I thought about the iBasso DX50 via USB,but not sure what USB OTG fully means !
1.
Found through Google : http://en.wikipedia.org/wiki/USB_On-The-Go
2.
The short of it : Basically it's a way for an Android(-based) device to interface with another device as a host/controller, the opposite of how some HT receivers and newer cars can function as a host to an Android device and use it as a media storage source. The DX50 uses an Android-based firmware, and its USB sync port was designed to function in OTG mode (with the appropriate adapter).
3.
OTG and USB Audio : Another audio application (actually the first one that was implemented/discovered) was that OTG enabled USB audio on some Android devices, most popularly the Galaxy S3. In some cases it works flawlessly, as the S3 has the software and if it is hooked up to a DAC or DAC-HPamp that powers all of the DAC section on its own (PSU or battery) without taking more power than an Android can supply through USB (fullsize computers do 5v). In the pics below the Android with a 32gb/64gb microSD card functions as a touchscreen music server, sending audio out in digital form to be decoded and later amplified by a circuit designed for hi-fi playback.
4.
iOS, CCK, and USB audio : On iOS devices, a similar trick can be done (actually this was discovered before OTG USB Audio) using the USB adapter Camera Connection Kit.
Quote:
I have a spare ext HD and a couple of vintage amps/speakers and I wondered what I would need to read/view HD FLAC files?
Or is there another way without using a laptop.
Any suggestions would be appreciated
Thanks
5.
Some powered USB hubs allow some Android devices to work with a DAC and HDD simultaneously : There are systems on the Android DACs thread (link to one page below) where they were able to use powered hubs that allowed both sending power to the DAC as well as powering an HDD
and allowing the Android access to its contents. If you own an Android device already, check the list at every page that is a multiple of 5 - DanBa posts a link to Google Docs there with updated info.
http://www.head-fi.org/t/595071/android-phones-and-usb-dacs/4650#post_10536572
6.
Dedicated Music Server : Other solutions would be to set up a music server, which come in two types. First, dedicated music servers, which are essentially the decoding circuits of CDPs but the CD transport is augmented with or totally replaced by an internal HDD and/or connectivity options, like USB ports or in some cases LAN or WLAN. The latter serves two purposes: access to an NAS, and for those with speaker systems and sit far from the player or just have very large libraries, allowing control via a touchscreen (Android or iOS) device, and you can browse the content without going near the player as well as have the same interface as music players on such devices.
Just a few audio servers in the market today:
Aune S1 - SD, USB, and LAN port visible
Marantz' music server - all ports in the rear, including a WiFi antennae; also has decent headphone output, plus USB input for firmware and thumb drives. Basically a Marantz CDP without a CD transport.
Pioneer's, with connectivity options similar to Marantz
The Cocktail Audio X10 has a DVD drive that can rip CDs into its own internal HDD, then look up track tags online if equipped and set-up with the WiFi antennae or LAN connection. It also has a built-in speaker power amplifier, and I've heard it drive lower efficiency Duevel Planets without difficulty at sane volume levels.
One of the music servers by Olive, one of the originals among these products. Can also rip and organize files on its own, and has an internal HDD.
6.
For limited budgets - Android miniPC servers : The problem is that the least expensive among those would cost around $400 ( the X10); the alternative then is to set-up a headless audio server. Originally it was done with a MacMini, but with Android MIniPCs, you can set up one of these to work with another Android device as a display and remote control (ergo, "headless" as no monitor or TV is necessary past the set-up), and has USB ports for storage drives and digital output.
