Analogue clipping from digital sources


Given the high output (typically >2v in RCA, >4v in balanced mode) there is in my experience a significant risk of overloading both the analogue stage of the DAC and any pre- or power amp downstream. Fighting that with low volume settings on the attenuator only further aggravates the issue. In my case I have to run the InnuOS Zenith’s Mk3 output at 85% to deal with audible overloading of the DAC/ amp with audible distortion. Anyone with similar experience?

antigrunge2

“IMO Phillips and Sony made a stupid mistake when they set the Redbook spec to 2V output with digital gear, more than many amps need to overload.

The CD was invented in 1982, with full knowledge of this. The reasoning is that a PREAMP could/can easily handle 2V input. Amps may not, but since the idea was never to directly connect a CD player at full output to an amp, I’m not sure why this is an issue. Also, higher voltage = less noise (its complicated) and less need for additional gain downstream.

Also, Ralph is right for an AMP, 2V might be overload but preamps have been 100% aware of the CD standard since then and are built for it, so I disagree. Preamps (and preamp stages) today can easily handle 2 V input and put out whatever arbitrary fraction of that you need for an amp.

Older gear though had far too much gain or too low a supply rail which could cause an issue.  By too much I mean it had a lot more gain than we can use, which contributed to noise.  Better to have lower gain and wider use of the volume knob.

Also, Ralph is right for an AMP, 2V might be overload but preamps have been 100% aware of the CD standard since then and are built for it, so I disagree.

@erik_squires FWIW the high output digital problem is one of the issues that any preamp manufacturer has to find a way to deal with. With a phono section or tuner, you might need 15dB of gain to work with most power amps, but you (most of the time) don't need any for digital.

We've been lucky in that our patented direct-coupled output section of our preamps is neutral enough and is able to prevent coloration from the interconnect that there is still a benefit using our preamps with a digital source.

@atmasphere  but phono stages have additional gain just for them.  It's true that you almost don't need any gain for CD's, but tape decks and tuners were often near that, no? 

The 2V peak outputs should not be a surprise anymore.

Still, that's not to say any particular maker or model doesn't overload more easily than others.

In my read a good DAC analogue stage may only need an additional preamp where switching to analogue sources is required. Absent that the pre adds distortion.

thank you to @atmasphere and @erik_squires for explaining an obviously important issue that hasn’t been sufficiently discussed

but phono stages have additional gain just for them.  It's true that you almost don't need any gain for CD's, but tape decks and tuners were often near that, no? 

@erik_squires No. quite often a tuner or phono section will make 1Volt. A cassette machine makes 1 Volt (@ 0VU), as do consumer (not pro) reel to reels (also @ 0VU).