Just start at page 1 and you might come accross some jewels on the way and learn a thing or two 🙂
No, there is not an exact schematic of the 'Blowtorch' on this thread or any other.
As I stated before, I generally don't publish my schematics, because I don't want to be obligated to bail someone out, who tries to make one and gets into trouble.
I previously stated that this is not an easy design to make. One of the main problems is the 'cherry picking' or limited availability of the fets used in the design. I can only use the highest Idss devices in this design, because the output follows the input, and this is what gives me some current drive capability. I can use only about 20% or so of the V series parts that I have on hand, and then match them to each other. The rest must be put aside for another project. Think about what that would cost most of you to do the same thing. I can just hear the whining now! So, either you would make a compromised version, and then be disappointed with the results, or you would demand an alternate solution from me. I would rather avoid the responsibility entirely.
As I stated before, I generally don't publish my schematics, because I don't want to be obligated to bail someone out, who tries to make one and gets into trouble.
I previously stated that this is not an easy design to make. One of the main problems is the 'cherry picking' or limited availability of the fets used in the design. I can only use the highest Idss devices in this design, because the output follows the input, and this is what gives me some current drive capability. I can use only about 20% or so of the V series parts that I have on hand, and then match them to each other. The rest must be put aside for another project. Think about what that would cost most of you to do the same thing. I can just hear the whining now! So, either you would make a compromised version, and then be disappointed with the results, or you would demand an alternate solution from me. I would rather avoid the responsibility entirely.
No one is interested in power supplies?
We have the advisability to subjecting our ideas to the best audio designers, and some people prefer arguing on woods...
Schematic of the series regulator idea based on the LM3886.
We have the advisability to subjecting our ideas to the best audio designers, and some people prefer arguing on woods...
Schematic of the series regulator idea based on the LM3886.
An externally hosted image should be here but it was not working when we last tested it.
Why are you scratching by left hand beside right ear, Richard ? 😎 You can do it with one opamp + one darlington... 😉
Yes you are quite right !!! Except the voltage handling, the push pull design, and the simplicity, I like very much your “Why are you scratching by left hand beside right ear” expression 
Hi, John
Message fullky received here... Loud and clear...
The "V" Jfets series... Oh ! Yes ! They have MUCH discrepancies between 12 mA and 20 mA Idss that are just the same V range... I personnaly target more 12...14 mA as I can still pick some and from your own reverse engineering studies, no real need for higher ones would be mandatory...
Just to make it clear for other guys here, I LOVE to repair or fix some of previous Levinson/Dennesen stuff... Most from your own designs. And "reverse-engineering" is NOT to copy annything but to FIX problems from careful analysis... For sure, some friends have copies for their own study/comments/suggestions... But no one even thought to have a company built with this reverse...Or even to sell unpublished sshematics... I am formerly a lawyer, and won't lay such a risky game...
Anyway, I just pushed here the Blowtorch Line amp... Vendetta is much more problematic, and no one could ever "clone" any but you (and perhaps me on some models...)... Now, like you, I have matched V parts available here at home... Wise a precaution, eh ?
Frankly speaking, for an Vendetta upgrade, I would simply switch to paralleled 2SJ109 & 2SK389 as you suggested some years ago on another Forum for the JC-2... Would replace both 2SJ72s and 2SK147s, and from my understanding, also 2SJ75s & 2SK240s...
But, again, and sadly, V types are rather rare (not here, as I bought stocks when I understood why you favored V types.... ).
Will introduce in my own study the 3.18 uS RIAA constant that is now missing all serious MC phono cartridge pre-pre....
Any project to do so from your side ? And what about a JC-3 renewal study/upgrade with all Forumers... Here, you would CLEARLY be the boss...
Anybody interested in such an experiment ?
Jbaudiophile
jbaudiophile
Message fullky received here... Loud and clear...
The "V" Jfets series... Oh ! Yes ! They have MUCH discrepancies between 12 mA and 20 mA Idss that are just the same V range... I personnaly target more 12...14 mA as I can still pick some and from your own reverse engineering studies, no real need for higher ones would be mandatory...
Just to make it clear for other guys here, I LOVE to repair or fix some of previous Levinson/Dennesen stuff... Most from your own designs. And "reverse-engineering" is NOT to copy annything but to FIX problems from careful analysis... For sure, some friends have copies for their own study/comments/suggestions... But no one even thought to have a company built with this reverse...Or even to sell unpublished sshematics... I am formerly a lawyer, and won't lay such a risky game...
Anyway, I just pushed here the Blowtorch Line amp... Vendetta is much more problematic, and no one could ever "clone" any but you (and perhaps me on some models...)... Now, like you, I have matched V parts available here at home... Wise a precaution, eh ?
Frankly speaking, for an Vendetta upgrade, I would simply switch to paralleled 2SJ109 & 2SK389 as you suggested some years ago on another Forum for the JC-2... Would replace both 2SJ72s and 2SK147s, and from my understanding, also 2SJ75s & 2SK240s...
