RME Fireface UC vs SSL 12

[AnalogSteph]

No that is regarding the RME 800/802/UFX line. Ports are not arranged on same channels on all RME devices.

OK, assuming it's an 802, that would still mean mic 11/12 gain of +40 dB = -24 dBu in max. This is not anywhere near line level.

Reading the specs, I have a hunch that the Line 1-8 inputs have only two actual hardware gain settings for +19 dBu ("Lo Gain") or +13 dBu max ("+4 dBu") respectively, with the +2 dBV ("-10 dBV") setting being provided by applying digital gain to the latter post-ADC. The block diagram would seem to support that. This would put these inputs at a substantial disadvantage when handling super low signals. Even when assuming some non-negligible source impedance, the difference still be around 30 dB, at which point the 116 dB(A) dynamic range would have shrunk to a mere 86 dB(A), and worst-case to 80 dB(A). If then your actual peak levels aren't anywhere near fullscale, you could easily end up with a SNR reminiscent of analog media.

In sum, the question remaining is why your synths are so insanely quiet. I can get like 2.5 Vrms (+10 dBu) tops out of my crappy old Yamaha keyboard's headphone out... granted, the noisy power amp in there means it barely makes it into the 80s of dB anyway, but still.

 

[GearNostalgia]

OK, assuming it's an 802, that would still mean mic 11/12 gain of +40 dB = -24 dBu in max. This is not anywhere near line level.

Reading the specs, I have a hunch that the Line 1-8 inputs have only two actual hardware gain settings for +19 dBu ("Lo Gain") or +13 dBu max ("+4 dBu") respectively, with the +2 dBV ("-10 dBV") setting being provided by applying digital gain to the latter post-ADC. The block diagram would seem to support that. This would put these inputs at a substantial disadvantage when handling super low signals. Even when assuming some non-negligible source impedance, the difference still be around 30 dB, at which point the 116 dB(A) dynamic range would have shrunk to a mere 86 dB(A), and worst-case to 80 dB(A). If then your actual peak levels aren't anywhere near fullscale, you could easily end up with a SNR reminiscent of analog media.

In sum, the question remaining is why your synths are so insanely quiet. I can get like 2.5 Vrms (+10 dBu) tops out of my crappy old Yamaha keyboard's headphone out... granted, the noisy power amp in there means it barely makes it into the 80s of dB anyway, but still.

Yes I have wondered the same. I have gotten to the same conclusion that it is weird that I have to crank things up so high to get a good level in. I it the same across my JD990, Nord lead, Emu Morpheus and Roland D550. Gain levels are set to max on all units. If I use headphones jack on any synth with the same headphones I have connected to my RME 802 it will make me go deaf. The difference is so huge. It has been about the same when people have brought in other synths to my studio. Max them up. The mains output out to powered speaker is no problem on the other hand. No need top to turn gain knob on the speakers to more than 2.

You mentioned that you measured the output of your Yamaha. Is there an easy way to measure the outputs?

 

[AnalogSteph]

I it the same across my JD990, Nord lead, Emu Morpheus and Roland D550. Gain levels are set to max on all units. If I use headphones jack on any synth with the same headphones I have connected to my RME 802 it will make me go deaf.

I find it odd that all 4 of them would have the exact same issue. What kind of cables are you using to connect them to the RME? Maybe the issue lies there.

Going by the D-550 service manual, the headphone jack should have an absolute crapton of output. BB PCM54 DAC with an I/V using 2.7k (that's roughly 1.9 Vrms full-scale, I think), -6 dB (at least that's what I assume when alternating the DAC output between both channels), -6 dB, +12.5 dB, volume pot, -10ish dB, ~24 dB on +/-12 V. Will probably go into clipping at ~+18 dBu limited by supplies if digital output goes anywhere near fullscale, so be careful when cranking it. Don't overdo it either way, an M5218 is only like a 4558 opamp and not the last word in slew rate or lack of distortion.
The line-outs (rear jacks UPPER and LOWER, output amp +11 dB fixed) should still be good for roughly 2 Vrms (+8 dBu) tops. Those should plug into the 8-12 INST inputs using 1/4" TS instrument cables (who'd have guessed?) while requiring a relatively modest gain setting of about +23 dB. The headphone jack would need a 1/4" stereo (TRS) to 2x 1/4" TS splitter cable.

 

[GearNostalgia]

Not given cables much thought. Half of the cables are plain Hosa 6,3mm TS cables that I have had since 20 years or so that I had with my analog mixers Spirit/Mackie. I have added a few later on. Some Roland and some cordial.

Your observation about the D550 feels exactly the same as on my other synths. The outputs are way higher on the phones out than what I get from the phones out from the RME. If that is the way it is supposed to be I guess I could perhaps by another headphone amp and connect that to the outputs from the 802. I am considering getting a headphone amp and listen directly the line outs from the synths to compare that with the sound from the RME and see if it sounds the same.

 

[AnalogSteph]

Not given cables much thought. Half of the cables are plain Hosa 6,3mm TS cables that I have had since 20 years or so that I had with my analog mixers Spirit/Mackie.

Those should definitely work with the line output.

Your observation about the D550 feels exactly the same as on my other synths. The outputs are way higher on the phones out than what I get from the phones out from the RME.

There are two volume controls effectively in series for the headphone out, one in TotalMix FX on the digital side and the hardware pot on the front of the device in the analog domain. Since the latter seems hard to miss, have you checked the former? It goes without saying that the input level control (fader) is relevant as well.

I would want to be checking what kind of recording levels you are getting on the digital side, and how loud a software-generated signal of a defined level (let's say -18 dBFS) can be played back. REW is well-suited for this. As long as you only have relative headphone levels to go on, you'll be chasing your tail.

At a maximum of +16.8 dBu (5.36 Vrms) and presumably no excess gain, the output may not be quite as loud as the D550's but shouldn't be a total slouch either. (When using low-impedance headphones, the lower output impedance of 30 ohms may well make up for it.) What kind of cans are you using? There should normally be sufficient output even for 600 ohm K240Ms.

I am considering getting a headphone amp and listen directly the line outs from the synths to compare that with the sound from the RME and see if it sounds the same.

Assuming you need unbalanced connections only, a Topping L30 II should easily do it. Atom Amp 2 as well. 1/4" TS <-> RCA cables are readily available.