Signal path to main output

[lehasb]

I think there's an error in the signal path to the main output. From my testing and https://www.youtube.com/watch?v=YUucqDjB2GY it seems that inputs 3-4 don't route to the main out, just 1-2. I have no idea how to diagram that properly, but it would be very useful to have it shown when you're trying to figure out the routing.

If anyone can contradict me and explain how it works differently, please feel free to. I'd rather be able to get 3-4 from the main out, and was very confused when I tried to and it didn't work.

This is the only mostly complete diagram that I was able to find, so many thanks for making it in the first place.

[kmitch95120]

Can you clarify what you mean by inputs 3-4? Are you referring to the USB inputs or the XLR input channels on the front of the unit?

[kmitch95120]

Also, can you provide a timestamp for the video referenced?

[bugith]

I think there's an error in the signal path to the main output. From my testing and https://www.youtube.com/watch?v=YUucqDjB2GY it seems that inputs 3-4 don't route to the main out, just 1-2. I have no idea how to diagram that properly, but it would be very useful to have it shown when you're trying to figure out the routing...

Do you feel my update here addresses your question or not ? I'd be glad to check again against your very question and eventually update the drawing so that it's easier to understand.

[EDIT]: whatever, Michael's work clearly shows (small arrows on right and left of the MIX control knob) that all 4 playback channels from computer USB are directly routed to the 4 A/B outputs whatever any switches/knobs settings and are audible as long as there is signal coming from the computer, when only USB 3-4 and nothing else will reach the phone (Monitor A/B switch set to B and Phone volume not 0) and only USB 1-2 may reach (as long as the MIX knob is slightly unstuck from IN end) both the Main outputs (Main Out knob not to Min) and the Phone jack (Monitor A/B switch set to A and Phone volume not 0).
In other words USB 1-2will never reach the Phone in Monitor B position, and USB 3-4 will never reach both Main Out and Phone when in Monitor A position. The only way to get USB 3-4 at Main Out and Phone is to externally patch 3L+4R B outputs to Analog combo 3+4 Inputs and unstick MIX knob out of the PB end.

That said, when it comes to analog inputs, and specifically about IN3-4 accordingly to the last sentence above, you will get IN1-4 at Main Out as long as MIX knob does not stick to PlayBack (PB) position.

Do you see something wrong in what I say? Maybe that doesn't meet your hope to get USB3-4 internally routed to Main Out but this is the way the box is designed. Why they didn't allow to route USB3-4 PB to Main Out is perhaps a business segmentation decision to not offer a too much versatile device at such a sensible price, I can't say.

[kmitch95120]

I find this all very confusing. There is no error in the diagram re: XLR Input 3/4 nor USB 3/4. Adding ADC and DAC blocks to the USB signals in the diagram doesn't change the flow of the signals.

Also, I find the changes you made to the inserts paths to be less clear without the switches. Each insert connector has a switch which is what the diagram was trying to show. Maybe moving the switches closer to the insert TRS connectors would be helpful, but removing the switches doesn't seem helpful.

[bugith]

This is not an electronic schematic diagram. The inserts having a switch inside (like any insert connector, if not the inserted device would be shorted or the route in to out in the host device would be broken when no other device inserted) is stated on the diagram.

You said "it seems that inputs 3-4 don't route to the main out". Where do you see this ?

[kmitch95120]

@bugith Was this for me to answer or was it for someone else?

[bugith]

@kmitch95120 the answer was for you (and anybody reads), but my bad, when answering I thought the comment above was posted by @lehasb : you see that when I say "Where do you see this?". I know you have clear view of the flow.
Yes, you're right that adding ADC/DAC do not change the flow, but this helped me to figure the flows. I thought it could help others when I understood that USB is bidirectional, so to represent this I had to show something in the box that splits send/receive instead of just shorting the 8 wires to the USB jack. Analog to Digital and Digital to Analog say the direction, but again you're right, the arrows are enough to point the way. I just assumed (wrongly?) that anybody understand Digital as the computer side, to DAW & from DAW.
I'm OK the inserts part should be better. When I saw your initial drawing, I found the switches were too far away from jacks and I also wanted to represent that each insert has 2 signal wires. The way I did (2 wires accurately connected to the correct pins of the jacks, plus a text stating tip and ring role) seemed to me the best way ATM. I was surprised that musician friends of mine that have 40+ years long behind playing with audio devices didn't knew that... hmmm one of them, who is a math professor even has problems to figure the conceptual difference between inputs and outputs although my efforts :-)
What about my drawing of analog input section? I hope it addresses the #1 issue by @freixas

Thank you for the job and the idea to post it here. 👍
[EDIT] I just posted a drawing v1.2.2 in my fork that states 48V scope and shows a better (IMO) horizontal Monitor switch that highlights better the different playback flows between 1-2(A) & 3-4(B)

[lehasb]

I was finding an issue with routing XLR 3-4 to the main out, the USB side of the diagram is definitely correct.

Based on what you're saying, my statement is wrong. I'll set up a careful test this weekend to confirm if I missed something in the setup or if maybe my equipment is just faulty.

[bugith]

Your MIX knob must be unstuck from PB end to make sure you can find any XLR Input signal available on Main Out.
Have a nice day.

[kmitch95120]

@lehasb Let us know how it goes. You may have a defective unit. I seem to recall several 2-channel Cirrus sLogic ADCs in that path when I took the cover off. While the MIX knob typcially affects all 4x channels, it could be the circuitry feeding into it.

@bugith I like the horizontal monitor switch as well as the XLR/TRS changes. I'd still like to see a "switch" concept in the insert path so it's clear that it's an either/or function. I don't think the ADC/DAC blocks are necessary in the USB paths, but if you feel they help, we can leave them.

Open a PR if you want to update this repo. I'd suggest calling it 1.3 since there's enough changes.

[bugith]

Thank you for inviting me to your repo kmitch.
I do not know how to create a PR, I can try to learn (hope this is not too difficult), but I'm quite ashamed my .dia file will you show poor skills in Dia editor once you dig in sections I changed from yours. You can check this yourself from my repo. Can I push it as is?

[bugith]

Done. I hope you can control what I pushed because I guess I also sent README.md ... and the wrong (now old according your 1.3 upgrade wish) 1.2.2 .pdf. There is also stuff you may not want in the title block cartridge.

[lehasb]

I forgot to respond to this, sorry, but I did confirm that the issue was with other equipment setup, not with the diagram being inaccurate. I'll close the issue as not needed.