2. amps-preamps
  3. 1284911452

Tube newbee question

After 30+ years of solid state I now have a bran new Octave V70se currently running sed winged KT88's. I noticed 1 tube glowed a much a brighter blue than the other 3. 2 nights ago (day 5) I also noticed the blue would flicker with the bass. I turned the volume from a 9 o'clock position to about 10:30 when 1 cornor of the tube seemed to get super bright - then a bright blue flash occured with the Octave going into protection mode. Also heard a thud/pop from my right speaker. Recycled power and verified that the bias was set corectly - which it was. I left it in for a couple more hours and it still works but has a much brighter blue glow to it. Octave included a spare KT88 and the next moring I replaced that 1. Well that spare tube also has a brighter blue side. Note I will not put that original back in. Today I swapped that tube position to another and it still has a brighter blue side in the different spot. Today is day 7. So for now I have to assume I had 1 bad tube. My question is seeing a KT88 or even 6550 that glows a brighter blue than the rest a problem to worry about? The last thing I noticed is that both tubes that glow blue brighter needs to have the bias turned lower. The tubes are supposed to be a match quad set.

I also have a matched quad set of EL34's and a matched quad set of 6550's on order. All are factory sed winged c's. I want to eventually pick a favorite tube which is why I got the other sets.

Last my Octave dealer forwarded my concern to Octave and we are waiting for a response. I would like to get any opinions if this is something to worry about.

THANKS
xti16

Showing 5 responses by xti16

xti16 OP
1,525 posts
 
Newbee
Thanks for the response. I'm interested if 1 glows more than the others it a possible problem? Octave offers an option called the black box that increases the capacitance 4 fold and a super black box that increases it by 10 fold. Do you think that may be part of the fluctuating? I'm driving Dynaudio C1's (which love current).

Thanks
xti16 OP
1,525 posts
 
Thanks Griffithds
I'll keep them in mind. Hoping Octave will replace it. I did just buy the V70se and 2 additional quad sets of tubes.
xti16 OP
1,525 posts
 
Yes I am getting a replacement.
xti16 OP
1,525 posts
 
I live in a suburb of Chicago. My speakers are Dynaudio C1's. Funny you mention the black box. I've asked my Octave/dyn dealer to set me up with a black box demo. I read avsforum and Mick from Dynaudio recommends the black box for the C1's and super black box for the larger speakers.

I was able to audition the Jubilees with the Dynaudio Consequence UE at a private showing. All I can say is WOW.
xti16 OP
1,525 posts
 
Thanks for the Info Rrog. I got my replacement last night and it glows just like the other 3. Octave protection is great. Just got a demo Octave 'black box' which increases the capacitance 4 fold to about 60,000uf. Helps in all ways. Control - power - sound stage - imaging - depth. I think it's going to be a keeper.
More to discover