• mjfe87
  • mjfe87
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Topic: Slew rate and phase response of RME equipment

I noticed the new ADI-2 Pro is praised for its 'high slew rate' and wondered a) how slew is measured and b) are slew specs available for other RME devices including the various Firefaces and Octamic preamps?

Secondly, I've recently been researching the phase response of equipment (i.e. the extent to which two different frequencies are reproduced by a preamp or converter within phase) and wondered if this is ever taken into consideration by RME when designing their units?

I've noticed a lot of expensive American preamp designers cite these sorts of specs and am always surprised they're not mentioned by more mainstream manufacturers.  I'd appreciate people's opinions on whether these parameters matter or not!

Eastwood Records
www.eastwoodrecords.co.uk

mjfe87's Website

2 Reply by MC

  • MC
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Re: Slew rate and phase response of RME equipment

That would be a discussion quickly drifting into personal opinion and better placed in a forum like Gearslutz. Where you most probably already find such threads.

Note that the ADI-2 Pro is not praised for its 'high slew rate'. The marketing text takes over a property of the used op amps:

Selected SoundPlus operational amplifiers maintain highest SNR, lowest THD and high slew rate under all conditions.

Note also that talking about slew rate does not make much sense in most cases. A sufficient slew rate is a given as long as the unit can handle higher audio frequencies without distortion - and the ADI-2 Pro can definitely do that. We do not and never did publish slew specs on any of our units, as mostly the slew rate is limited/fixed by the involved AD and DA conversion. Please Google on theory and how to measure this.

Regards
Matthias Carstens
RME

MC's Website

3 Reply by mjfe87 (edited by mjfe87 2017-04-01 11:47:48)

  • mjfe87
  • mjfe87
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Re: Slew rate and phase response of RME equipment

MC wrote:

That would be a discussion quickly drifting into personal opinion and better placed in a forum like Gearslutz. Where you most probably already find such threads.

Note that the ADI-2 Pro is not praised for its 'high slew rate'. The marketing text takes over a property of the used op amps:

Selected SoundPlus operational amplifiers maintain highest SNR, lowest THD and high slew rate under all conditions.

Note also that talking about slew rate does not make much sense in most cases. A sufficient slew rate is a given as long as the unit can handle higher audio frequencies without distortion - and the ADI-2 Pro can definitely do that. We do not and never did publish slew specs on any of our units, as mostly the slew rate is limited/fixed by the involved AD and DA conversion. Please Google on theory and how to measure this.

Thanks for clarifying Matthias.  Would slew rate not measure how an amplifier handles the onset of two high frequency signals with different amplitudes?

And did you have any thoughts on phase shift?  Or can we assume a flat frequency response implies phase coherence across the spectrum?

I was careful not to post on GS because I'm looking for level-headed answers!

Eastwood Records
www.eastwoodrecords.co.uk

mjfe87's Website

4 Reply by MC

  • MC
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Re: Slew rate and phase response of RME equipment

The phase of the ADI-2 Pro is documented in both the manual (it depends on the selected filter for AD/DA) as well as in the measurements shown  in the German Studio Magazin review that you can download on the left of the ADI-2 Pro webpage.

Regards
Matthias Carstens
RME

MC's Website