This was presented at BAF four years ago, and I thought I had written
it up, but if I did I can't find it.
Here's the graphics of a nice line level gain stage which has no loop feedback.
it up, but if I did I can't find it.
Here's the graphics of a nice line level gain stage which has no loop feedback.
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Thank you for sharing - it looks like it could be good opamp alternative for whammy headphone amp !
And easily built on a small perfboard with dip8 adapter.
LS jfet line stage by Mr. Pass at BAF video
PSU V(-)(+)= 45V
LS jfet's Idss range = 15 mA
output gain = 15 dB
output impedance = 1K5
All this specyfications numbers are right ?
Please correct if not Kind regards
PSU V(-)(+)= 45V
LS jfet's Idss range = 15 mA
output gain = 15 dB
output impedance = 1K5
All this specyfications numbers are right ?
Please correct if not Kind regards
Built it a few years back. My favorite linestage I have built and tried over many others. I do not understand why someone has not designed a board for this schematic. Not hard to build on a perfboard but probably more interest if a board were available. Not the prettiest wiring but hey it works and it is quiet even with linear supply. Better sounding to me than the couple of BA-3 pre builds I have done. You may notice I placed some caps on the output just to prevent any DC in case some was there. I bought the 2 set of 8 j-fets from the store in C grade and got close enough matching for the pairs needed.
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Oh yeah, I mis-titled the thread. No balanced here.
Baad Papa, you mislead me.
You know, I need balanced. ....
Actually, there is a balanced output version of this circuit, as per Chris Hornbeck's proposal from 2011 (post #148) :
phase splitter issue
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There is one in first post of this thread:.... I do not understand why someone has not designed a board for this schematic....
LSK pre - BAF 2013
There is one in first post of this thread:
LSK pre - BAF 2013
I built your version of this design as well and it performs to my ears admirable as well.
Thanks Mr. Pass.That sounds right.
Characteristics looks yummy: low noise and distortion, no feedback loop, excellent frequency wide band response etc.
LS jfet's line stage (PCBs + jfets) if available in DiyAudio Store can be new popular 2018 Top five best seller DIY kit.
Superb line stage alternative choice to match with Aficionados amplifiers
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My version is in post #66.I built your version of this design as well and it performs to my ears admirable as well.
Post #1 has PCB for MR Pass' version with few values changed for different Idss grade JFETs and some housekeeping parts added.
This was presented at BAF four years ago, and I thought I had written
it up, but if I did I can't find it.
Here's the graphics of a nice line level gain stage which has no loop feedback.
Dear Mr, Pass,can I use the 2SK389V/2SJ109V to replace the LSK170C/LSK74V?
Thanks
Leo
can I use the 2SK389V/2SJ109V to replace the LSK170C/LSK74V?
I think so. Worst case would be adjustment of some resistor values.
Is there an article that explains how the preamp works and what the parts do ?
Or perhaps this is an opportunity for a (very) mini tutorial Nelson ?
There's a you tube video.
YouTube
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