This was the old Motolora app note about medium power audio amps using darlington devices. I had it, can't find it anymore, can't locate it on the 'net, and it's driving me crazy! Happy to trade for a scan of some other useful thing- old Dynaco catalog, Onkyo T-15 tuner service manual, SWTP Tiger amp docs, or whatever else might be useful from my library of obsolete technology 
Hi,
I've found AN485-D, "High power audio amplifiers with short circuit protection", from 1985 by Motorola.
35>100W amplifier design with CFP output.
Maybe you tought of 485D application note instead of "483B"?
http://sixtek.uw.hu/an485d.pdf
I've found AN485-D, "High power audio amplifiers with short circuit protection", from 1985 by Motorola.
35>100W amplifier design with CFP output.
Maybe you tought of 485D application note instead of "483B"?
http://sixtek.uw.hu/an485d.pdf
I found that one also, but there are several audio related app notes that disappeared from Motorolas listing quite early. Possibly these "special" notes were only released to members of the secret audio society. You are a member, aren't you? 
Pretty sure my number is correct, as I built several amplifiers based on their circuits. I'm going to try the local antique wireless people, as they have a large collection of old data. I notice that nobody seems interested in darlington outputs these days, but I recently tested the amp I built from the app note, and was surprised at how well it did. I also used to have an Integral Systems 200 amp. It did 100W/ch using a single pair of darl outputs on huge spider heat sinks. Seemed risky to me, but it worked well and was very inexpensive. Thanks.
Pretty sure my number is correct, as I built several amplifiers based on their circuits. I'm going to try the local antique wireless people, as they have a large collection of old data. I notice that nobody seems interested in darlington outputs these days, but I recently tested the amp I built from the app note, and was surprised at how well it did. I also used to have an Integral Systems 200 amp. It did 100W/ch using a single pair of darl outputs on huge spider heat sinks. Seemed risky to me, but it worked well and was very inexpensive. Thanks.
tsss, the black devil by Georg Schwarz/Gerhard Haas is still on my wishlist.
It features a single ended input stage, one transistor for voltage gain and a pushpull darlington output stage.
The authors promise "tube sound" with second harmonic distortion only.
And of course it has electrolytics at input and output!
I have still two pairs of BDX64/67 and I will try them in this circuit.
Conrad Hoffman said:This was the old Motolora app note about medium power audio amps using darlington devices. I had it, can't find it anymore, can't locate it on the 'net, and it's driving me crazy! Happy to trade for a scan of some other useful thing- old Dynaco catalog, Onkyo T-15 tuner service manual, SWTP Tiger amp docs, or whatever else might be useful from my library of obsolete technology
Do you mean this?
Attachments
Hi,
This is my first post here.
I’ve located this thread after searching for the Motorola application note AN-843A for Darlington transistors.
I noticed one of the members in this thread had a copy, in PDF form, but before I contacting the member directly, I felt it only right to resurrect the thread before doing so.
The reason for trying to locate the AN-843 application note is because I need to gather some background info on the HH TPA25-D power amplifier, which by my deduction uses Motorola Darlington transistors.
I’ve seen a summary of the application note in a 1971 copy of Wireless World, but I’d like to locate the original Motorola version.
A circuit for the HH TPA25-D would be nice at some point, but that’s for a separate post!
Regards.
Terry.
This is my first post here.
I’ve located this thread after searching for the Motorola application note AN-843A for Darlington transistors.
I noticed one of the members in this thread had a copy, in PDF form, but before I contacting the member directly, I felt it only right to resurrect the thread before doing so.
The reason for trying to locate the AN-843 application note is because I need to gather some background info on the HH TPA25-D power amplifier, which by my deduction uses Motorola Darlington transistors.
I’ve seen a summary of the application note in a 1971 copy of Wireless World, but I’d like to locate the original Motorola version.
A circuit for the HH TPA25-D would be nice at some point, but that’s for a separate post!
Regards.
Terry.
