8,27 and 8,72 on Q6 then. They were tighter on Mikes measures (texted on tape and bags), but not when I control measure. If Mike is there, what method did you use?
I measure at 10V with HP power supply, through a Fluke 87V.
I make sure that room temp is 72 degrees (heat pump can do well here)
For the 2sk170's I don't measure for too long, under 5 seconds.
I would concur in my system it might have been more ideal in practice, but I'd rather have a little more low end than not enough. At some point I would like to do drive rack like VGeorge and use microphone to help adjust bass. Not in the cards today, power outage killed HDMI TV Monitor - so no USB digital sound or Playstation for the kid. Getting that fixed or replaced is priority. 🙁
Strange. My values follow yours (Q4,5,6) but have much larger deviations between the pairs. I do have 28 degrees C inside, som 82 F but I wonder if this can do it.
Remeasured once again with 9 V 100R and got about the same. Changed the resistor to 10R and writed them values in (x).
Well, maybe my Uni-T UT60E is bugging me and the values arent far out anyway.
PS. In my measures Idss rises some 100 microA the first 30-60 seconds.
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Temp, touching even, different DVM tolerances, time allowed to settle, can do it. Q6 only has to be higher idss than Q5, not closely matched.
Now you just need to keep the finished preamp in the fridge! It should sound "cooler" and "darker". 🙂
Polaris Electronics.
Ok, I'll arrange it like this:
Ch1 Q4 8,44 Q5 7,14, Q6 8,27
Ch2 Q4 8,56 Q5 7,71, Q6 8,72
tomorrow🙂
I also think this is how I will arrange R1+ Rx1-4
47 47 18 18 6,8
This gives me those combinations:
47//47 = 23,5
47//18 = 13,5
47//47//18 = 10,2
47//18//18 = 7,55
47//6,8 = 5,94
47//47//18//6,8 = 4,08
47//18//18//6,8 = 3,58
47//47//18//18//6,8 = 3,33
And 47 alone ofc. Thoughts about that?
Ok, I'll arrange it like this:
Ch1 Q4 8,44 Q5 7,14, Q6 8,27
Ch2 Q4 8,56 Q5 7,71, Q6 8,72
tomorrow🙂
I also think this is how I will arrange R1+ Rx1-4
47 47 18 18 6,8
This gives me those combinations:
47//47 = 23,5
47//18 = 13,5
47//47//18 = 10,2
47//18//18 = 7,55
47//6,8 = 5,94
47//47//18//6,8 = 4,08
47//18//18//6,8 = 3,58
47//47//18//18//6,8 = 3,33
And 47 alone ofc. Thoughts about that?
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I would swap the Ch2 Q5, Q6 to Ch1. Since Ch2 Q4 will drop a bit more than Ch1 Q4 from B+ not to continue the trend.
Just found out that I had ordered some extra K170 from Mike. Those had better coherence to my measuring method. Unfortunately none in the Q4 region.
So if I arrange it:
Ch1 Q4 8,44 Q5 7,71, Q6 8,72
Ch2 Q4 8,56 Q5 7,14, Q6 8,27
Is there any reason for me to change for example Ch 1 Q4 from 7,71 to a 7,14?
The 9ers is ordered as a quad. I dont remember what project I had in mind but maybe I should keep that as a quad and not use it as Q6es.
So if I arrange it:
Ch1 Q4 8,44 Q5 7,71, Q6 8,72
Ch2 Q4 8,56 Q5 7,14, Q6 8,27
Is there any reason for me to change for example Ch 1 Q4 from 7,71 to a 7,14?
The 9ers is ordered as a quad. I dont remember what project I had in mind but maybe I should keep that as a quad and not use it as Q6es.
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Soldered up and tested the PSU meanwhile. 41,5 AC sec unloaded, about 49,5 VDC@127 mA (390R dummy) and 48,5@145mA (335R). Might eventually sneak up to the 50 depending on the final setting. Am I clear with that or do I need to us the RD/Link?
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yes, if the supply rail fuses blow, or you turn the quiescent current right down, or you disconnect one amplifier and test the other one.