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After hearing what the Chord Hugo M-Scaler did for the Qutest DAC when Dave M had them both at my place, I’d been planning to get the M-Scaler to go with my Hugo TT2 DAC. Until I started playing with HQPlayer… For those of you who haven’t been paying attention, the M-Scaler is an upsampling device that goes between your digital source (bridge/endpoint for computer based playback, transport for disc based playback) and your DAC. The M-Scaler then up-samples the music (PCM only I believe) to the highest rate your DAC can handle (or less, if you prefer). I believe the M-Scaler just passes DSD straight through (DaveM?). The M-Scaler uses some sophisticated algorithms to do the up-sampling and dithering, with up to 1 million taps on the digital filter (the digital filters in most DACs have 256 taps).

HQPlayer, on the other hand, is a software package that runs on a PC, and also performs sophisticated up-sampling & dithering. HQPlayer isn’t free, but a suitable PC and the software can be put together for <$1K rather than the $4700 or so a new ($3k or so used) M-Scaler costs. You can test HQPlayer without purchasing a license, the only limitation is that it will only run for 30 minutes at a time with the trial version. That actually made the desktop version essentially unusable on the Mac Mini I’m running Audirvana on as it took more than 30 minutes to scan my music library, and it won’t start scanning where it left off when you restart the program…. Compared the the M-Scaler, HQPlayer fits the DIY ethic a little better HQPlayer has up-sampling options up to at least 2 million taps on the digital filter. HQPlayer also has a few other capabilities which fit right in with computer based playback. HQPlayer can be used as a stand-alone single box music playback system like the one here: viewtopic.php?f=4&t=2057. If you’re going to do up-sampling, you’ll need a more powerful PC than the minimum suggested in that thread… I’ve not tried it that way, so you’re on your own for that solution… HQPlayer can also function as a bridge/endpoint, or as a server feeding music to a bridge/endpoint. It can be used as either a desktop application on Windows/Mac/Linux, or as a dedicated embedded solution on a Linux box with no GUI, which is how I’m using it. Everything I’m going to say about HQPlayer from here on out will be based on the embedded Linux version. One disadvantage of HQPlayer (at least the embedded version) is that it doesn’t talk directly to Tidal/Qobuz etc. I’ll show you how I worked around that shortly.

So, to show you how the pieces all fit together, here’s how my digital data flow looks both before and after the addition of HQPlayer…

W/O HQPlayer:

Music source on a NAS, or from Qobuz → Audirvana on a Mac Mini → Bridge/Endpoint w/mpd & upcmpdcli → USB to the Hugo TT2. If one added the M-Scaler, it would go between the Bridge/Endpoint and the Hugo TT2.

With HQPlayer:

Music source on a NAS, or from Qobuz → Audirvana on a Mac Mini → HQPlayer on a Core i7-8700 based PC → same Bridge/Endpoint as above but with networkaudiod rather than mpd/upmpdcli → USB to the Hugo TT2. By using Audirvana as the music server in this case I get access to all the on-line streaming options that Audirvana supports, and off-loads all the server related processing from the HQPlayer PC.

I haven’t had HQPlayer & an M-Scaler in the system at the same time, but I can tell you that the improvements with HQPlayer are quite similar to the improvements heard with the M-Scaler.

So, a few pros & cons of each….
HQPlayer:

Pros:
• Much lower cost.
• More flexibility. Not only can HQPlayer function as a stand-alone solution or a server solution as mentioned above, but you have a boatload of options for up-sampling algorithm & dithering. It’s quite possible that the best choice in one system may not be the best choice in another system…
• Better integration with non-Chord DACs. The M-Scaler can up-sample to 705.6k/786k, but can only output at that rate over a 2xcoaxial connection. I’m not aware of any non-Chord DACs that can take that as an input. With HQPlayer/networkaudiod you can up sample to 705.6k/768k (at least, the configuration options go all the way up to 1536k, but I don’t know of any DACs that could accept that yet) and output that rate over USB (which is what I’m currently feeding my TT2) so it ought to work with more DACs.
• At least the way I’m using it, one less box in the rack.
• HQPlayer can either up-sample DSD to the highest DSD rate your DAC can handle, or convert it to the highest PCM rate your DAC can handle.

Cons:
• Not a plug-and-play solution, you’ll have to build this yourself (that’s why we’re all here, right?)
• You have a boatload of options for up-sampling algorithm & dithering. I know, this is a pro too. But there are so many possible combinations of up-sampling algorithm & dithering (40 up-sampling algorithms & 10 dithering options) that one could easily end up lost down a rabbit hole trying to decide which one works best…..
• Delay. I’m waiting of the SSD to arrive later today to build the i7-8700 embedded solution, but with 2M taps and up-sampling to 705.6/768k, it took the 4 core VM on the i7-8700 I was running for testing about 6sec for the music to get through the HQPlayer box. Doesn’t matter to me for music, but would be a real problem in an HT environment. The M-Scaler has 0.6sec delay, but there’s a video mode that drops that to a small enough number to work with video (at least according to Chord, not tried personally).

