Tube Rolling w/Crack

[ipetruk]

RCA 12AU7 are usually the cheapest and among the best tubes for Crack. Unlike power tubes, here price does not normally correlate with quality. With power tubes 5889 and GEC are normally much better than stock

[monsterdonkey]

I’ve got a few RCA 12AU7 variants including a clear top, a grey plate, and a black plate 5963. They all sound great with my TS/Chatham 2399. The clear top is a little bright with my GE 6080, but good with the 2399 and 6AS7G. I think what I’m looking for changes from time to time. Sometimes a dark recording needs that little top end boost. The other day I plugged my Sennheiser HD600 directly into my NAD C740, which I can’t remember doing since building the Crack almost ten years ago because why would I, and was pleasantly surprised.

[Mucker]

........ the donkey was large ... big .... huge ... gigantic ..... it was a Monster ..... a monsterdonkey! I have nothing else .......

[trickyricky123]

RCA 12AU7 are usually the cheapest and among the best tubes for Crack. Unlike power tubes, here price does not normally correlate with quality. With power tubes 5889 and GEC are normally much better than stock

I can see RCA 12AU7 and RCA 12AU7A? Any significant difference between these?

[Paul Birkeland]

No, the A suffix means it works properly in circuit with lots of tube heaters strung together in series.  This isn't something you're going to run into much in modern HiFi.

[alanchongth]

Hi, I am new here. Can Russian 6H5C (6N5S) use directly in Crack 1.1? Thanks in advance ...

[Paul Birkeland]

Yes.

[alanchongth]

Good day. I have another question, can E80CC be used directly in Crack 1.1 without speed ball upgrade? I have speed ball kit but not yet implement. I am planning to enjoy Crack original version for a while, then only upgrade to speed ball version.

Thank you.

[Paul Birkeland]

I would change the 22.1K plate loading resistors to 47K/2W resistors if you want to do that.

[N72826]

Hello everyone,
I performed some mods to my crack w/speedball which I can get into detail about later, but for now I just wanted to get some opinions on this because the mods aren't relevant to my question.
I swapped the 12AU7 to a Valvo 45 degree getter ECC82. The listing I bought was $68 and didn't contain a date of manufacture or testing information but I just wanted to spend as little money as possible to get a feel for this tube. I heard the ECC82 to aim for is the Valvo ECC82 Long Plate Foil D Getter 56' but they are $500≥ on ebay and I wasn't sure I was willing to drop that much on a tube.

I think the tube sounds great despite how much I paid for it. The bass has been improved significantly and the music feels closer or more present like I'm in between the sound. I guess if I'm getting really nitpicky, the treble sounds a little muddier but I will have to swap back and see. The only real issue is I hear a hiss that remains a static volume regardless of the volume knob position that is predominantly in the left channel. When I'm playing music, I obviously don't really notice it but I just wanted to hear if there is anything I can do about it or if I simply get what I pay for(I'm assuming the latter is true.)

I would leave a link to the listing here but I guess I'm not allowed. so if you really care to check out the listing yourself to see how much of a gamble it was:    ebay . com/itm/155521619912

I also don't know what the numbers on the sticker indicate but I assume the testing information? I can take some photos of it myself because I know the listing photos are really difficult to make out. It seems like the sticker reads 11.0 and 9.5 but I'm really uncertain.

EDIT - 01/30/2024: I am letting the tube burn in because I looked around online and that is what many others suggested including Mucker who replied below this post. From what I can tell now thinking about it/listening, the hiss is definitely dissipating and has gotten significantly better since I initially powered it on.

I created this post to ask about the hiss but my true question stems from a bit of FOMO. Is there a lot I could be missing out on by using my tube instead of the very specific version I mentioned above that is manufactured in 1956? To put it another way, what really distinguishes my tube (which I assume was manufactured more recently and is therefore cheaper) from the other listings that seem to be confirmed to have been manufactured in 1956? I'm really enjoying it and don't see why I would want to buy another one other than to say I have it at this point, or to find one that tests better.

