By what I've read so far I assume that there is no provision to balance the tubes in the PP pair. After a year of use one tube could be weaker than the other creating a situation where one tube will hog more of the current. You should check the individual bias of each tube to see if they are still well matched. Running a weak tube hard is a recipe arching and failure. I've had a tube (6550) fail under those conditions and short the grid to the plate. Fortunately it only smoked the grid stopper resistor, though it was a 5 buck tantalum. As previously mentioned it could also be a weak input or driver tube. A swap of all left and right channel tubes except the output tubes will confirm this. Then start swapping back the individual pairs to find the culprit.
Biasing your Tubes to your Room
As I move down the road of enjoying an all analog system, every once in a while there seems to be some kind of breakthrough accidental or otherwise. Whether it being moving into a quality tube amp, or adding another pair of speakers to the output chain,
today I was switching around my output tubes on my Scott 340B.
I was getting a bit more sound out of my right channel than my left.. and this has been going on for quite some time. Subtle enough to not be overly concerned, but always there
ever so slightly.
However, my readings were spot on as far as millivolts go.
So I decided to just trust my ears and tune the bias screws
to my ears.
I literally took the listening experience to another level.
Now the question remains.. by supplying a bit more juice to the left channel.. is it my ears? the room itself? The tubes?
Ultimately it's a listening experience.. and although using the bias to tune to your room or you.. is not conventional wisdom, it's without a doubt tuned the experience very tight and offering a much more refined listening experience.
While some might suggest I am shortening the lifespan of my tubes, I don't really mind replacing them a year early if the quality of the experience is substantially superior to what the technical specs suggest or insist.
Anyone had a similar experience?
today I was switching around my output tubes on my Scott 340B.
I was getting a bit more sound out of my right channel than my left.. and this has been going on for quite some time. Subtle enough to not be overly concerned, but always there
ever so slightly.
However, my readings were spot on as far as millivolts go.
So I decided to just trust my ears and tune the bias screws
to my ears.
I literally took the listening experience to another level.
Now the question remains.. by supplying a bit more juice to the left channel.. is it my ears? the room itself? The tubes?
Ultimately it's a listening experience.. and although using the bias to tune to your room or you.. is not conventional wisdom, it's without a doubt tuned the experience very tight and offering a much more refined listening experience.
While some might suggest I am shortening the lifespan of my tubes, I don't really mind replacing them a year early if the quality of the experience is substantially superior to what the technical specs suggest or insist.
Anyone had a similar experience?