John Curl's Blowtorch preamplifier part II

[Steve Eddy]

Originally Posted by EUVL

One set of transformer winding missing in what you posted.
So not the same.

I didn't say it was the same.

se

[Steve Eddy]

Originally Posted by john curl

Steve's circuit shows a complete lack of understanding of modern design...

Nah. I just like things simple and don't care to be a slave to the numbers game.

...and that approach is virtually worthless, except for vacuum tubes.

How do you figure?

I would argue that it's decidedly better suited to solid state than tubes.

se

[Steve Eddy]

Originally Posted by simon7000

Steve Eddy's circuit is from a very early solid state design.

Yeah? Can you show some examples? I took the idea from Warren Gilson's 1978 patent.

It uses a choke because it is supposed to show how you can design audio circuits without a transformer and save money! Interstage and output transformers were the mindset of the day.

Gilson had other reasons.

Note that it uses all PNP transistors! Probably point contact types. The heatsinks were really needed as 5 watts would have been a lot of power!

The schematic is mine. It wasn't scanned out of a book. Gilson used N-channel MOSFETs. The schematic is basically my headphone amp, sans the 1:5 input transformers and attenuators. I went with PNP's because I liked them better than NPN's.

se

[john curl]

Poor design, just the same.

[Soundminded]

Originally Posted by john curl

Soundminded, I appreciate your opinion on this subject, but not your conclusion. We have found that in the reproduction of music, LEAVING OUT certain distortions, makes the listening process easier and more exciting. Trying for that extra .01% in the usual types distortion that we measure, I agree, is a waste of time.

You are a prisoner of a method of thinking about a problem that paces back and forth down the same mental rut over and over again. That rut is so deep that you can't see over the rim anymore.

Your concepts of distortion are so narrow, limited, and imbued into your mental process that you can't conceive of a larger reality. The disortions to sound fields are not in terms you understand, they have to due in large part with the geometry of the fields. In reproducing large venue acoustics which constitute the overwhelming preponderence of what listeners at public performances hear, there are in addition gross time distortions as the sound field the listener in the audience hears never makes it into the recording. Look at where the microphones are located and at their directional sensitivity and compare it to what exists where the audience sits. There is no comparison. The one serious effort to record what the audience hears, binaural recordings doesn't work either. It is a complete failure too.

[john curl]

Simon, please, what does this submission of circuits relate to wearing ballet tights? Does anyone know WHY dancers wear tights? Do you also know that we wear a matching pair of shorts over the tights for modesty sake, AND we wore a DANCE BELT that puts a Jock Strap to shame in elastic strength and containment.

[Steve Eddy]

Originally Posted by john curl

Poor design, just the same.

Brilliant.

*yawwwwwwn*

se

[simon7000]

Originally Posted by Steve Eddy

Yeah? Can you show some examples? I took the idea from Warren Gilson's 1978 patent.

Gilson had other reasons.

The schematic is mine. It wasn't scanned out of a book. Gilson used N-channel MOSFETs. The schematic is basically my headphone amp, sans the 1:5 input transformers and attenuators. I went with PNP's because I liked them better than NPN's.

se

Gosh darn golly, I saw that exact circuit in a 60's home electronic organ circuit!

Pain in the "A" to fix as by the 80's the PNP germanium output transistors were getting pretty scarce. The output choke was "fist" size, the heatsinks the 6 x 4 12 fin design and the output transistors were TO3's. The earlier version used a modified all copper TO5 which took a bolt into the top to attach to a heatsink. The drivers were TO5 cased. Put out almost 10 watts at 5% THD!

I used to have the "reference" design data sheet for the amplifier, which made fixing it even easier. It was I believe from Bendix.

So what was the patent claim?

[simon7000]

Originally Posted by john curl

Simon, please, what does this submission of circuits relate to wearing ballet tights? Does anyone know WHY dancers wear tights? Do you also know that we wear a matching pair of shorts over the tights for modesty sake, AND we wore a DANCE BELT that puts a Jock Strap to shame in elastic strength and containment.

John,

Gotta go away, the image of you in tights just gets to me.

[john curl]

You should of seen me in them 50 years ago. I looked great!
The reason for the tights is to be able to properly see your legs, which is the tool you are refining, and still keep them warm. This is important.