Digital Phono Preamp

Very interesting Martin, thanks! What I can’t figure out from the specs is if it has customisable loading/capacitance. It clearly does the RIAA DSP though…

Pretty close to the usual MM numbers of 47 kOhm and 100 pF

The RME Input impedance is 45 kOhm @ 1 kHz and input capacitance is 150 pF

I think that the “it” in this sentence is the RME. The configuration that @meltemi posted is an SUT coupled to the RME. The RME may have adjustable loading/capacitance but in this example is doesn’t matter as it is preceded by the SUT and it is this that which raises voltage to a level suitable for the RME and provides the loading . However loading an MC via an SUT is not the same as loading in an active headamp partly because the voltage gain and loading are interdependent. Further as a practical consideration the result is sonically less sensitive to loading than with MMs. The link below is a lengthy but good explanation. Of course the comments are made with eventual reference to their products but in general the explanation is universally applicable. BTW MC cartridges are not sensitive to capacitance which is mainly of significance with MM pickups.

http://www.rothwellaudioproducts.co.uk/html/mc_step-up_transformers_explai.html

As the RME Input spec is similar to that of a standard MM phono input the SUT preceding it should work well. Most modern MC cartridges have an internal impedance of 10 ohms or lower ( yes , there are exceptions). As many SUTs effectively exhibit an input impedance of 100 ohms this will likely suit a wide range of cartridges insofar as it matters.

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Yes. I get “that” some favor sut to phono pre. I understand that it is just personal preference. What i dont understand is what about it is preferable. Is the sound more dynamic or softer or smoother or rounder or is the difference just a mental preference. Thx. B

Here is a link to measurements of the RIAA function of the RME ADI 2/4 Pro SE:
RME ADI-2/4 Pro SE - RIAA mode measurements | Audio Science Review (ASR) Forum

However, I personally prefer a high-end analog phono pre (including RIAA) together with a professional ADC without RIAA (e.g. dCS 904).

I really find this question difficult to answer. I tend not o listen along those lines - it either sounds “right” or not to me . Further communicating such things seems as if I would be implying that such an experience will result when the different way people hear may mean something else to each individual. For example if I say something sounds smoother ( and I am not), someone else may interpret the sound instead as being “lacking” in some way, say its impulse behaviour. We are all different and do not necessarily react in the same way.

Another issue is that although I happen to use and like transformers I do not consider them as a necessarily superior technique. My choice has been bound by availability and budget and I am sure I could be ecstatic if If as an alternative I could afford the CH phono preamp ( up to 39,500 gbp) :smile:. In general SUTs have a reputation of offering lower S/N ratios but at this level I am sure that units with active gain such as this are fully competitive.

I think that I also need to mention that another aspect is the choice of SUT itself. They are not all of equal status.

Sorry this is all inconclusive. So we’ll settle on:

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This is very helpful Pete, thanks. I have (as you can maybe tell) no experience with SUTs and hadn’t thought through the implications. Your and Martin’s posts have been a real eye opener.

You probably already deduced this but how i describe is much like you. You say “right” and i personally use more real or believable. I used these other descriptives to see if i could pry those types of descriptives from you. Totally get it. I have a john curl phono stage but still listening for more reality. Thx

There’s a 905 for sale currently. DCS dCS 905 ADC - Stereo Analogue to Digital Converter (1302408657) | Gebrauchtgerät | D/A Wandler | Angebot auf audio-markt.de

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If people are interested I will repeat myself from a few weeks back. This ADC has balanced inputs and if it is for digitising vinyl you will need to ensure that your phonostage has balanced out. Further this was a unit designed for the professional studio market and is not plug and play. Please try to familiarise yourself with the user manual to ensure that you are happy that you have the relevant expertise.

Incidentally I attempted to find and post a link to the manual but cannot find the one I looked at earlier. May you have better luck.

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905Menu.pdf (64.7 KB)
905ManualE.pdf (1017.6 KB)
dCS905.pdf (39.8 KB)

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Good points, being a professional unit it has DSD on SDIF-2 and PCM on AES limited to 96 one wire, 192 for dual and DXD only on Quad AES. So caveat emptor as Phil said.