We are not worthy but
Mr.Curl,
We are still waiting for a diy design from you.............🙄
Wishful thinking I suppose..............😀
Jam
Mr.Curl,
We are still waiting for a diy design from you.............🙄
Wishful thinking I suppose..............😀
Jam
That's it thanks. You could trivially add the preamp voltage and current noise. The parallel/series network transformations are great old school stuff that everyone should know.
acoustic scaling
Perhaps I should add that one of the team involved - 'D Short', credited on some later BBC papers -was a tutor of mine at Uni just over 20yrs later, and though I grew up to become an architect I learnt a lot on the way 😉
[size=-2]Davey also had us using tapping machines and checking logs the long way round. The very, very long way around...[/size]
It is also amazing how much of what one might consider 'structural acoustics' has yielded to cheap computation since - and I'm only talking 10-15yrs. A few rules of thumb more or less and we get to reliably specify treatments to achieve target RT60s and speech clarity criteria in run-of-the-mill spaces from classrooms to lecture thatres via healthcare consult&exam rooms with specified privacy constraints - and we know the results will work.
Perhaps I should add that one of the team involved - 'D Short', credited on some later BBC papers -was a tutor of mine at Uni just over 20yrs later, and though I grew up to become an architect I learnt a lot on the way 😉
[size=-2]Davey also had us using tapping machines and checking logs the long way round. The very, very long way around...[/size]
It is also amazing how much of what one might consider 'structural acoustics' has yielded to cheap computation since - and I'm only talking 10-15yrs. A few rules of thumb more or less and we get to reliably specify treatments to achieve target RT60s and speech clarity criteria in run-of-the-mill spaces from classrooms to lecture thatres via healthcare consult&exam rooms with specified privacy constraints - and we know the results will work.
PS The author of the paper I linked, H.D Harwood, is probaby better known for founding Harbeth Speakers.
Just to remind everyone: The Levinson JC-2 and JC-3 schematics are on this website and have been built by serious DIY'ers. It is my personal opinion that anything else designed by me, in recent years, would be better served by buying a used unit, such as an HCA2200, 1200, 1500, A21, or A23, for example. Why start from scratch? Usually, these designs are fairly complete and up-to-date, so major reconstruction would be a waste of time.
It just a matter of tolerance.
Some carts can't stand up to the demonic messages that are heard on some records when played backwards.
😱
Best Regards,
TerryO
Jan, this is a 'quibble'. Of course, DIY Audio has a lot to do with the 'joy' of drilling your own chassis, finding all the parts from 10 different sources, learning how to solder, then meticulously making a circuit board, then putting some circuit that another DIYer has come up with. Kind of like making your own boat from scratch, or ski's, or whatever.
For many contributors here, a simple circuit, is all that they want to do. No problem! However, my circuits are made with difficult to find parts, have a significant amount of matching required, which demands a large selection of active devices, and a whole array of 'housekeeping' circuits that provide protection, and convenience to the user.
I don't understand the exact design and operation of several versions of those extra circuits, as they are added on to my 'essential' design in Taiwan, by other engineers.
However, everyone, ever think of the advantages of buying a used, and 'out of date' Parasound amp, or its equivalent? You get a FIRST RATE chassis and heatsink, hard to get parts are already matched and installed. You get a first rate John Curl circuit design usually composed of a complementary differential jfet input stage, push pull VAS, and a lot of fast complementary output devices, best available at the time of construction. You also get a huge transformer, relatively large cap array, and protection from shorting or overtemp.
You can buy these circuits, for a small proportion to what they cost retail new, as they are both somewhat used, and an obsolete model number. However, they ARE in essence much the same as the latest Parasound amps.
Now, what can you do as a diyer to 'IMPROVE' these amps? Well, if you asked John Curl, he might tell you to just clean it up, make sure the bias is turned up to a good level, and to leave it alone. Yet, in other models, he might tell you to 'clean up' the amp by REMOVING extra caps, added in Taiwan for the 'eye' rather than the ear, swapping out some caps for other quality caps, changing some resistors, critical to the sound, and sometimes the wrong part was used initially, etc, etc.
This is where I can contribute to DIY audio besides trying to keep a high level ongoing discussion going, no matter what. Any questions?
For many contributors here, a simple circuit, is all that they want to do. No problem! However, my circuits are made with difficult to find parts, have a significant amount of matching required, which demands a large selection of active devices, and a whole array of 'housekeeping' circuits that provide protection, and convenience to the user.
