design help needed

Sorry, it's a James circuit and uses log pots. The Baxandall circuit is active and uses lin pots.

To OP: take a look at

and for some ideas.

- YD.

It's a Baxandall circuit. It's fine with linear pots.

I read in alt.binaries.schematics.electronic that The unknown Posterchild wrote (in ) about 'design help needed', on Thu, 8 Sep 2005:

Why don't you take up brain surgery instead? How on earth do you hope to get anything to work if you don't understand ANYTHING about it?

--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

I read in alt.binaries.schematics.electronic that T N Nurse wrote (in ) about 'design help needed', on Thu, 8 Sep 2005:

It absolutely ISN'T a Baxandall, which IS an active circuit.

--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

typical

The fets are not in ay way connected to the tone controls.

You're talking out of your arse.

You clearly know bugger all about audio circuits.

That circuit is about the worst trash I've seen in several decades.

Graham

It does I'm afraid.

There are much, much better examples of what you're looking for out there.

There's so much that's fundamentally wrong about the link you posted that I barely know where to begin. It takes truly the wrong approach to just about every single aspect of design.

Graham

Worse than that - the 'balance' control shorts out all of the signal at 0% or

100% travel !

Whoever came up with that abortion should be strung up.

Graham

For starters, do you want something battery powered ?

You want to mix 2 inputs and then have a common EQ ? Just 2 band ?

I don't see the point of 'balance'. Why not simply have a volume control for each input - then you don't even need a master volume ( unless you specifically really do want one ).

Graham

All to common today John. look at some of the clueless posts here in s.e.d.

You recall Charlie Boy got himself in hot water for saying kids today all expect to be rock stars or brain surgeons too ? p.s - without having studied anything of course

Graham

No it isn't.

You use linear pots around a ( Baxandall ) circuit with feedback That one isn't one. Try finding the feedback loop !

If anyone has the National Semiconductor Audio Handbook the difference is explained on pages 2-40 thru 2-48. ( active vs passive tone controls ).

The Audio Handbook has been reprinted btw. Amazon has it. A good reference work despite its age.

Graham

I think you are looking at the first version. My comment refers to the 'improved' version.

--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

I have the Oct 1952 paper, but I notice in the references in RDH that there was a "correction" article in Nov 1952. Can you tell me what the "correction" was?

I also notice in RDH a reference to an article by E. J. James in Wireless World, Feb.

1949, titled "Simple Tone Control Circuit". I wonder if that is the "James" tone control referred to in this thread. Do you also have a copy of that article, and is it just a passive version of Baxandall's 1952 circuit (with or without a tap on the treble control)?

Oops! You're right, I should have looked closer.

Err no. Peter Baxandall's contribution is this cut and boost circuit in it's a passive form. He later (1952) added an active version which looks similar but goes around a feedback loop. So both are Baxandall circuits.

P. Baxandall - "Negative Feedback Tone Control" Wireless World, vol 58 Oct 1952 p.402

"James circuit (also known as the Baxandall passive tone circuit).."

N.htm

...for a very full explanation - although not for the faint of heart at maths. Don't worry, it's in English.

But, you're right, the pots are log - I should have looked closer and realised it was passive. .

I read in alt.binaries.schematics.electronic that T N Nurse wrote (in ) about 'design help needed', on Fri, 9 Sep 2005:

Maybe 'known as', but it isn't. The Baxandall circuit is NOT the same as the James, but arranged in a feedback loop. The Baxandall treble circuit has ONE capacitor in series with the slider of the pot., which in the original circuit has a centre-tap on the track, with a switch to optionally ground it.

--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

I read in alt.binaries.schematics.electronic that T N Nurse wrote (in ) about 'design help needed', on Fri, 9 Sep 2005:

Complete nonsense, and I have the Wireless world articles to prove it.

--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

I don't have a schematic for a mid freq control ( variable frequency ). Is that what is referred to as a mid sweep?

Uhhh... This sort of thing is way outside the people in alt.guitar.

Please don't crosspost.

Zoid