John Curl's Blowtorch preamplifier part II

[john curl]

GK you are apparently a technician and have no idea the reason for this design approach. You don't have to agree with it. Just live with and love the circuits you respect.

 

[syn08]

It does?

C'mon, has global NFB, servos, trimming, etc... you must love it

Really, for the early 80's it's not that bad. Can you show one of those more sophisticated designs of the time?

 

[GK]

Can you show one of those more sophisticated designs of the time?

Nope, they're just a figment of my imagination. Nobody knew how to design audio with discrete components before JC, period - He is THE genius, as he modestly points out himself.

 

[simon7000]

It does?

I've worked on old Sansui, Marantz and Sony (and other) pre/control amplifiers older than that that were lightyears ahead in terms of sophistication.

Elegance or Sophistication?

I vote that this is an elegant circuit. Yes there are some things that can be improved. But when you build and live with a design hopefully you learn something.

Thanks for showing a circuit.

 

[scott wurcer]

Well I listened to this with John Dennesen (still use his alignment protractor) and it sounded very good. He was using a Linn with his air-bearing arm and I forgot the cartridge/speakers. It was my first "high-end" session.

 

[scott wurcer]

Nothing kills a thread faster than a real circuit. And Federmanns thread gets 5 stars!

 

[john curl]

Actually, wading through the criticism of a 'real circuit' even decades after it was produced by the 100's, and won world acclaim, is what kills my enthusiasm for helping those who know no better.

 

[scott wurcer]

Well I heard Smokey Joe's is gone. It figures these days. That was my kind of place, electric frying pans and Leonard Cohen. You can always **** money away at Chez Pannise but there is something missing.

 

[john curl]

Dick Sequerra says hello, told everything about his spark plugs.

 

[stinius]

Nothing kills a thread faster than a real circuit. QUOTE]]


Sad but true.

 

[john curl]

Actually, why I asked Scott to post this schematic was for the SERVO example, not the whole circuit, that cannot be made exactly as shown, because the parts are not available, in any case. When things settle down, I can go back to my tutorial.

 

[GK]

Elegance or Sophistication?

I vote that this is an elegant circuit.

I think it could do with another trimpot and a redesign for an even greater dependency on component matching.

But when you build and live with a design hopefully you learn something.

ZZZZZZzzzzzzzzzz...........

 

[john curl]

Only a child wants an idiot proof design. That is like wanting to take your Daddy's tractor to the dance, because it always starts and runs on just about anything. ;-)
The challenge here is to use minimum through-path circuitry with both inverting and non-inverting output for absolute polarity.

 

[GK]

That is like wanting to take your Daddy's tractor to the dance, because it always starts and runs on just about anything.

Great analogy.

 

[Steve Eddy]

The challenge here is to use minimum through-path circuitry with both inverting and non-inverting output for absolute polarity.

Couple of transformers and FETS?

se

 

[john curl]

IF only I liked transformers, but you are correct, it would be simple.

 

[Steve Eddy]

IF only I liked transformers, but you are correct, it would be simple.

I'll have to whip up something one of these days and send it down to Berzerkeley and see if I can't change your mind.

se

 

[kamskoma]

DVD and SACD for me, please. CD sucks!

If you rip a CD with some good ripping software to a lossless format and put it on a server, connect to the server and stream the ripped CD to your two channel stereo, it sounds much better, can anybody explain why?.

I think that the most CD players have some problem to execute the streaming data.

Kamskoma

 

[john curl]

Not good enough for me. We used a $20,000 server at the last show, and it did NOT make the grade.

 

[scott wurcer]

Since when is cost a guarantee of quality? Programming sophistry trumps cash outlay any day. Any Linux geek worth his salt can make a $350 off the shelf machine serve bit perfect lossless data.