Teardown, few basic measurements and personal thoughts of the Focusrite Solo Gen3

[pcdinh]

Oh, good review. Scarlett Solo 3 is quite cheap too. Slightly more expensive than Topping D10

 

[Guillermo Luijk]

Given the rather low maximum output power provided on the headphones-out and the lack of dedicated output buffers, I really think that the headphones are directly driven by the NJM8065 opamps, so sensitive headphones are required for monitoring purposes. I’ve used sensitive AKG K550 closed headphones, in a very quiet environment (quiet bedroom at night with no audio pollution sources) and the volume was very loud to my ears when I got the knob volume over 2 o’clock (couldn’t pass over 2 o’clock, because I can about my hearing). However, when using Audio Technica ATH-20X monitoring headphones the knob volume could be maxed out without feeling that my hearing will get damaged. I also tested the sound with Hifiman HE-560, but I felt like the volume is around 25% then needed, so low indeed, but it was clean and free of audible distortions.

Hi trl, I'm looking for new headphones to have a more linear studio response than that of my Sennheiser Momentum On-Ear. I'm considering the AKG K702, but I wonder if the Scarlett Solo headphone output will be able to drive it properly.

You made a comparison with the AKG K550, which is just a bit more sensitive than the K702, making me thing the K702 could perform nicely with the Scarlett Solo for monitoring purposes without the need of extra amplification. The K702 nearly doubles the K550's impedance but in the end sensitivities are similar and according to measurements (see below), the needed output Vrms levels can be achieved by the Scarlett headphone output (0,331 Vrms to get 94 dB SPL on the K702, while Focusrite claims a max output of 1,734 Vrms as determined by the 5V USB power supply limits). The K702 needs some more Vrms than the K550 but in exchange would need less current and a bit less total power for the same dB SPL (which I think can even be a good thing to prevent distortion).

What seems a contradiction is your experience with the Audio Technica ATH-M20X, because according to the same sources these 51 ohm headphones are more sensitive than the AKG's and very close to my Sennheisser, which I cannot set it passed 12 o'clock because it gets too loud for my ears. The ATH-M20x just needs 0,108 Vrms to generate 94 dB SPL while the K550 needs 0,257 Vrms ???

- Are you sure your source was the same when you turned the knob to the maximum with the ATH-M20X without having a loud output?
- Given the figures above and your experience, do you think the AKG K702 is a good idea to be used on a Scarlett Solo 3rd Gen without extra headphone amp? I'd really love to try it given its highly flat response.

Needless to say that anyone is invited to participate in exposing opinions about using the AKG K702 with the not very capable in terms or output power Scarlett Solo (or any other USB powered Scarlett which I guess have the same limitations).

Regards

 

[trl]

Momentum and K550 are a good match with Solo3.
ATH-M20X is low in power, but ATH-M30X is driven with quite a lot of authority, so no issues with this one (I own both ATH cans and K550).

 

[Monstieur]

What is the headphone output power at 32 or 60 ohms?

 

[trl]

27mW/33Ohms, per https://www.audiosciencereview.com/...rlett-2i2-audio-interface-gen-3-review.10187/.

Headphones output is for monitoring purposes in a quiet studio and with headphones having a sensitivity above average (>95dB/mW SPL).

 

[bennetng]

MIC input with both AIR and Direct Monitor buttons pressed
​

You can easily see the effect of harmonics increase when AIR button is pressed, but also the odd distortions and decrease of output volume caused by the Direct Monitor. Not sure what is causing such kind of effect when Direct Monitor is pressed, but this is usually not pressed while doing recording, so it shouldn't matter much.

You created a feedback loop with both direct monitor and software input engaged, they have different delay and when mixed, created a comb filter effect.

In 2002, Tom's Hardware reviewed a Creative Audigy card with horrible RMAA results. Creative realized it was a feedback loop and contacted the RMAA team with a step-by-step guide to pacify the customers. The guide is still in RMAA's website. Scroll down and find the Audigy1 Setup Guide:
http://audio.rightmark.org/download.shtml

 

[trl]

Thank you for sharing this Creative "Live" particularity, but the AIR effect has been explained on manufacturer's website and it works as expected, as you can see in my posts.

