Here's the original Baxandall article in Wireless World, Oct. 1980, p. 57.
http://www.americanradiohistory.com/Archive-Wireless-World/80s/Wireless-World-1980-10.pdf
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Yes, I got that at a first glance of the circuit, and fortunately the "infinite gain" happens when you turn the volume to the max (of course). Not an issue for me either.
I think I could even go with two pots, one for left one for right. Just to put the feedback very close to the opamp, as I am not using the layout by Bruno. And I get balance capability as a bonus.
An advantage of this active circuit is that the dual linear pots that are used
will track much better than passive dual audio taper pots.
You can do that but it will again negate one important advantage of this setup, namely that the tracking of the two channels when changing volume is almost perfect.
Jan
I am pretty sure he meant tracking of 2 pots in the sensitivity control of a stereo gear.
From Bruno:
"Carbon ink is notably nonlinear for instance. Other types may be better. At low frequencies the temperature dependence of the resistive material becomes noticeable. This circuit arrangement helps minimize the impact on distortion of these problems."
Source:
The G word: Demo project - A balanced volume controller | EDN
"Carbon ink is notably nonlinear for instance. Other types may be better. At low frequencies the temperature dependence of the resistive material becomes noticeable. This circuit arrangement helps minimize the impact on distortion of these problems."
Source:
The G word: Demo project - A balanced volume controller | EDN
Thanks, I did not know that he misused "Tracking" term for non-linearity of resistors... I will ask him if he comes to BAF.
The Baxandall circuit linked by Rayma doesn´t have the infinite gain issue (you can set maximum gain), and should give a nice log feel. So it´s a great choice.
EDIT:
The baxandall might need a capacitor between wiper and non-inverting input. And the non inverting input is biased with a 22k to ground on the TI schematic. So the wiper current is significantly increased compared to Putzeys circuit.
(And I like what Scott proposes, "Muntzing")
EDIT:
The baxandall might need a capacitor between wiper and non-inverting input. And the non inverting input is biased with a 22k to ground on the TI schematic. So the wiper current is significantly increased compared to Putzeys circuit.
(And I like what Scott proposes, "Muntzing")
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ooh will search that out. I recently bought all three volumes of Jeroen van Veen's minimalist piano recordings. 28 odd hours of minimalism is possibly excessive, but some real gems in there.
Alexandre: You realise you are committing heresey presenting a circuit with so many nasty 8 legs in and not an obsolete FET in sight 🙂
Disclaimer, I will be scattering G-word gain stages around like candy at some stage of my rebuild 🙂
Disclaimer, I will be scattering G-word gain stages around like candy at some stage of my rebuild 🙂
Thanks for the link, now I am out for reading and getting nostalgic feelings! 🙂
But in his article he postulated an excuse for the sharp curve at the beginning, "noise floor". 😛
The baxandall might need a capacitor between wiper and non-inverting input though. And the non inverting input is biased with a 22k to ground on the TI schematic. So the wiper current is significantly increased compared to Putzeys circuit.
(And I like what Scott proposes, "Muntzing")
(And I like what Scott proposes, "Muntzing")
I've listened to a fair bit of Philip Glass and I'm afraid to say I find him a bit of a one trick pony. Will give that a listen though, I like minimalism usually
I view Glass as having several phases. His 'Arpeggio hell' phases can get wearing, but his later stuff it very good. I also like Steve Reich and a number of the other composers of that vintage.
But I have only really scratched the surface of the minimalist movement. Much to still discover 🙂
But I have only really scratched the surface of the minimalist movement. Much to still discover 🙂
Going to UCSD's grad student music recitals (speaking of Reich), were, ummmmmmmmmm, interesting. Some were bizarredly fun, some were downright terrible.
Yes... I have to say though, that I really like the jfets in my I/V converter (used with current output DACs). I have tried a few classic multibit dacs with basically the same jfet stage and I have had excellent results. I´m not saying it isn´t possible to get it right with opamps, but I prefer not to make changes to a winning team. They work wonderfully well in common gate.
This is not the exact one I am using but I might rebuild it more or less like this (I borrowed Scott´s common mode servo):
Attachments
Radio 3 does a composer of the week each week. A few weeks ago was Messiaen and his organ music. The first recording they played I was wondering how on earth someone could have read the score for that, and then they announced it was Messiaen himeself playing. I suspect few perform some of them any more!
I've recorded a few of those.... Copland, Sibelius, Rautavaara (this one was fascinating as he participates in the program) even Charles Mingus and my favourite Scott Joplin
Brilliant stuff and yes it can be ridiculously complex. I forgot my introduction but IIRC it was on an old Spanish organ with the Vox Humana stops (?). This effect was wonderfully used by Popol Vuh in their Kinski film scores (must have LP's). BTW Philip Glass did wonders on the "Mishima" soundtrack, I love this film others might not.
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