[Dangerman]

I am a tube newbie and need some help.  Only one component in my system has tubes--my Lite DAC 60 (purchased from GR Research w/mods).  I've had it for about 3 years, and it is on for several hours a day.  I recently noticed that my system sounded thin and out of balance.  Both channels still have sound, but one has much lower volume and lots of hiss.  I did an A/B comparison of the DAC and my receiver's on-board DAC, and it was obvious that the problem is coming from my DAC.

I switched out all the cables, but the problem persists.  Then I pulled the tubes and reversed them.  Low and behold, the problem is still there, but now in the other channel.  So, I know it is the DAC, and I know that the problem is with one of the tubes.

Here's the questions:
1.  Does this description sound like one of the tubes is dead?

2.  When a tube goes bad, will the sound stop, or degrade over time? Will the tube still glow?

3.  How do I figure out what tubes I need to replace my old ones?
 
Thanks for the help.

[JerryM]

I am a tube newbie and need some help.  Only one component in my system has tubes--my Lite DAC 60 (purchased from GR Research w/mods).  I've had it for about 3 years, and it is on for several hours a day.  I recently noticed that my system sounded thin and out of balance.  Both channels still have sound, but one has much lower volume and lots of hiss.  I did an A/B comparison of the DAC and my receiver's on-board DAC, and it was obvious that the problem is coming from my DAC.

I switched out all the cables, but the problem persists.  Then I pulled the tubes and reversed them.  Low and behold, the problem is still there, but now in the other channel.  So, I know it is the DAC, and I know that the problem is with one of the tubes.

Here's the questions:
1.  Does this description sound like one of the tubes is dead?

2.  When a tube goes bad, will the sound stop, or degrade over time? Will the tube still glow?

3.  How do I figure out what tubes I need to replace my old ones?
 
Thanks for the help.

Yes, it sounds like a tube has definitly gone bad. Sometimes tubes just stop, but most of the time they exhibit exactly what you have described.

Do the tubes have any markings or numbers on them? If not, call Danny at GR; he'll help you out with what tubes you need to get her up and running again. 

Have fun,
Jerry

[HAL]

The other group you can contact is Sonicraft.  They did the Lite Audio DAC-60 mods.  They can help with tube replacements. 

[Pez]

Call the manufacturer??? Just pop the thing open pull the tube out and determine what make it is. Then google "<tube type> equivalent" and that will tell you what to use.

[HAL]

Depends on when the DAC-60 was moded as in some of the later mods, they changed the tubes for NOS tubes. 

If the tubes have no labels, then they are the NOS tubes that Sonicraft supplied, not the stock Lite Audio tubes.

[Dangerman]

They are 6922s.  The originals are Sovtek.  I want to replace then with something good, but not too pricey.

[HAL]

The NOS tubes were an upgrade in sound to me and not very pricey from Sonicraft. 

[Pez]

I would try the JAN Philips 6922. I have heard great things about them. I don't know if $20 is too pricy buy it'd probably be worth it.

[Pez]

Check it out. Tons of choices. Roll like villan son. http://thetubestore.com/6dj86922types.html

[HAL]

The reason why I mention the Sonicraft tubes is that they did a lot of listening to tubes to determine a very good sounding one with the mods.

Good luck with the selection.

Happy Holiday's.

[rollo]

The reason why I mention the Sonicraft tubes is that they did a lot of listening to tubes to determine a very good sounding one with the mods.

Good luck with the selection.

Happy Holiday's.

 Good idea. It would be prudent to read about the sonic flavor of the NOS tubes. Then one can make a educated selection. Some are rich some are bright and thin. Each system is different and maybe no tube is a overall winner.


charles