But, again, and sadly, V types are rather rare (not here, as I bought stocks when I understood why you favored V types.... ).
Will introduce in my own study the 3.18 uS RIAA constant that is now missing all serious MC phono cartridge pre-pre....
Any project to do so from your side ? And what about a JC-3 renewal study/upgrade with all Forumers... Here, you would CLEARLY be the boss...
Anybody interested in such an experiment ?
Jbaudiophile
jbaudiophile
Hi, Upupa & Richard,
Interesting schematics... Mostly because it is a rational use of now inexpensive parts to go further the usual LM317 family limits with good specs...
Upupa, yes, things could be made much more simple in an "academic" way of thinking... But Richard just mixes nowadays technologies with old fashioned "revisited" schemes....
Some years ago, a French Audio/electronics magazine published a "clone" study for a gigantic US power amplifier : EAD Power Master 2000 (half the Blowtporch price...)... : 5 x 350 W (yes !!!) made with a quad LM3886 push-pull for each channel... The revue reduced it to stereo and 2 x 250 W continuous and 350 with impulse signals ... Not bad at all : mainly 2nd and 3rd harmonics, and a 900 nS rise time...
Anyway, such a power op-amp is already an op-amp... Nothing that a separate DIP8 IC with some parts around couldn't achieve... Yes... But Richard's idea is quite innovative, and would even be a good candidate for moderate power amp regulation...
Here, Richard, can drop me a line if you need some help on that one !
Jbaudiophile
PS : Can post the "EAD" clone schematics if anybody interested in..
Interesting schematics... Mostly because it is a rational use of now inexpensive parts to go further the usual LM317 family limits with good specs...
Upupa, yes, things could be made much more simple in an "academic" way of thinking... But Richard just mixes nowadays technologies with old fashioned "revisited" schemes....
Some years ago, a French Audio/electronics magazine published a "clone" study for a gigantic US power amplifier : EAD Power Master 2000 (half the Blowtporch price...)... : 5 x 350 W (yes !!!) made with a quad LM3886 push-pull for each channel... The revue reduced it to stereo and 2 x 250 W continuous and 350 with impulse signals ... Not bad at all : mainly 2nd and 3rd harmonics, and a 900 nS rise time...
Anyway, such a power op-amp is already an op-amp... Nothing that a separate DIP8 IC with some parts around couldn't achieve... Yes... But Richard's idea is quite innovative, and would even be a good candidate for moderate power amp regulation...
Here, Richard, can drop me a line if you need some help on that one !
Jbaudiophile
PS : Can post the "EAD" clone schematics if anybody interested in..
It is not good example, JB... LM's family of power amps are, due technological die's limits, still only quasicomplements, with all disadvantages, which have this connection.... 😉 Lets rather talk about " adult " amps.... 😎
Perhaps there are better chip power amps choices for this purpose (PSU series regulation), for the moment it’s more a generic term for a chip amp to me, and also because a lot of people here seems to appreciate it (as a good and cheap audio power amplifier).
In fact it would be interesting to test the few chips available on the market corresponding to the PSU specifications: power, voltage, current, noise bandwidth and stability etc...
Upupa which would be your choice for this use?
In fact it would be interesting to test the few chips available on the market corresponding to the PSU specifications: power, voltage, current, noise bandwidth and stability etc...
Upupa which would be your choice for this use?
If you mean PS, so there isn't big choice ( if you mean to use power opamp ), 'cos all are quasi... But ideal should be to use LM 4780, one ch. noninverting and second inverting + common reference voltage... Reference voltage must be low, 'cos this amp isn't stabil by low gain...
Hello, Upupa
I only half agree with you here...
It is true that LM series can't achieve full symetry due to its quasi-complementary output stage topology...
But Richard's idea is interesting, as I used a close one for spliting a single supply voltage into symetric ones with little parts... I used a L165 at the time.... I just referenced the non-inverting input to the single power supply midpoint (with 2 equal resistors), tied the inverting input to the output with only a series 1 ohms & 0.22 uF return to the incoming "zero volt" branch (that became -V at the output)... Was done !
Very good specs indeed, although Ididn't measured it at the time... I just "forgot" this trick for years, and I am happy that Richard revived it.... I just wouldn't "stick" exactly on his idea, but for high voltage amplifiers (say, over 40V supplies), it's a good and cheap way to have regulated voltages (the oher would be to use TL783 as a driver for a pass transistor... But still no symetry, I am afraid...)
Regards
Jbaudiophile
I only half agree with you here...
It is true that LM series can't achieve full symetry due to its quasi-complementary output stage topology...
But Richard's idea is interesting, as I used a close one for spliting a single supply voltage into symetric ones with little parts... I used a L165 at the time.... I just referenced the non-inverting input to the single power supply midpoint (with 2 equal resistors), tied the inverting input to the output with only a series 1 ohms & 0.22 uF return to the incoming "zero volt" branch (that became -V at the output)... Was done !