En esta práctica se analizará la etapa de amplificación de audio de la figura 4 del boletín
técnico de Motorola (nota de aplicación AN-483B).
http://www.ing.unlp.edu.ar/electrotecnia/circelec/lab5.pdf
técnico de Motorola (nota de aplicación AN-483B).
http://www.ing.unlp.edu.ar/electrotecnia/circelec/lab5.pdf
also in this one
we have the Motorola darlington circuit
http://www.ing.unlp.edu.ar/electrotecnia/circelec/practica5.pdf
See this university Amplifier Lab page:
http://www.ing.unlp.edu.ar/electrotecnia/circelec/
we have the Motorola darlington circuit
http://www.ing.unlp.edu.ar/electrotecnia/circelec/practica5.pdf
See this university Amplifier Lab page:
http://www.ing.unlp.edu.ar/electrotecnia/circelec/
Please let me know, whether the AN-483B include the
Motorola article from Mr. R. Lender, title:
"Power Amplifier with darlingon output stage"
Motorola Inc., Geneva, Switzerland,
7.9.1974 internal report (July 9. or Sep. 7 - I don't know)
To get this article I started the follow thread:
http://www.diyaudio.com/forums/soli...age-large-voltage-swings-lenders-circuit.html
Last edited:
do you mean this German diy project?tsss, the black devil by Georg Schwarz/Gerhard Haas is still on my wishlist.
It features a single ended input stage, one transistor for voltage gain and a pushpull darlington output stage.
The authors promise "tube sound" with second harmonic distortion only.
And of course it has electrolytics at input and output!
I have still two pairs of BDX64/67 and I will try them in this circuit.
Hello Members of The Diyaudio
This is an answer to an old question, about the Motorola Appliction notes AN-483B, AN-484A, and AN-485.
I had photocopies of them, and I have scanned them.
As I am very new to this post I need to know, if I can attatch them to a post, or if I need
to have a homepage to host them.
I also have the little booklet: Audio output designing, with silicon complementary transistors.
Regards to all from Soeren Poulsen Denmark
This is an answer to an old question, about the Motorola Appliction notes AN-483B, AN-484A, and AN-485.
I had photocopies of them, and I have scanned them.
As I am very new to this post I need to know, if I can attatch them to a post, or if I need
to have a homepage to host them.
I also have the little booklet: Audio output designing, with silicon complementary transistors.
Regards to all from Soeren Poulsen Denmark
Here is a spanish PDF with Motorola AN-483B
http://www.ing.unlp.edu.ar/catedras/E0215/list.php
http://www.ing.unlp.edu.ar/catedras/E0215/list.php
Small World indeed.
I studied SS amplifier design between 1972/1975 using, among other stuff, that exact same Application Note and doing the same Lab work.
Not surprising, that one you linked to is from UNLP=Universidad Nacional de la Plata (at the Buenos Aires Province Capital), while I studied at UBA (Universidad de Buenos Aires), at Argentina's Capital City.
Anyway there's only 50Km between them, we shared some Professors and anyway it was cutting edge Technology way back then, so I guess many other Universities used that as teaching material.
Our study went way beyond what's shown in that AN, we also learnt to design the PSU, Thermal Stability (an often ignored problem) and short circuit protection.
Thanks for posting, that certainly brings back many warm memories.
I studied SS amplifier design between 1972/1975 using, among other stuff, that exact same Application Note and doing the same Lab work.
Not surprising, that one you linked to is from UNLP=Universidad Nacional de la Plata (at the Buenos Aires Province Capital), while I studied at UBA (Universidad de Buenos Aires), at Argentina's Capital City.
Anyway there's only 50Km between them, we shared some Professors and anyway it was cutting edge Technology way back then, so I guess many other Universities used that as teaching material.
Our study went way beyond what's shown in that AN, we also learnt to design the PSU, Thermal Stability (an often ignored problem) and short circuit protection.
Thanks for posting, that certainly brings back many warm memories.
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