennheiser HD800 with upgrade to S cable

I know that everyone has their favorite tube combination and I am no different than anyone else.  I started out a couple of years ago with economical headphones with no amp.  I bought a less expensive headphone amp with two small tubes.  I could not believe the difference that the amp made.  I worked my way into a Darkvoice 336 and thought I had arrived.  This amp also started me into the tube acquisition and rolling phase.  I ended up with about 50 tubes.  It can become an obsession.  I buy fewer tubes these days but I still roll them.  In the meantime I have purchased a kit from Bottlehead w/speedball.  The kit is together and working extremely well - I have not added the speedball.  I read that someone had trouble after installing speedball and I decided to leave well enough alone. 

Please excuse the long post as I am just now getting to the meat of this message.  I have found by far that my favorite tube combination is the RCA 6F8G Vintage Vacuum Audio Tube Smoked Glass Bottom Getter NOS and the Genalex Gold Lion B-749.  I do not need to strain and analyze with these tubes.  I can immediately tell what I am listening too.  The spaciousness of the sound-stage and the dimensionality of the instruments is immediately apparent.  If you decide to give the 6F8G a try, please remember that it requires an adapter. (readily available on eBay)

Please note the Attachment photo of the 6F8G

Thanks to everyone for the helpful information that comes from this Site

 

[Kitchener]

There’s no need to be anxious about the Speedball.
If building the Crack went smoothly, you should have no problem following the manual for the Speedball. The manual is up to the Bottlehead standard; idiot proof in other words.

I certainly don’t think you have to worry about the quality of the components bought from Bottlehead.

Besides, the posts about problems after installing the Speedball are from a minority of customers, few customers post about how their Crack is working just fine but everyone who has problems will post about it to get help.
-as they should, the Bottleheads are super helpful and want you to succeed with their product.