Besides the ES9038 + Amanero DAC that I’m using for the discrete op-amp showdown review; I am also planning to give reviews on a handful of popular DAC accessories. Most of these are intended to improve sound quality and some of secondary functions they also provide to the circuit/s.
For Part 1 of this I am just going to list all the accessories and give information on them and link to where you can find one similar. Here is the list of DAC accessory hardware that will be tested:
This is a dedicated TCXO clock module that currently has a 100 MHz TCXO unit by JYEC installed. This unit can give you the signal in 3 ways simultaneously: MCK, MCK/2 and MCK/4. so you could provide a 100 MHz, 50 MHz, and 25 MHz signals all from this unit at the same time. You can read more about this module here!
This is one of the more controversial modules as it claims to increase SPDIF signal fidelity through means that are not 100% grounded in engineering/circuit design. I have read in multiple text books that just inserting the right frequency and amplitude of “noise” can actually increase fidelity based on listening, not measurements. This is the one I am most interested in putting through its paces. Read more about it here!
On the left we have a simple I2S 2-Way switch or it can be used a buffer too (one wire in and one wire out). These are very affordable and can make a headache into a simple solution if you have two I2S devices with only one I2S input on your DAC! Read more here!
On the right we have a USB Isolator that uses magnetic coupling to separate the power in from the PC from the device on the opposite end. These are seen all over Ebay and range anywhere from $10-$15 for this model up to $200 for the top end models on Ebay. The main difference is that this module can only do Full Speed USB, not High Speed USB (like most DACs use). I am trying to figure out a way to turn two of these units into a high speed USB isolator, but haven’t had the time really to work on this guy by itself yet. Read more about it here!
Here we have two devices that offer more ways to convert digital from micro USB straight to I2S using the PCM2706 DAC by Burr-Brown. Read more about the OTG to I2S DAC here!
Or the UDA1380 dev board allows you do a lot of things!! This will allow you to convert analog audio recorded by the device directly into I2S! You can also use the Line-In jack to convert any device by a 3.5mm jack directly into I2S. This board can handle the reverse direction also! So you can input I2S and output either by the headphone jack or the line-out. So this little guy gives us a lot of flexibility with how to get into or out of the I2S interface. Read more about it here!
This doesn’t really fit in with the rest of the accessories, but I’d still call this a possible accessory for some so I wanted to include. I made a mistake on this purchase, but I am still keeping it until I figure out a good use for it. I could try this with the XLR outputs of the DAC and see if it sounds better or worse with this board converting to RCA or if the DAC sounds better out of RCA on its own. Read more here!
Here is the most flexible of the I2S related accessories. This allows you to take in up to 4 signals in optical or coax and output them in I2S. The unit uses multiple WM8804 chips to accomplish this. You can also find the reverse of this board, take I2S and turn it into SPDIF. Read more about it here!
Lastly we have a simple 4.2 Bluetooth module with APT-X support. I have another one that takes I2S directly, while this one uses line in. I will make a decision on which one to use after I see how difficult it is to tap into a line in on the DAC. Read more here!