Sonore ultraRendu v1.3

[JohnSwenson]

Since Jesus has said I can give some info on what has changed with the ultraRendu,here goes:

there are foure major changes:

1) bigger size.

This allows some of the other changes to happen. The microRendu was designed very small so it could fit behind a DAC with a solid adapter between them. This was done to get the highest Signal Integrity (SI) at the DAC input. Over the lifetime of the project several companies have been producing some short high quality USB cables which makes the "box behind the DAC" concept not as necessary as before. This lets us use a larger box which allows some improvements to the design.

 

2) much lower jitter clock.

When the microRendu project was started really good clocks were large and expensive so the choice was made to go with with a good but not best available clock. At this point we didn't understand how critical this next step in lower noise clocks was for many USB input DACs.

 

But now VERY low noise clocks are much smaller and less expensive than they were (still not cheap, but significantly less than before) so it was decided it was very important to use these in this design. This is probably the most important improvement over the microRendu.

 

3) replacing switching regulators with ultra low noise linears

In the MicroRendu the ultra low noise regulators were used for the clock, the hub, the USB subcircuit in the processor and and the clocking tree in the processor. But the processor core and the memory chips were run from switching regulators. This was done to cut down on the heat generated. If linear regulators had been used for these high current circuits the small case would not have been able to dissipate the heat and would have been too hot.

 

With the larger case there is enough surface area to support the linear regulators for the processor core and memory chips.

 

4) improved board layout.

With a larger board we have been able to layout the processor subsystem such that the power and ground noise it generates bypasses the clock and hub circuits, significantly decreasing their affect on the output jitter.

 

#3 and #4 together prevent the power and ground noise generated by the operation of the processor from affecting the ultra low noise clock, supplying the USB output with a very low noise clock signature.

 

That is about all I can say for now.

 

John S.

[JohnSwenson]

1 hour ago, mikicasellas said:

 

Most of us are very interested, but i believe i speak for my self and no doubt for so many others that would like to know more clearly about these details in order to be more interested 

The info I presented several posts up is as much as I can do right now.

 

John S.

[JohnSwenson]

36 minutes ago, Confused said:

 

 

 

 

Did you get any further clarification regarding this question.  My apologies if I have missed it!

Because of the change from switching to linear regs the ultraRendu will draw more current than the microRendu. Exactly how much I do not know. Someone that has both is going to have to do that measurement.

 

And to complicate things, it is going to depend on the input voltage.

 

John S.