Thanks to all of the contributors so far, this has turned out to be a great thread. I appreciate hearing about all of the experiences and especially about gear I never heard or saw myself.
I want to take a moment to acknowledge that our pleasure, our hobby, our interest and the industry has been advanced by people like the late Dr. Marshall Leach Jr. as well as others who researched, studied and shared their work with a needy/greedy audience.
Dr. Leach’s paper in 1976 was, I believe, a turning point and fuse lighter for the solid state amplifier market. Our hobby and expectations and the quality of products we can afford to buy would most likely be something entirely different without that paper and without his work. Certainly, many manufacturers took advantage of his proposal almost verbatim. If you understood his paper, you can read almost any amplifier schematic for the next 20 years before Class D amps came to the fore and identify each section in it.
His paper was at the same time a recipe and a challenge. It said "Here is how you make a good amplifier" and at the same time "See if you can make something even better." Engineers no longer had to hunt in the dark and search for the secrets to good solid state amps. All the parts and their use were laid out before them, while at the same time opportunities to improve upon and leave their own marks upon the discipline also opened up.
I should also point out that designers like Nelson Pass have long taken a different approach, and looked to simplify as opposed to enhance or perfect. And we are grateful for that approach as well! But when Nelson looks to simplify or others to re-think components they are constantly challenged by the Leach legacy. We can’t just remove sections, or alter feed back circuits. We must do so AND get sound as good if not better by doing so. Dr. Leach left a clear foil and challenge for others to take up, and improve upon. This is how progress gets done. We can say "Oh, amp X is nothing like the Leach paper..." but it is impossible to say these amps were not informed and challenged by it.
I should point out and thank Nelson Pass as he is quite active in the DIY community, sharing his thoughts, and tinkering "out loud" for the benefit of this community.
So, to people like Nelson pass as well as the late Dr. Leach, and the universities which create environments so students can learn from people like him, I would like to offer a heart-felt thank you. They enabled the industry, the hobby and ultimately the music.
Best,
E
I want to take a moment to acknowledge that our pleasure, our hobby, our interest and the industry has been advanced by people like the late Dr. Marshall Leach Jr. as well as others who researched, studied and shared their work with a needy/greedy audience.
Dr. Leach’s paper in 1976 was, I believe, a turning point and fuse lighter for the solid state amplifier market. Our hobby and expectations and the quality of products we can afford to buy would most likely be something entirely different without that paper and without his work. Certainly, many manufacturers took advantage of his proposal almost verbatim. If you understood his paper, you can read almost any amplifier schematic for the next 20 years before Class D amps came to the fore and identify each section in it.
His paper was at the same time a recipe and a challenge. It said "Here is how you make a good amplifier" and at the same time "See if you can make something even better." Engineers no longer had to hunt in the dark and search for the secrets to good solid state amps. All the parts and their use were laid out before them, while at the same time opportunities to improve upon and leave their own marks upon the discipline also opened up.
I should also point out that designers like Nelson Pass have long taken a different approach, and looked to simplify as opposed to enhance or perfect. And we are grateful for that approach as well! But when Nelson looks to simplify or others to re-think components they are constantly challenged by the Leach legacy. We can’t just remove sections, or alter feed back circuits. We must do so AND get sound as good if not better by doing so. Dr. Leach left a clear foil and challenge for others to take up, and improve upon. This is how progress gets done. We can say "Oh, amp X is nothing like the Leach paper..." but it is impossible to say these amps were not informed and challenged by it.
I should point out and thank Nelson Pass as he is quite active in the DIY community, sharing his thoughts, and tinkering "out loud" for the benefit of this community.
So, to people like Nelson pass as well as the late Dr. Leach, and the universities which create environments so students can learn from people like him, I would like to offer a heart-felt thank you. They enabled the industry, the hobby and ultimately the music.
Best,
E