Tube Rolling w/Crack

[Blue]

It is definitely the DAC, or the combination of everything together.
The same songs on vinyl are much more pleasing. No harsh highs, or harsh silibance!
My ears feel extremely comfortable now

It’s too bad the DAC produces the harshness, but I can live with it.
Thanks guys!

[JLDub]

That's unfortunate. It would seem just because something measures well, (thanks ASR) doesn't mean it will sound pleasing to the ears. I personally have the mimby and love it. You could swap tubes and it may curb your frustrations with the DAC, or you could sell the DAC and get something less harsh. Good luck!

[Jake1]

Hey!  So I was just looking into tube rolling and read the stickied post and a few others for info.  I've been struggling to find info on what all the different letters and numbers in the tube names mean, and how to determine if they're compatible.  I was looking at some Mullard CV2984 6080 6AS7 tubes that I think are compatible, but wanted to confirm here first. I also had a few other questions, and any help would be appreciated!

-What does the info on what all the numbers/letters mean as far as compatibility goes?
-What is the difference between military vs nonmilitary tubes?
-Does the speedball installation make a difference with tube compatibility?
-Would accidentally using an incompatible tube cause damage to the amp or voltage discrepancies?

Thanks

[Paul Birkeland]

-What does the info on what all the numbers/letters mean as far as compatibility goes?

That's a bit of an overly general question.  You'd have to ask the specific differences between two specific tube labels to ask a question that's more answerable.

-What is the difference between military vs nonmilitary tubes?

Sometimes there isn't any beyond a different box and some different printing on the tube. Sometimes there is an extra mica support inside the tube, sometimes there are other modifications for better shock/vibration performance.  This is dependent on the tube itself and what the datasheet might or might not call out.

-Does the speedball installation make a difference with tube compatibility?

Nope.

-Would accidentally using an incompatible tube cause damage to the amp or voltage discrepancies?

Yes!

[Chris65]

What does the info on what all the numbers/letters mean as far as compatibility goes?

There were/are no universal numbering or code system for tube designation. There are some general rules but even these don't always apply. This site may give you some insight:
https://www.vintage-radio.com/repair-restore-information/valve_valve-numbering.html

[Jake1]

Thanks for all the info!  Also is the  Mullard CV2984 6080 6AS7 tube compatible with the crack?  And how do you check the compatibility between tubes and amps?

[Julyan9]

Thanks for all the info!  Also is the  Mullard CV2984 6080 6AS7 tube compatible with the crack?  And how do you check the compatibility between tubes and amps?

Yes it is. The amp takes 6080/6AS7 tubes. You can read the first page of this thread to see which tubes you can use with the crack.

[Tom-s]

For compatibility, check the first page. Search the web for equivalents. Use the search on this forum for previous threads concerning the same question/tube. If you're still in doubt, ask here.

[Paul Birkeland]

Also is the  Mullard CV2984 6080 6AS7 tube compatible with the crack? 

The CV2984, the 6080, and the 6AS7G are all different tubes.  They all work in the Crack.

[Rossputin]

In my limited experience researching tubes and buying a few: on eBay some tube sellers will include multiple tube identifying numbers for a tube that's obviously only one of those. Not necessarily trying to deceive but rather including the identifiers of tubes that can usually substitute for each other with only modest differences between then. The issue is that what a seller might thing is a reasonable substitute might not be in your own particular application so you have to do a little more homework.

I'd love for someone more expert to respond to my interpretation of the situation.

[Paul Birkeland]

on eBay some tube sellers will include multiple tube identifying numbers for a tube that's obviously only one of those.

Yes, this allows someone searching for a 6080 to see the CV2984.   The opposite will also be true though, where someone selling a garden variety 6080 will also add CV2984 in the title to appear in the results for searches of CV2984 (there is 1 legit CV2984 on eBay at the moment, but plenty of other listings that pop up when you search for them).

[Jake1]

In my limited experience researching tubes and buying a few: on eBay some tube sellers will include multiple tube identifying numbers for a tube that's obviously only one of those. Not necessarily trying to deceive but rather including the identifiers of tubes that can usually substitute for each other with only modest differences between then. The issue is that what a seller might thing is a reasonable substitute might not be in your own particular application so you have to do a little more homework.

I'd love for someone more expert to respond to my interpretation of the situation.

Yeah that makes a lot of sense.  That's what confused me in the first place because I thought all of those different labels meant different things.

[loz_the_guru]

Hi all,

Anyone have any suggestions for purchasing tubes in the UK? There's a limited selection on ebay, and all seem a little more expensive than prices i've seen quoted elsewhere. A quick google search wasn't particularly revealing either!

Any UK based crack fans help me out?

[Chris65]

Not in the UK, but can suggest https://www.langrex.co.uk. Not necessarily the cheapest, but they do have a large stocks, and prices can be reasonable.

[Deluk]

I'm in the UK and Langrex are only about 65 miles from me. I have bought a couple of valves from them via eBay, no problems. Mullard CV2984 (£30) and Svetlana 6AS7G (£12). Both new and work well. Currently, have the 6AS7G in. Small differences with both compared to the original 6080 supplied with the kit with the 6080 may be coming out top for me. I'm using a Mullard CV4003 with them. Found that one in a box of sundry tubes I had in my stash.
Crack with Speedball to fit sometime, maybe this winter.