John Curl's Blowtorch preamplifier part II

[Joshua_G]

Michael,
Sound reproduction systems are, to a high degree, up to personal taste and preferences, what sounds excellent to one may sound mediocre to another. Also, there is matter of integration between components, especially between pre-amp, power amp (or integrated amp) and speakers.

Many tube amps are colored, however, those designs which sound clean and neutral are really excellent – to my taste and preferences. Most SS amps I heard are "analytical", "lifeless" "not musical". That being said, right now my phono stage and pre-amp are tubes and the power amp is SS – and my setup sounds to me excellent. However, the amps I use at the moment are not the final word and I intend to give a try to some others. I have a tube power amp which sounded great with my previous speakers but exaggerates low frequencies with my present speakers. So, to a high degree it's a matter of integration.

[john curl]

Well said, Joshua. Even though I have never made a commercial tube design, I was taught tube design in college (yes, I am that old), and used tubes primarily for my first 10 years in hi fi, and for 5 years before that even, with a 1938 Gibson tube amp (pp6L6) open loop, and an electrodynamic magnetic coil speaker. (what comes around, goes around). I have listened to McIntosh, Marantz, Dyna, and Fisher for decades. Still do, sometimes, yet I just don't have that much to contribute to tube design. I like complementary circuits, because I can think 'upside down' unlike some friends of mine. ;-) Only solid state gives me that advantage.

[mos57]

Originally Posted by john curl

I like complementary circuits, because I can think 'upside down' unlike some friends of mine. ;-) Only solid state gives me that advantage.

Do you like complementary circuits because its allowing complementary distortion cancellations?

But for this purpose each stage (both side up and down devices) must operate in class A.
If each device operate in class AB there is much odd distortion at the end, i think.

Francesco.

[john curl]

Class A is my middle name! ;-)

[john curl]

It must be pointed out that single ended is ALWAYS Class A, Complementary design gives you a choice to bias Class A , Class AB, or even Class B. Class A is always best, but you do get more power from Class AB or Class B.
All my discrete preamps are Class A throughout. My power amps are Class A up to the output stage, which is usually Class AB, in order to get more power from a given heat sink.

[mos57]

Thanks John.

In order to obtain minus distortion, other a complementary circuit, you also arrange a mix of different devices? What are?

As you know, gm of jfet and mosfet tends to be arise from higher current, meawhile gm of bipolar tends to be as contrary to higher current.

Francesco.

[scott wurcer]

Originally Posted by mos57

Thanks John.

As you know, gm of jfet and mosfet tends to be arise from higher current, meawhile gm of bipolar tends to be as contrary to higher current.

Francesco.

No, Fet's go roughly as the square root of current and bipolars are directly proportional to current. There are limits, but not of interest for small signal amplifiers.

[john curl]

Scott is right. we can go forward, now.

[kannan_s]

Hi John
How about the internal signal wiring choice of Blowtorch ? Would that be same today ? or different ? your experiences with signal wiring is something that we can learn
kannan

[Bas Horneman]

How about the internal signal wiring choice of Blowtorch ?

Oooohhhhhhh boy....here we go again