I don't know what you are doing, but I am writing an article or more correctly, collecting material for the JFET Companion where the goal is to have as much as possible collected on JFET functionality, mathematical calculations & formulas, definitions, explanations of different amplification architectures and illustrations. For someone who does not know these things (like me), this will be a great document once its done.
Oneminde
Oneminde
> collecting material for the JFET Companion where the goal is to have as much as possible collected on JFET functionality, mathematical calculations & formulas, definitions, explanations of
https://www.amazon.com/Designing-Field-Effect-Transistors-Siliconix-Incorporated/dp/0070575371
http://www.bitsavers.org/components/siliconix/Designing_With_Field_Effect_Transistors_1981.pdf
https://www.amazon.com/Designing-Field-Effect-Transistors-Siliconix-Incorporated/dp/0070575371
http://www.bitsavers.org/components/siliconix/Designing_With_Field_Effect_Transistors_1981.pdf
Thanks for the material, I will go over it and check if it contain something useful that I can add.
The JFET Companion is complete.
- The JFET companion was written to be a support for learning and understanding JFETs and assorted quality factors. It contains both definitions and key descriptions found in different lectures and articles. The reference material can be found at the end of this paper if you wish to read the sourced material in its entirety. Due to different “styles” used in describing what JFETs are, their function and how to operate them, I have taken the liberty to reorganize the literature in such a way that it is more coherent and linear, from simple to advanced.
- This document was created in part to teach myself what JFETs are in order to quantitatively and objectively perform calculations, simulations and measurements, and as support for a preamplifier project I am working on. It’s the authors first time being involved in an electronics project on this scale, so it was important to collect information and data such that the project could proceed with a focus on quality and great understanding of what’s involved when selecting JFETs and controlling their range of operation with a minimum set of damaging and destructive parameters for music reproduction.
- Although this document will focus on JFETs, I have included a bonus section which will cover a few amplification stages and topologies as well as describing the underlying structure of the preamplifier that I am personally working on. The preamplifier use something called a Voltage and Current Buffer and what that is among other things will be covered in the bonus section, but is not essential for the JFET section.
You can read online or download: The JFET Companion.pdf - Google Drive
Oneminde
- The JFET companion was written to be a support for learning and understanding JFETs and assorted quality factors. It contains both definitions and key descriptions found in different lectures and articles. The reference material can be found at the end of this paper if you wish to read the sourced material in its entirety. Due to different “styles” used in describing what JFETs are, their function and how to operate them, I have taken the liberty to reorganize the literature in such a way that it is more coherent and linear, from simple to advanced.
- This document was created in part to teach myself what JFETs are in order to quantitatively and objectively perform calculations, simulations and measurements, and as support for a preamplifier project I am working on. It’s the authors first time being involved in an electronics project on this scale, so it was important to collect information and data such that the project could proceed with a focus on quality and great understanding of what’s involved when selecting JFETs and controlling their range of operation with a minimum set of damaging and destructive parameters for music reproduction.
- Although this document will focus on JFETs, I have included a bonus section which will cover a few amplification stages and topologies as well as describing the underlying structure of the preamplifier that I am personally working on. The preamplifier use something called a Voltage and Current Buffer and what that is among other things will be covered in the bonus section, but is not essential for the JFET section.
You can read online or download: The JFET Companion.pdf - Google Drive
Oneminde
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Cool.
99% of the material in the companion isn't mine, but a friend of mine who is rather clever when it comes to math found a few flaws with some of the formulas. So we'll eventually go over it and correct the mistakes and upload an edited version asap we have some time left over.
No one. I went over UGS thread as a precursor to the original French threads. Still have some left to go over.
Oneminde
Great thread Oneminde, very interesting and detailled.
I'll follow this with a lot of interest 😉.
I'll follow this with a lot of interest 😉.
You have a link to Rod Elliot's site. This month he began moving it off an annoying host-service to another host and URL.
Elliott Sound Products (ESP) website
I would object to the notion that "BJTs are current controlled" (pg5) but it does depend on the user's level of enlightenment. Enhancement vs depletion normal biasing is also different. Cherry-Hooper Low Pass Amplifiers is a thick read but gives a unified insight.
Elliott Sound Products (ESP) website
I would object to the notion that "BJTs are current controlled" (pg5) but it does depend on the user's level of enlightenment. Enhancement vs depletion normal biasing is also different. Cherry-Hooper Low Pass Amplifiers is a thick read but gives a unified insight.
PRR; If the experts say something and I don't know anything better, all I can do is to agree .. LOL.
The current controlled comes from this:
Source: https://nptel.ac.in/courses/113106065/Week%206/Lesson13.pdf
I think that's it 😉
PS: I've had a week or so off from the project but should return shortly. Much of what I do now is research and preparation, so naturally it will be a bit quiet from time to time.
