Hi folks, Douglas Blake told me there was an interest here in a DIY version of my Null Tester device that compares two signal wires to see if they pass audio differently. Doug asked me if I'd consider making the tester available as a kit, but that would be more work for me than I'm willing to do. One reason is there are two minor problems with the circuit that need to be fixed. Another is I'm not convinced enough people would want to build (or buy) a device that can test only wires to justify the effort.
When I told Doug I'd be glad to hand this off to someone else to complete the last 5 percent needed, he asked me to post here. Doug said there are plenty of people here who are knowledgeable enough to fix the remaining problems. One is the meter VU driver needs to be re-worked to be more accurate. Another is for some reason the 2 watt LM380 output amplifier clips at too low a level, and I never got around to figuring out why. So:
Is anyone here interested in taking over this project and turning it into either a DIY kit of parts or a complete commercial project? I'd be glad to split any potential profits 50-50 if it actually made a profit!
When I told Doug I'd be glad to hand this off to someone else to complete the last 5 percent needed, he asked me to post here. Doug said there are plenty of people here who are knowledgeable enough to fix the remaining problems. One is the meter VU driver needs to be re-worked to be more accurate. Another is for some reason the 2 watt LM380 output amplifier clips at too low a level, and I never got around to figuring out why. So:
Is anyone here interested in taking over this project and turning it into either a DIY kit of parts or a complete commercial project? I'd be glad to split any potential profits 50-50 if it actually made a profit!
(Too late for an edit)
I could picture a slightly revised version as a showroom display item where customers could test the difference between their cables and other cables, to build confidence in their purchases. Sort of a "hook up cables and push the button" kind of thing.
I could picture a slightly revised version as a showroom display item where customers could test the difference between their cables and other cables, to build confidence in their purchases. Sort of a "hook up cables and push the button" kind of thing.
This article explains quite a lot about the Null Tester device and shows part of the schematic:
Build a Null Tester Device
At this point I don't consider the circuit proprietary because I decided not to try to make it into a commercial product. So I'd share anything anyone needs. My main point in posting here, at Doug's urging, was to see if anyone who is savvy enough to take over would be interested.
I would take it myself, except that I really don't feel qualified to setup into someone else's project, especially when it's working with high gain circuitry of the kind needed to evaluate very low level signals. I'd give myself a 50/50 chance of success with it... and you deserve better. There are many very talented people here...
One thought you might like to explore with your new partners is that of co-operatively updating the design and making the circuit board available. Lots of people here are creative enough to handle the casings and other parts themselves. There are small run companies who can turn out the boards for you at reasonable prices by mail-order and there is a store attached to these forums you may want to check out.
There are many possibilities.
Sorry for the delay, I've been up to my eyeballs writing a magazine article showing how to measure capacitor distortion.
I don't want to post the complete schematic in a public forum for the entire world to see, but I'm glad to send it to anyone here if you email me from my home page: Ethan Winer - Home Page
I'm sure you have seen the earlier work on that from Jung and Marsh and Bateman's article (https://linearaudio.nl/sites/linearaudio.net/files/Bateman EW 07 2002 test oscillator.pdf). Ed Simon has done a lot on that as well published in Linear Audio.
I have two Radiometer CLT-1 component linearity analyzers and could possibly verify measurements if you would like. I did that many years ago for Bateman.
I have two Radiometer CLT-1 component linearity analyzers and could possibly verify measurements if you would like. I did that many years ago for Bateman.
Interesting project.
A lot of power amplifier reviews from Stereophile show diagrams with the distortion wave form (fundamental notched out) - check out post #2 under
https://www.diyaudio.com/community/...st-possible-thd-n-really-the-best-way.367692/
for any examples.
These diagrams say a lot more about the audible sound impression than the value "THD+N"
Are there a diy project (THD+N-only) where I can create with help of a scope such diagrams (maybe for compare different integrated op-amps ?
A lot of power amplifier reviews from Stereophile show diagrams with the distortion wave form (fundamental notched out) - check out post #2 under
https://www.diyaudio.com/community/...st-possible-thd-n-really-the-best-way.367692/
for any examples.
These diagrams say a lot more about the audible sound impression than the value "THD+N"
Are there a diy project (THD+N-only) where I can create with help of a scope such diagrams (maybe for compare different integrated op-amps ?
this is a pc based project
http://libinst.com/Audio DiffMaker.htm
http://libinst.com/AES Audio Differencing Paper.pdf
also of interest:
Distortion measurements by use of signal nulling method
http://www.renardson-audio.com/dtest.html
http://www.renardson-audio.com/distortiontest.pdf
http://libinst.com/Audio DiffMaker.htm
http://libinst.com/AES Audio Differencing Paper.pdf
also of interest:
Distortion measurements by use of signal nulling method
http://www.renardson-audio.com/dtest.html
http://www.renardson-audio.com/distortiontest.pdf
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