Peter Baxandall did some consulting for us at KEF. He was an engineer's engineer. His reports were amazing to read both from their clarity and from his infectious pursuit of the understanding of the circuits.
One of the greats.
David Smith
It would be great to see a vastly more on the old WW, E+WW, EW front...
There's loads of references to articles everywhere one looks but the actual articles... not to be found!? (other than a few well circulated and well known ones). Surely no one would mind them being put on line after all this time!?
Is the magazine still in existence even? Haven't seen or heard anything about it since around 2006!
There's loads of references to articles everywhere one looks but the actual articles... not to be found!? (other than a few well circulated and well known ones). Surely no one would mind them being put on line after all this time!?
Is the magazine still in existence even? Haven't seen or heard anything about it since around 2006!
Hear hear.
At this distance of time, can you tell us anything about the work he did for you?
Some more WW articles are avialable here, including a couple of Baxandall's.
Vacuum Tube Design and Applications Notes
Vacuum Tube Design and Applications Notes
The KEF KM1 needed a transformer input stage for highest CMRR. He came up with a very low distortion input stage which worked the transformer into a virtual earth gain stage (if I remember correctly). I think he also designed the predecessor to the KEF Kube bass extending circuit.
I know I have a few of his letter/reports in my archive. will look for them this weekend. (let the kids see what real engineering looks like
)David
The following link will take you to the Electronics World website:
Electronics World - Electronics World
I have lots of Wireless World magazines from 1934 to 2003 with gaps in the seventies. If anyone needs something, I am willing to scan and post as requested.
If anyone has some to sell, I am still looking to complete my collection.
Michel
Electronics World - Electronics World
I have lots of Wireless World magazines from 1934 to 2003 with gaps in the seventies. If anyone needs something, I am willing to scan and post as requested.
If anyone has some to sell, I am still looking to complete my collection.
Michel
Kid standing by ready to learn!(let the kids see what real engineering looks like
David
Thank you for sharing.
A couple of Peter Baxandall letters.
We were designing a very high power studio monitor based on 7 drivers and 8 Quad 405 MkII amp cards. Peter helped with transformer input circuitry, modifications to the Quad amp cards and other details.
One PDF deals with extending and flattening the Quad's response. The second PDF is of an interesting conversation between Laurie Fincham and Peter. The Sony PCM F1 (early 16 bit Digital Audio recording unit) was just coming out and Peter and Laurie were both looking at pre production samples. Peter found shortcomings in the metering so he came up with a wide bandwidth very accurate PPM (peak program meter).
Graphs are calculated and plotted by hand, of course.
David Smith
We were designing a very high power studio monitor based on 7 drivers and 8 Quad 405 MkII amp cards. Peter helped with transformer input circuitry, modifications to the Quad amp cards and other details.
One PDF deals with extending and flattening the Quad's response. The second PDF is of an interesting conversation between Laurie Fincham and Peter. The Sony PCM F1 (early 16 bit Digital Audio recording unit) was just coming out and Peter and Laurie were both looking at pre production samples. Peter found shortcomings in the metering so he came up with a wide bandwidth very accurate PPM (peak program meter).
Graphs are calculated and plotted by hand, of course.
David Smith
Brilliant. Any circuit by Peter is worth examining closely.
This is important historical stuff!
Do you have any more?
I probably have 8 letters in all, but half are on input transformer testing. Not of general interest.
Here is a good one apparently after Laurie and Peter had a kickoff meeting about the "High Power Monitor" (KM1). It talks about soft limiting (a feature not used in the end.) Transfer functions, gain optimiazation and how Peter designs a Baxandall tone control.
Regards,
David Smith
By the way, I saw an amp with transformer in such mode connection was patented quite recently. The patent must be invalid since Peter Baxandall drew it before in this letter!!!
http://www.diyaudio.com/forums/atta...eless-world-valve-articles-past-pjb-km1-2.pdf
http://www.diyaudio.com/forums/atta...eless-world-valve-articles-past-pjb-km1-2.pdf
I'm not sure Peter was claiming it as a new invention. He talks about it as if it was somewhat common.
re: the patent. I'd have to see what they are actually claiming, the general operating mode or some specific form of it. My impression of the patent office is that they are happy to let you patent just about anything and then, if there is a conflict later, they'll let fight it out in the courts.
David
Electronics World
Hi
Wireless World was re-branded to Electronics World in the 90's. The magazine still exists and you can subscribe at Electronics World - Electronics World
Hi
Wireless World was re-branded to Electronics World in the 90's. The magazine still exists and you can subscribe at Electronics World - Electronics World
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