I use hand matched 2SK3320's on mine instead :
One Last Attempt at Discrete Opamp in DIP8 Footprint
Cheers,
Patrick
One Last Attempt at Discrete Opamp in DIP8 Footprint
Cheers,
Patrick
Patrick,
The noise floor looks a tad lower on the 2SK170 plots.
While you had access to the AP did you measure noise?
Thanks DT
AP is not the best tool to measure noise.
A Wurcer LNA and a good sound card can do better.
Or a LNA + a proper Spectrum analyser with high resolution.
Patrick
A Wurcer LNA and a good sound card can do better.
Or a LNA + a proper Spectrum analyser with high resolution.
Patrick
Patrick,
Measuring noise is well within the skillset of the AP2722. On my bench the AP2522 using the same software as the2722 measures to low single digits uV’s. Turn off the generator; run the FFT and autorange will zoom right in on the noise floor showing 1/f noise and the rest. You can adjust the Circuit Under Test to tailor the distortion and noise profiles to your liking. Tune the sweet spot.
Take a look at Linear Audio Volume 4, John Walton uses his 2722 plus a custom 40dB gain LNA to zoom in on regulated power supply noise.
Scott's 60dB LNA is also a fine tool with resolution headroom to spare.
Thanks DT
Believe me, I have had noise measurments with a 2722 (alone).
You still need a LNA, be it 40dB or 60dB.
Then it does not matter whether the analyser is a 2722 or a sound card.
Cheers,
Patrick
You still need a LNA, be it 40dB or 60dB.
Then it does not matter whether the analyser is a 2722 or a sound card.
Cheers,
Patrick
sound warmth
Hi. 2sk209gr is interesting part.It has about 10dB more H2 but has less H3 than 2sk170bl.Maybe it sounds better than 2sk170 because of more H2 adds warmth to sound and H3 is lower so sound may be nicer? Anyone compared them and could tell about sound? I have reel of 3000pcs of 2sk209gr.Did not have a spare time to play with them yet but i want to try them a lot.
Hi. 2sk209gr is interesting part.It has about 10dB more H2 but has less H3 than 2sk170bl.Maybe it sounds better than 2sk170 because of more H2 adds warmth to sound and H3 is lower so sound may be nicer? Anyone compared them and could tell about sound? I have reel of 3000pcs of 2sk209gr.Did not have a spare time to play with them yet but i want to try them a lot.
Attachments
Further to the publication of DimitriDanyuk on SMD JFET noise, I was considering how to use the BSR58 in actual applications.
Measurements Rate New SMT Low-Voltage JFETs Under Consistent Conditions - An Update Using Modern JFETs | audioXpress
No curve tracing data can be found on the net, so I bought some and did my own measurements.
This is just a random sample. So not sure how typical it is.
Also to limit dissipation, I restricted the drain current to below 12mA.
Vgs at 10mA = 0.92V
Yfs at 10mA = 12.8mS
In order to limit dissipation to realistic values, one would need a source resistor of 100R or more.
And the output impedance of a source follower would be almost 200R.
2x 2Sk209GR in parallel is for me still better choice.
Patrick
.
Measurements Rate New SMT Low-Voltage JFETs Under Consistent Conditions - An Update Using Modern JFETs | audioXpress
No curve tracing data can be found on the net, so I bought some and did my own measurements.
This is just a random sample. So not sure how typical it is.
Also to limit dissipation, I restricted the drain current to below 12mA.
Vgs at 10mA = 0.92V
Yfs at 10mA = 12.8mS
In order to limit dissipation to realistic values, one would need a source resistor of 100R or more.
And the output impedance of a source follower would be almost 200R.
2x 2Sk209GR in parallel is for me still better choice.
Patrick
.
Attachments
I have always wondered how the much-talked-about J113 performs in terms of noise.
Just found this wonderful website which has all the information one likes to have :
https://www.mvaudiolabs.com/diy/modern-jfet-noise-measurements/
I leave you to draw your own conclusions.
For me, no surprises with 2SK170 and 2SK117 ( = 2SK209 SMD ).
So I reafirms what I woulld use for source followers / buffers in applications like active crossovers.
And the J175 / 176 are actually better than I thought.
Cheers,
Patrick
Just found this wonderful website which has all the information one likes to have :
https://www.mvaudiolabs.com/diy/modern-jfet-noise-measurements/
I leave you to draw your own conclusions.
For me, no surprises with 2SK170 and 2SK117 ( = 2SK209 SMD ).
So I reafirms what I woulld use for source followers / buffers in applications like active crossovers.
And the J175 / 176 are actually better than I thought.
Cheers,
Patrick
Attachments
Don't forget the brand new devices from TI, JFE150 and matched dual JFE2140. Hell must have frozen over for them to be newly introduced, but they look very promising! (There's another mention of them elsewhere on this forum by someone at TI, IIRC.)