I don't understand the exact design and operation of several versions of those extra circuits, as they are added on to my 'essential' design in Taiwan, by other engineers.
However, everyone, ever think of the advantages of buying a used, and 'out of date' Parasound amp, or its equivalent? You get a FIRST RATE chassis and heatsink, hard to get parts are already matched and installed. You get a first rate John Curl circuit design usually composed of a complementary differential jfet input stage, push pull VAS, and a lot of fast complementary output devices, best available at the time of construction. You also get a huge transformer, relatively large cap array, and protection from shorting or overtemp.
You can buy these circuits, for a small proportion to what they cost retail new, as they are both somewhat used, and an obsolete model number. However, they ARE in essence much the same as the latest Parasound amps.
Now, what can you do as a diyer to 'IMPROVE' these amps? Well, if you asked John Curl, he might tell you to just clean it up, make sure the bias is turned up to a good level, and to leave it alone. Yet, in other models, he might tell you to 'clean up' the amp by REMOVING extra caps, added in Taiwan for the 'eye' rather than the ear, swapping out some caps for other quality caps, changing some resistors, critical to the sound, and sometimes the wrong part was used initially, etc, etc.
This is where I can contribute to DIY audio besides trying to keep a high level ongoing discussion going, no matter what. Any questions?
Just one- since many people here build circuits at least as complex and demanding (take a look at the Pass forum, for example), why don't you give it a shot anyway? The capabilities of many amateurs are pretty high. Heck, if I worried that my designs were too complex and demanding for a beginner, I would never have published any of them. Same with Jan- his stuff is generally pretty advanced, yet they're out there for experienced builders, and beginning and intermediate amateurs can use these as learning tools.
SY, it is not something that I do well. Many of my designs are already published, and available, IF someone wanted to build them. Nelson Pass has his own place and following here on this website, apparently free and clear of a good deal of what I have to deal with on a regular basis. I was never offered such a place on this website, and I have 'settled' for nudging this thread though 'thick and thin' under continuous moderation. To try to do more here would be rather tedious, and besides, I design circuits for a living, and I had better put my circuit design experience into new designs that will reach the marketplace, in time, as unlike Nelson, I am still dependent on making a living to continue.
One thing that I find rather sad, is that my design expertise is continually challenged, even though I have been doing circuit design successfully for more than 40 years, and many of my original design concepts are now built into many audio products, without regard to the fact that they too, were originally challenged as either too complex, expensive, or darn right confusing, 40+ years ago.
One thing that I find rather sad, is that my design expertise is continually challenged, even though I have been doing circuit design successfully for more than 40 years, and many of my original design concepts are now built into many audio products, without regard to the fact that they too, were originally challenged as either too complex, expensive, or darn right confusing, 40+ years ago.
Cause and effect. Nelson is happy to develop and publish designs for construction by us amateurs. There were so numerous and so popular, a section was created, where Nelson is supportive, encouraging, and cheerfully helpful. That's not your personality. 😀
Not everyone is good at documenting and explaining, i.e., turning a project into a readable and educational article. Anytime you're ready to do diy projects, I would be more than happy to provide that end of the process for you. A few of those, with positive member reaction, and we'd be more than happy to have a John Curl section of the website.
Ah, I just remembered something about the hall I worked on. The acoustical consultants had something in their contract like rights to "final cut" that auteur film directors demand. I suppose that can't be absolute given life-safety regulations, etc.
I've cross-referenced this concert hall discussion to a discussion on room acoustics where measurement also seems to be short of providing all the answers... yet.
As Sy points out, John Curl isn't responsive to providing DIY designs. Maybe kind of the same worry since he doesn't have "final cut" privileges when people construct his designs at home. Of course, you can view this is as a virtue or a fault on his part.
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Hell Boy, i'm always positive to Mr C's contributions (here).
So you'll only need a couple of suckers more, i'll bet this place is filled with arsenic kissers.
(my profound rudeness helps me cope with the psychopathology of everyday life)
Juergen, do you know if Mr Skritek's bookie is still printed ?
I have the '88 edition, couple of years ago i asked a bookshop to order the 99er for moi, but they weren't able to deliver.
Amazing.de tells the same tale, just a couple of used ones left for the desperate.
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a quick googlerie offers nothing new. It seems to be not in print anymore.
My copy is from '88 too. I don't think a newer edition would provide more info on analog circuitry than the oldie already provides. So no upgrade necessary for me.
regards
My copy is from '88 too. I don't think a newer edition would provide more info on analog circuitry than the oldie already provides. So no upgrade necessary for me.
regards
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