Tube Rolling w/Crack

[Laudanum]

I thought the Crack transformer was only capable of 3.5 amps, max, for filament supply for both tubes .  Or is it 3 amps?   Or am I just nuts.  If it's what I think it is, it probably isnt much wonder why the amp is running hot.

[Lee Hankins]

Desmond, you are correct, I installed an additional 3A filament transformer..

[Paul Joppa]

Desmond, you are correct, I installed an additional 3A filament transformer..

I hope that's a misprint, if you're drawing over 5 amps!

[Laudanum]

Desmond, you are correct, I installed an additional 3A filament transformer..

Got it.  I was wondering how in the heck it was running at all   

[nick-seattle]

I got all the tubes in and did some rolling. Very short summary. All tubes are awesome and add their unique character to any music.

5998 - very relaxed, very deep. very smooth. The reference tube.
7236 - very close to 5998 at a fraction of the cost (~$20). It's not as relaxed, but at the same time more dynamic.
Sylvania Gold Brand 6080 - very liquid tube, you just want to continue listening. The price is unbelievable - $9 a tube!
Bendix 6080 - very dynamic, very detailed - superb performance during complex passages, separates instruments like no other - think Mozart Sym. 41. Very hard to find

[dwilli852]

Picked up an Amperex/Valvo Bugle Boy 12AU7 made in 1957 at Hamburg according to the information I have about the date code. May be the best sounding 12au7 I've heard in the Crack with NOS RCA 6AS7 and HD 650s.

[dwilli852]

Got a couple RCA branded 6AS7 tubes from the mid 1950's. Both are black plates. Both are great sounding tubes.. At $9.95 for the pair plus $5.50 shipping a good bargain. Looking for a 5998 and WE 421a but not willing to pay the high prices.

[jrihs]

This looks interesting!....

http://www.ebay.com/itm/1-RAREST-12AX7-TYPE-TUBE-EVER-MADE-ONLY-ONE-SAMPLE-CIRCUTTRON-OR-12AU7-NOS-NIB-/290717388630?pt=Vintage_Electronics_R2&hash=item43b01b4f56

[Laudanum]

Got a couple RCA branded 6AS7 tubes from the mid 1950's. Both are black plates. Both are great sounding tubes.. At $9.95 for the pair plus $5.50 shipping a good bargain. Looking for a 5998 and WE 421a but not willing to pay the high prices.

Related to your other post as well  ... I have a few Amperex Holland (Herleen)  12AU7's and they are probably my favorite 12AU7's for Crack.  Maybe not exactly your Hamburg Amperex but I bet it shares similiar sonics so I think I understand your liking this tube.  And I agree, they sound great with the RCA 6AS7's ... or atleast my Herleen tubes do.  Also great with the 5998 so hopefully you can find one and see, or hear, for yourself.  Those 5998's were always a bit elusive from what I understand but really elusive lately.  I was fortunate to find the ones I have when I did.  All mine were purchased as used but 2 of the 3 that I have were tested as new and even look like they could have been NOS.  The 3rd had a bit of use but still tests very strong (emission tester anyway)  and sounds great.   They are all different ... same dimpled plates as all of them but different getter (top, bottom).  They all sound the same, regardless.  To my ear anyway.  Im sure you'll find one or two.  I got lucky when I found mine. 

[jrihs]

I've always had good luck with ebay 12au7's but I've just had my 3rd 5998 refunded for having a weak right channel. For all the trouble I wish I had just bought a 421a from a more reliable source. The two are very similar, but to my limited experience, the 421a is slightly more transparent while the 5998 has a slightly bigger presentation (perhaps more bass impact?). Hopefully I will be comparing again soon. 4th time a charmer I hope, as its on its way!

[Dr. Toobz]

I've noticed that output tube rolling has tended to be more of a crapshoot than the driver. Case in point: I bought two NOS 6AS7G tubes on eBay and both hum and/or emit a high-order harmonic of 60Hz hum - one noticeably - and that was followed by a 7236 that had no cathode emission. The 5998 I owned before that was very microphonic. Turns out the quietest and most reliable tube I've found so far was the original, lowly 6080 supplied with the kit. It's dead quiet - but seems to be a bit bland or lacking in character compared to other tubes I've tried.

[nick-seattle]

I actually had a fairly good experience with output tubes on Ebay. I got all the tubes mentioned before (about 10 in total) without any problems. I was about to return GB 6080 due to crackling noise in one of the channels, but after I contacted seller, I figured out that the noise was coming from driver tube - the seller was very relieved . Even the 5998s that I got recently which were listed as weak are performing admirably and test quite well. Ebay is definitely a lottery, but with protection

[nick-seattle]

Here is an interesting tube that I recently found by accident. Sylvania JHS 12au7 Black Plates. It's the 12au7 version not the 5814 - 5814 has a different plate structure. I rolled that tube yesterday and compared this to JHS 5814 & JHS 6183 - all black plates. This tube won hand down. Very creamy and lushes sound with superb bass. I couldn't find info about that tube anywhere, so want to share my finding with the community. A very cool, cheap and unique tube. I rolled with along with CBS-Hytron 5814 from 1954 - and this one won Not just me, but I tried this with a few friends as well, all of them agreed in the blind testing that JHS 12au7 is more creamy and has more body.

If you are interested in the full review (it has a large picture) - you know where to find it
http://tubemaze.info/sylvania-jhs-12au7-black-plates/

[Paul Joppa]

A quick note here; many tubes are available as used, and are often tested for emission. Low emission would be a problem if you were pushing the limit on current. Specs are variable but I see 125mA for a 6080WA and 140mA for a 5998A. Crack only needs 30mA; even our experimental high-current Crack is running 60mA or less.

I'm not saying every weak tube will still sound good, just that it's always worth actually listening before making judgements.

[nick-seattle]

A quick note here; many tubes are available as used, and are often tested for emission. Low emission would be a problem if you were pushing the limit on current. Specs are variable but I see 125mA for a 6080WA and 140mA for a 5998A. Crack only needs 30mA; even our experimental high-current Crack is running 60mA or less.

I'm not saying every weak tube will still sound good, just that it's always worth actually listening before making judgements.

Ahh. So that makes a lot of sense. Even more savings with Crack!!! What about Driver tube? How hard is it being pushed? I definitely see immediate issues with tubes with emission below 85%.