seems to be too much misunderstanding of 50 year old "conventional" EE signal, feedback theory here to see the use/application of many "new" theory results
more recent than ~1960 EE theory results that could be helpful sometimes in amp design or crossover production tolerancing would be Kharitonov's theorem polynominal root result and subsequent applications to robust design using "Classic" frequency domain toools
Describing functions can also help with high feedback amp's clipping nonlinear stability analysis
but I can't get John Curl to follow a Bode Sensitivity analysis showing his claim of what he did with the JC-1 preamp "inner loop" doesn't even modify the loop gain in the direction he claimed to want
I don't know if you intended 'here' to mean 'on this particular thread' or as DIYA as a whole website. If the latter then when you have a free moment, skip over to my blog and tell me if there's any prior art for my DAC design? You'd be perhaps the best person here to judge that with your considerable technical reading background.
misremembered the #, it is the old Levinson JC-3, which, unlike the Blowtorch, has been published for a long time now, John has made specific claims about the added "inner feedback" resistors correcting Otala's PIM in this specific design, my examination, sims are in this thread
search this thread for user: jcx, keyword jc-3 should get you to the right epoch
search this thread for user: jcx, keyword jc-3 should get you to the right epoch
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Yes. This site would be sufficiently "public" to be deemed a disclosure I think (disclaimer: I am not an attorney). That was to some extent a strategy in mind when I published the recent post on inverting current conveyors. I can't patent any of it specifically now, but if someone else attempts to and later sues me for infringement, I can cite the post.
Ah I hadn't caught that post until you mentioned it here
Why is it in 'Digital Source' incidentally?I might point out that the math and higher level technology that is used as the foundation for many of the discussions on this thread serves (only), to help one to understand functionally what is going on with a particular topic. This is how it is taught in school. Experience should in-turn convert the concepts into real mental images. If you, for example, understand what a high pass filter does using the mathmatical description to help you visualize what is going on, you might be able to describe what a filter does without quoting a mathmatical explanation.
I like to think that things explained this way are easier for an interested DIYer to pickup the underlying concepts... If they want to expand to the next level, then they need to dig into the sublties and the math to apply the technology. Actually building stuff is where you really learn about the details...
The creation of another DIYer!
Mike
Ah I hadn't caught that post until you mentioned it here
It was prompted by EUVL's minimalist IV converter thread (Zen Sen Cen something) which I found when I was on the verge of sending another LTE to Jan Didden, and instead (having found the thread here) simply mentioned my concerns about DAC output Z interactions with said converter in Patrick's thread. I have since become more sympathetic to EUVL's approach, and it sparked some further development, one outcome of which is my post (which has gotten zero replies --- not sure if that is a bad sign or a good sign =] ).
Brad
Another -- yes, it can be claimed. Published anywhere in any language at any time.
Regarding the subject of switches awhile back.... switches tend to be left in one position for a long time... like to the phono or what ever is the favorite source input. If silver-silver is used, oxide will build up on it (if air get to it). So, its good to wipe it back and forth a few times every now and then. Or it will create high distortion esp. at low voltage levels.... below the break thru oxide voltage level. Gold over silver is nice and reliable for long term stationary use.
A good, highly technical, book in my library is Electric Contacts by Ragnar Holm and Switch Engineering Handbook by J.R.mason
A good, highly technical, book in my library is Electric Contacts by Ragnar Holm and Switch Engineering Handbook by J.R.mason
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I agree, Richard. Also it is an advantage to put switches like this in a static environment that does not have much air circulation with the outside world.
Also, Ragnar Holm is MY reference, also, has been for the last 30 years, due to the early research that you and Walt did on contacts.
Also, Ragnar Holm is MY reference, also, has been for the last 30 years, due to the early research that you and Walt did on contacts.
John, somewhere you have indicated your preference of using fast high Ft transistors at output stages. Could you please share your thoughts in this relation?
One could hardly distinguish by standard measurements between properly designed amps with 20MHz and 60MHz transistors at the output. If not measurements, then what idea behind your preference?
One could hardly distinguish by standard measurements between properly designed amps with 20MHz and 60MHz transistors at the output. If not measurements, then what idea behind your preference?
It never occured to me that by 'body of knowledge' you meant exclusively (or even mainly) a DIY website containing copious amounts of misinformation and largely wasted efforts by some of us to correct that misinformation. Your comment appeared to say that none of us (apart from you and JC) have added anything anywhere to the body of knowledge. I took 'here' to be part of identifying the people who have made no contribution, not the place where they have made no contribution.RNMarsh said:
Will you now tell us that when you said 'body of knowledge' you didn't really mean a body of knowledge?
Reading the posts of this and other forums, it is not difficult to see that there are definite groups of forum participants.
Members of the first group are open minded and tend to share their experience and even some know-how.
Members of the second group never share own results affecting and improving sound. They prefer to repeat standard book knowledge and eventually to pick up some useful practical findings, but never express any appreciation to authors of interesting posts.
The third group participants try to become popular by demonstrating their knowledge and experience with a hope for possible business effect.
Of course, their are more groups of participants.
The only conclusion I would make from these observation, members of the second group make forum discussion boring.
Members of the first group are open minded and tend to share their experience and even some know-how.
Members of the second group never share own results affecting and improving sound. They prefer to repeat standard book knowledge and eventually to pick up some useful practical findings, but never express any appreciation to authors of interesting posts.
The third group participants try to become popular by demonstrating their knowledge and experience with a hope for possible business effect.
Of course, their are more groups of participants.
The only conclusion I would make from these observation, members of the second group make forum discussion boring.
Dividing into groups is not very helpful, but if a division is needed I would propose:
1. those who understand electronics, to a reasonable extent
2. those who think they understand electronics, perhaps because they have built a lot of stuff
3. those who know they don't understand electronics, but are keen to learn
Group 1 can help group 3 by answering their questions. Group 3 can help group 1 by asking questions; explaining things to someone else helps sharpen knowledge. Group 1 can help each other by explaining things which are gaps in others' knowledge.
I would add that 'standard book knowledge' often seems boring, or even wrong, to some of those who don't possess it. It is the starting place for real expertise; you can't build without a foundation.
1. those who understand electronics, to a reasonable extent
2. those who think they understand electronics, perhaps because they have built a lot of stuff
3. those who know they don't understand electronics, but are keen to learn
Group 1 can help group 3 by answering their questions. Group 3 can help group 1 by asking questions; explaining things to someone else helps sharpen knowledge. Group 1 can help each other by explaining things which are gaps in others' knowledge.
I would add that 'standard book knowledge' often seems boring, or even wrong, to some of those who don't possess it. It is the starting place for real expertise; you can't build without a foundation.
This is a definite problem, which is also being mentioned here by Richard Marsh.
Those who believe they understand electronics and possess a strong fundament, actually they have no idea how to build a GOOD SOUNDING stuff.
At the same time, of course, they are excellent in building a reliable audio gear, as well as properly working electronic instruments and sensors.
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