MicroSD Memory Card Transport Project

I got my SDTrans384 and have been enjoying sound better than I have ever heard from my system. Thanks and congratulations to Bunpei and Chiaki for this incredible piece of hardware!

A couple of minor issues - when I copied my files onto the SD card, some of my albums play with their tracks scrambled. Has anyone else had this problem? Is there a solution for it? I'm thinking I could copy tracks over one by one in the correct order, but I'm hoping there's something easier.

The other problem is gapless playback. On tracks that should be joined together, there is about a 1 second pause in playback. Is there a cure for this, or is this a limitation of the SDTrans?
 
A couple of minor issues - when I copied my files onto the SD card, some of my albums play with their tracks scrambled. Has anyone else had this problem? Is there a solution for it? I'm thinking I could copy tracks over one by one in the correct order, but I'm hoping there's something easier.

The other problem is gapless playback. On tracks that should be joined together, there is about a 1 second pause in playback. Is there a cure for this, or is this a limitation of the SDTrans?
There is small tool for sorting tracks in correct order - UMMSort. The second approach - combine all tracks in one WAV file. You get gapless playback also.
 
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@seeteeyou,

Thanks for the umssort link. I need to download and use it on some of my folders to get my desired play order.

It's been pretty quiet here for the last year. BUT it looks like there may be another run of SDTrans384 soon... see here:

GB: SDTrans384 - A micro SD card digital transport

A few weeks ago I did a pretty extensive modification to mine. It involved replacing all of the on-board regulators with small LT3045-based boards from ldovr.com. Given that the SDTrans384 has readily available external voltage insertion points, it made this mod pretty easy. Nice upgrade in definition too. Clocks possibly next, I've got some of the higher-quality NDKs from Lorian's group buy. Though I really want to put a Pulsar clock there!

Then the super-tweakers at tirnahifi.org are back on the SD card player train again:

Computer Audio Blasphemy, nige tries Another SD Card Player - Tir Na HiFi

They are working with some SD card players made in China and with some mods have gotten results they are very happy with. A couple of them have SDTrans384 for comparisons (and I have a couple of their SD card players to try)... very curious what will be found comparing them. Expect some mods to their that are wildly beyond what I've done to my SDTrans384 so far!

Also they are looking to use WiFi-enable micro SD card adapters to enable a mobile application to update the files on the card and possibly even operate the player. The former at least could be applicable to our SDTrans. Though they started down thi path with a WiFi-enabled SD card, they've settled on Panasonic industrial SLC cards as the best sounding one they've tried. So they are trying the WiFi-adapter while sticking with the SLC card.

About a year ago I heard from Bunpei that they liked a special Sony card. I've gotten a couple and they are noticeably better than any others I have, though I don't have an extensive collection of various brands. I need to get one of the SLC cards to give it a try.

Here's that Sony card:

Amazon.com: Sony Class10-Adaptive MicroSDXC Card SR-64HXA 64GB: Computers & Accessories

Anyone got anything else interesting to report.

Greg in Mississippi

P.S. A year or so ago, I used a 4-relay remote unit to interface with the external control connection points and give me remote operation. I know you can get a unit from Tachyon, but this was a quick and easy solution and VERY inexpensive! Here's a similar one from Amazon (I got mine from EBay, but that one is no longer listed):

Amazon.com: Buying Choices: MagiDeal 12V 4CH Channel IR Infrared Wireless Remote Control Learning Relay Module 8M
 

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My basic AC supply is a somewhat upgraded K&K Audio 12 watt Low Voltage Power Supply with larger PS caps (United Chemi-Con KYB line) and a few other tricks

My reference supply for my SDTrans384 is a pair of Uptone Audio LPS-1.2 Ultracap supplies with each feeding one side of a Stammheim dual 3||LT3045 power supply with the two sides paralleled at the output. I use the same line of caps on the Stammheim supply. I really haven't spent any time comparing different cap options though. These were what OPC used for his similar dual 4||LT3042 supplies. I got good results with them there, so have stuck with them.

Got any suggestions?