I know I won't receive an answer that satisfies my line of questioning without being able to directly compare my tube to the more sought after and expensive version but I just thought I would ask because this question isn't really limited to this tube. So considering the following question that is broadly applicable to any tube, why are the newer versions/recreations cheaper and less sought after? Is it a classic case of elitism? Or are there genuine differences in how they are manufactured that could lead to different sounds? And should I even care?

[Tom-s]

I also don't know what the numbers on the sticker indicate but I assume the testing information? I can take some photos of it myself because I know the listing photos are really difficult to make out. It seems like the sticker reads 11.0 and 9.5 but I'm really uncertain.

That's the test result. The listing states it was tested on a Funke W19s.
This is a quality emission tester from Funke. That has a regulated anode voltage (150V voltage reg tube) and tests at 0 or -2V bias.
In case of the 12AU7 / ECC82 it tests as a diode.

To compare what would be the estimated result I allways suggest to look up other listings with tubes from this the tester used in the add. This gives a better idea of what the result should be.
As it now supposedly is tested "gut"/ good. The Funke is known as a tester that make's every tube look "good".

But this isn't whole story. Good on testers is a very widely used term.
When a tube gets more use; it wears out the cathode. And the insulation between heater and cathode may get small cracks. That can be heard as a hiss when used.

The following information is borrowed from a French forum.
First is the tube curves for ECC82 and how it should test in the Funke.
Second is a picture of the Funke W19. As you can see a good ECC82 is 17-20mA or thereabouts.

Curves.

Funke ECC82.


Hope this helps anyone for future purchases.

[N72826]

Hello Tom!

Thank you for the insightful reply, I learned a lot and really appreciate it.

I think you provided the answer to my main question when you said the following:

When a tube gets more use; it wears out the cathode. And the insulation between heater and cathode may get small cracks. That can be heard as a hiss when used.

I think my misunderstanding was in thinking that these tubes are even made anymore. I just assumed people were going after the 1956 versions because they were the "originals." When in reality, I think what you are telling me is that any sought after tubes were only produced for a limited amount of time, and that the ones that go for more money are the ones that have the least amount of usage and therefore test well after all this time. I am easily confused with all these iterations of what seems to be the same tube with only a couple years between the manufacturing date and various descriptors that attempt to uniquely identify each listing.

My interpretation of your reply might still be wrong but I think I understand it now. If I am wrong and there are "re-issues" of vintage tubes than feel free to answer my only remaining question, why would people go for vintage stock when there are re-issues that very likely have less cathode wear?

I want to be certain that my previous question isn't one that warrants a response because you cleared everything up pretty well. But I have a proclivity of casting a healthy amount of doubt on my interpretations just in case

[Paul Birkeland]

why would people go for vintage stock when there are re-issues that very likely have less cathode wear?

The reissues that do exist don't really sound anything like the originals.  The old stock tubes tend to also last a whole lot longer than the new ones, though there have been some improvements over the last few decades.

[N72826]

The reissues that do exist don't really sound anything like the originals.  The old stock tubes tend to also last a whole lot longer than the new ones, though there have been some improvements over the last few decades.

Hello Paul!

That's interesting, I will keep that in mind going forward. And thank you guys for responding so quickly, I didn't expect all my questions to be answered so efficiently.

After having swapped back to my 12AU7, I can say for certain that there is noticeable difference in clarity compared to my ECC82. I didn't know how to evaluate test results until Tom explained it and provided the image showing the tube should land at at 17-20mA on the Funke. My ECC82 sticker says 11.0 and 9.5
Now I understand why I got it for $68.   

Oh also, my ECC82 is labeled K63 D9R, just noticed that recently as I was swapping the tubes out. Not sure what to make of that but I'm going to look around and determine what I even have because the ebay listing didn't specify the year or anything really. I think 63 means 1963 but I will set aside the speculation lol

Do you have any 12AU7 sub ins that you would recommend I take a look at if I'm trying to aim more bass heavy? I absolutely loved the bass when using the ECC82 and I think it helps that I'm also using the Tung-Sol 5998 in place of the 6080.

[Paul Birkeland]

 If you have a Speedball in your Crack, what are the OA and OB voltages on the small board with that tube?  That can be used as a bit of a test for whether the 12AU7 is near the end of its life or is relatively fresh.