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Topic ClosedIs the ADA PitchTraq Harmonizer Analog?
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HackettFan View Drop Down
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Points: 7951 		Direct Link To This Post Topic: Is the ADA PitchTraq Harmonizer Analog?
    Posted: September 28 2012 at 17:03
Does anyone know if the ADA PitchTraq Harmonizer/Pitch Transposer is analog? Does it work without pitch to voltage conversion?

I suspect that the magnificent ADA PitchTraq might be analog because its forerunner, the slightly awful A/DA Harmony Synthesizer, was analog (http://hammer.ampage.org/files/Device1-4.PDF). The PitchTraq also has a lot of background hum characteristic of analog (although one tends to forget the background noise because it is very effectively minimized by adjusting the ratio of input and output level and just leaving it be).

I suspect that it does not use pitch to voltage conversion because I have never been able to outplay it and the timbre is magnificent. There are no tracking problems with it and I'm always astonished when I hear of tracking as still an issue of concern. "Hadn't ADA solved that?" I ask myself. The only answer I can give is that it doesn't use pitch to voltage conversion, so it's not an issue. Near as I can figure the A/DA Harmony Synthesizer was conceptually similar to the Analog Harmonizer schematic on SynthDIY.com (http://synthdiy.com/files/2007/analog-harmonizer_rfharmsch1.jpg) (http://synthdiy.com/files/2007/analog-harmonizer_rfharmsch1.jpg). It used two alternating delays that were sped up to create pitch changes. When one sample elapsed (because it was sped up), the other would kick in in alternating fashion. Did the PitchTraq perfect this approach? Or is there some untold story about how they were way ahead of Roland when it came to pitch to voltage conversion?

I really would like to know what is happening here. One disclaimer: I have never designed my own circuit board nor put together a even a single circuit board kit. I just try to be a well read guitarist.
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Points: 7951 		Direct Link To This Post Posted: September 30 2012 at 09:45
I really don't know why the ADA PitchTraq never caught on. Hopefully someone else in the forum has some experience with it. There is a paucity of historical info about it on the Internet.
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Points: 37575 		Direct Link To This Post Posted: December 31 2012 at 14:28
I cannot find a schematic for this device on the interwebs so the only answer I can give is I don't know.
 
Judging by the touch switches and display there is evidently a lot of digital electronics inside the box. Pitch-shifters and harmonisers generally quantise the source signal using either BBD (Bucket-brigade devices) and some digital clocking or a combination of ADCs DACS and digital memory and some similar digital clocking. 
 
It could be argued that none of these are purely analogue in that sense because the input is cut-up into slices and then slowed down or sped up to create the change in pitch (and then mixed with the source to create harmony) and the master clocking, even if derived from the source using phase-locked loops or some other form of frequency synthesis, is a digital signal. Certainly BBD is a time-domain sampling methodology and suffers all the failings of sampling theory, so going digital in this application is not a major hurdle, and in many ways is the better solution.
 
Both versions will have some analogue noise (hum, buzz etc) associated with them because there is an analogue path through the device and a lot of digital switching involved, given the current state of ADCs and DACs personally I find it unlikely that anyone could honestly tell whether it used a BBD or a ADC/memory/DAC method just by listening to it. Yet I'm sure some analogue purists would argue until they are blue in the face that they can
 
However, BBDs fell out of favour relatively quickly so very few commercial units used them, though they are still popular with some home-build enthusiasts (if you can find stocks of them, I believe only one manufacturer is still producing them).
What?
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Points: 7951 		Direct Link To This Post Posted: January 01 2013 at 00:48
Originally posted by Dean Dean wrote:

I cannot find a schematic for this device on the interwebs so the only answer I can give is I don't know.
 

Judging by the touch switches and display there is evidently a lot of digital electronics inside the box. Pitch-shifters and harmonisers generally quantise the source signal using either BBD (Bucket-brigade devices) and some digital clocking or a combination of ADCs DACS and digital memory and some similar digital clocking. 

 

It could be argued that none of these are purely analogue in that sense because the input is cut-up into slices and then slowed down or sped up to create the change in pitch (and then mixed with the source to create harmony) and the master clocking, even if derived from the source using phase-locked loops or some other form of frequency synthesis, is a digital signal. Certainly BBD is a time-domain sampling methodology and suffers all the failings of sampling theory, so going digital in this application is not a major hurdle, and in many ways is the better solution.

 

Both versions will have some analogue noise (hum, buzz etc) associated with them because there is an analogue path through the device and a lot of digital switching involved, given the current state of ADCs and DACs personally I find it unlikely that anyone could honestly tell whether it used a BBD or a ADC/memory/DAC method just by listening to it. Yet I'm sure some analogue purists would argue until they are blue in the face that they can

 

However, BBDs fell out of favour relatively quickly so very few commercial units used them, though they are still popular with some home-build enthusiasts (if you can find stocks of them, I believe only one manufacturer is still producing them).

Thank you, Dean, for looking into this. Very enlightening. Sounds like it most likely has a foot in both camps. Happy New Year to you.
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