USB Device For My McIntosh MX123 Processor

I am a long time "Daily" reader and this is my first question to this excellent community of "Music Lovers"! I would really appreciate any thoughts anyone might have on this.

I have been using a “Flash Drive” with an “Extension Cable”, because I don’t want to keep Plugging & Unplugging it from the back of the MX123, because I think I will wear out the USB “Music Port” on the MX123. I do this to add & edit music on the “Flash Drive”, which I do 2-3 times a week. I DON’T HAVE USB 3.0. I NEED A USB 3.0, THAT IS COMPATIBLE WITH 2.0 USB.   I would like to use a 2TB USB Drive (FAT 32) with an “Extension Cable” to the MX123. Will the MX123 supply the power for this HD through the single “USB Music Port”? Is there a preferred USB Hard Drive that will be better for “Music”? It needs to be “FAT32” “Formatted” right off the shelf. Years ago I reformatted a Hard Drive and it corrupted it and it became a very expensive “Brick”.

McIntosh USB Limits & Guidelines

McIntosh cannot not guarantee that all USB memory devices will operate or receive power. When using a portable USB hard disk drive (HDD) which comes with an AC/DC adapter, use that device’s supplied adapter.

“Do not use an extension cable”    I believe all USB HDD have extension cables. Is that the case?

The USB port on the rear panel labeled “Power Supply” can only be used to supply power (5 V/1.5 A). It cannot be used to play music files. (Use the jack labeled “USB” for music.)


USB memory devices will not work via a USB hub.

It is not possible to use this unit by connecting the unit’s USB port to a PC via a USB cable.

Do not use an extension cable when connecting a USB memory device. This may cause radio interference with other devices, or may cause a voltage drop on the 5V supply line.

USB File and Folder Limits (McIntosh Owner’s Manual)

The MX123 can support up to 5,000 files with a maximum of 500 folders and eight directory levels.

Different USB memory devices may have different allowable number of files dependent of capacity and

file size. Memory capacity is 2GB with a FAT16 formatted device and 2TB with FAT32 formatting.

Memory capacity FAT16 : 2 GB, FAT32 : 2 TB  (exFAT is not supported.)

Number of folder directory levels: 8 levels*   Number of folders: 500   Number of files: 5000*

Note 1*: The limited level number includes the root folder.

Note 2*: The allowable number of files may differ according to the USB memory device capacity and the file size.

Note 3: The USB port can only supply 0.5A or less to a USB device.

Only USB memory devices conforming to mass storage class standards can be played on this unit. The audio format types and specifications supported by this unit for playback are as follows………WMA, MP3, WAV, MPEG-4 AAC, FLAC, Apple Lossless & DSD



I’m an IT/Tech guy (day job) so I can tell you that USB 3.0 is definitely backwards compatible with USB 2.0. You may want to try a faster USB drive. There is also USB 3.1 and USB 3.2 available (also backwards compatible) Since you frequently upload new music to the drive, faster storage would make sense.

If you must use an extension cable, I would suggest using a USB female to male cable with a built-in repeater. Best connection is the shortest connection in audio, always. If possible, just plug in the USB to the port on the processor.

I recommend a Samsung portable SSD like the newest T7 models. I’ve used T3, T5, snd T7 and like them all. They come with an 18” USB-A to USB-C cable. If you get a spare A to C cable you can leave the cable plugged into your MX123 while you add more files elsewhere. 

In my experience extensions have never mattered.

Only 2 devices out of 7 have had a .5 TB limit for powering, all you can do is try.

USB 3 only matters on a flash drive for faster loading. 

exFat has always worked identically to FAT32. 

AQ USB A to C cables sound better than generic

I've had multiple SanDisk failures. And their warranty service blows chunks. No problems yet with $87 Leven 2TBs. Silicon Power drives ithave also never failed me.

Thank You very much to all of you for taking the time and giving me this Great Advice. Sharing your “Real Life” knowledge & experiences on these Audio Topics is invaluable! You just can’t get this out of a book! Now, I will have the info I need to find a good USB Device to “Load-Up” my Hi-Res Songs and I am looking forward to it!

“Music Is What Feelings Sound Like”