[Carlos3]

What are the differences between the 6922 and 6DJ8 tubes?

 

[Hirsch]

Quote:

Originally posted by Carlos3 What are the differences between the 6922 and 6DJ8 tubes?

The 6922 is designed to handle higher power than the 6DJ8, and for longer life. Otherwise, they're the same. A 6922 will work in a 6DJ8 circuit. The converse is not always true, as a circuit that pushes a 6922 hard may overload a 6DJ8. Usually they are interchangeable.

 

[ServinginEcuador]

In order of longevity and toughness of the tubes the order goes like this: 6DJ8 - 6922 - 7308. I think it is something like 2500 hour longevity for the 6dj8; 5000 for the 6922 and about 10000 for the 7308.

Other than that they are the same exact design and pinout. The higher the longevity the more the tube can handle voltage wise, so replacing a circuit specifically designed for a 7308 tube with a 6dj8 will DRAMATICALLY reduce your tube life. You might only get a few hundred hours out of your 6dj8 in this case for example.

 

[Carlos3]

Thank you both.

 

[headphonecrazy]

Quote:

Originally posted by ServinginEcuador In order of longevity and toughness of the tubes the order goes like this: 6DJ8 - 6922 - 7308. I think it is something like 2500 hour longevity for the 6dj8; 5000 for the 6922 and about 10000 for the 7308. Other than that they are the same exact design and pinout. The higher the longevity the more the tube can handle voltage wise, so replacing a circuit specifically designed for a 7308 tube with a 6dj8 will DRAMATICALLY reduce your tube life. You might only get a few hundred hours out of your 6dj8 in this case for example.

I've replaced my 6922s with some Siemens CCa. What do think them and their lifespan?

Thanks

 

[ServinginEcuador]

Quote:

Originally posted by headphonecrazy I've replaced my 6922s with some Siemens CCa. What do think them and their lifespan? Thanks

A CCa tube is a hand selected set of tubes from Siemens with extremely tight tolerances and the lowest microphonics of all their 6922 tubes. They only allowed some 5-10% of all their 6922 tubes to be chosen as CCa tubes.

IMHO, these were the best sounding tubes of the entire 6dj8/6922/7308 family. I bought two pairs of early 60's tubes, the ones with the dull grey all around the middle section, and thought that they were absolutely incredible sounding tubes. A little dry sounding, but very detailed and nice. I had mine cryo treated and that gave them a little longer life and a slightly different sound. (In a good way different.)

 

[kuma]

Quote:

Originally posted by ServinginEcuador IMHO, these were the best sounding tubes of the entire 6dj8/6922/7308 family. I bought two pairs of early 60's tubes, the ones with the dull grey all around the middle section, and thought that they were absolutely incredible sounding tubes. A little dry sounding, but very detailed and nice. I had mine cryo treated and that gave them a little longer life and a slightly different sound. (In a good way different.)

Agreed. So far nothing remotely come close to Cca's clarity and frequency extensions.

 

[george]

If you go to Audio Asylum to the FAQ section and look under Joe's Tube Lore, http://www.audioasylum.com/scripts/d...oes-tubes.html you will find a good bit of information regarding these as well as other small signal tubes. Also Vacuum Tube Valley http://www.vacuumtube.com/ publishes a magazine and under back issues you can order Issue 7 from Spring/Summer 1977. The lead article is "The 6DJ8 and other Frame Grid Tubes" which also gives you a good overview of what was made and the differences between the different tube types. ServinginEcuador summed it up well though in terms of the evolution. The latter tubes (7308) were made to be more durable than the earlier versions.