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post #16 of 27
Thread Starter 
Quote:
Originally Posted by Steve Eddy View Post


I don't know. That's just plain weird. What DACs do this?

se

 

There are at least two that I know of. One is the Calyx 24/192 DAC, the other is the Matrix X-Sabre DSD DAC. Both of them are fully balanced (no phase splitter), output 2.2Vrms through RCA and 6.8Vrms through XLR.

post #17 of 27
Quote:
Originally Posted by Jd007 View Post
 

 

There are at least two that I know of. One is the Calyx 24/192 DAC, the other is the Matrix X-Sabre DSD DAC. Both of them are fully balanced (no phase splitter), output 2.2Vrms through RCA and 6.8Vrms through XLR.

 

This makes perfect sense.  6.8Vrms is about +19dBu, which is +15dB above studio reference level of +4dBu.  That would be a normal "Professional" output level, and would match perfectly to a console's balanced line level input.

 
I used to build line amps that would clip at +21dBu, and another version that would clip at +24dBu, both balanced output.
post #18 of 27
Thread Starter 
Quote:
Originally Posted by jaddie View Post

This makes perfect sense.  6.8Vrms is about +19dBu, which is +15dB above studio reference level of +4dBu.  That would be a normal "Professional" output level, and would match perfectly to a console's balanced line level input.
 
I used to build line amps that would clip at +21dBu, and another version that would clip at +24dBu, both balanced output.

So would 6.8Vrms balanced or 2.2Vrms RCA clip on consumer equipment? And how come RCA is not 3.4Vs if its just half of balanced output?
post #19 of 27
Quote:
Originally Posted by Jd007 View Post


So would 6.8Vrms balanced or 2.2Vrms RCA clip on consumer equipment? And how come RCA is not 3.4Vs if its just half of balanced output?

 

2.2Vrms, RCA = consumer level for consumer equipment (and refers to the MAXIMUM undistorted output level)

 
We need to forget the relationship of balanced=2x unbalanced.  It only applies to a portion of circuit design, not at all to product design.  
 
For product design, if the balanced output is intended to interface with pro gear, there will be a 14dB difference in level over the unbalanced output, or it simply won't play nice with pro gear.   For the "consumer" balanced output, all bets are off, it makes no sense what they do, especially since there's no point to balanced lines in consumer gear anyway.
post #20 of 27
Thread Starter 
Ok thanks for the answer. So basically the XLR output is elevated from the single ended beyond the normal doubling in power. I hope 6.8vrms is still fine for consumer balanced amps though
post #21 of 27
Quote:
Originally Posted by jaddie View Post

This makes perfect sense.  6.8Vrms is about +19dBu, which is +15dB above studio reference level of +4dBu.  That would be a normal "Professional" output level, and would match perfectly to a console's balanced line level input.
 
I used to build line amps that would clip at +21dBu, and another version that would clip at +24dBu, both balanced output.

Can't say it makes sense to me to go 15dB above line level reference for a fixed output device like a DAC.

se
post #22 of 27
Quote:
Originally Posted by Jd007 View Post

Ok thanks for the answer. So basically the XLR output is elevated from the single ended beyond the normal doubling in power. I hope 6.8vrms is still fine for consumer balanced amps though

If you're going to be using reasonably efficient headphones, you could end up with a lot of excess gain in the system which means limited volume control (i.e. slamming your eardrums six inches into your skull at nine O'clock on the volume control).

se
post #23 of 27
Quote:
Originally Posted by jaddie View Post

2.2Vrms, RCA = consumer level for consumer equipment (and refers to the MAXIMUM undistorted output level)

Where does that come from? The only thing close to a consumer reference level near that level is the Red Book standard for Compact Disc which is 2 VRMS.

se
post #24 of 27

2.2V?  I dunno.  It showed up in a spec the OP posted.  It's like 2V with a little headroom. Aren't bigger numbers better?

post #25 of 27
Quote:
Originally Posted by jaddie View Post
 

2.2V?  I dunno.  It showed up in a spec the OP posted.  It's like 2V with a little headroom. Aren't bigger numbers better?

Ha--theirs goes up to 11, of course...:smile:

post #26 of 27
Quote:
Originally Posted by jaddie View Post

2.2V?  I dunno.  It showed up in a spec the OP posted.  It's like 2V with a little headroom. Aren't bigger numbers better?

No, the way you wrote it made it sound like it was some sort of standard.

se
post #27 of 27
Quote:
Originally Posted by Steve Eddy View Post


No, the way you wrote it made it sound like it was some sort of standard.

se

Yeah, sorry, I'm sure it is to somebody.  

 

I've always considered consumer line level to be -10dBu, which I guess is about .25V, but anything near by...

 

They're using 0dBV now, so that places -10 at .316 Vrms, a whopping 2dB difference.  It doesn't matter a lot, because in recording there have been nominal reference levels anywhere from -15dBFS to -20dBFS depending on who you are, what you're recording and what A/D you're using. The early Sony PCM stuff referenced at -20dBFS, though back then we didn't have any dBFS to kick around, the term hadn't been invented yet. 

 

 Who cares?  The important figure is the voltage at FS anyway.

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