The feedback-loop created by pressing the Direct Monitor button is something to be expected and I don't think there's a way to improve the measurements with this button pressed. The differences in measurements is not so dramatic and I think the Direct Monitor can be used briefly while recording the audio, especially if the recording software is lacking internal software monitoring (very unlikely). I usually use Garage Band or Ableton Live for recording and i prefer to use the internal software monitoring feature.

 

[bennetng]

Just an example of what direct monitoring can do:

I have an ADI-2 DAC and I really love that I can apply the EQ to sound from other devices like game consoles and have have system wide crossfeed from my couputer without using latency and stutter prone virtual loopbacks though a DAW.

Direct monitor is probably not very useful for interfaces with very few (the AIR button?) or no hardware DSP effects. For interfaces with DSP effects, like those from RME, Motu and Creative/EMU cards they are much more useful.

...or take a look at what the kX driver for Creative/EMU cards doing system-wide signal routing/effect processing without using any DAW. You can even write your own DSP module with the built-in code editor, and the effects support MIDI automation.

https://github.com/kxproject/kX-Audio-driver-website/blob/master/screenshots.pdf

 

[maverickronin]

...or take a look at what the kX driver for Creative/EMU cards doing system-wide signal routing/effect processing without using any DAW. You can even write your own DSP module with the built-in code editor, and the effects support MIDI automation.

I think it's been at least a decade since I had a Creative card. Seems like they added a lot more features to the kx drivers since I used them last.

And with the wonder march of "progress" you now have to compile the damn thing yourself. FFS Microsoft...

 

[bennetng]

I think it's been at least a decade since I had a Creative card. Seems like they added a lot more features to the kx drivers since I used them last.

And with the wonder march of "progress" you now have to compile the damn thing yourself. FFS Microsoft...

kX driver was coded by volunteers -- an unofficial driver. However it contains proprietary assets from Creative and it was closed-source. IIRC the lead developers had signed an NDA to obtain those assets. Perhaps the NDA is expired or Creative don't care about it anymore since the driver is only compatible with legacy Creative/EMU cards with the EMU 10kX DSP.

 

[Interference]

Hi @trl, thanks for your review!

Could you please comment on how you did the measurement of the line and instrument inputs? I am reading something near 0.x dBFS but at minimum gain I would not expect the line output to saturate the line input which has a pretty substantial headroom.

And when you say "measurements were done in loopback mode at an output level of 1.145V RMS" you mean open circuit voltage? I would expect the voltage to drop a bit when you drive the microphone input, due to its relatively low impedance.

 

[trl]

Hello,

Could you please comment on how you did the measurement of the line and instrument inputs? I am reading something near 0.x dBFS but at minimum gain I would not expect the line output to saturate the line input which has a pretty substantial headroom.

I am not sure I fully understand the question.
Sweet spot for lowest THD on jack outputs is at around 2 o 'clock, in case this helps.

Hi @trl, thanks for your review!
And when you say "measurements were done in loopback mode at an output level of 1.145V RMS" you mean open circuit voltage? I would expect the voltage to drop a bit when you drive the microphone input, due to its relatively low impedance.

Jack output connected to XLR or jack from the inputs, so the circuit is closed. Voltage is not dropping at all when closing the circuit...or at least I haven't noticed that. I should be able to do measurements for 2V RMS if required, but I guess same Gen3 was recently measured by Amir here: https://www.audiosciencereview.com/...rlett-2i2-audio-interface-gen-3-review.10187/, in case this helps.

This studio interface is good-enough for SOHO audio recordings and also for simple audio measurements as well, even for power amps if placing a resistive divider in front.

 

[Interference]

Thanks for the feedback!

Hello,
I am not sure I fully understand the question.
Sweet spot for lowest THD on jack outputs is at around 2 o 'clock, in case this helps.

