Sorry about the 2SK222 I think BDENT had about 50-100 and they went fast after someone on Yahoo posted it. It's Sanyo and because it never caught the eye of the audio world there aren't a dozen folks on ebay selling them like the 2SK170. Also it's a low Idss thing for phantom powered mics where the minimal circuit has the FET at Idss. The J310's have the two little squiggles, I forgot if that was Vishay or Fairchild or what? They were from eBay, but guaranteeing the noise will be problematic on any of them. I managed to scavenge at SOT23-6 test socket at work for the BF862's. If you haven't checkout syn08's 32-BF862 phono stage a noise record (without magnetics) I think. Though he did have to use ferrite beads to suppress all that RF gm.
I plan to buy a bag of 500 or a 1000 2SK222's next time I'm at the Akihabara.
I plan to buy a bag of 500 or a 1000 2SK222's next time I'm at the Akihabara.
I received the BF862 and J310s, sorting the BF862s was not too bad after all. Used 2 pieces of adhesive copper foil for a fixture (and soldered wires to the foil). I found 40 seconds to be about right for 10V supply to get Idss.
The biggest surprise I had was the linearity of the J310 in a gain of 2-4 configuration with a health supply voltage(40V). I was looking for a no loop feedback simple gain of 2-3 circuit with voltage output of 1-2Vrms for a filter project where there is loss in the filter.
If preliminary results hold, the J310 delivers with nice results, gain of 2-3 with .008% thd kinda numbers at 1 VRms. Requires some tweaking though. I had a 5K resistor on top, 1k on bottom, load of 6.8k. A b1 after this would be an interesting line stage for those who need some more oomph.
Bob
The biggest surprise I had was the linearity of the J310 in a gain of 2-4 configuration with a health supply voltage(40V). I was looking for a no loop feedback simple gain of 2-3 circuit with voltage output of 1-2Vrms for a filter project where there is loss in the filter.
If preliminary results hold, the J310 delivers with nice results, gain of 2-3 with .008% thd kinda numbers at 1 VRms. Requires some tweaking though. I had a 5K resistor on top, 1k on bottom, load of 6.8k. A b1 after this would be an interesting line stage for those who need some more oomph.
Bob
The current production LSK170's are great!
Somebody may still have some or maybe time for round two!
Also guess Linear is getting ready to release a complement soon!
Unless going for mic pre the 2SK222 that Scott mentions as
good sub, I personally don't know of anything that was
really better for audio.
Somebody may still have some or maybe time for round two!
Also guess Linear is getting ready to release a complement soon!
Unless going for mic pre the 2SK222 that Scott mentions as
good sub, I personally don't know of anything that was
really better for audio.
coloradosound said:
It's really great for low level signal amplification where low noise and high gain is important. But the low Vp and high gain may work against it for other applications with line level signals. Even with a lot of degeneration. This point was made by Borbely in his first Final Frontier JFET article from 10 years ago when comparing the 2sk146 and 2sk170.
hi
Trying to decide between the 2sk369 and BF861 for active filter base on B1.
the BF861 need Heat Sink?
thanks
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an idea for replacement 2SK170 I have posted under #4840 on page 484 - go to
https://www.diyaudio.com/forums/pass-labs/124889-b1-buffer-preamp-484.html#post6740337
https://www.diyaudio.com/forums/pass-labs/124889-b1-buffer-preamp-484.html#post6740337
check out this new thread
Better Audio by UHF/RF jFET Replacement (<5pF) for 2SK389/2SJ109+2SK170/2SJ74
Better Audio by UHF/RF jFET Replacement (<5pF) for 2SK389/2SJ109+2SK170/2SJ74
There are some who claim specs are all, and they do not even need to hear the preamp or amp, to know how it sounds, just based on specs.
There are those who know that right amount of distortion with predominantly 2nd harmonic and negligible amount of feedback yields to listening bliss.
There are those who know that right amount of distortion with predominantly 2nd harmonic and negligible amount of feedback yields to listening bliss.
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Because the second statement is correct, is even the first correct.
Even if the graphics from attachment are not directly comparable due to different measurement conditions, the perceived sound impression agrees very well with the character of the distortion (fundamentally notched out). That's why I'm not interested in connecting amplifiers for listening tests, that have a sawtooth-shaped or triangular-shaped character in terms of residual distortion - even in cases, where THD-values are extrem low.
OTOH - if there are sine wave character of residual distortion, even high values of THD around 0,1-0,5% are barely audible or provide additional lovely sonic character.
I always like to check such amplifiers for a listening test.
If one check this distortion character of a wide range of measured amp models in stereophile I note, that not really the most of them have sine wave character. And unfortunately not one with a Class AB output stage with 20-50mA quiescent current.
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