IF you use a feedback network, then you will always have a 'shelf' at some high frequency. This will track any passive RIAA better. However, I don't have a negative feedback high frequency roll-off, so I just let it roll off slightly at 50KHz or more. in order to make the overall cartridge-preamp response, flatter.
Right John,
but the graph presents a inflection point near 1kHz without that resistor. I´m not worry so much with that slight diference at high frerquency. I´m really worried about variations at mid band and I think if we solve all possible "problems" ( don´t get me wrong, please! ) on simulation we will know what to do in practice if necessary.
Thanks again John !
eD
but the graph presents a inflection point near 1kHz without that resistor. I´m not worry so much with that slight diference at high frerquency. I´m really worried about variations at mid band and I think if we solve all possible "problems" ( don´t get me wrong, please! ) on simulation we will know what to do in practice if necessary.
Thanks again John !
eD
I don't mean to be provocative when I say that it is my view that calculation and or simulation of every possible detail prior to building and listening (after basic measurements) will seriously restrict the designer. On the other hand the designer who knows the components sonic characteristics and design concepts from a sonic viewpoint can often from that background design more intuitively and, from a sonic viewpoint, more successfully. Those who theorize to the Nth degree before building actually restrict themselves as I see it in much the same way as the ancients restricted themselves by their use of oracles and casting of bones when faced with serious decision making.
To me the whole skill involved in successful audio design is as much an art form as it is a scientific/technical skill. (Despite our views of the more obvious works of Picasso and Dali few people realize how extensive were their skills as draughtsmen, painters and their handling of their materials.) I believe that the consistently good designer needs to have as much scientific knowledge as possible and also needs to be able to thoroughly see the practical technical implications and limitations of that knowledge. Such designers can come up with a large number of very acceptable designs and the marketeers can then add their skills. But the designer who has the intuitive approach, coupled with a deep technical knowledge and understanding unfettered by too much hidebound 'professionalism' will think outside of the envelope - 'laterally' if you like - and come up thereby with perhaps fewer but sonically highest level designs compared to those who work within the strict regime (or handcuffs) of the audio designer's 'Oracle', the simulation package.
To me the whole skill involved in successful audio design is as much an art form as it is a scientific/technical skill. (Despite our views of the more obvious works of Picasso and Dali few people realize how extensive were their skills as draughtsmen, painters and their handling of their materials.) I believe that the consistently good designer needs to have as much scientific knowledge as possible and also needs to be able to thoroughly see the practical technical implications and limitations of that knowledge. Such designers can come up with a large number of very acceptable designs and the marketeers can then add their skills. But the designer who has the intuitive approach, coupled with a deep technical knowledge and understanding unfettered by too much hidebound 'professionalism' will think outside of the envelope - 'laterally' if you like - and come up thereby with perhaps fewer but sonically highest level designs compared to those who work within the strict regime (or handcuffs) of the audio designer's 'Oracle', the simulation package.
brianco,
nobody in this forum has a original schematic of Vendetta circuit from John Curl.
We looking for one circuit closer to Vendetta that we can get. Besides this, some original parts are not available anymore. We must to use similar parts and because this, the "new circuit" may presents a few different specifications, and this make us ask to "child´s father": Is this modification ok?! The result of simulation is far way from real ?!
Because we ( interested in Vendetta´s clone ) want that very,very good reputation and natural sound from the original design. Only this. No transcendentally think of !!
regards
eD
nobody in this forum has a original schematic of Vendetta circuit from John Curl.
We looking for one circuit closer to Vendetta that we can get. Besides this, some original parts are not available anymore. We must to use similar parts and because this, the "new circuit" may presents a few different specifications, and this make us ask to "child´s father": Is this modification ok?! The result of simulation is far way from real ?!
Because we ( interested in Vendetta´s clone ) want that very,very good reputation and natural sound from the original design. Only this. No transcendentally think of !!
regards
eD
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Hi eD,
Thanks for this.....it certainly is a task to ask "child's father" for any hard information. It would seem to me that there is no chance whatsoever of you getting any really serious guidance regarding any truly unique design factor.
JC does give clues however and it has long been held that this is the best form of teaching. Contained among the many posts which he has made are many such clues not only to his classic designs but also to the Power Supplies involved. [I have gleaned that he is very particular regarding this aspect of design.]
I wish you well and hope that you can solve the mysteries presented by your simulations. But do bear in mind that the models upon which your programmes are based are more likely to be flawed than are the collective views of the probabilities involved in the actual circuits. It is too easy to get off on the wrong track if such models are less than perfect for purpose.
I know that an exercise such as this 'back-engineering' project can be very exciting indeed. However if I had the skill to actively take part in this I cannot help but feel that I would rather use the time and skills in developing a new design based on the simplest principles and developing that forward until I achieved a design with which I was happy to listen to music.
JC in his brief riposte above talks of accurate reproduction of audio sources being his intention. Fair enough; however we should all remember that the first source is the music itself. And music is NOT the series of ever more processed series of electrical impulses which are garnered by the microphones! Despite the best intentions of those who measure every possible aspect it is the recreation by electronics of an actual performance which is the nub of it all - and the ears will always be the final judge of success or failure.
And JC himself has often enough inferred the same point.Good luck,
Brian
Even in the simulation.
Although not yet achieved good simulation models for Hitachi mosfets but even if I can, I think I have almost no improvement
eD