DPA PDM2 - convert RCA's to BNC's??

[spa317]

I run a PDM2 two box dac with a CEC TL5100 transport, with G&D Transforms clock upgrade. A fellow audio pal says if I were to convert both units from having RCA connections to 75ohm BNC connections, then use a 'true' 75ohm digital cable (obviously terminated with BNC connections also), I would notice a major improvement in performance.

Does this sound a worthwhile upgrade? I was of the (possibly mistaken) opinion that most digital devices have RCA and maybe optical connections (like my DPA), but didnt think many use BNC connections, and that it was becuase there was not much/any difference, but my friend says there is "no way" an RCA can produce a signal as digitally accurate as a BNC connection as RCA will not produce 75ohm digital signal?

Appreciate any thoughts on this one!

[tubenut]

Your friend is right but the implementation of this on a DPA may be harder then some. IE, if you panel mount a BNC and need to use flying leads to hook to the PCB you probaly loose as much as you gain. The BNC needs to be directly mounted to the PCB or hooked up with 75 ohm co ax digital cable (preferably crimped to the bnc, not soldered). If I remember correctly this may not be easy on DPA without drilling as the panel mount rca they use is soldered on to the PCB in a funny way then protrudes through a big hole without contact with chassis....

Also, the BNC ground should not touch the chassis of the units, ie use isolated sockets.

However, with a little care and ingenuity gains can certainly be had.

[martin clark]

Tubenut has it spot-on about the mounting of phonos to PCB in DPA equipment. You'll struggle to find enough clearance to mount chassis-isolated BNCs.

You will not get a 'massive gain' with the changeover to BNC on a PDM2. However - if you really want a mod that does make a heckuva difference, use the Deltran link - so that the local clock in the DAC drives the transport. Either find a DPA transport for sale (and park the CEC - the all-DPA combo will better it) - or modify the transport you have to accept a Deltran clock input. IIRC, Chevin Audio in the UK can help you with this and supply/fit a suitable circuit board.

[spa317]

Thanks for your feedback Guys!
I will try and contact Chevin and find more about a Deltran conversion for the CEC. I actually replaced a DPA transport (using the deltran link to PDM2) with the CEC, and prefer the CEC sound, more analogue and musical to me.

So, hopefully with a deltran link the overall combination will be even better!

Mark