Mind you that this thread is about the Blowtorch and as Jbaudiophile mentioned we are not copying anything because there is no original. What we try to do is to gain a better understanding of open loop line stage designs and all closely related issues.
Many have contributed with questions and proposed circuits in a constructive way. Those who want to learn and take it a step further pose more questions, which to me is very normal. It also keeps the discussion going and is not aimed at copying anything!
Now if you want to learn to drive a car, you are not going to learn to drive when only being told how to start the car. I think you get the idea.
Being on the forum is an exchange of information, knowledge and ideas from which all hopefully learn. My critical note seems to have given some a reason to start flaming me, which I find very childish.
The core of my comment is that I and a lot of others want to learn seriously! Having digested and thought through the information given by John, for which I thank him, it is also understandable that more questions come up, which keeps the discussion going. I feel I'm left in the woods at THAT point! It is NOT about copying the Blowtorch!
Many have contributed with questions and proposed circuits in a constructive way. Those who want to learn and take it a step further pose more questions, which to me is very normal. It also keeps the discussion going and is not aimed at copying anything!
Now if you want to learn to drive a car, you are not going to learn to drive when only being told how to start the car. I think you get the idea.
Being on the forum is an exchange of information, knowledge and ideas from which all hopefully learn. My critical note seems to have given some a reason to start flaming me, which I find very childish.
The core of my comment is that I and a lot of others want to learn seriously! Having digested and thought through the information given by John, for which I thank him, it is also understandable that more questions come up, which keeps the discussion going. I feel I'm left in the woods at THAT point! It is NOT about copying the Blowtorch!
If you can learn something, go to your local patent office and there you can find really many informations...Be prepare, that you will be there minimal one week.... 😉 Don't wait, that JC give you all his private knowledges....Very good " school " is also papers from Erno Berbelly and JAES papers from Malcolm Hawksford... JC isn't only one.... 😉
john curl said:
This might be greatly a question of personal taste. I have also tried a lot of comparisons between global NFB a non-global NFB designs. Sometimes I tend to prefer non-global NFB line stages, especially for jazz and mainstream music. For complex classical music, like great symphony orchestra, the properly designed NFB line stage is much much better, IMHO, regarding accuracy and resolution, especially regarding sound of bow instruments and brass.
Pavel Macura
Exactly my point... Do It YOURSELF! ... that's what John did.
Now there are even people insisting that John should not discuss this unless he willing to post more... more of HIS hard earned secrets/tricks. John will tell there are no secrets. He has also said that this amp would not be a good candidate for mass production... what does that tell you? Hint... begins with an "M".
Hi, Poobah,
Seems that we're not on the same wavelength... I don't want John Curl to publish any schematics he doesnt' want to, even for the Blowtorch... But discuss is another thing... The do & don't game he accepts(ed ?) is (was?) enough for me.
But... Where did you take from that anybody want to have a Blowtorch mass production started ? Big imagination, I guess... I used John Curl's JC-3 schematics to build a pair for myself and another one for a friend... For sure, seems that it would be mass production, if I understand fully what is your point !...
Later I built Nelson Pass A40 (still have them...)... Another mass production... Still 4 !... I never heard that the first two were patent granted, and I just used the PUBLISHED schematics with some tweaking and the parts available here... AS MANY OTHERS DID ! Mass production ? OH YES ! Several hundreds and probably several thousands of them have been built throughout the world and are still working fine... And me amongst all those defrauders and cloners... Sigh ! Thanks to have made me conscious taking of that ! Perhaps I am better to go and fish, no ?
And YES, for sure, we all forumers are industrial guys with gigantic companies, just lurking on US patents to have the job done here... And we are all trying to take bread out of John Curl's mouth... Just NONSENSE !
Just HAVE ANOTHER LOOK on the purpose that John Curl had with the Blowtorch : it was an EXPERIMENT at first, and ONLY that...
Turned to a small high priced production series, mostly for friends, as regretted Bob Crump told me. Nothing more... And I even discussed the topology with him BEFORE the Blowtorch question was introduced by Darry on the Forum. I am more interested by WHY Curl's prefered some topologies for now, as I have been collecting/back engineering most of his work for 25 years...
