Tube Rolling w/Crack

[StivVid]

I didn't mean to disparage any tubes in particular.  I'm only saying that I think I'm tending to favor 6080's over 6AS7G's and wonder if anyone else is too?

I guess I should have included a better description of my setup:

Stock Bottlehead Crack
Sennheiser HD600 headphones
Sendstation line-out dock
iPod Classic 120GB

I'm sure my preferences will change if and when I add a stand-alone DAC to the equation.  I'm thinking of trying the Pure I-20 iPod dock with built-in DAC.  Seems like good bang for buck, and that's what I'm all about.

[Paul Birkeland]

It's pretty tough to tell on the 6AS7 vs. 6080 debate, as nearly all of the varieties of internal construction of one type can be found in the other (excluding the 5998, and some of the newer Soviet equivalents).

(I spend my money on AU7's.)

[adamct]

I consider the Pure i-20 (like the Crack) to be one of the best buys in audio. I own three of them. The built-in DAC is quite good, and you can always use it later to feed a stand-alone DAC through the optical or coaxial outputs. The only thing to beware of is that it isn't suitable for watching movies on an iPad, since the iPad assumes you are using the video out on the Pure and cuts the display on the iPad itself. But for listening to music, it is outstanding.

Best,
Adam

[Nick Tam]

Hello, all.  Seems like there's a definite preference on this forum for the sound of 6AS7G tubes over the less glamorous looking 6080 tubes.  Granted, I only have an RCA 6AS7G and an Amperex (made by RCA).  Both of those tubes sound very loose on the bottom end and both have a very faint high pitched ringing in the right channel.  Most 6080's I've tried, on the other hand, have much tighter, controlled bass and are dead silent--not a hint of microphonics with most--especially military JAN versions.  I'm listening to the line output of my iPod Classic.  The best combo I've found so far, by a wide margin, is an RCA JAN CRC 6080WA paired with an RCA 5963.  Everything opens up with this combo.  Tight, controlled bass; very present and detailed midrange; a nice airy spaciousness to the treble.  I also have a Sylvania Gold Brand 6080, which is nearly as good but not quite; and a Sylvania JAN 6080WB which sounds slightly lifeless compared to the other two 6080's.

I don't have a 5998 and I know this tube is universally praised.  I'm just curious as to why most people seem to prefer the ST shaped tubes to the good ol' straight 6080?  To my ears, they don't sound better.  Anyone else?

Other 12AU7 tubes I've tried in my rig:

unknown brand 6189
Conn 12AU7A
RCA Cleartop 12AU7A
RCA Command 5814A
GE 5-Star 5814A

Rather than why people "prefer" the ST shaped 6AS7G over the 6AS7 is simply because of variety and the more definite change in sonic characteristics to the Crack and most probably, looks. The mass produced straight bottle 6AS7 from different brands are mostly sonically identical, with some claims that the Sylvania dual halo getters, sylvania 6080 gold brand, sylvania/cei 7236 and the Mullard/GEC/Valvo 6080 to be sonically superior or to some degree, "better". For one, the Sylvania 6080GB is one of the few straight bottle 6AS7 tubes that takes musicality of the Crack sound a notch further having owning one of these but is quite a rare find as of now. The premium Graphite series Bendix/Tung Sol 6080WB and the Cetron/Tung Sol 7236 come up more often on ebay than the low-end premiums but at a much higher cost, and are often compared and considered to be equally as good or even better than the 5998.

The RCA 6AS7G on the other hand is more "popular" due to being dirt cheap and easy to get your hands on, and makes a very obvious change to the Crack sound. It slows down the pace of the Crack and has good musicality and looser bass, giving the Crack a more vintage tube-ish sound. On the other hand, the premium 6AS7G types, the 5998/421a and GEC brown base are known to yield improvements and are relatively common on ebay despite their soaring prices.

I have done an extensive report on the 6AS7 tubes in case you have missed it: http://www.bottlehead.com/smf/index.php/topic,3453.html

[Laudanum]

The ST shaped tubes obviously look "cooler" but it has nothing to do with my preference.   The RCA and some of the other inexpensive 6AS7G's just plain sound better to my ears than any of the 6080's that I happen to have.  Im not spending money on the high dollar 6080's, my biggest tube expenditure when to a 5998 and a couple spares.  That's what I normally run in crack and Im extremely pleased with the sound but the RCA gets rolled in too.   The RCA 6AS7 does have a bigger bottom but with Speedball and Film output caps I dont find it bloated or flabby except with one set of my cans and only then with limited source material.  In fact, I find that tube fun on a good deal of material.   I agree with Nick, it tends to sound more vintage tubey.   Our tastes all differ.  Mine isnt generally looking for that "proper" or dead accurate sound.  And again, I sure dont priortize with tube shape being at the top of the list.

