My implementation of the Cordell Distortion Analyser

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EUVL,
good idea to build it with SMD components.
Maybe you could use analog switches, type 4066 or similar, to switch resistance and capacitance. (As you've surely realized I would not use the rotary switch. I would be able to replace them with the analog switch but do not know if this would lead to a degradation in performance).
Certainly at this point would be even nicer to use the best performing components.
Add, as suggested by Bob, a frequency counter, a RMS digital voltmeter, etc. ..
Although it would retain the "core" !
But these things are outside my ability.
Maybe you ....?
Regards
Giuliano
 
Of course, Patrick. Not a problem for me to build frequency counter or RMS to DC converters, there are many schemes in the network.
Replace the 1496 and / or implement a new AGC with gain control voltage IC, in this I mean.
Maybe in future...I will become good...meanwhile I build the original which is already a good thing!
Thanks and Regards
Giuliano
 
EUVL,
good idea to build it with SMD components.
Maybe you could use analog switches, type 4066 or similar, to switch resistance and capacitance. (As you've surely realized I would not use the rotary switch. I would be able to replace them with the analog switch but do not know if this would lead to a degradation in performance).
Certainly at this point would be even nicer to use the best performing components.
Add, as suggested by Bob, a frequency counter, a RMS digital voltmeter, etc. ..
Although it would retain the "core" !
But these things are outside my ability.
Maybe you ....?
Regards
Giuliano

IC analog switches are a definite possibility, but I don't know how much degradation would be introduced. I would definitely replace the range switch with a relay arrangement. The frequency tuning switch might be able to be replaced with a four-gang, well tracking potentiometer arrangement. Depending on noise and distortion degradation, replacement of the frequency tuning switch by some kind of IC VCA's might be an option as well. Use of a PIC microcontroller is also a definite possibility.

Cheers,
Bob
 
This is a simplified schematic of the use of solid-state gang potentiometer.
Removing the CS, except one, you can perform the calibration potentiometers.
Bob, you write "four-gang potentiometer", but should not be eight resistors of S3 ?
Forgive me if I said something obvious or wrong, but I'm not very expert.
Regards
Giuliano
 

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I started building my Cordell analyzer when the article came out. I didn't have many resources, parts or smarts, so it took me three years to finish it. After all this time some of the front panel lettering has worn off, but I still use it often in spite of having other analyzers available. The noise floor and residual beats 'em all. Here's a couple photo links-

http://www.conradhoffman.com/BC_thd_face.jpg

http://www.conradhoffman.com/BC_thd_internal.jpg
 
I started building my Cordell analyzer when the article came out. I didn't have many resources, parts or smarts, so it took me three years to finish it. After all this time some of the front panel lettering has worn off, but I still use it often in spite of having other analyzers available. The noise floor and residual beats 'em all. Here's a couple photo links-

http://www.conradhoffman.com/BC_thd_face.jpg

http://www.conradhoffman.com/BC_thd_internal.jpg

Very good, really well built it!

Giuliano
 
I started building my Cordell analyzer when the article came out. I didn't have many resources, parts or smarts, so it took me three years to finish it. After all this time some of the front panel lettering has worn off, but I still use it often in spite of having other analyzers available. The noise floor and residual beats 'em all. Here's a couple photo links-

http://www.conradhoffman.com/BC_thd_face.jpg

http://www.conradhoffman.com/BC_thd_internal.jpg

Conrad,

Thanks for your kind words (and your patience in building it!)

Cheers,
Bob
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.