As long as only one type of signal (DSD or PCM) is connected there is no need for any sort of switch. :)

If the same source puts out both DSD and PCM from the same outputs then you will have no issues at all.

What that means practically is that if the signals are driven from different sources, you likely *do* need the OTTO-II - because you do want to accidentally drive one signal with another. For instance on source trying to drive a line low while another tries to drive it high. That's a short. :)

So the otto-II acts to switch between two inputs, and thus isolate them from each other.

In short one output should never be connected to another unless both outputs can be made a high impedance when the other is active.

Hi Russ,
After installing OttoII, DSD signals give rock-steady lock, but I2S (coming from vortexbox via USB2 to WaveIO) is not stable anymore: a lot of unlocks per minute. The only thing I changed was the position of the USB input on the source Switch. F.I.: pos.1= Toslink1, pos.2=Toslink2, pos.3= Coaxial, pos.4= USB.
I soldered the trigger for the sidecar on pos. USB where it logically has to be. When I've build the DAC a year ago, I removed the coaxial input and used that position to switch the sidecar in order to get a stable lock, but i did not remember anymore why I did that. After a little mind searching I remembered the way I solved the problem of the DAC not syncing solidly with I2S.
After resoldering the sidecar trigger to pos.3 all signals give rock-solid lock.
But I still have no hunch why this can happen.

Results becoming obvious after a few hours listening:

1. SACD's have gotten a new dimension: music is flowing in a very analog but very precise way.
2. I've seen some complaints in this forum sound quality, after placing OttoII, is clearly decreased. This in in my humble opinion absolutely not true. On the contrary, I have the distinct impression precision and liveliness of music has increased. Especially I2S seems to profit from the addition of OTTOII (maybe better isolation between sources?)
Short: I'm very pleased with the results .
Thank you Russ and Brian for the great help and advice you offer when things go wrong.
Kind regards,
Henri

I like to do so, but my knowledge of digital is not quite up to date and certainly insufficient to do a reasonable discussion about it.
Now that I think of it: I'm puzzled by the fact position 3 of the switch module gives a stable lock for DSD or I2S signals while position 4 doesn't.
Do you know why?
ps.: I've listened now for a longer time and there definitely is an increase in sound quality . Imaging is better, music is more fluent and ambient atmosphere is more perceivable.
Thanks for the excellent product.

Edited by user Friday, February 8, 2013 4:59:46 PM(UTC)  | Reason: Not specified

To the best of my knowledge, there has been one such statement.

It may have nothing to do at all, unless the relay in not engaging fully. :) Was just a theory.

It could have something to do with the PCM/SPDIF detection on the DAC. I am as curious as you, as I can't replicate.

Cheers!
Russ

I fully agree. Sound quality is excellent and is even increased after placing the OttoII in BIII. I can not explain it technically, but I sure can hear it.