[StivVid]

Appreciate all your responses.  I'm really enjoying my crack.  Enjoyed building it too.  Think I might build another.

[ualcap]

Back in 2010 Dr Toobz commented on  the Russian 6H13C tube. "sounds a little sweeter and more "tubey" than the 6080 in there before". I've rolled several different combinations of input tubes with this particular tube. I thank a great combo that gives you that sweet "tubey" sound is a RCA 12AU7A clear top/ 6H13C . This is an inexpensive way for new tube rollers to get that classic tube sound from your crack. Plus it has that ST shape so can go for the cool factor as well. Remember to give it some burn-in time.
Try them you may lke them.

[orri]

ualcap; how are the microphonics on the 6H13C? Is it quiet?

In my local store they have two ECC82 tubes available. Does anyone have experience with these and how do they compare with the stock driver tubes?

ECC82 /12AU7WA   RTC FRANCE- VALVE= 12AU7   (29$)

ECC82-JJ   JJ TWIN TRIOCE ECC82/12AU7   (33$)

[ffivaz]

I tested a new JJ ECC82 and did not hear any real difference with the stock NOS 12au7a (RCA ?) shipped with my Crack.

[Laudanum]

Orri ...  the JJ ECC82 is kind of unique for the type, the plates are like the 6DJ8's.  But they shouldnt cost more than about $10 or $11 dollars.   JJ also has an ECC802 with has more of the standard, long flat plates like most 12AU7's.  These are more expensive, around $20.  I think they are marketed as a premium tube and have gold pins.  Premium being a relative term.  Anyway, point is that the JJ tube shouldnt cost anywhere near $33.    I have a couple of the JJ ECC82's.  I like them but with a good supply of NOS 12AU7's in my stash, there are others I prefer.

ffivaz ... I had an new production EH shipped with Crack, so you are lucky to get the NOS tube with the kit (depending on how one feels about the EH I guess).   You are also lucky in a way if you cannot hear any difference between 12AU7's.   New production tubes are easy to find and inexpensive   

[orri]

Laudanum...I live in Iceland where we have only one tube dealer (you can laugh now). So that, along with high custom and shipping fees explains the price. The dealer also has the ECC802-JJ   JJ/ECC802/ A12AU7 GOLD PIN you mentioned at 41$.

How would you compare the sound of these tubes I mentioned compared to the stock ones? I'm curious since installing the speedball I find the Crack a bit too bright and I'm looking for a tube that could reduce the brightness a bit...

[ffivaz]

Laudanum, I said NOS, but it was maybe used

Orri, I read somewhere (can't remember) that the JJ was a quite bright sounding tube. But I may be mistaken.

[Paul Birkeland]

The RTC is probably worth a shot, I wouldn't pay $5 for the JJ (unless it's more than 5 years old).

-PB

[Laudanum]

Orri ...  I agree with Paul, for that type money I'd rather take a chance on the RTC but I dont have any to give you feedback on.    The JJ's I own are all from atleast 10 years ago.  I have heard of problems with the newer production JJ's.   

I may have missed it but I dont know what stock 12AU7 tube was included with your Crack kit.   If I were looking for a warmer sound and tube options were limited I may be inclined to focus on the output tube.   The RCA 6AS7 tends to have a bigger bottom and isnt what I would consider bright up top (or overly detailed either for that matter).   I always seem to be mentioning these tubes and I know some members complain of the bass being too fat or loose.  But it may warm things up and balance out the sound to better suit your tastes.  I'm not really biased in terms of this tube, I actually dont run it normally.  I normally am listening to a 5998.    Personally, Im not all that enthralled by the Russian 6H13C's.   I find the treble a bit brittle/harsh/hard.  But systems, headphones and ears all make a world of difference so YMMV.  There are some 12AU7's and subsititutes that I find a bit less bright.  Some of the RCA's (NOT the clear tops).  I have a couple nice sounding GE 6189's and also some of the Holland made Amperex tubes.   I got good deals on all of these, great deals on the Amperex (and some Philips and rebrands).  All bought on ebay which may be your best option based on your geography.   I have a bunch of 12AU7's and variants but I dont have any uber expensive tubes so those I mention are based only on the tubes that I have and on my mortal ears and my limited audio vocabulary.   

[danosol]

I have a question.  I'm currently running a 12BH7 and a 6AS7 tube setup in my Crack.  Even though the Speedball will allow the 12BH7 without mods,  will the 12BH7 have any adverse effects on the 6AS7, such as tube life?