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Does load need to be attached to properly measure output voltage? - Help with proper way to measure
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dariedel2  
#1 Posted : Monday, November 2, 2015 2:35:08 PM(UTC)
dariedel2

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Hello,

When test measuring AC voltage at IVY III output, does load need to be attached? should constant sine wave signal be played for proper measurement?

Also, is it safe to use DMM probes while playing sound and while hooked up to amplifier?

I would just like confirmation of proper way to measure!

Thanks,
Doug Riedel
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Brian Donegan  
#2 Posted : Monday, November 2, 2015 3:48:18 PM(UTC)
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Quote:
When test measuring AC voltage at IVY III output, does load need to be attached?


No.

Quote:
should constant sine wave signal be played for proper measurement?


Yes, ideally you would use something like a 1kHz sine wave. Music is too dynamic, unless you have a scope, and even then...

Quote:
Also, is it safe to use DMM probes while playing sound and while hooked up to amplifier?


Yes. Typically DMM probes (in voltage mode) will be a high impedance to prevent shorting.
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dariedel2  
#3 Posted : Monday, November 2, 2015 9:44:53 PM(UTC)
dariedel2

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Brian,
Thanks, but when it is stated output voltage should be 2.0, at what standard volume or output?
For example, I played 1000hz sine at about 50% (through JRiver) via usb interface to 8 channel buffalo III and I got about 10.8 mV AC on DMM. When I played at 0% volume, I got 0.4 mV AC.
Should the test be done at 100% volume?

Thanks,
Doug
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Brian Donegan  
#4 Posted : Monday, November 2, 2015 10:16:04 PM(UTC)
Brian Donegan

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Yes. You are trying to test maximum output level (I assume).
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dariedel2  
#5 Posted : Monday, November 2, 2015 10:43:02 PM(UTC)
dariedel2

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Brian,
Ok so when it's stated the output voltage of the IVY should be 2.0v rms, that voltage reading was taken at maximum level, correct?

I adjusted the 2nd stage gain resistors, per Russ's recommendations, and I just want to test the output voltage of the IVY. Please explain method to measure with DMM (true rms) and under what scenario should I see the stated 2.0volts rms? Full volume? Half volume? 3/4 voume?

I can't seem to find any information about proper way to test.

Thanks,
Doug

Edited by user Tuesday, November 3, 2015 10:00:52 AM(UTC)  | Reason: Not specified
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dariedel2  
#6 Posted : Tuesday, November 3, 2015 2:23:34 PM(UTC)
dariedel2

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Brian or Russ,
I measured only 200mV on my ivy's from buffalo 3 in 8 channel mode(at full volume). I made adjustments per Russ's recommendation to R13-R16. I didn't make any adjustments to R1-R4.

I will say, even at the 200mV output voltage, the sounds gets as loud as I could want. Should I still adjust some resistors to get closer to 2 volts? Will SQ improve if output voltage on ivy is higher even though it plays loud enough as is? Will DR improve with the higher voltage? I'm happy as is but if some minor tweaks will make it better, I want to pursue the changes!
Thanks,
Doug

Never mind! The test signals generated in JRiver are at -20dB which makes sense I only had 200mV at what I thought was full volume. To be sure, I played sine at try full volume, and I got 2.03volts on both single end and balanced outputs.
I will try to be more patient before posting questions next time.

Edited by user Wednesday, November 4, 2015 2:34:23 AM(UTC)  | Reason: Problem solved....there was no problem
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