Advice : from Allo Boss 1.2 to Pro-Ject Pre Box S2 Digital

Good morning,

I need advice from all of you who are much more experienced than me (I am now approaching this wonderful world)

Currently my setup consists of:

I would like to know in your opinion if it makes sense to switch from my dac to DAC Pro-Ject Pre Box S2 Digital

what do you think?
thank you all!

Although I don’t have experience of either devices mentioned, I had a similar dilemma a couple of years ago when I was seeking to upgrade my IQaudiO Pi-DAC+.

My recommendation is to audition the S2 and other similar priced DACs. You may find there is a marked improvement or you may not. In my situation I found that everything I tried up to £400-500 retail wasn’t an improvement worth the outlay.

In the end, I waited and eventually spent much more on the upgrade … ultimately exposing another weak link in my audio chain.

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Thank you, my only problem is that there are no shops or spaces to listen to these products.
Unfortunately I have to buy and then listen, I have to listen to the advice

I have the Allo Boss DAC original edition and two Pro-Ject Pre Box S2 Digital DACs. I don’t believe there is that much difference in SQ. Go for the Pro-Ject Pre Box S2 Digital if you want MQA. Otherwise I would spend the money on other components.


Plus the Pro-Ject Pre Box S2 Digital has a very nice headphone output, although a bit under powered when using high impedance full size headphones, for example the Sennheiser HD800. However the Pro-Ject Pre Box S2 Digital headphone output sounds great with low impedance headphones, for example the Beyerdynamic T5p or any headphone that can be used with a portable music device, aka smart phone.

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Surely your issue is one of networking. The S2 does not have a network interface and I would definitely not rely on the usb output of the Pi.

You can always order via Amazon and return if you do not like it …

I’m not so sure about this. A lot of us have no problem with the RPi’s USB output. If this doesn’t work for you, there are USB and S/PDIF interface boards for your RPi.

Agreed, Esskay, I’m just pointing out that for some of us the idea of connecting a dac to a Pi usb output is enough to make us run for the hills! All of our experiences and expectations vary. Mine has informed me that jitter problems result from using a Pi usb output.

My Mistake :slight_smile:
I forgot to write a fundamental thing: I want to put the new DAC attached directly to the Nuc;
I would like to permanently remove the raspberry

The usb out of the NUC is also likely to be problematic for SOME. Not everyone notices the problems caused by jitter. I currently have a Pre Box S2 attached directly to a Windows 10 machine. I have a separate mini computer set up as a Roon Rock server. In either case (attaching to the mini computer or the Windows 10 machine) I found that using an iFi Purifier 3 between the usb input on the S2 and the usb cable really did reduce jitter to an extent that I was happy to go without using a network audio adapter (eg my stream box ultra S2 which I use elsewhere in my house). The iFi Purifier comes in at £129 - seemingly pricey but honestly worth it. Your milage may vary - I’m just giving you my experiences which seem identical to your situation.

Thanks guys for your endless support!
So then I got to the point: I will definitely take the Pro-Ject Pre BOX S2 + an iFi Purifier 3.
Question: does the pro-ject have a PRE, can I connect the rcoutputs to my Denon or risk burning something?

Last thing about my Raspberry … I don’t understand a thing about MQA:

1: Set to “Decoder and Render”

2: Seto to “only render”

the question is: does the MQA appear to work?

I wouldn’t recommend buying the Purifier until you’ve heard the S2. I’d argue that it was designed to connect to a PC via USB and as such the input adequately deals with the “noisy” environment. Do you really think Pro-Ject would claim jitter rates of 100 Femtoseconds if this was an issue?

Regarding MQA, yes it is working correctly, but you’ve not set it up correctly in Roon for the Boss. In the settings you specify the DAC capabilities, so for the Boss it is neither decoder nor renderer: Roon will then decode, i.e. perform the first unfolded. For the S2, this should be set to either decoder and renderer or renderer only if you want Roon to decode. This is useful if you want to apply DSP to the MQA stream.

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Thank you,

but what is the difference between my dac and the project if both can run mqa?
Will buying the project feel better the music in mqa or will it be identical?

Your current DAC isn’t MQA capable whereas the S2 has full MQA capabilities. This means it both decodes and renders MQA. The Boss can do neither. Roon is decoder only.

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