C4S learning resources?

[Deke609]

I'd like to understand how the Camille Cascode Constant Current Source (C4S) works - i.e., how the various components operate together to provide a source of constant current.  I've seen old references on this forum to a handbook by John Camille, but haven't been able to locate a copy. Is it available somewhere? Or is there another resource I should look to?


Many thanks,


Derek

[Deke609]

Bump.


I came across a post on diyAudio from Doc B. in 2007 suggesting that Bottlehead put the C4S in the public domain some time ago, so I'm assuming there's no intellectual property protection issue.


I already have the schematic (from the the SII kits I have), but I'd love to read the handbook or whatever documentation used to be supplied with the old BH C4S kits.  Is there a digital copy kicking around somewhere?  Or, with BH's permission, would someone with a hard copy be willing to scan it and post/email it?  @Doc B or @PJ: would that be ok?


I know Morgan Jones has a version of a cascode constant current source in his book (of which I have a copy), but I'd like to read what John Camille/BH had to say about the BH version, if at at all possible.


According to Doc B's 2007 posts on diyAudio, John Camille also published a bunch of info about the C4S in Sound Practices in the 90s, but I have no idea how I'd go about locating a copy of that.


Edit: just discovered that hificollective in the UK sells all issues of SP on CD for $25 (plus almost that much for Fedex, unless one wishes to risk UK Royal Mail). I've ordered a copy. But still hoping a copy of the BH C4S material can  be made available.


Many thanks,


Derek

[Paul Birkeland]

The PDF for the paper manual is still floating around.  The problem is that it really needs to be printed out on a duplex printer and stapled into a book to be readable.  It also covers the really, really old C4S PC board that hasn't been in production for about 20 years, and assumes you're using the LEDs that are also out of production.

While you might want to say that it needs a rewrite, I would argue that you could just fill in the gaps by asking any questions you have here. 

[Deke609]

Thanks PB. I'd be very interested in seeing that PDF. And I promise not to request a re-write.

[Paul Birkeland]

I'll talk to Dan and PJ about it when I see them tomorrow.

[Deke609]

Awesome. Many thanks PB.

[Deke609]

I've come across some excellent online lectures about basic solid state electronics: diodes, bipolar junction transistors, mosfets, etc. I think they make a good complement to NEETS Module 7 (the US Navy's electronics learning publication). The lecturer is UCLA Prof. Behzad Razavi - a google search shows that he's won a number of teaching awards. And having watched about 16 of his 1 hour lectures, I see why. 

Search youtube for "Razavi Electronics" if interested. 

So far, the math hasn't been too crazy. Not much more difficult than working with Ohm's law -- I think derivatives have only popped up a few times, and generally the most difficult stuff involves logarithms and exponents - high school level math, so not so bad.  But still quite a workout for my middle-aged brain.

cheers, Derek

[caffeinator]

Hi Deke609,

The NEETS series are indeed a great resource, and thank you for the tip about the lecture series - I'll give it a look! Definitely a good way to break up the monotony of COVID lockdown and learn something in the bargain.

I tried a search on 'constant current source theory' and got a lot of hits, below is but one of the many returns:

https://www.electronics-notes.com/articles/analogue_circuits/transistor/active-constant-current-source.php

Stay safe and healthy!

david

[Deke609]

Cheers David. that's a good overview of basic topologies. I've done similar searches, but always found (not surprisingly) that the discussions always presuppose a basic knowledge of BJTs/FETS, etc -- which I've never had. And, for better or worse, I've never been able to absorb formulas without at least a rudimentary conceptual understanding of the relationships they describe. Instructions a la "Just plug this into that formula to get the answer" don't do it for me.  As a result, I'm a *bit* of a slow learner -- to put it generously.   

[Doc B.]

Just found this, cracked me up.

http://acronymsandslang.com/definition/369380/C4S-meaning.html

CCSs as used in tube amps are discussed well in Morgan Jones' Valve Amplifiers, including a C4S style design.