This for the output volume or the input gain? In the last two graphs I read (below) -0.2 and -0.4 dBFS so I guess input gain is not at the minimum. I would also expect distortion to be lower if you lower the gain, but at some point noise will take over, worsening the overall THD+N figure.

Jack output connected to XLR or jack from the inputs, so the circuit is closed. Voltage is not dropping at all when closing the circuit...or at least I haven't noticed that.

Mic input is 3 kOhm, line output is 430 Ohm, from the voltage divider you should get a voltage drop of (3000/3430) ~ 0.87 when measuring under load. Line input should not be affected as it has much higher impedance.

I should be able to do measurements for 2V RMS if required, but I guess same Gen3 was recently measured by Amir here: https://www.audiosciencereview.com/...rlett-2i2-audio-interface-gen-3-review.10187/, in case this helps.

This studio interface is good-enough for SOHO audio recordings and also for simple audio measurements as well, even for power amps if placing a resistive divider in front.

Thanks. Yes I was aware of the review, I replied here because I was more interested in seeing the loopback performance, especially if this series can finally replace my E-MU 0404 which is unbeaten by most entry-level interfaces (however it has limited headroom on the line input). I will see if I can score one for cheap and compare the two in my usual test conditions.

 

[trl]

In loopback, 1 minute ago, with 1KHz sinewave, volume knob a bit over 2 o'clock, Foobar playing 1KHz @48KHz from audiocheck.net file, I got the below graph on the right channel:

2.05V RMS
​

The line input impedance is high and will not affect the output voltage coming from the balanced jack outputs in any way. I unscrewd the jack and measured the RMS voltage in real-time and obviously I got the same 2.05V RMS with and without the jack plugged into the Line IN.

 

[Interference]

In loopback, 1 minute ago, with 1KHz sinewave, volume knob a bit over 2 o'clock, Foobar playing 1KHz @48KHz from audiocheck.net file, I got the below graph on the right channel: [...] 2.05V RMS

Thanks, I appreciate the additional info. Then it is not clear to me what does RMS = -0.2 dBFS refer to. One would expect that to be the FS of the ADC, but the specs report a max input level of 22dBu (at minimum gain) and 2.05V are just shy of 8.5 dBu.

The line input impedance is high and will not affect the output voltage coming from the balanced jack outputs in any way. I unscrewd the jack and measured the RMS voltage in real-time and obviously I got the same 2.05V RMS with and without the jack plugged into the Line IN.

This is consistent with what I said before: mic input should have a voltage drop, line input should not.

 

[bennetng]

but the specs report a max input level of 22dBu (at minimum gain)

https://www.audiosciencereview.com/...erface-reviewed-and-measured.9398/post-246906

 

[trl]

Thanks, I appreciate the additional info. Then it is not clear to me what does RMS = -0.2 dBFS refer to. One would expect that to be the FS of the ADC, but the specs report a max input level of 22dBu (at minimum gain) and 2.05V are just shy of 8.5 dBu.

The Full-Scale here is relative to approx. 2.1V RMS and not to Focusrite's actual full-scale. To do that I would need to re-calibrate ARTA accordingly and re-measure again.

 

[Interference]

The Full-Scale here is relative to approx. 2.1V RMS and not to Focusrite's actual full-scale. To do that I would need to re-calibrate ARTA accordingly and re-measure again.

Thanks for the clarification. Nevermind, the scale normalisation can as well be arbitrary as long as it is known. Now I have my answer, thank you

P.S.: according to my measurements, this interface is basically on par with the glorious E-MU 0404. I guess I should go for a Clarett for a reasonable upgrade.

 

[Music1969]

Hi @trl , from the manual it appears the rear line outputs are BOTH balanced and unbalanced?

So with TS-to-RCA cables I can connect direct to my integrated amp?

My integrated amp only has RCA inputs.

From Focusrite Scarlett Solo 3rd Gen Manual:

 

[trl]

I thought it has been already replied: no matter what they state in their datasheet, it is never recommended to connect mono jack in any of the stereo outlets! Hence, I strongly recommend you to only use TRS jacks connected to balanced equipemts (TRS/XLR on the other side, without pins shorted backside or on the PCB).