Behriger umc204hd maximum input voltage

[Chipsosaurus]

Hi all,

so I´m trying to figure out, what is the maximum peak voltage, that is safe for the line input of my sound card. According to Quick start guide -> https://www.fullcompass.com/common/files/24700-BehringerUMC404HDDatasheet.pdf, the max input level is 20 dBu, which is almost 11volts, which seems quite a lot to me compared to other sound cards. Am I missing something or is this right?

Thank you 🙂

 

[Mark Tillotson]

7.74Vrms. So 11V peak, so probably using standard +/-15V opamp circuitry.

This isn't some +/-5V limited internal soundcard, its professional audio equipment which is usually +/-15, 17 or 18V dual rail depending on which opamps are used.

 

[PRR]

7.74Vrms. So 11V peak, so probably using standard +/-15V opamp circuitry.

Not that we should care, but.....

It is USB powered (the bigger 404 has wart option). While they could jack that to +/-15V, the ADC is probably low-volt, so why? Put an 11/2.4 pad in front to keep big inputs in range of a 5V ADC. Padding-down is the easiest thing in audio.
Behriger umc204hd https://media63.music-group.com/media/sys_master/he1/hdc/8849614274590.pdf
Sample audio ADC: http://www.ti.com/lit/ds/symlink/pcm1802.pdf

It "must" accept input from standard +/-15V studio gear. It doesn't have to use that level internally.

Another clue: the output is rated +3dBu! 1.55V peak! 3.1V p-p! Which strongly implies a 5V opamp.

(Yes, there is a "48V phantom", but deriving this from 5V USB is easier than deriving the whole shebang from USB.)

Here's a too-simple (no CMRR) pad to turn +/-11V inputs into 0.6V to 4.4V output for a 5V ADC.

EDIT-- the ADC chip I linked actually likes 3Vpp input not 3.8V. So pad a little more.

 

[Mark Tillotson]

Indeed I think you're right: Budget DAC Review: behringer UMC204HD | Page 3 | Audio Science Review (ASR) Forum

 

[Chipsosaurus]

Thanks for all your answers guys, much appreciated.