Phono Box DS3 B output impedance

@lewm I can raise it a bit for 6.7Vrms / 2.46kΩ input impedance but then the dynamic range is less satisfactory. So if output impedance is low enough, I would rather keep the 4,5 Vrms / 1,66 kOhms setting. I'm trying to figure out if the ratio of output Z to input Z is about 1:10 as you have guessed.

I emailed Pro-ject first but they read my email too quickly and sent a specs sheet without the information I needed. Will try again on Monday!

I am not sure why you prefer Pro-ject phono box over other brands. The xlr output imp on Schiit Skoll is only 10 ohms. Fully discrete, true balanced output and more dynamic. The SINAD from the 3rd party (asr) rated 78 for DS3 but 81 for Skoll.

Oh, you save a bunch of green.

1.66K divided by 200 = ~8/1, so not quite 10/1, but the difference is trivial. There is nothing magic about the 10X rule of thumb.

The fraction of signal voltage transferred is defined by the fraction Zi/Zo+Zi. When the ratio of output to input Z is 1/10, that fraction says 92% of signal voltage is available to the driven device. When it’s a ratio of 1/8, about 89% of the signal voltage is transferred. No big deal.

@lanx0003, I considered the Skoll indeed but Schiit products are hard to find here in France so I had no opportunity to listen to it first. I was offered a good deal for a demo DS3 B so I went for it as I was very satisfied with sound and flexibility.

+1 @boozendormi  Now knowing you are in Europe, I could relate to your situation.

+1 @lewm but forget not that the 110-ohm impedance of an XLR cable also plays a role. Suddenly, you have 1660/(1660 + 200 + 110) = 84.3%. No big deal? I’m afraid not. I believe this should have some impact, at the very least, on the conversion quality of an ADC.

For impedance matching, I usually aim for a much higher ratio than 1:10—often by another order of magnitude. That said, there are exceptions in the market, such as Denafrips DACs, which have a relatively high output impedance. Even with an output impedance of 5000 ohms, their strong current delivery allows them to drive most (pre-)amplifiers effectively. Additionally, their transformer-coupled output stage provides a degree of impedance matching.