SqueezeBox Duett : a sympatic caps tip

[GaryB]

Gary, did you try the 2 caps lampizator tip near the regulator on the top of the SB wifi PCB ?

I believethe wifi as rj45 are bit accurate and buffered after in SB before traitment with the master local Clock. So it's maybe an internal local ground loop or change in local impedance somewhere in the SB because of PS dispatch when you use WIFI conf ?

Yes, I did add the 2 caps to the wifi regulator.

Regarding the question of why turning off the wifi should be better, I agree with you that it must be related to power supply noise.

After the 74xxx chip I measure the C42 cap : around 75 nF ; r19 is 116 ohms, r38 is 216 ohms : all buzz with spidf output with my "voltmeter".

There is a self already before de spidf output after the resistor and cap : it's L5...

Gary, do you notice a huge difference with your additional self coil ?

Thanks for checking on the exact resistor values. Those numbers make sense since 216||116 = 75 ohms. I think that the right transformer does improve the sound but the size of the improvement is dependent upon the rest of the system. Before investing in a transformer, you can do a simple experiment to see if this type of change will be a big improvement in your system. Just unsolder the inductor L5 and use a small wire to short the SMD pads together. Or you can even leave L5 in place and short it out with a small bit of wire. Doing this is a good improvement in sound already for me but it would be interesting to see what others think.

--Gary

 

[Alabama978]

Yes, you can wire directly from the Duet to the Subbu V3 DAC. Just remove the SPDIF RCA connector and use a good 75 ohm coax to make the connection. I like RG174, a 75 ohm miniature coax cable but any 75 ohm cable would be OK.

---Gary

Gary, I found your post when looking for miniature coax for my Lampizator and DAC project. Just wanted to let you known that RG174 is 50 Ohm and not 75 Ohm. If you have used RG174 I am guessing you are not getting the optimal impedance match.

 

[GaryB]

Gary, I found your post when looking for miniature coax for my Lampizator and DAC project. Just wanted to let you known that RG174 is 50 Ohm and not 75 Ohm. If you have used RG174 I am guessing you are not getting the optimal impedance match.

You are right that I quoted the wrong coax in my earlier post. The correct coax is RG179, which is what I have been using. RG179 is 75ohm impedance.
---Gary

 

[Alabama978]

No problem Gary, just wanted to mention it in case you made a mistake and weren't getting the best performance out of the gear you have 😉