RogerAF
Well-known member
First: let me thank you all for a "lively" discussion.
Second: since JR suggests I ask a question, here are some: did anyone read any of the sources I posted? Or all of them? Or none?
Third: I can understand using parallel input resistance to obtain noise figures. I wasn't aware that that was the subject being discussed. Sorry about that.
Fourth: the summing circuit has been around for a long time. It gets its name from its use first in analog computing. It behaves in pretty much the same way with DC--doesn't need to be AC.
Fifth: I appreciate the efforts to educate me in audio electronics. I began my career in the early 80s and recognize I still don't know all there is to know. My thanks.
Sixth: Since I am new to this forum I understand my knowledge and experience are unknown to y'all. A little bit of my CV: I stopped being a working musician at age 30 and went to electronics school. After gaduating, I began working as a service tech for a concert sound company in Honolulu in the mid-80s. I branched into recording studio service in the late 80s. I was the only independent electronic tech serving Honolulu for almost 20 years (1987-2007). I have worked on consoles by Amek, MCI, Neve, Soundcraft, SSL, and Yamaha; among God only knows what others. I can't think of a single one of those that has a different basic summing design--inverting summing op amp. Perhaps my understand of the technical electronic engineering principals is flawed--I'm still a guitar player at heart. I have designed and built mods, and custom interfaces, and even though retired now, I still fiddle around with stuff that interests me. Like audio electronics.
I promise not to jump on every thread and pontificate on things I know little or nothing about. I will always try to be polite and well spoken. If someone knows more than I about a subject, I hope to be a good student. New knowledge is always welcome.
Second: since JR suggests I ask a question, here are some: did anyone read any of the sources I posted? Or all of them? Or none?
Third: I can understand using parallel input resistance to obtain noise figures. I wasn't aware that that was the subject being discussed. Sorry about that.
Fourth: the summing circuit has been around for a long time. It gets its name from its use first in analog computing. It behaves in pretty much the same way with DC--doesn't need to be AC.
Fifth: I appreciate the efforts to educate me in audio electronics. I began my career in the early 80s and recognize I still don't know all there is to know. My thanks.
Sixth: Since I am new to this forum I understand my knowledge and experience are unknown to y'all. A little bit of my CV: I stopped being a working musician at age 30 and went to electronics school. After gaduating, I began working as a service tech for a concert sound company in Honolulu in the mid-80s. I branched into recording studio service in the late 80s. I was the only independent electronic tech serving Honolulu for almost 20 years (1987-2007). I have worked on consoles by Amek, MCI, Neve, Soundcraft, SSL, and Yamaha; among God only knows what others. I can't think of a single one of those that has a different basic summing design--inverting summing op amp. Perhaps my understand of the technical electronic engineering principals is flawed--I'm still a guitar player at heart. I have designed and built mods, and custom interfaces, and even though retired now, I still fiddle around with stuff that interests me. Like audio electronics.
I promise not to jump on every thread and pontificate on things I know little or nothing about. I will always try to be polite and well spoken. If someone knows more than I about a subject, I hope to be a good student. New knowledge is always welcome.