Greg in Mississippi
 
I’ve discovered that the Ps side affects SQ far more then we think.
My regs are by Akko which is suppose to be very low noise & low Z & yet
i’ve made mark improvement by playing with the PS caps.
I’ve also tried the PPSD bypass caps though there’s some improvement,
I can’t really say the sound is really to my liking.
 
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@Julf... Doubtful. Doesn't matter, very audible. I ask you don't insert yourself & your views into conversations where you and they are not wanted. Thanks.

@sumotan, I'm totally with you on the impact of PS quality on the SQ.

Which Acko regs are you using... his latest with what appears to be the LT3045 or the earlier ones with the ADM715x reg chips (which are still very good)?

I have Panasonic PPS film SMD caps at the output C of each power rail on my SDTrans384, but haven't tried to get the copper ones Bunpei & Chaiki like. Are those the ones you're using?

What in the sound is not to your liking? What do you think will move it in that direction?

Just curious.

Greg in Mississippi
 
Here you go Greg. To be honest am not too sure which version are the regs as I bought the shole set from a fellow member her. As it it is there’s 3 regs of 1.2v,2.5v & 3.3 v which is use to power CN 1,5 & 7.
Im getting very good results with the tweaking of main PS caps. Do wonder if somemore improvement can be had if I change those on board 1200 & 470uf caps. Not having the schema doesn’t help matters. What really surprised me was the effect that I got just tweaking the PS caps for the FGA supplies.

Cheers
 

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@sumotan,

John Swenson (who now posts mostly over in Computer Audiophile) has talked about how many of the things we hear in audio are VERY hard to measure. Given his design and engineering chops, I think that adds a lot of credence to that. He's working on a test setup designed to measure the impact of upstream clocks right now... the current big thing over there is using aftermarket clock generators/distributors to feed clock signals to various devices upstream in their computer playback setups. John thinks he can do better... very interested in what he comes up with.

Again, I haven't used the PPS caps recommended by Bunpei. BUT I've used Panasonic, Rubycon, Wima, and another (who's manufacturer I don't remember & can't find right now) and found them useful, but not a silver bullet. Power supply bypasses for DAC analog stages, output stages, & clocks, good. Analog filters, not as much, but better than MLCCs. I still prefer polyprops for filter use. Coupling bypasses in some situations, good, but not all cases. For DAC analog stages & clocks, I'll also use them as the output and reference bypass caps on the reg circuits. BUT as with anything like this, one's mileage will vary... that's why some prefer Delta-Sigma DACs and others R2R DACs.

The regs you have from Acko are his previous model, the AKR75, which uses the (again, still good) ADM715x regulators... I can see the model in the picture and also enough of the reg chip package to ID it. That was what I'd planned to use on my SDTrans384 mod before the LT3042 ones came out. The ADM715x ones are good (that's what Twisted Pear is using in their latest regs for the Buffalo DACs) AND I'm not sure there's a ton of reason to switch.

On changing out the pre-post regulator caps on the board, I am sure that will make a difference... but whether any is a positive or negative diff to one's ears and listening preferences is hard to predict. That takes a lot of time and care to do... instead I'm focusing on things I'm pretty sure will make positive diffs, such as better regs and power supply sources. BUT if you try it and find some you like, I'd be happy to try them out.

I DO find it really important to keep path-lengths short for digital supply final regulators to their consuming devices. That's why I mounted my regs right on the back of the board with a very short link up to each input point. I have plans to try multiple raw DC supplies at some point, but that's low-priority right now. I do that other places... my Soekris DAM1021 DACs are fed from 4 fairly serious separate supplies, each feeding one of the 4 regs on the board (which I also just upgraded, LT3042-based board for the 3.3V clock & FPGA & 1.2V FPGA rails, Sparkos discrete regs for the +-5V shift register supplies... and each is as close to the power consumer as possible).

But back to the SDTrans384, while I replaced the on-board regs (even removed them), I used the power feed that was the input of each to power my add-on regs, to keep things simple. BUT I did it so it'd be easy to disconnect and feed each separately when I try that.

Thanks for sharing!

Greg in Mississippi