Very good specs indeed, although Ididn't measured it at the time... I just "forgot" this trick for years, and I am happy that Richard revived it.... I just wouldn't "stick" exactly on his idea, but for high voltage amplifiers (say, over 40V supplies), it's a good and cheap way to have regulated voltages (the oher would be to use TL783 as a driver for a pass transistor... But still no symetry, I am afraid...)
Regards
Jbaudiophile
Richard's schematic don't make floating ground ( although it can be used for it ), it is normal VR...
Justcall...., not very subtle, but I get the message....
Given the many topics which have been addressed in this thread to some extend my proposal, some posts ago, was to start different threads about specific topics as PS, Open loop, DC-Servo, etc. designs.
Valuable information is now scattered throughout the thread and because posters jump from one topic to another, important questions, like for instance Grollins last, do not get answered. Furthermore I'm afraid it will largely remain a discussion and exchange of information amongst ourselves.
It would serve both JC and us DIYers if he gets his own corner on this forum like Nelson Pass. In that way we can have structured threads with specific topics for the benefit of all who seriously participate and contribute to discussions. This has also been proposed by someone elso earlier in this thread and of course I wholeheartedly support that idea.
Well folks, it has an interesting exchange, up to this point. I hope that we can stay on track and discuss audio topics that make exceptional designs. After all, if you are going to DIY something, then you should make the best audio design that is practical for you to make. It is cheaper and easier to buy, new or used, typical audio products at the local hi fi outlet. Why waste your time with making anything less than the best than you can make?
John -
you're sure? I've had a lot of opportunities to compare own designs with Aleph 3, Classé CAM-350, Classé Omega preamp, Ayre VX. Good systems, good speakers (Wilson Audio Maxx, Sophia e.g.). Are my designs worse sounding? Definitely not! So why not to take a challenge! It's a lot of fun, if nothing else.
you're sure? I've had a lot of opportunities to compare own designs with Aleph 3, Classé CAM-350, Classé Omega preamp, Ayre VX. Good systems, good speakers (Wilson Audio Maxx, Sophia e.g.). Are my designs worse sounding? Definitely not! So why not to take a challenge! It's a lot of fun, if nothing else.
Gentlemen,
I only want to mention that for me, this is the most technically interesting thread at the Forum for a long time, since perhaps the original Aleph-X thread.
I admire Richard for his endless energy & innovation with circuitry and topology. And I thank John for sharing with us his knowledge & experience.
I understand, without endorsing, that there are people in the forum who are interested in cloning established high end products, to the last resistor and cable. There are plenty of such examples at the Pass Forum. That was also how I started with DIY. But I now find it much more fulfilling in understanding at least what I build, and am not shy in changing things around, even designing my own. Maybe they are not always perfect: maybe it is not first time right, but it certainly is a lot more fun than soldering a group-buy clone board. Believe me, you don't know what you are missing along the way.
I only hope that we are not silly enough to kill this thread ourselves, and get back to circuitry discussions soon.
And for those who might want to criticise my lack of technical contribution, my sincere apologies. I am currently 80% finish with my linestage, which is essentially a no NFB version of Uli's circuit. So I have nothing to add for the moment. But I find the discussions here enormously interesting. So please do not ruin it for all of us.
Patrick
I only want to mention that for me, this is the most technically interesting thread at the Forum for a long time, since perhaps the original Aleph-X thread.
I admire Richard for his endless energy & innovation with circuitry and topology. And I thank John for sharing with us his knowledge & experience.
I understand, without endorsing, that there are people in the forum who are interested in cloning established high end products, to the last resistor and cable. There are plenty of such examples at the Pass Forum. That was also how I started with DIY. But I now find it much more fulfilling in understanding at least what I build, and am not shy in changing things around, even designing my own. Maybe they are not always perfect: maybe it is not first time right, but it certainly is a lot more fun than soldering a group-buy clone board. Believe me, you don't know what you are missing along the way.
I only hope that we are not silly enough to kill this thread ourselves, and get back to circuitry discussions soon.
And for those who might want to criticise my lack of technical contribution, my sincere apologies. I am currently 80% finish with my linestage, which is essentially a no NFB version of Uli's circuit. So I have nothing to add for the moment. But I find the discussions here enormously interesting. So please do not ruin it for all of us.
Patrick
Greetings M. John Curl for this 1001 post 
and for all that we learned until there, I think that the next 1000 ones will be as interesting and enlightening as the last ones! 
Merci et Bravo M.Curl alias
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and for all that we learned until there, I think that the next 1000 ones will be as interesting and enlightening as the last ones! Merci et Bravo M.Curl alias
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EUVL said:
Patrick, maybe could you post it here and we could discuss it, eventually with Uli, of course if he is interested.
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