microRendu and MAC6700 USB input [Resolved -- Added Resync Delay]

Hi all, first-time poster here. I finally have an issue worth posting about, so hopefully someone can shed some light on the problem I’m having.

My 2-channel system consists of a microRendu (v1.3) that feeds USB into a Schiit Gungnir Multibit that feeds balanced analog into a McIntosh MAC6700 receiver, whose amp stage drives my Sonus Faber Olympica III floorstanders. This setup works perfectly fine with Roon, no complaints here. The problem shows up when I have tried to take the Gumby out of the system and feed the USB directly into the MAC6700. Under this configuration, I have difficulty getting Roon to start playing music. I’ll start playing a track and from the Roon interface everything looks fine (Roon sees my mR and the track appears to be playing) but no music comes out of the speakers. In order to get it to play, I have to stop the track, press the skip-back button, and then play again, and then the music flows as it should. From that point, I can then use Roon like usual with no problems… EXCEPT when I change to a track that has a different bitrate or format, and then the same issue occurs.

I thought that I might need to update the firmware on the receiver, so I got in touch with a McIntosh tech and he verified that I’ve already got the most recent firmware installed. I explained my situation to him, and he got back to me with this feedback:

> I looked up the Sonor microredu manual. It looks like it is not allowing the MAC6700 USB section to perform the asynchronous USB audio function. If this is what you want to do you will need a different box that has coax or toslink digital out so you will not need asynchronous function.
> Your MAC6700 DAC’s USB requires a Mac or Win computer with either’s built in driver or the McIntosh driver on the Windows computer.

> I do not know what driver is in the microredu nor is it an Apple or Windows computer that we designed the MAC6700 to communicate with.

It sounds odd to me that the mR would not be communicating properly with the receiver’s USB DAC. Can anyone corroborate this? Is there a reasonable fix for this problem, or should I just get used to the stop-n-start dance if I wish to stick with just the MAC6700’s internal DAC?

Are you rebooting the microRendu and McIntosh when switching up? Think that might be worth a try to sync the USB.

I tried that just now, to no avail. In fact, this time around it took several tries of stop-reset-play the track in order to get it to play.

Is it possible that I may need to get the 2.5 software for the mR in order to fix this? Or maybe send it in for the hardware upgrade?


The reboot was worth a try.

Maybe Jesus (Sonore’s manufactuer) could weigh in on this.

I inadvertently fixed this problem while setting up my new ultraRendu. In Device Setup under Settings for the device, the Resync Delay was at a default setting of 0ms. I changed it to 100ms just to see what would happen, and the issue I was having with the McIntosh receiver playing Roon via USB input is now gone.

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