18 Jul
2016
18 Jul
'16
6:59 p.m.
On Monday, July 18, 2016 10:30:47 AM EDT Robert Edge wrote:
Do whatever you want. I can't explain it to you
any more clearly.
On Mon, Jul 18, 2016 at 10:25 AM, Len Ovens <len(a)ovenwerks.net> wrote:
> On Sun, 17 Jul 2016, Robert Edge wrote:
>
> If you don't believe me, do this simple test:
>> feed a 1kHz tone in to the input
I already said that I did that and verified it works.
Unless MAudio had started to make these cards without
a volume control chip, your distortion is upstream,
not from the 1010LT card.
Or the card is not being used correctly. Check your settings.
Are you sure the Patchbay/Router tab settings are correct?
Or... your card has a partially fried preamplifier IC? Hey, it happens.
This card has an ak4*** chip with full analog attenuator and amplifier.
(And, uh... if /you/ don't believe /me/ then look at the 'About' tab
in Mudita24 and see who one of the authors is.)
But seriously, I hope this helps in better understanding the card and
tracking down the real source of the distortion, which cannot be
a properly functioning card.
Tim.
>>
>> set 'analog volume' control in software to 0dB
>>
>> connect to ardour or your choice of recorder with decent metering. set
>> meter
>> point to 'in'
>>
>> increase volume of test signal until you are getting 0dBFS. no matter
>> how much
>> you increase the level of the test signal from here it will continue to
>> read
>> 0dbFS. turn the signal generator up a good few dB so you are well in to
>> clipping.
>>
>> record a bit of this. you will see a squared off wave.
>>
>> now turn down the 'analog volume' control until you are seeing a nice
>> comfortable
>> level. do not change the level of the test signal generator.
>>
>> record again.
>>
>> the result will still be clipped.
>>
>> in fact it will be identical to the first signal you recorded, just
>> scaled down.
>>
>> I mean, you guys do whatever you want, but that is what is actually
>> happening in
>> your signal chain.
>
> How do you know this is digital and not analog clipping? The result would
> look the same.
>
> signal path:
>
> AC -> resitor -> buffer -> digitally -> ADC
> in pad on amp controlled
>
> card analog gain
>
> if the input signal after the input pad has p-p higher than amp's power
> rails allow, the signal will be squared off, just as you are seeing. The
> gain stage would be a part of the ADC chip BTW. The buffer amp is probably
> not, but rather a gain stage added to allow the use of mic level inputs.
> (M-Audio advertise it as a Mic Pre)
>
> --
> Len Ovens
> www.ovenwerks.net