23rd December 2008
Lives for gear
REVIEW: Ploytec GM5 USB Midi Interface
This chip was brought to my attention via the Midibox forums and is produced by a company called Ploytec (Ploytec GmbH . USB Audio and more) out of Germany who produces various midi odds and ends. They also offer the PCB for this project but I opted for the Midibox (tk_gm5_bulkorder [MidiBox.org]) version which has the correct jumper pinout for connecting to a Core module. The uC itself is an Atmel AVR AT90USB162 which is a very high performance 8 bit chip with 16kb of FLASH and a onboard 512b EEPROM. The price of the chip is 4.50 € and the 1x1 pcb is another 3.00 € ($ 10.50 US). Parts from Mouser came to another $12.00. It is worth mentioning that this chip is a TQFP32 package which is a SMD so you will need an appropriate iron to solder this in.
The chip is class compliant so it runs without and drivers under win32/win64/mac/linux but also has a dedicated driver for win32 to overcome the shortcomings of the generic windows midi driver. 5 in/out ports are available per chip and a 5x5 PCB is in the works but for my tests I am only using the 1x1 PCB which was the only thing available at that time.
Test Setup: Vista32, same USB port, same midi cable with a loop back using Miditest 4.6. I run 2 Midiex 8s and also had some other interfaces (my Novation controller and a Midisport 1x1) to test against. For those who don't know how to interpret these results, low numbers and tight groupings are what you want to see.
To summarize that rather long list, the GM5 bests the Midex 8 by about a factor of 2 pretty much down the board and by about a factor of 3 for the midisport. The max deviation is also very impressive with max of 1.67 (!) ms making this the tightest timed midi interface I have used to date. For less than $25, I really dont think it gets any better than this..
Midex 8 with Directmusic Driver: