K170/J74 are
Discrete,
Through-hole,
complementary,
and originally designed for linear audio.
They are likely the last devices of their kind. All current new production stuff is surface mount and/or IC. For DIY the 170/74 are about perfect. Tube guys use the audio specific tubes all the time, nobody complains.
Would a new N/P pair useable for audio, and available in a package solderable by humans (SOT-23 or SOT-89) be warmly received by out group? Most certainly. 😀
Discrete,
Through-hole,
complementary,
and originally designed for linear audio.
They are likely the last devices of their kind. All current new production stuff is surface mount and/or IC. For DIY the 170/74 are about perfect. Tube guys use the audio specific tubes all the time, nobody complains.
Would a new N/P pair useable for audio, and available in a package solderable by humans (SOT-23 or SOT-89) be warmly received by out group? Most certainly. 😀
Linear Systems produce dual jfets N and P channel's package.
3 $ one pcs if group buys of 1000 pcs probably metal cans cost +
DMOS Switches, JFET Amplifiers, BIFET Amplifiers, MOSFETS
superb pretenders for buffer B1 V3 if Papa Diy blessing ?
3 $ one pcs if group buys of 1000 pcs probably metal cans cost +
DMOS Switches, JFET Amplifiers, BIFET Amplifiers, MOSFETS
superb pretenders for buffer B1 V3 if Papa Diy blessing ?
Attachments
Sorry I did not look on the web, is it a complimentary j/k pair in one case or parallel jj kk pairs?
3 Bucks each？Sounds like a bargain, but I doubt the actual price you will get when quoting them as private customer… Am currently using paralleled BF862 in B1, fortunately they aren't oscillating despite the fact that i forgot to use separate gate stopper.
Nice, except for, you know, the camera person not showing the money shot - the last two slides, including the full finished project. 😕
Interesting to know this dual Linear Systems jfet´s.
Thanks to Mr. Bob Cordell.
Camera man was not focused on high resolution video.
Application notes from Bob Cordell: http://www.cordellaudio.com/JFETs/LSK489appnote.pdf
Different application notes: http://www.linearsystems.com/lsdata/appnotes/LSJ689_P-Channel Dual JFETs.pdf
Different application notes: http://www.linearsystems.com/lsdata/appnotes/LSJ689_P-Channel Dual JFETs.pdf
Mr. Pass 
show today B1 Triode with Korg Nutube.
First Watt with warm electrons in the vacuum !!!!
2sk77b and 2sk180 new projects
show today B1 Triode with Korg Nutube.First Watt with warm electrons in the vacuum !!!!
2sk77b and 2sk180 new projects
Attachments
also remember that Iron Pre SE is practically really good B1 (V.2) with autoformer gain
Iron Pre (Bal) ..... well , that's two previous ones , with balanced autoformer
Iron Pre (Bal) ..... well , that's two previous ones , with balanced autoformer
also remember that Iron Pre SE is practically really good B1 (V.2) with autoformer gain
Iron Pre (Bal) ..... well , that's two previous ones , with balanced autoformer
Really nice one.
@ Marc Brown
Thanks for sharing.
Documentation conclusions are promising
You're welcome. I'm glad to be able to contribute, even though my EE skills are sorely lacking. [emoji6][emoji106]
I'm relatively newbie builder (F6, B1, and several Carmody speakers). I'm planning a B1R2 point-to-point. Thought I'd ask for feedback on this draft layout, to be built on 5"x5" acrylic sheet.
It has 3 inputs at the top, connecting to board just above R201, 101, etc, below the grounds. From that same point, inputs feed along the arrow path down to the selector control, then back over (right) to volume control, then in towards R203, 101 via holes marked L, R. Output is just above R205, 105. (Sorry, some erasures still showing faintly on the scan.)
Any opinions, suggestions, or feedback from those more seasoned than me would be appreciated, if you're in the mood to have a look. If I get a working version of this, I'll upload it so that maybe I can contribute something back, after having gotten so much from these threads.
