distortion analyzer recomendations?

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#261
Attached a screen shot of my M-audio Audiphile 192 card in loop through (line out connected to line in) measured with Audiotester. Audiotester will cost you €35.

But I personally prefer ARTA for most of the work. Both programs have their advantages.

😉
 

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#263
I really would like to modify the power supply from 110VAC to 220VAC for my new VP-7702C.

Fig, A is as wired for 110VAC (factory setting). The primary coils are assumed and drawn based on the resistance measurement with my DMM.

Fig. B is a guesswork based on Fig. A. Could I find the 220VAC setting by measuring resistances between the connection nodes?

Any advice?

>>🙂<<
 

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#268
anatech said:

... and use some current limiting in case you get the phases reversed on one winding.
Click to expand...


Yeah, I should . . .

Anyhow, I believe that my Fig. A and B in post #263 are wrong.
I have changed Fig. A to Fig. C and Fig. B to Fig. D.

From the original VP-7702C, I can see only the blue, brown, black and pink wires in Fig. C. The resistance values are as measured, and the coils are drawn as assumed.

My plan is as shown in Fig. D. The resistance values are as measured. And, I have sent this copy to a Korean diyer who has made the voltage conversion from 110 to 220V with the same equipment, and I have just got his confirmation that Fig. D would work.

So, I'm gonna go ahead as in Fig. D . . .
Am I too fearless . . . ?

>>🙂<<
 

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#271
It seems that I've been lucky in the voltage setting to 220VAC.
I've changed the wire arrangement as shown for 220VAC.
All work! And, I measure secondary voltages of 24-0-24 VAC.

If someone buy VP-7702C, he or she could refer to this info about the power transformer.


>🙂<
 

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#273
FastEddy said:
Too bad. All of my audio gear is oriented toward Apple OSX ... I also have that M-Audio "Audiophile" gadget, but in the FireWire connected stand along box. ... Do you know of any comparable software for OSX?

(I could run it in BootCamp, but then ...)
Click to expand...

I'm also looking for Audio Analysis software for the OSX and found this for $599:

http://www.faberacoustical.com/products/electroacoustics_toolbox/

Has anyone used this software. They also have spectrum analyzer called Signal Scope Pro here of $249.00

http://www.faberacoustical.com/products/signalscope_pro/

Just thought I would see if anyone has used this software before I buy.
 
#275
Pjotr said:


Uhhh… I doubt, have looked around that site: You need a big buck of $$ for that :xeye: I wonder if it brings you any more in the end than ARTA and AUDIOTESTER for 1/10 to 1/40 of the price.

Your limitation is the soundcard in the end.

Cheers 😉
Click to expand...

Thanks for those, they are new to me. Yes, the soundcard is the limitation, but the software used, and understanding levels, impedance, etc. are also important. So ultimately, it ends up that one must use the right tool for the job at hand. The input and output levels of the soundcard are big limitations. So is the soundcard input impedance in many cases. But, if you this and plan accordingly, you can use it for incredible low distortion work.

For instance, if you want to test an amplifier to see how much power it puts out before it clips, I would never use a soundcard! I'd use a function generator, analog scope with 10:1 probe, and AC multimeter. And some *big* 4 and 8 ohm power resistors.

FYI, there were some other threads here people may not be aware of on this subject - see
http://www.diyaudio.com/forums/showthread.php?s=&threadid=137843

and

http://www.diyaudio.com/forums/showthread.php?s=&threadid=41115

both very good material buried in both those as well.
Bob
 
#277
jackinnj said:



For $599 you can purchase a Tektronix SG505WO, SG505WR and AA501A all in a nice TM504 with enough money left over for a couple bottles of decent Bordeaux.
Click to expand...


After thinking about this, I realized the source on a soundcard has real limitations for setting the level - i.e. you can't get a low distortion output over a wide range (60db) of levels. If you build your own, you are stuck with one frequency.
So I bought an SG-505, and TM503, but went for different plug-ins. I am still a confirmed FFT guy for measuring distortion - I MUST see the harmonics and where they are. So I plan to use the SG505 with soundcards and FFT analyzers for distortion.

For the other plug-ins I bought a true rms ac voltmeter (with dB readout). I picked the tek DM501A ($50 used). To read the exact SG505 output level, and useful for frequency sweeps, to find the -3db point, high level measurements, etc. And the DC509 ($60) Digital Counter to read the exact frequency the SG505 is putting out. Useful loudspeaker work finding resonances, etc.

With that TM 503 combo (SG505, DM501A, DC509), a scope and 24 bit sound card/software, you can do most audio measurements with great precision on speakers, amps, and line stages. Of course there's always a need for more 😀, like the HP 8904A that just showed up here.
Bob
 
#278
BFNY said:


So I bought an SG-505, and TM503, but went for different plug-ins. I am still a confirmed FFT guy for measuring distortion - I MUST see the harmonics and where they are. So I plan to use the SG505 with soundcards and FFT analyzers for distortion.
Click to expand...


The SG505 will get down to 0.0004% THD+N% it's just not automated.

The SG5010 can be programmed via GPIB, equals the SG505 in terms of numerics, but you rarely see them.

To see the residual you just connect a sound card analysis FFT program to the "Function Output" of the AA501 -- you could probably use software as inexpensive as Audacity for this. You can also see how well the fundamental is notched out, and what kind of birdies you're picking up...
 
#279
FastEddy said:
" For $599 you can purchase ... a couple bottles of decent Bordeaux. " 😀

That software may be worth it, if you are setting up a serious professional lab.

The other leads for software are really appreciated too. Thanks: Working on it ...

:smash:
Click to expand...

I got that price wrong, it's actually $499.00 and that's their high end software. I have a low noise and distortion (0.0009%) sound input/output device (E-MU 0404) to use with the software.

I may just get the $99.00 signal scope which has all the features I'd use along with their Signal Suite for $39.00.

http://www.faberacoustical.com/products/signalscope/signalscope_details/
 
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