Edmond,
I think that the people that you call innocent and ignorant are highly functional people with high intelligence levels and they
have the responsibility to manage their money as they will.
No one is using force to make them buy a directional wire.
It is not children we are talking about.
Sigurd
I think that the people that you call innocent and ignorant are highly functional people with high intelligence levels and they
have the responsibility to manage their money as they will.
No one is using force to make them buy a directional wire.
It is not children we are talking about.
Sigurd
Edmond Stuart said:
John,
one circuit topic that is puzzling me still, is what the best way to cascode a JFET is, and why that way is the best. I have read that cascoding adds higher order harmonic content, but not been able to verify this.
I like to use my JFETs at about 10V only, and thus need to cascode them with a telescopic cascode. All the time....
Now, to use a JFET or BJT or MOSFET?
To use driven telescopic cascode or a cascode referenced to GND is another issue. I made some sims, attached below, that shows how much better it is to use a driven telescopic cascode when only BW is the major goal. (I also put this sim on the Baxandall thread where Walt J commented on it but would like to share it here, too. Maybe news for someone.)
What are your thoughts about the optimal way(cost not relevant) to make a telescopic cascode thinking about sonics and measurements?
Sigurd
one circuit topic that is puzzling me still, is what the best way to cascode a JFET is, and why that way is the best. I have read that cascoding adds higher order harmonic content, but not been able to verify this.
I like to use my JFETs at about 10V only, and thus need to cascode them with a telescopic cascode. All the time....
Now, to use a JFET or BJT or MOSFET?
To use driven telescopic cascode or a cascode referenced to GND is another issue. I made some sims, attached below, that shows how much better it is to use a driven telescopic cascode when only BW is the major goal. (I also put this sim on the Baxandall thread where Walt J commented on it but would like to share it here, too. Maybe news for someone.)
What are your thoughts about the optimal way(cost not relevant) to make a telescopic cascode thinking about sonics and measurements?
Sigurd
john curl said:
Terry Demol said:
Well said, Terry. One can get excellent sonic results with. For line level preamp, there is no such demand for ultra low noise, so we can choose HIGH level of emitter degeneration. Considerably high standing current helps as well. We compared with FETs ....
If it is fraud, then the police can go ahead and do their work. Is there proof enough for fraud that a judge would do something?
Sigurd
Sigurd
Steve Eddy said:
This is a tough call. Every type of cascode has both advantages and disadvantages. I have used 4 different types over the years with many circuits.
It is actually possible to cancel the 2'nd harmonic in a jfet with proper resistive loading on the output. It is tricky, but it would measure better than a cascode, at least at lower frequencies. This is the so called 'triode' effect as triodes can do this too.
It is actually possible to cancel the 2'nd harmonic in a jfet with proper resistive loading on the output. It is tricky, but it would measure better than a cascode, at least at lower frequencies. This is the so called 'triode' effect as triodes can do this too.
If cables are non-directional, and the signal is non-directional, why do we have an OUPUT on the source and an INPUT on the amp? I mean, isn't the signal supposed to go FROM output TO input?
(This is not a troll, I have an answer, which may even make sense ;-)
Jan Didden
(This is not a troll, I have an answer, which may even make sense ;-)
Jan Didden
janneman said:
I don't know. Perhaps someone else can uh... poynt you in the right direction. 😀
se
Sigurd Ruschkow said:
Cascoding - FET or MOSFET.
Nelson Pass is the true 'cascoding man'.
He has investigated this a lot ...
If you post in Pass Labs forum - he will join in, for sure 😉
Although John Curl surely knows these things, too,
he may not have invested as much effort as Nelson Pass into cascoding, specifically.
Besides, Nelson can afford share his knowledge a bit more openly.
It is good for Pass Labs' business as well as for Mr Pass' reputation among us DIY People.
Lineup
-------------------------------------------------------------------
References:
http://www.passlabs.com/pdf/articles/cascode.pdf
Sigurd Ruschkow said:
My point was that whether or not legal actions may be taken, we should expect the claims made by those trying to sell us something not be fraudulent in the first place.
se
I assume that Nelson Pass has his own forum. His approach and writing style is easier to understand for DIYers.
As I said, every cascode is different. I tend to use folded cascode mostly, with fet to fet. This is the basis of the Vendetta input stage, and the CTC Blowtorch.
For large voltages, usually a mosfet is the best cascode device. To save money, a bipolar transistor will generally work, and a jfet for the cascode is generally the best, overall.
