John Curl's Blowtorch preamplifier

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But what specs are desireable for say a power amp output stage.

High transconductance, well complementary P-channel part.

Or a gain stage.

See above.

Do you just test them with a curve tracer

No. Enjoying the look at the datasheet saves you this work.

switching applications. Are these very linear?

Not at all. Switching does not care at all about linear properties. But for switching high transconductance is helpfull, so it meets partly the requirements of above.

Have fun, Hannes
 
AX tech editor
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syn08 said:


Apparently JC moved his personality and design ideas here. I guess PMA is trying to suggest that "we" had an agenda to determine JC to leave this forum.


Well if that is the case it is JC's choice of course, he a big boy. He's been to other forums before, and left for his own reasons.

But now I have a problem; what do I do with my pitch fork? eBay? ;)

Jan Didden
 
janneman said:



Well if that is the case it is JC's choice of course, he a big boy. He's been to other forums before, and left for his own reasons.

But now I have a problem; what do I do with my pitch fork? eBay? ;)

Jan Didden

PWV Design Inc, I wish you a successfull IPO.

EDIT: I like Andy's avatar as a corporate logo. Can you imagine an official press release with that logo on top of the pages?
 
PMA said:
This is a Blowtorch thread, no global FB complementary-differential preamp. I would like to mention that I have just designed and built another non global feedback, complementary-differential preamp. Based on BJTs again, with different output stage - I gave up a diamond buffer and used another push-pull output class A stage, with much higher bias current. Right now it is under listening tests, and seems to be promising. I am moving step-by-step to John Curl and Charles Hansen design philosophy.
This preamp would not be a DIY project.

I am just working on a new preamp. It is a complementary-differential circuit again, with 389/109 JFETs as input devices and Hitachi MOSFETs as output devices. No diamond buffer. It will be built in a milled Al box with walls at 8mm thickness. The prototype PCB is already in production, the box starts tomorrow. I am very curious to compare this with another project of mine, complementary-differential preamp with heavily degenerated BJTs.

Question is: bipolars, JFETs or :worship:? :rofl: :rofl: :rofl:
 
Wavebourn said:


I don't understand, what do they expect from such postings on DIY forums? Do lawyers/doctors/bankers and other potential buyers really read them? :bigeyes:

Don't underestimate the power of name/reputation. If you want to get into this business, sucking up a JC-like name may be worth more than four PhD's in electroacoustic. More or less valid even in the academia, but in particular valid in this sad industry. You don't need to really respect those JC-like names, in fact you are allowed secretly to despise them and call them in private "suckers". Use them, and then dispose them, that's the secret :(
 
syn08 said:


Don't underestimate the power of name/reputation. If you want to get into this business, sucking up a JC-like name may be worth more than four PhD's in electroacoustic. More or less valid even in the academia, but in particular valid in this sad industry. You don't need to really respect those JC-like names, in fact you are allowed secretly to despise them and call them in private "suckers". Use them, and then dispose them, that's the secret :(

You remind me an echo of old battles that still exists around Matti Otala's name.
 
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syn08 said:


Don't underestimate the power of name/reputation. If you want to get into this business, sucking up a JC-like name may be worth more than four PhD's in electroacoustic. More or less valid even in the academia, but in particular valid in this sad industry. You don't need to really respect those JC-like names, in fact you are allowed secretly to despise them and call them in private "suckers". Use them, and then dispose them, that's the secret :(


Sarcastic. And, sadly, often true.

Jan Didden
 
janneman said:
Sarcastic. And, sadly, often true.

One side effect of the subjective crap in the high end audio is that there's essentially no meritocracy. You don't need any formal education, training, certification, etc... Just declare your GEB membership, add some literar talent ala Mr. Fremer, and you are potentially good to go. The competition is though furious, and the establishment will do anything to persuade you that your GoldE are in fact TinE if you don't appreciate a certain product or device, so here's where the sucking comes handy.

I'm really sorry (and now I'm dead serious) that John was banned. I personally never minded his insults, in fact, as I said befor, each of them could potentially go straight to my resume :) I wish him luck in the other place, he's certainly a big boy. I don't plan to register in that other place, so enjoy :)
 
syn08 said:



I'm really sorry (and now I'm dead serious) that John was banned. I personally never minded his insults, in fact, as I said befor, each of them could potentially go straight to my resume :) I wish him luck in the other place, he's certainly a big boy. I don't plan to register in that other place, so enjoy :)

Actually, he was not banned. He was put into a read only mode for a while because continued ignoring warnings about discussing personalities when not invited to.

I wish him good luck as well, but he started there from mentioning names of famous people and famous amplifiers, while people continue discussing technical details, so let's see how long he will tolerate such luck of attention.
 
Wavebourn said:
Actually, he was not banned. He was put into a read only mode for a while because continued ignoring warnings about discussing personalities when not invited to.

I wish him good luck as well, but he started there from mentioning names of famous people and famous amplifiers, while people continue discussing technical details, so let's see how long he will tolerate such luck of attention.

This criticism does not apply to you Wavebourn - but to others; I believe that there is a degree of self righteousness with a couple of people on this thread which made it impossible for John Curl to say anything without being immediately brought to task by an opposing or ridiculing counterview being expressed.

(What I found amusing, but not unexpected, was that on checking a main protagonist's website that site was ( I am using Firefox on a Mac) one of the worst constructed sites I have seen. Images have been superimposed upon text thus blocking the text. I for one - had I been interested in doing business with that person - would have immediately lost that interest). Perhaps more time spent by some on housekeeping and less time playing the Witch Hunter General would remove some of the personality clash which has ruined an otherwise good thread.
 
brianco said:


This criticism does not apply to you Wavebourn - but to others; I believe that there is a degree of self righteousness with a couple of people on this thread which made it impossible for John Curl to say anything without being immediately brought to task by an opposing or ridiculing counterview being expressed.

There are different ways to express a counterview: either "I respectfully disagree with your position, because according to my information...",

and "You are a bad engineer" in case of a counterview, or "we did that 40 years ago" in case of agreement.

Do you see the difference?
 
brianco said:
(What I found amusing, but not unexpected, was that on checking a main protagonist's website that site was ( I am using Firefox on a Mac) one of the worst constructed sites I have seen. Images have been superimposed upon text thus blocking the text. I for one - had I been interested in doing business with that person - would have immediately lost that interest).

a) Mac users using FireFox visiting my web site attached, you do the math. I can't and don't plan to make everybody happy due to time constraints. Believe it or not, I have to work for a living as well.

b) I'm not interested in doing any Audio related business, so I couldn't care less anyway. What I do is for free so essentially you get what you pay for.

c) However, I'm pretty sure you already read my friendly note: http://www.diyaudio.com/forums/showthread.php?postid=1853951#post1853951 Your feedback, even in these particular circumstances, is appreciated. I'll see what I can do about, unfortunately I don't have a Mac to test with.
 

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