Tubes, tubes and more tubes. What if…

GlennDog

I ran into an audio snag the other night. The volume out of the right channel is significantly less than the left. So I rotated another piece of gear into where the little trouble maker is and voila! problem gone. So the issue has been isolated to the first component

Representative from the audio company is suggesting I swap out the tubes, which obviously makes sense. But getting to all my connections behind the black boxes is always challenging (read pain in the arse). Also, since the tubes are not exposed (they’re inside the chassis) I was thinking, why not reverse the cables instead of having to perform surgery?
Sounds like a much easier solution, right?

The representative is telling me that this won’t necessarily tell me if there’s a tube problem
I disagree. What do you say?

Thanks guys n dolls!

michaeljhsda2

Agree, reverse the cables.

GlennDog

michaeljhsda2 wrote: »

Agree, reverse the cables.

This solution would be sooo much better. Thanks

I had this same exact issue a few months back. I swapped out the tubes, no improvement and ending up having to ship the unit back to CS

pitdogg2

DANG IT.....
why do I feel baited and switched by the dang title....

GlennDog

pitdogg2 wrote: »

DANG IT.....
why do I feel baited and switched by the dang title....

Nah, don’t.
But maybe, if it was under the “what did you do to your stereo rig today” thread

Actually, I was hoping you and Doc would chime in with your vast knowledge 😳

pitdogg2

Doc has vast knowledge, I just have burnt synapses.
Reverse the cables, can't hurt may not help.
You have access to a tube tester?
Dave still own one? Is he close?

What tubes and gear are we talking about?

Nightfall

Dang. I was ready to buy some tubes. 😉

GlennDog

Reverse the cables, can't hurt may not help. … I was really hoping for a definitive answer

You have access to a tube tester? Nope

Dave still own one? Not sure

Is he close? Yeah. But if it’s going back to CS, I’d like to ship it out today

What tubes and gear are we talking about? DAC with ecc99 & 5963

michaeljhsda2

You could swap tubes and see if the problem follows to the other side....sounds like it needs to be shipped out, unless you have known good spare tubes to put in there.

GlennDog

I was hoping to avoid that. But I guess it’s the only definitive way to know

pitdogg2

Do you just have one of each tube Glenn?
I find those 5963 tubes very lifeless and dull. I've tried RCA bronze plates and CBS gray plates, neither lasted long for me.
They (5863/ecc99) are completely different tubes so unless you have two of each you really can't switch those between each other circuits.

mhardy6647

So --

GlennDog wrote: »

I ran into an audio snag the other night. The volume out of the right channel is significantly less than the left. So I rotated another piece of gear into where the little trouble maker is and voila! problem gone. So the issue has been isolated to the first component

So, without knowing what kind of "piece of gear" you rotated, it's a little hard to comment on your troubleshooting strategy in the abstract
Won't stop me from trying, though.

So - which cables do you propose to reverse? The ones going into the piece of gear you swapped out, or the ones that come out of it?

If the former, and if the low level follows the input channel, the problem's upstream of your "piece of gear" -- but of course that wouldn't explain why swapping out the "piece of gear" leveled the two channels.

If the latter, all it means is you will probably confirm which channel's low in your "piece of gear" -- which you already knew, right? You need to know why.

... unless, of course, you think the problem is with the cable itself -- in which case, I'd swap in a different pair of cables entirely and see what happens.

GlennDog

The 99s are JJs input tubes and outputs are Philips JAN 5963. Two of each.

Just swapped em around and equal vol from each channel! WTH?

I suppose it’s an overheating issue and something in the circuit is partially opening??

When this happened previously I was not informed of the corrective measures taken

Now what do you guys think?

invalid

GlennDog wrote: »

The 99s are JJs input tubes and outputs are Philips JAN 5963. Two of each.

Just swapped em around and equal vol from each channel! WTH?

I suppose it’s an overheating issue and something in the circuit is partially opening??

When this happened previously I was not informed of the corrective measures taken

Now what do you guys think?

Check your tube pins and tube sockets could just be a bad connection

mhardy6647

invalid wrote: »

GlennDog wrote: »

The 99s are JJs input tubes and outputs are Philips JAN 5963. Two of each.

Just swapped em around and equal vol from each channel! WTH?

I suppose it’s an overheating issue and something in the circuit is partially opening??

When this happened previously I was not informed of the corrective measures taken

Now what do you guys think?

Check your tube pins and tube sockets could just be a bad connection

A distinct possibility.

In terms of things heating up and changing... well... it certainly happens... but if that's the problem, it will present itself over time. Did the lower output on one channel happen gradually (or suddenly, for that matter) after the component had been "on" for a while?

If not... a component (resistor or capacitor, e.g.) breaking down when warm is not a likely culprit.

If so -- the age-old troubleshooting tool for such problems is a can of "circuit chiller". Don't spray tubes!


https://www.parts-express.com/max-pro-fr-777-777-freeze-spray-10-oz--341-460

so... what kind of equipment are you having (perhaps intermittent) trouble with, @GlennDog ?

GlennDog

It’s a new DAC with ecc99 input tubes & 5963 outputs. I picked up over this past summer.

I experienced this identical anomaly with the lower volume on the right channel several months ago. CS had a hard time identifying the problem. Then I reminded them that I use balanced connections and they were able to locate the issue right away.

Frustrating to say the least. I’m going to see how she works out with a couple of long listening sessions. Then I’ll reach out to CS to see what their thoughts are.

Thanks Everyone!!

mhardy6647

ahh, 5963 -- twin triode. A "computer tube"
(meant to hold up to the demands of vacuum tube digital logic circuitry -- specifically to survive being held in "cutoff" operating conditions for long periods of time)

https://jacmusic.com/techcorner/ARTICLES/English/Portraits/5963/index-5963-portrait.html

I don't know squat 'bout the ECC99 -- "modern" (relatively speaking) twin triode.
https://frank.pocnet.net/sheets/163/e/ECC899.pdf


Could be an issue with the socket tension, or maybe poor or cold-solder joints at the socket(s). Some JJ tubes have been notorious for quality issues (not all, though).

GlennDog

All 4 tubes are seated very positively. One might even say tight.

Probably the nature of a brand new socket. Normally, during extraction I’ll wiggle or rotate the tube while pulling up… These are definitely tight

Music’s been playing for 4 hours now and I must say, Eva Cassidy sounds intoxicating 😍

btw, thanks for the links!