John Curl's Blowtorch preamplifier

[john curl]

Stubborn, isn't he?

 

[CG]

Stubborn, isn't he?

I am but a miserable amateur in these matters, so it is not my place to say...

 

[john curl]

My op amp collection goes back 43 years, the same year as I started using computer aided design. I still have some 709's from that era, and hundreds of other different devices. If they were perfect for audio, I would use them exclusively.

 

[john curl]

Live and learn, CG.

 

[PMA]

They are just 'universal', not perfect. The tax for versatility is paid.

 

[syn08]

If they were perfect for audio, I would use them exclusively.

According to your own statement, you haven't tried anything new in the last 10-15 years. "What worked for me, works for me".

 

[john curl]

I change IC's all the time. I just use Toshiba, JUST LIKE YOU! For my input stages. Of course, my topologies are similar, I invented them.
Perhaps Porsche should throw away the BOXER engine concept, because it is old fashioned. How about a 5 cylinder? 7?

 

[Bob Cordell]

Yes, there is some good optical stuff. I'll have to run my latest hair brained idea by you.

See you at happy hour!

Hi Scott,

I'll look forward to it! Hey, most hair brained idea make more sense after a couple of drinks anyway.

Cheers,
Bob

 

[john curl]

How about Graphene transistors?

 

[courage]

John Curl :"I just use Toshiba, JUST LIKE YOU! For my input stages."

John, given the standard you have achieved with the BT, which types of either Toshiba or Hitachi Mosfets are the most suitable and in line with the performance you aimed for? The IR Mosfets used in the JC-2 maybe equals the BT performance but is not quite similar I guess.

Franklin

 

[john curl]

I use them all, not happy with any, either because of design defects or availability/

 

[Bob Cordell]

It is so surprising that people rely on computer simulation, when it can be done with a calculator, easily enough, or even pencil and paper. Just as it is almost impossible for us to write a short note, without a computer, we are becoming overly dependent on computers, AND their circuit models, rather than utilizing direct measurement and data sheet information.

John,

Most of us experienced engineers these days can walk and chew gum at the same time. We do all kinds of SWAGs in our head and with calculators. But as smart as we think we are, most of us are smart enough to know that our intuition and simplied models in our heads of things can sometimes lead us astray. That's when we augment with simulation.

We don't just simulate to see if something will work, we do experiments in simulation, much more quickly than they could ever be done in the lab. I'll be the first to admit that my intuition has sometimes failed me and I got a surprize when I simulated something.

Most of those of us who do a lot of simulating do not overly depend on it. We have a balanced approach.

Manufacturers models are not always great, and indeed manufacturers' spec sheets are not always accurate or complete. That is no reason to throw the baby out with the bathwater. Simulation in the right hands is good, as long as it is not abused and used to the exclusion of real-world measurements as well.

Suggesting that engineers who simulate don't measure is just as ignorant as suggesting that audio engineers who measure don't listen. As an engineer whom I KNOW measures AND listens, you should know that.


Cheers,
Bob

 

[john curl]

The computer simulation did not find what was wrong with SYN08's circuit.

 

[kamskoma]

Dimitri,

Do you mean that you use the PAP, I'll go crazy PAP is still alive.

A good pencil surpass any computer.


Kamskoma

 

[kamskoma]

John,

Quantum Satis

DS.
I won the Telefunken Bajazzo Sport 101L auction, it have a huge output transformer and a speaker with a heavy alnico magnet.

PS.
Kamskoma

 

[kamskoma]

Quantum Satis

Quantum Satis a good name for a proper preamp

Kamskoma = satisfied "more then"

 

[syn08]

The computer simulation did not find what was wrong with SYN08's circuit.

There's nothing wrong in the SYN08 circuit, as already mentioned, I have built and measured it. I don't publish armchair simulated circuits, you should know at least that.

John, you are so cute .

 

[gerhard]

Here's a silly answer
Nothing good has happened in audio in the last forty years, everything was already done forty years ago.

No, it's not silly. This is what happens when the culmination
of your personal work has been 25 years ago and you were
unable to top it since.
This forces you to deny any other progress made in this time.

regards, Gerhard

 

[kamskoma]

Ooh! maybe a partenship on the way

 

[kamskoma]

Neighbors

Do not settle in a apartment, the neighbor will drive you crazy, you can't enjoy expensive SOTA HiFi equipment, people will make all sort of noice including the noice from a decent 1 Ohm resistor.

Buy a tent!


Kamskoma