cross-quad
Hi Scott,
Indeed, it's an interesting topology, but I've never explored this one in detail, mainly because D. Self warned us about the 'negative (input) conductances inherent in its operation'. How serious is this warning?
Cheers,
Edmond.
scott wurcer said:
Hi Scott,
Indeed, it's an interesting topology, but I've never explored this one in detail, mainly because D. Self warned us about the 'negative (input) conductances inherent in its operation'. How serious is this warning?
Cheers,
Edmond.
scott wurcer said:
Thanks Scott.
I haven’t looked inside the MAT04 before, so this was very interesting.
Edmond, D. Self is warning about a lot of different things.
Re: cross-quad
Now would they put something on a data sheet that didn't work? 🙂 There are issues but I think they are managable without too much pain.
Edmond Stuart said:
Now would they put something on a data sheet that didn't work? 🙂 There are issues but I think they are managable without too much pain.
D. Self
True! Even in cases where it wasn't necessary, for example the alleged 'bat wing' x-fer function of MOSFET output stages, which was solely based on erroneous spice models.
Cheers,
Edmond.
stinius said:
True! Even in cases where it wasn't necessary, for example the alleged 'bat wing' x-fer function of MOSFET output stages, which was solely based on erroneous spice models.
Cheers,
Edmond.
Re: Re: cross-quad
OK, manageable without too much pain. Nevertheless, I still stick to an AD797 for my latest power amp design (or maybe a LME49710, if you don't mind 🙂)
Cheers,
Edmond.
scott wurcer said:
OK, manageable without too much pain. Nevertheless, I still stick to an AD797 for my latest power amp design (or maybe a LME49710, if you don't mind 🙂)
Cheers,
Edmond.
john curl said:
I posted one here a couple of weeks ago. I think it used about $1.50 in parts. The matching is a problem but as an experiment I would pull parts off a strip and wrap them with a little adhesive backed copper grounding tape in groups of 5. As a product it really is only an IC technique. The cross-quad looks promising as it has been used in a couple of discrete amplifiers, IIRC.
Re: cross-quad
Again this is sort of a positive feedback technique. Looking into the lower pair you have a derived "short". Which can look like a negitive impedance under some circumstances i.e. it makes a nice oscillator in Barrie's first V to F. 🙂
Edmond Stuart said:
Again this is sort of a positive feedback technique. Looking into the lower pair you have a derived "short". Which can look like a negitive impedance under some circumstances i.e. it makes a nice oscillator in Barrie's first V to F. 🙂
Current source/sink IC
I just received the 5/21/09 Electronic Design which features the new LT3092 monolithic full-floating current source/sink IC. It can source/sink up to 200 mA with Vin-Vout max of 40V. With so much of audio dependent on diff pairs, I wonder how this chip would stack up against the discrete designs.
REF: ED Online 21157
I just received the 5/21/09 Electronic Design which features the new LT3092 monolithic full-floating current source/sink IC. It can source/sink up to 200 mA with Vin-Vout max of 40V. With so much of audio dependent on diff pairs, I wonder how this chip would stack up against the discrete designs.
REF: ED Online 21157
Re: Current source/sink IC
Hi Chuck,
If you read the material carefully, you will find that it is great as a DC source but that the dynamic impedance and performance deteriorates rapidly with frquency, and that all kinds of 'band aids' are shown to prop it up at AC. And some of the more interesting areas (for audio) are conspicuously blank in the data sheet. Nice, but no thanks. My 2cts worth.
Jan Didden
chascode said:
Hi Chuck,
If you read the material carefully, you will find that it is great as a DC source but that the dynamic impedance and performance deteriorates rapidly with frquency, and that all kinds of 'band aids' are shown to prop it up at AC. And some of the more interesting areas (for audio) are conspicuously blank in the data sheet. Nice, but no thanks. My 2cts worth.
Jan Didden
Re: cross-quad
Might make it hard to use in an input stage unless it's buffered. There are also issues with driving it hard/transient response so it is probably better left buried on the interior of the circuit.
Edmond Stuart said:
Might make it hard to use in an input stage unless it's buffered. There are also issues with driving it hard/transient response so it is probably better left buried on the interior of the circuit.
scott wurcer said:
Prof. Hawksford, 1981, that's where I have originally seen the cross-quad and cascomp stages ideas. Some previous work could exist, though.
http://www.essex.ac.uk/csee/research/audio_lab/malcolmspubdocs/J4 Distortion correction circuits.pdf
EDIT: For those without IEEE library access, Gilbert's article on multi-tanh principle is available here: http://iroi.seu.edu.cn/jssc9899/33ssc98/33ssc01/pdf/33ssc01-gilbert.pdf BTW, I find very elegant that Gilbert is quoting Schmook and his 1975 work.
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