Oneminde
The current controlled comes from this:
- Common Base Configuration – has Voltage Gain but no Current Gain.
- Common Emitter Configuration – has both Current and Voltage Gain.
- Common Collector Configuration – has Current Gain but no Voltage Gain.
Source: https://nptel.ac.in/courses/113106065/Week%206/Lesson13.pdf
I think that's it 😉
PS: I've had a week or so off from the project but should return shortly. Much of what I do now is research and preparation, so naturally it will be a bit quiet from time to time.
Oneminde
While I am studying and going over the old threads surrounding the UGS, I think I have found worthy replacements. Its not 100% but I feel confident in this parts.
JFET; This one is fairly simple - Toshiba 2SK209BL. Its an N-chn and will also replace the P-chn. Comes in SOT-23 package.
BJT: I didn't want to mix SOT-23 and TO-92 package since that would mean "special cooling solutions", instead, since the JFET is a smd unit, then I wanted the BJT to also be an smd unit. Since many recommend the ON Semiconductor BC550/560 this was my initial choice, but they come in TO-92 package only. Fortunately there exist smd equivalent. BC850/860. So unless anything change or I discover that the BC850/860 does not work, these are the BJTs I have selected.
Oneminde
JFET; This one is fairly simple - Toshiba 2SK209BL. Its an N-chn and will also replace the P-chn. Comes in SOT-23 package.
BJT: I didn't want to mix SOT-23 and TO-92 package since that would mean "special cooling solutions", instead, since the JFET is a smd unit, then I wanted the BJT to also be an smd unit. Since many recommend the ON Semiconductor BC550/560 this was my initial choice, but they come in TO-92 package only. Fortunately there exist smd equivalent. BC850/860. So unless anything change or I discover that the BC850/860 does not work, these are the BJTs I have selected.
Oneminde
2SK209BL are not easy to source at all and then you need the complementary which is harder.... 2SK209GR is still available at Mouser though and you need quantity to find matching pairs.
Did you look at the transistors used in UGS6 ?
Did you look at the transistors used in UGS6 ?
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2SK209GR will work (Idss: 2.6-6.5mA) since the bias is around 4mA. 🙂. The GR is also much easier to find. Remember, there will be no complimentary for this amplifier. N-chn conducts equally well in both directions.
UGS6 ... UGS 6. Can't say I've read about a 6 version. It might appear in on of the threads I am reading, but if not, plz attach a reference or post link to what you refer to.
Oneminde
http://www.hifishock.org/galleries/.../integrated-amplifier/int-30a-3-pass-labs.jpg
but since you are going the 2SK209GR route disregard.
but since you are going the 2SK209GR route disregard.
The UGS6 use Diodes Incorporated ZVN2110 (MOSFET) and Nexperia BCP53 (BJT).
I know some use dual-package JFET and the equivalent to the 2SK209 is the 2SK2145 which many use. The reason I am choosing monolithic JFET is matching 🙂
I know some use dual-package JFET and the equivalent to the 2SK209 is the 2SK2145 which many use. The reason I am choosing monolithic JFET is matching 🙂
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I might have spoken early about the BJTs since Toshiba has some with very low NF.
Reminder: Wait to speak until you are done with all the UGS threads 🙂
Reminder: Wait to speak until you are done with all the UGS threads 🙂
Round 1 complete.
This is just to inform you that round 1 is complete, which included tracking down the essentials for the original UGS and UGS Muses edition. Now that I have all the material available, round 2 can commence which include redesigning the amplification section, choosing components etc. The UI will also be part of this. I will do sporadic updates and communicate with does who comment or ask questions.
Oneminde
This is just to inform you that round 1 is complete, which included tracking down the essentials for the original UGS and UGS Muses edition. Now that I have all the material available, round 2 can commence which include redesigning the amplification section, choosing components etc. The UI will also be part of this. I will do sporadic updates and communicate with does who comment or ask questions.
Oneminde
CMRR - Common Mode Rejection Ratio.
From Ine123's UGS Muses build thread.
At 0 amplification - Sign.in = Sign.out: -87dB
At maximum amplification: -76dB
Compared to Pass Laboratores XP-30: -60dB @ 1kHz
I will ofc do all sorts of measurements once the unit is built and tuned.
Some THD measurements
UGS adventures
From Ine123's UGS Muses build thread.
At 0 amplification - Sign.in = Sign.out: -87dB
At maximum amplification: -76dB
Compared to Pass Laboratores XP-30: -60dB @ 1kHz
I will ofc do all sorts of measurements once the unit is built and tuned.
Some THD measurements
UGS adventures
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