salas said:
Why not socket them and see which one you like better?
But if I had to vote, I'd pick the 2sk170, as that's what I've got here.
They have different pin out. I will have to test both by slight modification on perfboard if I will be curious enough. The 5459 has more Vp and good looking curves, is no slouch. It has potential.
I guess that the best will be to do 2SK170BL first so to keep near B1 and it remains interesting as a variation to DIYers, and after enough subjective evaluation, substitute 2N5459s and see what we have in hand for a much more accessible and cheap FET. I will use variable regulation with trimmers so I can get them B+,B- together or trim offset by introducing imbalance. That will let me listen for sweet spot PSU voltage as well. I will start with +/- 15V.
I guess that the best will be to do 2SK170BL first so to keep near B1 and it remains interesting as a variation to DIYers, and after enough subjective evaluation, substitute 2N5459s and see what we have in hand for a much more accessible and cheap FET. I will use variable regulation with trimmers so I can get them B+,B- together or trim offset by introducing imbalance. That will let me listen for sweet spot PSU voltage as well. I will start with +/- 15V.
Attachments
salas said:
Hi Salas
I would prefer the 2SK170 (cause I'll get 3 matched pairs and one quad from a group buy). Further I would appreciate a circuit without the 10µF or the 1µF caps. But, the original Pass circuit would be a nice try, too. So, it's your decision (what to solder first
).Please feel free to share your measurements and listening impressions. Good luck and hot iron!
Kalifa instead of Kalifa
J309 and J310 , as substitute for 2SK170V , even on steroids
for Papa-like buffer , probably with small source resistors ;
in case that you don't want to change those 9V cells too often
J309 and J310 , as substitute for 2SK170V , even on steroids
for Papa-like buffer , probably with small source resistors ;
in case that you don't want to change those 9V cells too often
Skorpio said:
I have now build the servo in and made it optional with a jumber. I have change the servo to only work in one single point, the output.
There is no sonic influence to me if the servo is in or not, but it my be because the correction it makes is so small?
salas said:
We are writing the year 2008 and these are the manufacturing tolerances of state-of-the-art producers!?
Shocking!
Please read the datasheet.
IDSS-classes are perfectly normal and don't affect much a circuit unless you parallel them. Manufacturing low-noise jfets does require strict quality control.
Don't forget jfets are not "state of the art" devices (not from a manufacturer point of view at least), the same and even better parts existed already in the 80ies.
Today jfets just consume area in the manufacturing plant, are phased out of production to allow manufacturing of higher $ parts.
Have fun, Hannes
Basically what I have done by now
Found some spare time, and populated the perf-board. Done half the point to point also. I am putting together 1 positive & 1 negative regulated PSU, 1 output delay relay circuit and 2 channels of capacitor-less B1s. Hopefully in the next few days I will find time to finish it and test it little by little. Will report.
Next post includes the awfully sketched schematic.
Found some spare time, and populated the perf-board. Done half the point to point also. I am putting together 1 positive & 1 negative regulated PSU, 1 output delay relay circuit and 2 channels of capacitor-less B1s. Hopefully in the next few days I will find time to finish it and test it little by little. Will report.
Next post includes the awfully sketched schematic.
Attachments
salas said:
Looks nice, but are you missing the 1M gate resistors to ground?
What type of resistors are you using?
Regarding the output resistor....
Does Nelson have a reason for making this 1k?
Is this to guarantee safety in the event of a short, or does 1k give better isolation from cable effects, or change sound quality relative to 330 ohms or so?
Does Nelson have a reason for making this 1k?
Is this to guarantee safety in the event of a short, or does 1k give better isolation from cable effects, or change sound quality relative to 330 ohms or so?