Tube Rolling w/Crack

[mosshorn]

Got my Sylvania 6AS7G in today, and I still hear some noise, could it perhaps be from the driver tube? I'll have an RCA soon to compare it to. Also, it was making a noise outside of my headphones when heating up, which I'm supposing is just it heating up, but I want to make sure

[Laudanum]

If it's the same noise, then yes, very possibly the driver.  Are you sure that the external noise is originating from the tube and not the amp itself?

[mosshorn]

Well, I went from annoying to bad. Looking under the hood, I found I didn't solder B7L or B8L, so I did. And now it won't power on -_- Back to the troubleshooting......


EDIT: Fixed it, and I swapped tubes again. The 6080 is significantly more noisy than this 6AS7, so I'll see if the RCA I have coming will remedy it.

[jrihs]

Sorry to repeat but I got bumped and rather urgent...

Does anyone have experience with CV4003's made by the English Electric Valve Co. Chelmsford? They look like the Mullard version. Do they sound as good though?

Anyone have anything by the English Electric Valve Co.? Perhaps rebranded mullards?

Thanks again!!!

[defenestration]

just threw a cheapo perma-test 12bh7 off ebay in my crack, initial impression is of a markedly more restrained and less fatiguing presentation, heavily compressed electronic music recordings are now much more listenable through my 'phones

ear fatigue is a big thing for me so I'm liking this so far

[Herrfish]

How about a 6520 in an non-speadball Crack? I don't see it on the list, but it appears to be an alternative.

[Paul Joppa]

6520 is - supposedly - a well balanced 6AS7G. The only one I ever saw was not at all well balanced between sections, so caveat emptor, but it should be otherwise identical to a 6AS7G.

[Herrfish]

Thanks Paul. Sorry for the elementary question, but this imbalance translates to a stereo imbalance between the headphones drivers?

[Paul Joppa]

Because the Crack output is a cathode follower, the gain difference will be much smaller than any difference in mu or gm (tube parameters). All tubes will have some difference in gain due to manufacturing variations, which though possibly audible are much much smaller than differences among solid-state devices. This is one of the things that makes it possible to forgo negative feedback in tube devices.

[jrihs]

Hi! Anybody have any opinions on Valvo 12au7's...not so much the 30 degree getters, which I hear are similar to telefunkens.
Thanks in advance.

[jrihs]

Hi all,

I am enjoying my E80CC very much. Juicy sounding, like an old english radio, and very detailed/clear. Percussion and wind Instruments are grand with this tube. Soundstage nearly as good...or maybe as good, as the Mullard CV4003...

Had a question though, I see the E80CC's advertised as both replacements for 12au7's and in yet other ads, as replacements for 12ax7's. Can the later be true? If so I'll try them in my phono stage as well...

Thanks in advance!

[Paul Joppa]

They are lying. E80CC takes twice the heater current of either 12AX7 or 12AU7, and has a gain of 27, not very close to 100 or 17 respectively. It will "work" in some circuits, that is sound will come out, but not the way the designer intended. In some cases it can do some damage. I think this has been covered in another thread ...

[BNAL]

Thank you all for the feedback.

I ordered the mullard and cifte tubes in platinum grade. But not with cryo threatment, i want to hear the original sound. May order some later to hear the difference

Know i just hope the crack will respond well to good tubes

Langendorf,

I did the same. I just put the Mullard in after listening to the CIFTE for a couple of weeks. I really like the CIFTE, becuase of its detailed sound and nice exstention. I have only listened to the Mullard for a couple of hours, but this is a very nice sounding tube as well. It seems to have a warmer sound. Not sure which I like better, but can say that this has been the biggest improvement in sound.

What do you think of the Mullard and CIFTE tubes?

Now I'm looking at what I want to try in place of the 6080.

[mosshorn]

Have an NOS RCA 12BH7 on the way, got a decent deal on it so couldn't resist What would the negatives of running it in a stock Crack be as opposed to the Speedball? Wirewounds perhaps?

[jrihs]

They are lying. E80CC takes twice the heater current of either 12AX7 or 12AU7, and has a gain of 27, not very close to 100 or 17 respectively. It will "work" in some circuits, that is sound will come out, but not the way the designer intended. In some cases it can do some damage. I think this has been covered in another thread ...

Thanks Paul, it sounds very different (better to my ears) with the speedball than it did before. Why is that? Please excuse if this was covered elsewhere...