If you're running your DAC straight into a power amplifier, and you're not using it at full volume, you're not hearing all it can do.
Let’s revisit the problem we've been discussing for the past few days. The best DACs in the world have a digital volume control. You set it to 30 or 40—something comfortable when connecting directly to your power amplifier—and you think, "That’s fine." But under the hood, the DAC is throwing away resolution and making the noise level worse. It’s giving you less signal while the noise and distortion hang around like bad houseguests. Your 100dB signal-to-noise ratio is now 70, maybe worse.
What loudspeaker engineer Chris Brunhaver proposed to me was a simple idea, but the impact is enormous. Instead of controlling volume losslessly inside the digital engine we let the DAC run full bore—where all the measurements we're impressed with reside. Full dynamic range, full fidelity, no noise. No compromises. And then, right at the output, we insert a beautiful analog stepped attenuator.
What’s an analog stepped attenuator? It's the precision volume control you would hope to find in your analog preamplifier—as I have waxed long and hard about in the past—the importance sonically of the analog volume control in a preamplifier. But now, we're placing it at the output of our new DAC, the PMG Signature 512.
If you're going through the new PMG Signature Preamplifier, then this is all a moot point. But if you're planning on using the new DAC directly into your power amplifier, as we guess about half our family members do, then you're giving up not only measurement purity but sonics as well.
Comparing the exact same digital engine and analog output stage in the PMG Signature 512, directly into the power amplifier, using on the one hand the lossless digital volume control versus this new analog stepped attenuator, the sonic differences are staggering. Unexplainably better.
This is partly what I love so much about what we do in our industry. Who'da thunk this would make such a difference?
All because Brunhaver made an off the cuff comment, “What if we just changed how we think about volume?”
It’s the kind of thinking that changes everything.
