Pro-Ject Pre Box S2 Digital: MQA HW decoding at reasonable cost

[Taz777]

44 minutes ago, RicaNeaga said:

Thanks. After some digging, I found out that in this price range one of the differences is the transformer used - a green chinese made one, a blue Talema (imported to China from the Czech Republic) one (that on ebay is even considered as a direct replacement for the green one by some chinese sellers for a 15$ extra), and probably the best option is the toroidal transformer (like some high end DACs have inside). The Audiophonics seems like a chinese rebrand, with a chinese transformer (green) inside.

 

I think I'm going to buy one with a Talema blue transformer, I don't want to spend extra for the toroidal one, since you consider even the green transformer to produce (in a certain board) an ok result, however I cannot decide on the power needed - there are 15W versions (that are capable of 2.0A / 2.1A) or 25W versions in that price range, that are capable of 3.5A / 4A for the 5V line.

 

Does the Pro-Ject Pre Box S2 Digital benefit somehow from the higher amperage on the 5V line? Probably not, since the default DC included in the box is a 1A one, however I just wanted to be sure. Thanks again  

 

I have a third Chinese-made Talema (blue) 25VA based LPS on the way. Very happy with the two that I already have.

 

The amperage will be fine as long as it equals or exceeds 1A. I would go for the 25VA (25W) one as that will have decent reserves of current. The current capability is what the LPS could provide to the equipment that it powers. It is not necessarily what will be supplied. getting the 25VA one may mean that the LPS runs a bit cooler and you may have options to use it in the future for equipment that needs a bit more power. However, you'll be fine with the 15W one too.

 

Be aware that on eBay, you sometimes have to send a message to the seller immediately after the purchase stating the input voltage you require (e.g. 110V or 230V reflecting the mains voltage in your country) and the output voltage (e.g. 5V, 9V, 15V etc), so read the advert carefully!

 

You may also want to check that you already have the correct cable to connect your DAC to the LPS. Some of the Chinese LPS's that I've seen come with a 5.5m (2.1mm centre) lead that suits DACs like a Topping D50, DX3 Pro, etc.

 

The Pre Box S2D needs a micro-USB at the external 5V power input jack. Check that the LPS has a 5V USB output jack - some don't. If it does then you can use a standard USB A to micro-USB cable. If it doesn't then you'll need to get a cable with the correct connectors on each end (i.e. the correct connector for the LPS 5V output jack and a micro-USB connector for the S2D).

 

One final thing to bear in mind is that the LPS's from the Chinese sellers on eBay rarely come with a mains cable (i.e. am IEC 'kettle' cable power lead). You may have one lying around at home.

 

I bought several of item number 273289214752 and this cable is superb for my Chinese-made LPS's. It's fairly short at 1.5m, soft and flexible, and a good balance in terms of price between a cheap IEC cable expensive 'audiophile' ones.

[Taz777]

15 hours ago, RicaNeaga said:

 

Thanks, although there's an option like this one - MicroUSB to 5.5/2.1mm DC Barrel Jack Adapter - I'm inclined to buy this LPS (79$ toroidal with micro-USB power cable) instead of probably the best one (on the long term, 99$, suitable for any upgrades to any other DAC) and also instead of probably the wisest choice (57$, cheapest talema LPS also with USB).

 

I'm going to think for it another day, maybe you'll have different opinions, and then I'm going to order one of those chinese LPSes.

 

Also, since I have active monitors that are very sensitive to any electrical noise, most likely I'm going to use iDefender3.0 directly linked also to the LPS, so the DAC will be fed only via the USB port (with both data and power), I think this would be the best option, however I'll also test the LPS linked directly to the DAC.

 

In the end, I'm also considering to buy only for testing iPurifier3 (and most likely just return it before 30 days have passed since its acquisition), probably only iDefender would make a day/night difference, but I'm very curious if the sound would  really be ''cleaner'' also with iPurifier (the complete link would be PC - iDefender & LPS - good USB cable - iPurifier - DAC). Hopefully in about a month I'll solve this puzzle and you can be sure I'll write here my findings.

 

Thanks again and feel free to judge those LPSes above  

 

The TeraDak one should be fine - it uses a different transformer depending on your country's mains voltage. I just don't like the way it's put together internally, but that's probably just a cosmetic thing.

 

The Talema one looks good (your 'wisest choice'). It's also usefully has two 5V outputs so makes connectivity a little easier.

 

The Nobsound one is essentially a bench power supply with variable voltage. Might be useful if you want to power DACs with a different inout voltage in the future, but I'd be petrified of accidentally turning the voltage knob and blowing the DAC!

[Taz777]

Question for someone who owns the Pre Box S2D: will it do MQA through the coax input? I know it will do MQA hardware decoding via the USB (computer) input.

[Taz777]

52 minutes ago, left channel said:

 

No it will not, sorry. John says that would have required increasing the size and price, so he decided to decode MQA only via USB. 

 

Okay, thanks. I was toying with the idea of buying one to try out with my Bluesound Node 2i streamer which only has coax digital out.

[Taz777]

2 hours ago, Miska said:

 

But Node2 can do decoding instead?

 

S/PDIF on the S2D is not so great though, so better used through USB only.

 

 

Yes it can but I don't like the analogue audio it produces. I did try again to listen to it a few days ago but connected my Topping D50 back in, as there's a significant improvement in the audio. Hence, I'm currently using the coax digital out on the Node 2i as the input to the D50.

 

The S2D would work with my desktop system via USB with no issues, but I really wanted to try it with my bedside headphones system that uses the Node 2i as a Tidal transport due to the higher quality sound (mainly due to the Amiron Home headphones.

[Taz777]

1 minute ago, Miska said:

 

Doesn't it output the decoded data also through S/PDIF? Or does the S/PDIF go muted when playing MQA?

My D50 external DAC shows 96kHz when I play an MQA track via the Node 2i - suggesting that the Tidal app within the Node 2i is doing the first unfold (as is normal) and sending the resulting bitstream to to my D50 via the coax output.

 

There is a setting for the Node 2i to specify an external MQA DAC. I would imagine if I set that then the Node 2i shouldn't decode anything and send everything out of its output ports (USB, coax and optical). I'd love to try this out but the price point of the S2D is a bit above my 'disposable' budget where I'd be happy to take a hit if it doesn't work out.

[Taz777]

21 hours ago, Miska said:

 

You'll get better quality by using MQA software decoding and using for example sharp filter setting in the DAC. Forget the stupid MQA lights (indicating worst possible quality).

 

 

Hi Miska, could you elaborate on what you mean by a 'sharp filter setting in the DAC' please? On my Topping D50 DACs I have seven filters that could use (after the Tidal app does the first unfold and sends a 88.2/96kHz bitstream to the SAC):

 

1. Apodising fast roll-off filter

2. Minimum phase slow roll-off filter

3. Minimum phase fast roll-off filter

4. Linear phase slow roll-off filter

5. Linear phase fast roll-off filter

6. Brick wall filter

7. Corrected minimum phase fast roll-off filter

 

Which of those would be classed as 'sharp'? Apologies for the off-topic question, but I guess the S2D would also have a similar filters list. I've been listening with filter 5 for months but have recently started using filter 7 which does sounds rather beautiful.