So, IMO, you are NOT in a better position than anybody else to judge other forumers willing, and surely NOT for pointing and shooting some of us as you did... And also NOT an advocate too for John Curl. Are you? He just knows what are the points he wants to discuss or not. Topologies he comments are most interesting to me that parts he uses, and that was my point...
Now, you last thread sentence was somewhat unclear to me... Should have understood that you only have the reduced and flowery Cambronne's language to use...?
jbaudiophile
Seems that we're not on the same wavelength... I don't want John Curl to publish any schematics he doesnt' want to, even for the Blowtorch... But discuss is another thing... The do & don't game he accepts(ed ?) is (was?) enough for me.
But... Where did you take from that anybody want to have a Blowtorch mass production started ? Big imagination, I guess... I used John Curl's JC-3 schematics to build a pair for myself and another one for a friend... For sure, seems that it would be mass production, if I understand fully what is your point !...
Later I built Nelson Pass A40 (still have them...)... Another mass production... Still 4 !... I never heard that the first two were patent granted, and I just used the PUBLISHED schematics with some tweaking and the parts available here... AS MANY OTHERS DID ! Mass production ? OH YES ! Several hundreds and probably several thousands of them have been built throughout the world and are still working fine... And me amongst all those defrauders and cloners... Sigh ! Thanks to have made me conscious taking of that ! Perhaps I am better to go and fish, no ?
And YES, for sure, we all forumers are industrial guys with gigantic companies, just lurking on US patents to have the job done here... And we are all trying to take bread out of John Curl's mouth... Just NONSENSE !
Just HAVE ANOTHER LOOK on the purpose that John Curl had with the Blowtorch : it was an EXPERIMENT at first, and ONLY that...
Turned to a small high priced production series, mostly for friends, as regretted Bob Crump told me. Nothing more... And I even discussed the topology with him BEFORE the Blowtorch question was introduced by Darry on the Forum. I am more interested by WHY Curl's prefered some topologies for now, as I have been collecting/back engineering most of his work for 25 years...
So, IMO, you are NOT in a better position than anybody else to judge other forumers willing, and surely NOT for pointing and shooting some of us as you did... And also NOT an advocate too for John Curl. Are you? He just knows what are the points he wants to discuss or not. Topologies he comments are most interesting to me that parts he uses, and that was my point...
Now, you last thread sentence was somewhat unclear to me... Should have understood that you only have the reduced and flowery Cambronne's language to use...?
jbaudiophile
I completely agree with jbaudiophile. None of us are after John's secret the BT. I don't see the problem of discussing a circuit or design-approach. It happens to be related to the BT because apparently you ar not aware of the fact that this thread IS ABOUT THE BT!! The earlier in this thread suggested haircut seems to be valid still. Now if I wanted to discuss a digital volume control I would definately be in another thread, wouldn't I.
Is DIY related to mass production??? I don't think so!! I've seen many DIY designs which looked and performed better than commercial designs. Let each one personally judge what is and what is not within their reach as DIYers. Furthermore John has only responded to a certain extend to questions and circuits presented by us DIYers. He has not provided us with any schematic whatsoever, so what secrets are you talking about. I for that matter do not need your patronizing attitude, when you don't even grasp the core of my comment.
Folks, I apologize, but I can't publish my schematics. I don't mind discussing general aspects of this design, especially in its simplified form. I also don't mind constructive suggestions as to how to improve it, or change it in some other way. Many of you on this thread, have done a good deal of 'reverse engineering' from the photos, and some good engineering development on how to make a design like this. For this, I commend you, but I can't give you EVERYTHING!
We are still making this preamp. We just finished 6 units this month, and we may build more in future, so my new business partner gets VERY angry with me, if I spill too much on this thread. We are also going to make a new phono stage, one of these days, so I don't want to be very specific about the Vendetta Research phono stage either.
However, I am interested in answering specific questions about audio design, and learning as much from you, as you might learn from me.
