I talked to Mike Sanders today. I wanted to get his recommendations for kt-88's as well as discuss the viability of kt-90's in the silver 90's. (Quicksilver makes a currant model that is very close to the silver 90's, the mono 100's, and he offers them with kt-88's or kt-90's, but does not list kt-90's as replacements for the silver 90's).
As I mentioned before, there is some glowing of the plates, so I initially ran them at 80 or 90 ma to minimize this, as opposed to the 100 ma specified for the silver 90's. It made me wonder if the silver 90's could handle the kt-90. Mr. sanders said the silver 90's are fine with the kt-90 tube. I told him about the glowing plates and he said that is a tendency, but he wonders about it himself. He runs the kt-90's in the mono 100's at 80 ma, but some dealers run them as high as 120 ma.
I also discussed with him the slightly varying bias currents I was experiencing. When I first installed the kt-90's again, it took some 2-3 hours before the bias would settle, it would not jump quickly, but it would be at say 95 ma, and over the course of time, drop to say, 85 or 90. Now, some time later of break in, it takes about 20 to 30 minites and starts off with what seems like 4-6 ma higher than what I adjusted them to before settling back. Mr. Sanders attributes this to the power draw of my conditioner, or my house, but I wonder if it is related to the plates, or both.
Anyway, I can attest to the LONG break in of the kt-90. Perhaps this is due to the unusually robust nature of this tube that seems to be what I am hearing about them. I am also aware of tubes that are more robust than the standard that do glow in the plates, although for most tubes this would be bad, and evan if they didn't fail would wear quickly. I do not know if this is a tube with a tendency to glow in the plates when used within its specs, or how long it will last operated like this, but if I adjust the bias in the silver 90's to where they don't glow at all, I get audible crossover distortion, and I like them best presently at about 95-102 ma, so that is where I have been running them and everything I have said about them has been at this setting.
I thought this may be interesting to you guys as it relates to the reliability, and maybe the break-in as well.
As I mentioned before, there is some glowing of the plates, so I initially ran them at 80 or 90 ma to minimize this, as opposed to the 100 ma specified for the silver 90's. It made me wonder if the silver 90's could handle the kt-90. Mr. sanders said the silver 90's are fine with the kt-90 tube. I told him about the glowing plates and he said that is a tendency, but he wonders about it himself. He runs the kt-90's in the mono 100's at 80 ma, but some dealers run them as high as 120 ma.
I also discussed with him the slightly varying bias currents I was experiencing. When I first installed the kt-90's again, it took some 2-3 hours before the bias would settle, it would not jump quickly, but it would be at say 95 ma, and over the course of time, drop to say, 85 or 90. Now, some time later of break in, it takes about 20 to 30 minites and starts off with what seems like 4-6 ma higher than what I adjusted them to before settling back. Mr. Sanders attributes this to the power draw of my conditioner, or my house, but I wonder if it is related to the plates, or both.
Anyway, I can attest to the LONG break in of the kt-90. Perhaps this is due to the unusually robust nature of this tube that seems to be what I am hearing about them. I am also aware of tubes that are more robust than the standard that do glow in the plates, although for most tubes this would be bad, and evan if they didn't fail would wear quickly. I do not know if this is a tube with a tendency to glow in the plates when used within its specs, or how long it will last operated like this, but if I adjust the bias in the silver 90's to where they don't glow at all, I get audible crossover distortion, and I like them best presently at about 95-102 ma, so that is where I have been running them and everything I have said about them has been at this setting.
I thought this may be interesting to you guys as it relates to the reliability, and maybe the break-in as well.