As I can use a headphone output as a line output (regarding to manufacturer’s manual) I’d rather to buy a TRC to 2RCA cable. I need your suggestion, guys
1. As now I have two volume knobs (Babyface and L30 ii) the question is about proper gain staging. How to set the optimal volume level and which volume knob of both devices should I use to be sure the sound of my amplified Sundara’s isn’t distorted and powered enough?
2. Is this the right TRS -> 2RCA cable I’ve chosen on Ali (a pic below)? Is it good enough in terms of quality?
What would you suggest?
I have the non-FS version of the Babyface Pro. And an L30 II, too!
You should probably just use an XLR to RCA cable. Not only does it free up the headphone jacks for headphones, and keep your desk less cluttered (XLR outs are at the back), it's one less [unnecessary] stage between the DAC and amp. Make sure it's not some weird cable that shorts pin 2 to 3 on the XLR end - I spoke with an RME engineer on the XLR outs because I had an amp with low input impedance (1064 ohms) and they told me it was good down to only 300 ohms. Not saying 300 is not a good spec, just that 0 (short) is lower than that, so that's not good (I also brought up the amp loading half the XLR out- he said it was fine)
To expand a little further, with my Babyface Pro (btw the FS version is almost unchanged from the original - the most noteworthy (and maybe the only noteworthy) changes are: handy-dandy physical gain switch and less-jittery clock) I used a passive preamp, it had both XLR ins and RCA ins, and XLR outs / RCA outs. Connected to it was the previously mentioned amp: never any problems. I'm not saying this because you should expect problems for any reason, just adding anecdotal information that half of XLR will be good connected to any device with input impedance down to ~1k ohm, provided the cable isn't constructed in a way that half isn't shorted (seriously, they make cables like that, so test it after you get it no matter what the box says). To test, put the ohm meter into all xlr pins, making sure you don't read under 1 ohm at any point, being careful not to touch the metal of the XLR end structure while you do so as some of them are conductive very close to the edge of the holes of the pins. If you don't have one, try to complete a circuit using the ground part of the RCA end and the pins - if two of the XLR pins reach the RCA ground, return the cable.
For level, you should leave the level at 0dB in TotalMixFX. You have the ability to go higher by 6dB - that is not room to use except when you've run out of gain elsewhere (ie. the L30 II is on high gain and its knob is up all the way). Since the L30 II has 17dB of gain, you should be able to push a maximum of over 30V into your headphones with RME's master gain at 0dB, playing a song normalized to near 0dB. Not all songs are, but the level at which the song would have to be recorded at for you to not be able to drive your headphones adequately from 0 is lower than any sane person would release. hahaha
The L30 II is an amazing headphone amp, very powerful, very low noise level - even dogs using IEMs in an anechoic chambers are pleased with the 144dB dynamic range
If your headphones of choice are IEMs, you won't need to use the medium or high gain settings ever. Though you probably won't hear any hiss at the medium gain setting, best practice is to turn the amplifier gain to the lowest setting that will provide the level you need, and adjust the volume control from there. It also lowers the risk of hearing damage if your computer freezes when the volume is up for a rare but important reason, and the noise it decides to get stuck on is a 70ms repeating loop of 4.8kHz clipping with a quarter wave of 16Hz underneath (wrecking both your ears and the 'phones)
The L30 II with the Babyface Pro FS should do you very well.
edit: and in the future, if you ever want to upgrade the audio output, its optical output isn't just for studio stuff, it has a SPDIF mode
