ART DI/O

Bill's Audio Cave

The word spread through the audiophile community during the summer of 2001 about the little Art DI/O, the little processor that could. Available for as little as $120, the DI/O is an D/A AND AD processor. It can handle digital signals from 44Mhz/16Bit to 96Mhz/24Bit. It's A/D section features a tubed output stage that can be used to add "warmness" to the digitized sounds.

Out of the box, the DI/O has embarassed some very expensive "high end" DAC's. Originally intended for the professional market, the DI/O has been siezed upon by a group of audiphiles and tweaked beyond recognition. There are a number of web sites and a discussion group devoted to the DI/O. With some relatively easy tweaks, the DI/O can become a top-notch DAC.

Among the many possible mods, I've only done the more basic ones but they totally transform the basic DI/O into something very special. The sound lacks much of the digital artifact and glare usually associated with low cost digital gear. This thing, paired with an inexpensive Pioneer DV-343 DVD player as a transport gives my Classe' CDP-1 (3.5K) a real run for its money. I'm impressed.

The mods I've completed to date include:

Replacing the diodes in the power supply with Shottkey's

Replacing all the capacitors with higher-value Panasonic FC's

Replacing the power transformer with a Stancor 3A unit

Replacing the TL-074 OP amps with National LT1362CN's

The output of the DI/O is 7V so that it works with the pro gear it was designed for. In order to use this unit with regualr audio gear the output voltage must be stepped down to about 2V. Jon Risch calculated the values required for a volatage divider to do this (see http://www.AudioAsylum.com/audio/digital/messages/25431.html The analogue outputs of the DI/O are 1/4" phono plugs and the resistors can be built inot the body of a phono plug. However, Jon also noted that the sound was better if the voltage divider was on the distal end of the analogue cable where it plugged into the preamp.

I have built both types of output cable for my DI/O. The first one used a phone plug from Radio Shack with the resistor network built into the phono plug. My better cable is a Jon Risch twisted pair (89259/89248) with the resistor network built into the RCA plug that goes to the preamp. The pictures below show the construction of the network so that it will fit into the body of a Cardas SLVR RCA plug.This cable is available from Wayne at Bolder Cables Wayne also offers a variety fo first-class DI/O mods for those who are not able to DIY.

I would be remiss if I didn't thank Wayne at Bolder and Craig Fraser for their helpful suggestions along the way.

Art DI/O Analogue Phono Plug and Voltage Divider Circuit. Click To Enlarge

Here's the voltage divider built into a Phono Plug from Radio Shack. The resistor values are those commonly avialable at Radio Shack. For what it cost, this plug and cheap resistors sounded pretty good when connected to a length of Belden 89259 cable. It is, however bested by the twisted pair design with Dale reistors in the voltage divider, shown below.

Steps to Make a DI/O Analogue Cable with a Voltage Divider in the RCA Plug. Click to Enlarge

Pictured here are the steps involved in making an analogue cable with the voltage divider in the RCA plug. For this to work, you need an RCA plug with a large-diameter body. The one pictured here is a Cardas SLVR. Click on Photo to Enlarge

For much more useful information about modding the DI/O, be sure to visit the sites linked below. Craig Fraser's site in particular has a wealth of infomtion about mods for the DI/O, from the simple to a complete rebuild. The DI/O discussion group on Yahoo is also a source of discussion as well as circuit diagrams and other useful information. Check it out!

Craig Fraser's DI/O FAQ

DI/O Discussion Group at Yahoo

Peak's History of the DI/O, Including the Volks Mods