If the world is depleted of Toshiba JFETs, maybe.
Until then, there is a better choice.
Cheers,
Patrick
Until then, there is a better choice.
Cheers,
Patrick
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Cascoding as shown is fine for a differential input stage, but wasn‘t the discussion about complementary source followers and resulting offset when voltage is changed?
Regards, J-C
Regards, J-C
Take a look at the top side,
if it has a line of about 2 mm long and it is positioned exactly in the middle then they're most likely authentic, for me it's first indicator to verify their authenticity based on physical looks only, so far I've never seen fake ones have it.
Better still, use EUVL's jig and measure the transconductances. The good ones are about 30-40 mS (mA/V).
I have a batch of fakes that test around 10 mS; they can still be useful in some less demanding area.
I have a batch of fakes that test around 10 mS; they can still be useful in some less demanding area.
A long ago j74 was at 1 euros.
Surely you have bought them at this moment.
Would you give 10 euros more for 1 piece ?
same applies for 6SN7
laws of Market - if you want, pay ......... if you don't , someone else will
laws of Market - if you want, pay ......... if you don't , someone else will
Long ago, gold was 120USD an oz.
"Surely you have bought them at this moment."
🙂
Cheers,
Patrick
"Surely you have bought them at this moment."
🙂
Cheers,
Patrick
And I still have an octet of the original Gold Lion KT88 "made in England"
Guess how much they're worth today? 🙂
Guess how much they're worth today? 🙂
Sorry and Linear just announced that they are going to start reproducing LSK389 Jfet dual N ch. Can replace a pair of matches 2SK170.. Problem seems to be the P channel.. You can not buy LSJ74 from Linear. 2SJ74 seems hard to find as well.. Especially in BL grade. GR is what I see mostly which is too low of IDSS for most projects
What about using high-end op-amps as replacement like AD797 which is used in e.g. Cedarburg input board for M2X?
Would such a solution introduce a lot more noise than pure discrete JFETs like 2SK's?
For M2X I prefer input boards like Norwood and Cedarburg over the pure discrete solutions.
I guess during a recording the signal has passed many op-amps?
I think one reason that input circuits must be "discrete" in high-end products is that op-amps will not be accepted by "audiophiles" and not because of "technical" reasons......or am I wrong?
Would such a solution introduce a lot more noise than pure discrete JFETs like 2SK's?
For M2X I prefer input boards like Norwood and Cedarburg over the pure discrete solutions.
I guess during a recording the signal has passed many op-amps?
I think one reason that input circuits must be "discrete" in high-end products is that op-amps will not be accepted by "audiophiles" and not because of "technical" reasons......or am I wrong?
M2x Norwood's input is a JFET opamp (AD744) designed by Analog Devices guru, and former member of diyAudio, Scott Wurcer.
M2x Cedarburg's input is a BJT opamp (AD797) also designed by Scott Wurcer.
Maybe the common theme is "IC opamp input". Or, maybe, ...
M2x Cedarburg's input is a BJT opamp (AD797) also designed by Scott Wurcer.
Maybe the common theme is "IC opamp input". Or, maybe, ...
Then we could make an amplifier with 1000 op-amps instead of 1000 JFETs?
https://www.analog.com/en/technical-articles/paralleling-amplifiers-increases-output-drive.html
In AD797 data sheet they discuss the noise generated by a single resistor in the circuit. I guess it is not easy to make a circuit using discrete transistors that performs significantly better? .....just the physical size of a discrete circuit will pickup more noise than a small well designed IC?
https://www.analog.com/en/technical-articles/paralleling-amplifiers-increases-output-drive.html
In AD797 data sheet they discuss the noise generated by a single resistor in the circuit. I guess it is not easy to make a circuit using discrete transistors that performs significantly better? .....just the physical size of a discrete circuit will pickup more noise than a small well designed IC?
Somebody has already "played" with this in small scale.
https://www.diyaudio.com/community/threads/parallel-op-amps.340720/
https://www.diyaudio.com/community/threads/parallel-op-amps.340720/
