Hi Scott,
Looking forward to your Magnus Opus! Deadline should be before the holiday season; you can go on holiday, I'll work on the manuscripts
I believe most articles in Vol 1 have some direct practical use except possibly Bruno's piece. I try to keep a balance; for instance, Ian Heggluns article on square-law class A can be build by people interested in the technology, while the annexes give the calculations for efficiency and distortion for those who are not interested in building per se, but nevertheless are interested in the details. Personally I am not that interested in, say, the umpteenth 300B amp (unless it s really, really different) and I assume my readers aren't either.
I understand that with this policy Linear Audio will never be a mass publication but I wouldn't want that anyway.
Nevertheless, I am interested in what think about this, the level of content, and why/why not.
I'd appreciate feedback by PM.
jan
Are you two doing that on purpose to annoy me? Opus is a 3rd declension neuter noun!
Jan, I am working on a headphone amp which utilizes the LME49710. I headed straight to Bruno's article. I had used a 47k ohm resistor in the feedback loop. I had a notion that less was better. I tried a 60k ohm resistor to reduce feedback further but noticed a jump in DC offset.
So I went back and dropped in a 22k ohm resistor. Offset was fine so gave it a listen and I do not have testing equipment, but I perceived the performance to have improved to my ears.
Bruno's article encouraged me to fiddle with the feedback and I'm happier now for having done it.
Forgot to tell you. I received several letters commenting on articles in Linear Audio. I put them on-line, together with the author's reply, so you don't have to wait for the next volume to read those comments.
It's all here: Linear Audio | Letters .
Also, Nelson Pass' article The Arch Nemesis published in Vol 0 has been put on line for free download: Linear Audio | Online Resources .
Have fun!
jan didden
It's all here: Linear Audio | Letters .
Also, Nelson Pass' article The Arch Nemesis published in Vol 0 has been put on line for free download: Linear Audio | Online Resources .
Have fun!
jan didden
Hi Ed,
Vol 2 will be out on the streets 1 September. You will get a heads-up before that.
Did you send me email that I haven't answered? I'm not aware of that.
jan
And yes! Volume 2 is out on the streets!
Again, the articles my authors have written are nothing short of fantastic. There is so much ingenious circuit design, great insight and incredible creativity around that we are often not aware of! It's a great privilege to work work with those personalities to bring out another great tech audio bookzine.
A short overview:
Bob Cordell is back with a very high quality KT-88-based tube power amplifier, based on the design that gpot lots of kudo's at a RMAF workshop.
Rudolf Moers goes on an ultra-linear adventure. If there was ever anything you wanted to know about the design, advantages and trade-offs in ultra-linear tube power amps, this article will surely answer it.
On the solid-state front, Kendall Castor-Perry designed a novel and ingenious gain-of-one power output stage that needs no adjustments or thermal compensation yet is extremely linear, even open loop. Our friend from Switzerland, Samuel Groner, came up with an equally high-performance push-pull transimpedance stage that could drive Kendall’s output stage, or any other, for that matter.
Nelson Pass has a sequel to the Arch Nemesis, transplanting the SiC power device with a custom-designed Static Induction Transistor, the Pass SIT 1.
Marcel van de Gevel describes a simple loudspeaker correction filter that gets away with standard value capacitors and a simple gain-of-one buffer amp as the active element.
EUVL, inspired by designs from Nelson Pass, Marshall Leach and others presents a minimalistic I/V converter for current output DACs based on jFETs and a floating power supply.
Stuart Yaniger shares with us some interesting insights and experiences related to controlled listening tests.
Last but surely not least, Gary Galo’s Guest Editorial provides a thought-provoking insight into the history, development and current state of digital audio.
There are also two book reviews: Rudolf Moer’s Fundamental Amplifier Techniques with Electron Tubes is reviewed by Guido Tent, while Kendall Castor-Perry gives his views on Douglas Self’s latest work The Design of Active Crossovers.
Several of you asked for designs that they could also build if they wanted. And yes, there are several in V2 that can easily function as a construction project. Bob Cordell has identified a current production output transformer for his design. The output stage of Kendall could be mated with Samuel’s push-pull transimpedance stage to form a novel, very high performance power amp, although you should be prepared for some real-world fine tuning.
EUVL even plans to provide some kits with PCBs and jFETs for his I/V converter through his account at diyaudio.com.
I hope you again enjoy reading this Volume; and if you have any comments, let me know.
But don’t forget to listen to your music!
jan didden
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