Pros and cons of upsampling

In the audio industry upsampling is the norm when it comes to converting digital audio to analog (DAC). In this post we are going to examine the advantages and disadvantages, the pros and cons, of upsampling.

Introducing a new up-sample filter: NOS-SRx

Almost 10 years ago I released the Revelation One filter, a serious improvement over Meridian’s apodizing filter (which they are still using today and on which the time correcting aspect of MQA is based). But even my RevOne filter turned out to have some drawbacks. Although it has less issues than Meridian’s apodizing filter, it still has the following issues that all (upsample) filters seem to share:

1) Muddying the lows.
2) Adding artificial spatiality.
3) Changing the tonal quality of the sound (voices, instruments, etc).

Support Revelation One on HD621

I have added support for Revelation One on the HD621. When I released the Revelation One filter (8 years ago) I have also tried to support the HD621, but I could not find the upsample filter in the firmware. Sometime ago I decided to try again, and this time I succeeded!

I (finally!) replaced my Octava switch with the HD621 in my setup, and played for the very first time in 8,5 years with the original Meridian apodizing filter and boy, that sounded bad! Especially compared to the current filter I am playing with …

Additionally, I have also added support for firmware revision v1.07 on the G61R.

Linear power supply for G68

A friend of mine exchanged the standard switching power supply in his G68 for a linear power supply. The result was a nice increase in sound quality. He did not use a standard power supply, but made one himself from standard parts:

• Toroidal transformer 6V 80VA.
• 5V print with LT1083 linear power regulator.
• Toroidal transformer 2x12V 50VA.
• +12V and -12V print with LT1963A/LT3015 linear power regulator.

Using an external DAC on the G68

Although the DACs in the G68 are pretty good, it is almost 20 year old tech and better ones are available nowadays. Or maybe you just prefer a NOS DAC over an oversampling one. But using the digital output on a G68 with an external DAC is normally impossible because the signal is encrypted using MHR. Even setting HS (High Speed) to N (No) will not help, as MHR is also applied on 44.1 and 48 kHz. To come around this problem there are 2 solutions, both with its advantages and disadvantages.

The ultimate audiophile upgrade for any 5V audio component

I know, this is a very bolt statement to make. It is similar to be ‘blown away’ by the sound, or other exaggerated terms to described the audio experience. But I have found a very cheap upgrade, that gives bizarre results. So hear me out, and let me know in the comments if this also works for you.

Concerns about sound quality MQA

Since I have the MQA decoder working with my Logitech Media Server, I have been listening to a selection of albums that I also have in CD format. I noticed 2 things:

1. There are a lot of albums in MQA that have an original sample rate of 44.1 or 48kHz. I counted them in my playlist and 10 out of 19 were not HD, so more than half. This is consistent with findings of others that keep lists of MQA releases on Tidal. Obviously the studio’s are going for quantity over quality.
2. Some albums sound strange, as if there is something wrong with it. The original CD or undecoded MQA file, up-sampled with the RevOne filter in my G68, sounds better and does not exhibit the issue. I have heard this problem before, read also my review and technical analysis of the Meridian Apodizing filter.

MQA decoder for Logitech Media Server

Wow, time is going quickly. It is already 3 years since my last post, and it did definitely not feel that long.

Last year MQA finally took off. In the beginning of 2017 Tidal started streaming MQA under their ‘Masters’ label. Also more hardware manufacturers added MQA decoding to their products. Most interesting was NAD adding support to their BlueSound product line. Already in June 2016 someone experimented with the decoding library of BluOS. A year later Måns Rullgård went further and released software to use this library to decode and render MQA and analyzed the way meta data is hidden in the stream.

MQA – Further explained

Sometimes things are simpler than you think. Also sometimes you have all pieces of the puzzle and you still do not see the big picture. MQA seems to fall into this category.

MQA – What is Meridian hiding?

I have been doing a lot of reading these last few weeks. There is quite some discussion on fora and audio news sites on Meridians latest invention called MQA. But what is MQA exactly and what is Meridian not telling us? This is what we will investigate in this article.

This article is based on info found on fora and audio news site, but mostly on technical descriptions from patents. I have not had the pleasure to listen to MQA myself, so I can not confirm nor refute any claims made on the quality of the sound.