Now I thank Poobah for sticking up for me in this case. I might remind him, good naturedly, that criticism of our wiring practices, first caused me to comment on this thread. Having designed numerous preamps over the years, shows me that we are still on the right track. Please note that our wires are NOT shielded. This makes for a better sounding wire, in our estimation. Also, we MAXIMIZE the wire spacing, and minimize the circuit board traces. Circuit board material, even teflon, is not as good an insulator as pure air, and we can keep the spacing between our wires (in air) at a much greater distance from each other. The thick almost airtight aluminum case is our electrostatic shield from the outside world. Does it look 'pretty'? Not really, it is darn hard to make it so. I am in charge of making it 'presentable' so I know this for sure. However, it works and is one way to do things. We still make designs that eliminate wiring altogether, if we can, but they are more potenially compromised, because of this. The JC-1 power amp and the upcoming JC-2 preamp (Parasound) are examples of 'wireless' layout, by the very same person who designed the Blowtorch circuit boards. You just can't have very much individual wiring in mass production, and get it right. At least, that is my experience.
In any case, let's talk about audio preamps in general, not just about my specific design.
We are still making this preamp. We just finished 6 units this month, and we may build more in future, so my new business partner gets VERY angry with me, if I spill too much on this thread. We are also going to make a new phono stage, one of these days, so I don't want to be very specific about the Vendetta Research phono stage either.
However, I am interested in answering specific questions about audio design, and learning as much from you, as you might learn from me.
Now I thank Poobah for sticking up for me in this case. I might remind him, good naturedly, that criticism of our wiring practices, first caused me to comment on this thread. Having designed numerous preamps over the years, shows me that we are still on the right track. Please note that our wires are NOT shielded. This makes for a better sounding wire, in our estimation. Also, we MAXIMIZE the wire spacing, and minimize the circuit board traces. Circuit board material, even teflon, is not as good an insulator as pure air, and we can keep the spacing between our wires (in air) at a much greater distance from each other. The thick almost airtight aluminum case is our electrostatic shield from the outside world. Does it look 'pretty'? Not really, it is darn hard to make it so. I am in charge of making it 'presentable' so I know this for sure. However, it works and is one way to do things. We still make designs that eliminate wiring altogether, if we can, but they are more potenially compromised, because of this. The JC-1 power amp and the upcoming JC-2 preamp (Parasound) are examples of 'wireless' layout, by the very same person who designed the Blowtorch circuit boards. You just can't have very much individual wiring in mass production, and get it right. At least, that is my experience.
In any case, let's talk about audio preamps in general, not just about my specific design.
" Wire on air " is only half part of input connection - where is the second one ? For what are you doing this ? Crosstalks ? Isn't better short nonusing inputs to source ground and this ground disconnect from internal circuity of preamp ?
Unshielded air wires - I tend to agree. I have also had excellent experience with simple unshielded lightly twisted teflon pair. The crosstalk is not an issue, if driven from low source impedance, as coupling capacitance is in pF. Yes, they do sound better than coaxials.
Mr Curl,
i'm enjoying everything you post on this thread, surprised even how much eventually trickles from your keyboard.
i'm enjoying everything you post on this thread, surprised even how much eventually trickles from your keyboard.
By well-considered conception can be length of input traces from input connector to preamp only several cm and input capacity can be near zero ( see that UK patent )....
A more general question then, to JC and all..
Some designers -most notably Dennis Morecroft and Tom Evans- are strong believers in non-metallic non-magnetic enclosures. Scientific reasons for these are given as reduction in eddy currents and whatnot, but more importantly DM , TE and others seem to have found sound quality can benefit from (say) an acrylic case.
Obviously, such preamps would suffer in some environments from noise pickup, and resolution means nothing if you have taxicab FM at -30db; but I'm asking if you have any feelings about the sound aspects of ally cases vs. acrylic in a low RFI situation.
I can see the blowtorch case was no accident, and I suspect the wide bandwidth design necessetated a shielded case for stability/ universatility reasons, but I'd be interested in your thoughts on case material and its effects.
Some designers -most notably Dennis Morecroft and Tom Evans- are strong believers in non-metallic non-magnetic enclosures. Scientific reasons for these are given as reduction in eddy currents and whatnot, but more importantly DM , TE and others seem to have found sound quality can benefit from (say) an acrylic case.
Obviously, such preamps would suffer in some environments from noise pickup, and resolution means nothing if you have taxicab FM at -30db; but I'm asking if you have any feelings about the sound aspects of ally cases vs. acrylic in a low RFI situation.
I can see the blowtorch case was no accident, and I suspect the wide bandwidth design necessetated a shielded case for stability/ universatility reasons, but I'd be interested in your thoughts on case material and its effects.
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