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Old 16th August 2013, 06:03 AM   #21
RNMarsh is offline RNMarsh  United States
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Might seem that way from the scketch of a note. It is an 'educated' guess based on the behaviour of the change is a lot like notch behaviour when tuning/phasing the notch or changing freq etc. . But, really just telling the difference seen is what a user would see and make assumption about the DUT data results. Different (very good) instruments with different results. Not saying why there are differences but they are Not showing the same levels. Now what would we think if we had very good ac/dc voltmeters this way?

Regarding the introduction of a second tone near the one being observed.... we went over that already... I havent seen the 725 like multiple tones... seems to confuse it.

My point is the 2H will be affected the most and that is also where i measurement the greatest differences as well.

The assumption I do make for now is that the 725 is more accurate in presenting the true level of the 2H just because it fits my model of reality. Granted its complex but so far the gang who did the 725 didnt miss much.

Thx-RNMarsh

Last edited by RNMarsh; 16th August 2013 at 06:11 AM.
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Old 16th August 2013, 06:39 AM   #22
1audio is offline 1audio  United States
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Now what would we think if we had very good ac/dc voltmeters this way?

I would look for alternate ways that come from first principles- Reference Voltage- KV divider Thermal converter- a day or two of tedium.

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The assumption I do make for now is that the 725 is more accurate in presenting the true level of the 2H just because it fits my model of reality. Granted its complex but so far the gang who did the 725 didnt miss much.

Thx-RNMarsh
The biggest hazard we all have with audio is our internal model. While it makes the process easier it can make seeing important details harder.

I have seen the same 2nd Harmonic with the pair I have and the next day the 2nd harmonic can be -130dB or more. I'm really not sure what its coming from or if its the generator or the analyzer.
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Old 16th August 2013, 07:37 AM   #23
RNMarsh is offline RNMarsh  United States
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Attachment 366032

Attachment 366033

Well between these two instruments it is consistant (so far?).

I havent seen anything with the 2722 because i cant get it into high rez mode. Drivers dont open. Used XT PC for these but cant do 2722 FFT and i7 PC yet. Then, I will be able to compare the A-P 2722 with these two and see what, if anything, is different. The WIN 8 is really goofy to use.

I seriously doubt if I will be able to do anything about any of this.... just curious to know how they all respond and what kinds of variations there will be.

Thx-RM

Last edited by RNMarsh; 16th August 2013 at 07:43 AM.
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Old 16th August 2013, 08:37 AM   #24
RNMarsh is offline RNMarsh  United States
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I would look for alternate ways that come from first principles- Reference Voltage- KV divider Thermal converter- a day or two of tedium.

I have seen the same 2nd Harmonic with the pair I have and the next day the 2nd harmonic can be -130dB or more. I'm really not sure what its coming from or if its the generator or the analyzer.

I meant what would you think of the various voltmeter brands giving different readings? I would want to find out which one was most accurate and use that one.

What I have seen so far which could contribute to the change is drift. Drift of the osc freq and drift of the notch/null circuits away from one another. And, at these levels it doent take much. That freq drift causes phase changes enough to cancel (wont add... its on the wrong side of the phase shifting).

And the analyzer and generator and notch are Not locked into one another. maybe it is with some all-in-One units (A-P?) but seperate boxes like this is asking for trouble.

Thx-RM

Last edited by RNMarsh; 16th August 2013 at 08:40 AM.
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Old 16th August 2013, 02:19 PM   #25
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Getting no-where fast with the A-P 2722 software. No time for this.... calling A-P Tech support to hold my hand..... WIN 8 plus a new A-P... both software to learn at the same time (?).
I am using Win7 with my SYS2722. I have WIN8 on my Samsung Laptop and am actually beginning to like it. I'll load the AP software on it and see if i can get it to work.

Can you get it to work in "Demo Mode" or is it a communications issue. By the way, demo mode is valuable to have on another PC to pull up data files.
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Old 16th August 2013, 03:39 PM   #26
1audio is offline 1audio  United States
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Originally Posted by RNMarsh View Post
I meant what would you think of the various voltmeter brands giving different readings? I would want to find out which one was most accurate and use that one.

What I have seen so far which could contribute to the change is drift. Drift of the osc freq and drift of the notch/null circuits away from one another. And, at these levels it doent take much. That freq drift causes phase changes enough to cancel (wont add... its on the wrong side of the phase shifting).

And the analyzer and generator and notch are Not locked into one another. maybe it is with some all-in-One units (A-P?) but seperate boxes like this is asking for trouble.

Thx-RM
They all (including the AP) have autotune and autonull. The implementations are different but they need it to keep the notch tuned. Similar to the AGC circuit. They do not use the generator to tune the analyzer. The circuits track the drifts automatically. I think the issues are different.
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Old 16th August 2013, 05:37 PM   #27
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Originally Posted by RNMarsh View Post
I meant what would you think of the various voltmeter brands giving different readings? I would want to find out which one was most accurate and use that one.

What I have seen so far which could contribute to the change is drift. Drift of the osc freq and drift of the notch/null circuits away from one another. And, at these levels it doent take much. That freq drift causes phase changes enough to cancel (wont add... its on the wrong side of the phase shifting).

And the analyzer and generator and notch are Not locked into one another. maybe it is with some all-in-One units (A-P?) but seperate boxes like this is asking for trouble.

Thx-RM
hello,
It is kinda like comparing two seven digit volt meters and discovering at the seventh digit they are off by 2 counts, isnt it?
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Old 16th August 2013, 06:19 PM   #28
RNMarsh is offline RNMarsh  United States
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They all (including the AP) have autotune and autonull. The implementations are different but they need it to keep the notch tuned. Similar to the AGC circuit. They do not use the generator to tune the analyzer. The circuits track the drifts automatically. I think the issues are different.
They might be different...of course, It just Looks as if it is related in this way. Mainly I am thinking about the low end and a bundle of parts to do the various functions which are not auto-nulled. I have wished someone reading these things would get into the auto-null design so we could end up with all the peices working well together and giving the $$$ makers a run for the money more than ever before.

-RM

Last edited by RNMarsh; 16th August 2013 at 06:23 PM.
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Old 16th August 2013, 06:21 PM   #29
RNMarsh is offline RNMarsh  United States
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hello,
It is kinda like comparing two seven digit volt meters and discovering at the seventh digit they are off by 2 counts, isnt it?
yes, or the last digit might as well be just a random number generator.
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Old 16th August 2013, 10:53 PM   #30
1audio is offline 1audio  United States
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I just setup and checked my 725a with Victor's oscillator. The 2nd harmonic measures -130 dB, the 3rd measures -150 dB. I clearly need to figure out what to tweak in the 590AR since its not at this level. It will probably require a reverse engineering task since documentation does not exist.
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