M-Scaler:

Pros:
• Plug and play solution, especially if you have one of the Chord DACs that can handle the 2xcoaxial connection.
• More easily moved from one system to another. Since the M-Scaler goes right before the DAC, you don’t have to get it in the local network if you take it to another house…
• Not enough options to make the obsessive compulsive among us have a seizure

Cons:
• Higher cost.
• No options for up-sampling algorithm or dithering. Probably no upgrade path for a new algorithm in the future, while an update to HQPlayer could easily add more choices.
• I don’t believe the M-Scaler does anything with DSD. Perhaps DaveM can chime in here...

So, there’s another option Now, I just need to get an M-Scaler in the house for some head-to-head comparisons...

Roscoe

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I can explain it to you, but I can’t understand it for you.

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Walt

I am using HQPlayer for the last 6 weeks or so and I am very happy with it. Even though HQPlayer itself is about $250, proper implementation of it could easily cost $2k-$3k.

First let me address your situation. Chord DACs convert DSD input to PCM and then to SDM 6-bit. I found Sync-L filter is the best filter in HQP. It used about 64mil taps as against 1 mil taps of M-Scaler. If you let HQP output PCM to TT2, you should be able to use Sync-L filter without an issue even on sub 1K servers.

In my server, I am using SOtM USB card powered by Sbooster LPS. Recently, we tried my HQP in Charlie's place with his Berkeley DAC. Both Charlie and Jim found the HF extension was rolled off. According to Charlie thats probably due to SOtM card, you need to get JCAT USB XE card (which costs about $1k) to get full resolution out of USB interface.

I am getting Spring 3 which does both PCM and DSD natively in NOS mode. Spring's DSD is supposed to be better, so I spent about $2K building the server with 12-core Ryzen 9 5900x CPU. Unfortunately, it is still not sufficient for converting 44.1 redbook to DSD512 using Sync-L filter. Jussi Laako (owner of HQP) says, I should be able to do it if powerful GPU like RTX3950 is added which costs about $2k by itself.

Because of the hardware limitation, I am planning on not converting the formats, but upscale PCM to 1.5Mhz and DSD to 512, both with Sync-L filters.

You missed on important feature of HQPlayer, Convolution Engine. You can generate room correction filters in software like REW and let HQPlayer apply them in digital domain. HQP being such sophisticated software, I bet it does job than many DDCs.



its not supposed to. Its strictly a Upsampling software. I am using roon to pipe music to HQP.

At least I don't have to get up in the middle of dinner and flip the digital...

Roscoe

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I can explain it to you, but I can’t understand it for you.

Roscoe,

I fully understand and agree with your rationale for using HQPlayer instead of the M-Scalar. I got my M-Scalar before I ran across info on HQPlayer. I had a Chord DAC (Qutest) already at the time and had planned an upgrade (buying Charile's DAVE, or as fall back the TT2 either new or used). I think your approach is what many are doing, so you are in good company.

I am actually not sure what the M-Scalar does with DSD, whether it converts to PCM and upscales, or just passes it thru. I know the DAVE has an option to convert DSD to PCM or play as DSD, but there are no options on the M-Scalar, it is just a black (or silver) box with luminescent jellybeans I got it for 44/16 material however, where it excels.

There is a box that will allow you break out a USB into two BNC for feeding a Chord DAC at 706kHz/758kHz. This is suppose to work better that trying feed high rate USB to a Chord DAC. The link is just a reseller (maker of my dual BNC cables), so you can probably find someone in the US to get it.

https://www.wavehighfidelity.com/storm- ... -convertor

David

The display on the Dave ought to tell you what it's getting from the M-Scaler....



https://audiowise-canada.myshopify.com/products/src-dx I think this is the manufacturer's site. In Canada, don't think there's anyone in the US to buy from...

Roscoe

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I can explain it to you, but I can’t understand it for you.

Roscoe, I'll be curious to hear your impressions when you can get the M-Scaler in the system at the same time as HQP to compare. Adding an inexpensive PC to the audio stream tends to just introduce noise (veiled presentation).

We heard other issues at Charlie's besides just HF softening. It was a general (slightly) downgrading of Charlie's system (transients, soundstage). Shashi speculated the Berkeley dacs may also be upsampling with software and HQP on top had no advantage. Perhaps it works best with non-oversampling dacs? I'll be curious to hear Shashi's setup when it's all dialed in but I think he's going to have $2-3k tied up in it?

Another reason can be the voltage of LPS uses. SOtM specified external voltage range from 6.5 to 9V. Charlie used it 7V where as I am using 9V. No way to be sure unless we compare both voltages.

Yes, external DDCs like HQP work best when the DAC is in NOS mode.

There is too much echo in my room. In the next 3-4 weeks, I will be adding another 8 absorbers to the 4 Already there.

The Chord TT2 does DSD up to DSD512. If you use a Windows based PC you can send the Chord TT2 native DSD via its USB type B input. A driver download to your computer is necessary for native DSD using a Windows PC. Without this driver or if using Linux computer the DSD is passed through as DSD over PCM (DoP). DSD (DoP) is not conversion to conventional PCM. It only puts the DSD into a PCM shell. The DSD itself is untouched, and once it is accepted at the input, the PCM shell is “stripped” and the untouched DSD is processed just like any other DSD.

We are talking about internal processing, not transport protocol.
Chord does not process 1-bit DSD.
1-bit DSD is converted to PCM which is again converted to 6-bit DSD to process.