• Registered: 2010-05-01
  • Posts: 24

Topic: RME ADI-2 DAC FS (AKM version) - turn on/off transient?

Hi there,

I've been measuring my ADI-2 DAC FS (AKM version) output stages (headphones TRS + XLR outs) yesterday just to find out the differences between the stock SMPS and an 12V LiFePo4 battery as power sources. As ADC, I used my RME Babyface Pro. To my surprise and definitely, as a testament to RME engineering, there's absolutely zero difference in noise spectrum / THD measurements. That's very good info and proves that stock SMPS is very good - you definitely don't need a battery.

But what I have found out instead, to my surprise, that either the headphones TRS socket or XLR outs emit a very small turn on/off transients which result in barely audible pops/clicks upon ADI startup/shutdown. I have first noticed with my headphones and now I notice it via my KH120s.

I don't remember these pops/clicks were there, but I may just have un-noticed them in the past.

So the obvious questions - "were" these turn on/off transients always there and is this the normal, stock operation of ADI-2 DAC FS or it definitely shouldn't be there?

(To be honest, I have overloaded the headphone output stage during the measurements several times with 1kHz sine wave, but according to the manual, this shouldn't cause any harm to it. It also wasn't a full scale 0dB sine either).

Thanks in advance for explanation.

  • From: Norway
  • Registered: 2021-06-21
  • Posts: 396

Re: RME ADI-2 DAC FS (AKM version) - turn on/off transient?

Good news. I always had a wet dream for battery drive. Now I dont have to pay for and pretend that it actually sounds better

Most electronics do some artifacts when they power up the systems and saturates the circuits. I think RME is quite good at this. Like you said, measurable, but barely audible. It doesnt pop your tweeters or eardums out.

ADI-2 DAC, ADI-2 PRO, DigifaceUSB, UCXII, ARC, HEGEL.h80, KEF.ls50, HD650, ie400pro _,.\''/.,_
  • Registered: 2010-05-01
  • Posts: 24

Re: RME ADI-2 DAC FS (AKM version) - turn on/off transient?

Happy_amateur wrote:

Good news. I always had a wet dream for battery drive. Now I dont have to pay for and pretend that it actually sounds better

I will not go off-topic, but I'm also not saying that battery won't help in some issues - you may go for it (or a medical-grade SMPS which is cheaper) in ADI-2 if you're experiencing leakage currents with planar magnetic headphones (I did experience it with my LCD-X, solved this with a medical grade 3-prong SMPS with ultra low leakage current), so I definitely see a value there. However, battery alone will not improve sound quality in ADI-2 DAC in any way, confirmed. Obviously it's an option when you're remotely doing stuff and don't have access to A/C power.

Happy_amateur wrote:

Most electronics do some artifacts when they power up the systems and saturates the circuits. I think RME is quite good at this. Like you said, measurable, but barely audible. It doesnt pop your tweeters or eardums out.

It could also have been that my standard turn on-off routine until yesterday was, when powering on - turn on ADI-2 DAC first (muted), insert headphones or turn on active monitors, unmute and play. Vice versa, turn off playback, mute ADI-2, turn off active monitors or remove headphones from the TRS socket, and finally turn off ADI-2 as the very last thing. So this way I've never got the chance to experience the barely audible pops/clicks.
I've also searched extensively on this forum and found a post (https://forum.rme-audio.de/viewtopic.ph … 07#p145507) from 2019 where some ADI-2 user experienced pops on turn on-off sequence and his dealer told him it's normal.

So I guess, but would be great if RME confirms too - this is the the stock/standard operation here.

  • From: Norway
  • Registered: 2021-06-21
  • Posts: 396

Re: RME ADI-2 DAC FS (AKM version) - turn on/off transient?

I didnt mean to say it was an unjust question. Only that I think you are in good hands here. You have lots of layers of security to your MO, mute turn off etc. I feel more confident to this. Then again I dont have active monitors. Im careful with my expensive IEMs and the PRO though. Ill have a similar routine to yours for those.

ADI-2 DAC, ADI-2 PRO, DigifaceUSB, UCXII, ARC, HEGEL.h80, KEF.ls50, HD650, ie400pro _,.\''/.,_