I stayed up late last night listening to music. I could not stop; it was like eating cookies or potato chips - just one more. And I had to get up very early this morning to going running with my group. So, the modified LuminAria must have made a difference, presenting a novel sound that kept me exploring my music collection.
Thinking about it, I think the sound may be clearer with more resolution. Certainly, these qualities are present but I cannot swear that it is better than before. The only sign that maybe things are better is I didn't want to stop listening.
I know Nelson Pass had said in his article about his second order harmonic generator that more than one H2 generator in a reproduction system may not be a good approach. I have VFET/SIT power amps in the chain and probably I had the case where two generators of significant H2 were present. The reduced second harmonic output of the choked LuminAria may be enough to remove it from play.
So, now with these modifications, I'm not sure this is a LuminAria anymore. It grew out of the LuminAria, but no longer has source resistor bias and has gotten heavier with the added iron. Gotta love heavy amplifiers. I think I'll rename it Brother of LuminAria. After all, he ain't heavy, he's my brother.
Thinking about it, I think the sound may be clearer with more resolution. Certainly, these qualities are present but I cannot swear that it is better than before. The only sign that maybe things are better is I didn't want to stop listening.
I know Nelson Pass had said in his article about his second order harmonic generator that more than one H2 generator in a reproduction system may not be a good approach. I have VFET/SIT power amps in the chain and probably I had the case where two generators of significant H2 were present. The reduced second harmonic output of the choked LuminAria may be enough to remove it from play.
So, now with these modifications, I'm not sure this is a LuminAria anymore. It grew out of the LuminAria, but no longer has source resistor bias and has gotten heavier with the added iron. Gotta love heavy amplifiers. I think I'll rename it Brother of LuminAria. After all, he ain't heavy, he's my brother.
It's a funny thing. I thought that this was my first time using the Hammond 157G as choke loads, but that's not true. I had completely forgotten that I had used them in my 2SJ28-2SK180 amp build (https://www.diyaudio.com/community/threads/mo-chokes-building-2sj28-2sk180-monoblocks.370479/). I was looking at the notes of that amplifier and was surprised to see that I had used 157Gs. After reviewing the distortion results of the 157G loaded 2SJ28 VFET of that amp, I just had to try that operating point with the 2SK82s in the revised LuminAria.
Luckily, it was fairly easy to change the voltages. The LuminAria power supply is regulated to about 140V and when I converted to fixed bias, I used a RC stage to drop the Vd to compensate for no source resistor. So, it was just a matter of shorting out the voltage dropping resistor in the RC filter to get 140V at the choke.
After fiddling around with the the gate voltages, I managed to lower the distortions again. Good thing I checked the notes on my 2SJ28-2SK180 amp.
Luckily, it was fairly easy to change the voltages. The LuminAria power supply is regulated to about 140V and when I converted to fixed bias, I used a RC stage to drop the Vd to compensate for no source resistor. So, it was just a matter of shorting out the voltage dropping resistor in the RC filter to get 140V at the choke.
After fiddling around with the the gate voltages, I managed to lower the distortions again. Good thing I checked the notes on my 2SJ28-2SK180 amp.
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2SK60 at this operating point could be a great driver for a 300B Tube with some voltage gain before , i will try to mix Vfet driver and Triode power amp as i already have one to mod .. a smart guy will do the opposite but who knows it can sounds good
the build is not as i always use the same few resistors and cap since the begining of my Diy
thanks to you Michael to show us the way with the luminaria and not be totally in the fog as we don't have any datasheet or curves of these 2SK60 at high voltage ..
question , as you use 600R resistor with the 2SK82 do i need to use a lower value than my 6K for the 2SK60 like 3K ?
thanks to you Michael to show us the way with the luminaria and not be totally in the fog as we don't have any datasheet or curves of these 2SK60 at high voltage ..
question , as you use 600R resistor with the 2SK82 do i need to use a lower value than my 6K for the 2SK60 like 3K ?
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