When using jfet to jfet cascode, usually a real separation between the input device is best, in order to have some real voltage across the input fet. However, properly done, the self biased cascode can be very good for microphone stages or other low voltage designs. Selection of the second stage device almost always demands a high Idss type, but that is cheap enough.
For large voltages, usually a mosfet is the best cascode device. To save money, a bipolar transistor will generally work, and a jfet for the cascode is generally the best, overall.
When using jfet to jfet cascode, usually a real separation between the input device is best, in order to have some real voltage across the input fet. However, properly done, the self biased cascode can be very good for microphone stages or other low voltage designs. Selection of the second stage device almost always demands a high Idss type, but that is cheap enough.
Lineup -
I do not want to post in the Pass forum. If I wanted to to do that, I would do it 😉
What I want to know more about is what other designers' experience is with different types of telescopic cascodes.
Sigurd
I do not want to post in the Pass forum. If I wanted to to do that, I would do it 😉
What I want to know more about is what other designers' experience is with different types of telescopic cascodes.
Sigurd
lineup said:
PMA - do not underestimate the skills and experience of DIYers. There are newbie DIYers and then there people with 30+ years of audio DIY.
I think that you now have your own audio company, and are going commercial, but were you not once an audio DIYer?
Even commercial companies have different skills and experiences - and target customers. To go commercial only means that one wants to make money on the business.
Sigurd
I think that you now have your own audio company, and are going commercial, but were you not once an audio DIYer?
Even commercial companies have different skills and experiences - and target customers. To go commercial only means that one wants to make money on the business.
Sigurd
PMA said:
Who has the authority to claim that an audio device is a fraud or not?
Also, the authorities 100s of years ago, even killed people that said that this and that was false. Later on, we learned that these killed people actually were correct in their statements..... earth is not flat for ex....
Sigurd
Also, the authorities 100s of years ago, even killed people that said that this and that was false. Later on, we learned that these killed people actually were correct in their statements..... earth is not flat for ex....
Sigurd
Steve Eddy said:
John - that is interesting! How to get rid of the dominant 2nd harmonic.
I still have to use cascoding as the voltages I most often use are too high for the sk170/SJ74, and I also want to stay below the "gate-current-knee".
Would you say that one drawback with cascodes is that they introduce higher harmonics?
Looking at my sims, one can see that the chosen cascode-BJT gives higher BW than the chosen cascode-JFET. More interesting would be to look at the harmonic spectrum for BJT vs JFET for cascode work. Hmmmm.....maybe one could simulate that....
One might argue that it is a waste to use an expensive JFET for cascode work when one could use a cheap BJT (for ex a 2SC2240 or even cheaper types), but if the goal is to have the best sonics, I would not hesitate to use a JFET for cascode work.
Sigurd
I still have to use cascoding as the voltages I most often use are too high for the sk170/SJ74, and I also want to stay below the "gate-current-knee".
Would you say that one drawback with cascodes is that they introduce higher harmonics?
Looking at my sims, one can see that the chosen cascode-BJT gives higher BW than the chosen cascode-JFET. More interesting would be to look at the harmonic spectrum for BJT vs JFET for cascode work. Hmmmm.....maybe one could simulate that....
One might argue that it is a waste to use an expensive JFET for cascode work when one could use a cheap BJT (for ex a 2SC2240 or even cheaper types), but if the goal is to have the best sonics, I would not hesitate to use a JFET for cascode work.
Sigurd
john curl said:
Sigurd Ruschkow said:
Not this way. I have had my own business since 1990. My contemporary small audio activities can be considered rather like a hobby. I am an EE professional, but not audio. I only graduated in EE/electro-acoustic 29 years ago.
I would say I was a true DIYer since 1969 till 1979.
Sigurd Ruschkow said:
There is an interesting story in the July issue of AudioXpress. An audiophile in the UK complained to that country's Advertising Standards Authority (ASA) about a Kimber cable ad.
The man challenged several claims because "he believed that (those claims) did not have the effect that was claimed". This was about mains cable effects, like less EMI inside the box, less distortion, lower noise floor etc.
The ASA submitted the claims to an expert for verification. The expert determined that the claims were unsubstantiated, and that the research papers provided offered no supporting evidence and were not peer reviewed. The ASA then told the advertiser to, quote: "cut the BS" and not use the claims again unless they could substantiate them with robust scientific evidence.
That's what I call consumer protection.
Jan Didden
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