Reclocking the Behringer DCX2496

Reclocking the DCX2496

Easy installation and sound improvement are the keywords for this high precision clock

As you may already know, replacing the internal clock of the DCX2496 brings more clarity to the sound due to reduction of the dreaded jitter. I had done such a surgery in my own DCX one year ago and a noticeable improvement could be noticed with the Tentlabs XO2 clock : accuracy, transparency and liquidity of the sound were definitely better. Maybe a short reminder of the situation would be profitable to the ones who never minded about that mysterious phenomenon. If you get really passionate about jitter (why not ?) you may want to read this document . I strongly advise you to ingest some aspirin and take a deep breath before starting but believe me, it's worth reading.

Lets get back to the DCX2496 : Selectronic has designed and developed a high-precision clock for the Behringer.

It has many advantages compared to what's available on the market, just to name a few : easy installation, low price, very high precision, optimized and easy implementation. Here I have to remind you that jitter isn't inherent only to the clock itself but has also a lot to do with wiring, location, power supply and other parameters (read again and again the above links). Lets check the main specifications of this high precision clock :

a low-noise integrated power supply.
ultra low jitter rate, temperature compensated clock.
very easy installation : I have installed three XO2s in friends DCXs and I wouldn't like to install one more because of those nasty SMDs. Just to take an example, withe the Selectronic's it's enough to ground C77 to block the original oscillator without having to remove it from the board. Just for the thrill, please compare easiness of installation to this document
optimized circuitry for greater jitter reduction : long wire runs are avoided, Selectronic uses very elegantly the onboard clock divider to obtain F2 (24.576MhZ / 2 = 12.588MHz) by injecting the clock signal on IC 3004's pin 51 (this IC holds an integrated divider by two) and puts out a perfectly halved signal on pin 47. Why bother with generating 1/2 clock frequency outboard with the rik of polluting it with noise ?
low price :49 euros TTC ! (kits are aloso avaliable with 8,4672 MHz, 16,9344 MHz et 33,8688 MHz frequencies for your CD player or any other digital device)

the clock installation is like a kid's game, just have a glance at the pictures below. The kit holds it's own power supply.

1) Cautiously remove R34 and C77 .

BEFORE...

...AFTER

Okay, it may be tricky to spot the difference, let me help you a bit :

2) Solder the inner wire of the coaxial (clock signal) onto R34 exit pad (see photo) - This is the link towards IC19a's CLK24 / 51 pin. Don't worry, the kit contains it's own R34 resistor for continued protection.

3) To inhibate original oscillator's functionning and avoid the noise it may generate, the coaxial shielding braid shall be soldered between ex-C77 pads. Easy isn't it ? It is advisable to secure the cable to the PCB using a small dab of suitable glue to avoid tearing off C77's pads as soon as cable moves a bit.

4) 12VDC power supply should be drawn from the DACs linear power supply board. For those who haven't installed it I strongly recommend to buy one. If not, a separate 12VDC PS may be installed in the DCX or taken from the +8V pin on X3 connector.

5) Finally install the new card on the DCX's power supply shielding, there's plenty of room there !