Tube handling/designations

Heat is the enemy of tubes- they ought to be kept clean of dust and fingerprints for the longest life. 6DJ8s and 6922s are capable of running a fair amount of current and so can get quite hot.

Tubes will not burst the way a halide bulb will burst from skin oil depositing on the tube. With halide bulbs, the oils are subjected to extreme heat which causes the oil to break down and carbonize. The black deposit that results will then absorb much more of the light being put out by the bulb than the rest of the glass on the bulb. The difference in temperature between the other part of the glass and the part with the black spot causes stress in the glass which can lead to failure. These bulbs are under extreme stress from the high pressure gas in them.

Tubes do not operate under similar conditions -- heat is lower, no significant light output to be absorbed by a spot on the glass, a vacuum instead of high pressure, etc.

Still, I don't see why caution would hurt, particularly with hotter tubes, like a 211 or 845.

You do not need to use all the same brand and there are certain positions that will affect the sound more than others. The 7308s and also CCas are generally, but not universally, considered to be the best of the the 6DJ8/6922/E88CC/ECC88 family of tubes. Google Joe's tube lore to get info on the sonic differences btwn diff brands and members of the family. And also be aware that BAT products are not GENERALLY considered to be as susceptible to dramatic changes due to tube rolling. Also be careful of counterfeit and dramatically over-rated (meaning sold as NOS but barely functional) tubes on (Fl)ebay!! You should consider a tube tester and get return rights on tubes. A legit seller will provide that. Also talk to members Kalidekol and Jsautter for tube sales and good advice.

I would recommend the Siemen CCA's in your VK 30. They are among the best in the 6 volt 9 pin family. I have not had a good experience using the 6dj8's in the BAT preamps. Other peoples experience may vary.

Your best bet is to replace all the stock tubes in your Bat VK 30. Also the 6922 tesla,s are a upgrade over the Sovteks but I recommend that you consider amprex bugle boys as a start in your quest for a bigger improvement in presatation and soundstage. Here is some additional info regarding these 6 volt 9 pin twin triode tubes...6dj8=ecc88 6922=e88cc 7308=e188cc tube(6dj8) cv2492=6922 and 7dj8=pcc88(a 7 volt tube that I have used with great sucess in my pre in leu of 6dj8's). Feel free to e-mail me in regards to extra quads of tubes that I have avaible from collection of slightly rolled tubes
Dennis

Thanks for the info guys.I've got one more though.Do I have to replace all of them to get a change in sound and do they all have to be the same brand?

Call BAT before you start sub'ing tubes. Most anything that takes 6DJ8's can take 6922/6h23's BUT not everything that takes 6922's can run 6DJ8's as effectively. They are not identical tubes. FWIW.

I just wash my hands first. DO make sure that if you get fingerprints on the tubes to wipe them off thoroughly. Washing tubes can be a problem since the paint usually washes off too...

I think you can use cv4004 also???
6922's are great tubes and easy to roll. Personally, I like Telefunken for any kind of tube, followed by Mullard and Amperex Bugle Boy/trumpeter(much better than the basic amperex). Golden Dragons are good, JAN can be good too.

Keep in mind that these will last 5000 to 10000 hours for good ones. So, to spend $100 for good ones vs $20 for Sovteks is worth the difference! You should be able to find nice pairs for $60 to $90/pr. Mint NOS Telefunkens will run more. The old tubes were made much better than some of today's junk like some russian and many of the chinese tubes.

Good sites to search for tube ideas:
Upscaleaudio.com
thetubestore.com
tubeworld.com pricey
tubesandmore.com
echohifi.com
jeffsoundvalues.com

When I handle my tubes I will generally wipe them off before I turn them on. Tubes don't get as hot as halide lights and I have never seen one blow out like a halide but I think a little caution is prudent.

There are many equivalent tubes to 6922. It gets a little confusing at times but you get used to it after a little while. Some of the tube types that can be used instead of 6922 are 6DJ8, ECC88, 6H23, 7308.

New Old Stock are old production tubes that have never been used. I don't know exactly why older tubes are better. It seems there was an art to tube making that has been lost after tubes went from being the pinnacle of high tech to a niche product. Some of the old tube makers are Amperex, Siemens, Telefunken, RCA, Tung-Sol, Mullard, Sylvania... There are some real nice new production tubes that are available now so not all the art is lost. I really don't use 6922s anymore so I don't know were to point to for new ones.

Cheers,
Jim