I'll start with DC +24 external supply (HP printer LPS) version, but then I'd like to run it from A/C mains via transformer and two Salas BIBs at +/-12VDC. (Does it make sense to bypass the splitter/filter at that point, or run from same V+/V- inputs? Opinions?)
View attachment B1R2-layout v2.pdf
It has 3 inputs at the top, connecting to board just above R201, 101, etc, below the grounds. From that same point, inputs feed along the arrow path down to the selector control, then back over (right) to volume control, then in towards R203, 101 via holes marked L, R. Output is just above R205, 105. (Sorry, some erasures still showing faintly on the scan.)
Any opinions, suggestions, or feedback from those more seasoned than me would be appreciated, if you're in the mood to have a look. If I get a working version of this, I'll upload it so that maybe I can contribute something back, after having gotten so much from these threads.
I'll start with DC +24 external supply (HP printer LPS) version, but then I'd like to run it from A/C mains via transformer and two Salas BIBs at +/-12VDC. (Does it make sense to bypass the splitter/filter at that point, or run from same V+/V- inputs? Opinions?)
View attachment B1R2-layout v2.pdf
I built a test version of the B1R2 on bench using layout attached above, but only one input, and DC +24V LPS from HP printer. It worked okay, but, with volume turned up, it was noticeably noisy on stronger parts of music, rougher, sounding broken up. [E.g., stronger guitar bits on Joni Mitchell's "A case of you"; Johnny Cash vocals.] Contrast is DAC straight into F6, which is crystal clean, clear, and musical at high volume by direct comparison. Distortion seems most noticeable in mid bass, as well as very upper range high vocals.
As a first attempt to improve, I eliminated the extra-long unshielded 24-gauge copper signal runs in case this was interference noise (no case yet). And I rearranged the ground scheme. (1) PS ground now has dedicated return. (2) Also separated L and R channels, giving each its own return to ground. (3) And removed R101, 201 from the circuit entirely.
Result was cleaner, an improvement, but still rough on those stronger -- louder, more complex -- bits of the tracks, when turned up. At lower volumes, however, I feel like I'm hearing more detail, musicality, and engagement in contrast with no buffer (though things are quite similar at lower volume, hard to tell).
Has anyone experienced similar -- increased noise, especially at higher levels -- with B1R2?
Could this all be due to the power supply? It seems like a very pronounced difference to me. I have Salas BIB planned down the road. But, I'd like to get the circuit in good shape before going further. Worth trying it with batteries first?
Other possibilities:
Perhaps an inadvertent JFET switch during build (unlikely, given my precautions, but lesson learned: mark them before building!) (using DIY store matched).
Poor quality RCA jacks in the test version.
Clipping due to signal from buffer?
As a first attempt to improve, I eliminated the extra-long unshielded 24-gauge copper signal runs in case this was interference noise (no case yet). And I rearranged the ground scheme. (1) PS ground now has dedicated return. (2) Also separated L and R channels, giving each its own return to ground. (3) And removed R101, 201 from the circuit entirely.
Result was cleaner, an improvement, but still rough on those stronger -- louder, more complex -- bits of the tracks, when turned up. At lower volumes, however, I feel like I'm hearing more detail, musicality, and engagement in contrast with no buffer (though things are quite similar at lower volume, hard to tell).
Has anyone experienced similar -- increased noise, especially at higher levels -- with B1R2?
Could this all be due to the power supply? It seems like a very pronounced difference to me. I have Salas BIB planned down the road. But, I'd like to get the circuit in good shape before going further. Worth trying it with batteries first?
Other possibilities:
Perhaps an inadvertent JFET switch during build (unlikely, given my precautions, but lesson learned: mark them before building!) (using DIY store matched).
Poor quality RCA jacks in the test version.
Clipping due to signal from buffer?
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