Yay! New toy

[Tony Moore]

Right, well, after a (for me) long time of not making any pcbs and soldering SMD I am back in the saddle.

I have all the parts to build an entirely new RTZ DAC including case so I thought, why not? I want to attempt to build on what I've learned from the previous two and improve on the power supply type and layout in the case. Much of what I did for the previous two DACs was constrained by the fact that I was using the PCM2DSD module as the link between the jlSounds I2SoverUSB in a direct physical layout. Now that I have the reclocker board with it's u.fl co-ax cables to the RTZ DAC main board then this no longer applies so a more logical layout can be achieved.

In addition, several people who I trust a lot with this stuff, think that the TI TPS7xxx regulator is better for audio and digital audio than the LT3045 which I have tended to use so far.

So I have got a couple of pcb designs on the way from JLC for LM78xx pin-compatible daughter boards with two variants , 5v and 15v. I have also designed a small "power hat" pcb that will sit above the RTZ DAC mainboard and hold the three daughter boards for the supply there. The other 5v supplies and the DC feed for the regs on the hat will be provided on a single separate pcb with the Block and Myrra transformers mounted. This should cut down on space requirements and also remove the need for much of the interconnecting wires.





I will report back once I have the new pcbs and have had chance to see if they fit/work and in my next assembly of the mk3 DAC.

[Tony Moore]

Another piece of news is that I now have a v17 updated reclocker designed which has a couple of extra features that would make it more widely useful to those people who have PCM DACs.

In a nutshell, the v15 reclocker was specifically designed to interconnect jlSounds I2SoverUSB, through PCM2DSD and to provide XO sockets and reclocking to the output DSD signals to the RTZ DAC.

The addition in v17 is allow the reclocker to be used with PCM (I2S) DACs. This change is to also have optional u.fl connections directly from the outputs of the I2SoverUSB so that those (I2S) outputs can be routed to the reclocker registers using co-ax links (there are already u.fl sockets on v15 since that was intended to allow the user to split the board in two and move the "dirty" devices (ie I2SoverUSB and PCM2DSD) away from the XOs physically.

Also on the new board is an extra reclocking channel so that DAC that require split L/R data lines can be accommodated. (Also some extra logic to provide an optional delay if required)

So with a PCM DAC the I2SoverUSB would be used to provide the I2S signals but the clocks would be XOs mounted on the reclocker and the BCLK, WCLK, and 1 or 2 data lines would be synched to the 22/24Mhz.

I have some of these boards on order from JLC. If anyone is interested please speak up!

[Tony Moore]

OK, pcbs arrived and one 15v module built:



It works! So now to the even tinier 5v module...

[Tony Moore]

[Tony Moore]

Assembled on old wine box!



Just need to get it working now. Some problem with reclocker I think...

Some systematic fault tracing tomorrow.