Exactly!
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As the Line Out is made for this I agree but I doubt the ground lift is necessary with just the DAI connected.
I am doubtful there will be an audible difference but can’t say for sure. As I do own the same amp and don’t have a XLR cable myself - @PamPurrs please give feedback once the order arrives and you had opportunity to test it.
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I ordered this, it’ll be here Tuesday. I’ll let you know if I can detect a difference.
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Did some more research and changed my mind.
I somehow missed the cab sim there. Should sound better/closer to what you are used to from the amp just like @Marcel said.
Also found this for the Rumble in the user manual. It might seem very technical but it helped me a lot to understand the order in which things happen internally:
I still don’t get why the Effect Return Input doesn’t work to return the signal after adding in the other parts with the DAI.
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As an aside in the spirit of technical accuracy, XLR connectors are used In pro audio because they lock into place and they accommodate three wires to drive balanced inputs, which increases noise rejection.
The signals on an XLR connector are positive, negative and ground. When the negative signal arrives at the input the negative signal gets flipped upside down and added to the positive signal. For the bass sound this results in a 6dB boost to the signal. For noise that the cable picks up on the way, however, when the noise gets flipped upside down and added to itself it always adds to 0 and goes away.
The signal level is driven on XLR balanced lines typically at a nice hot +4 dBu nominal while unbalanced connections are usually driven by the circuit at -10 dBV consumer levels. This gives a better signal to noise ratio right out of the gate.
Line level audio either on an unbalanced line or a balanced line doesn’t lose much level over distance, unless it’s longer than most people ever use. It’s a different situation than instrument cables.
As @howard points out the balanced signal allows an opportunity to lift the ground to eliminate ground loop problems. This can’t always work as easily with an unbalanced signal because with 2 wires, lifting one leaves you with no ground reference and a floating signal may not drive anything. With a balanced signal the positive is referenced against the negative, so the signal still gets through even if the ground floats at one end.
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You’d be surprised.
Ground loops can happen any time there are multiple paths to ground. There only need to be two paths to ground for this to happen. When using a DAI, there are often at least two (the DAI through its power supply if it is plugged in, and over USB’s ground to the computer through its grounding) and in many cases three or more (Pam would have at least two and maybe three, depending on if her DAI is plugged in or USB bus powered. I recommend plugged in BTW).
I cannot use my DAI without a ground lift because between my pedalboard PSU, my computer PSU, and my DAI, I have a ground loop that produces noise. But all it would take is two of those components to potentially have a noisy ground loop.
Note that these can occur by simply changing which outlets things are plugged in to.
tl;dr, Ground Lift is critical in cases where it turns out you need it 
XLR will have better sound S/N ratio qualities than 1/4" for other reasons as well but that’s a different topic. Dave touched on that. I strongly doubt it will be noticeable on a short cable. The cab sim on the DI, on the other hand, that’s pure gold
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It’s because the only purpose of that cab sim is to dirty up the signal on the DI a bit and make it sound more natural or better. Whereas for the effects loop you want it to be a pure signal because you may be doing your own cab sim or other things in the loop.
Look at it this way. The signal from the effects loop after return is going to one of two places - either back out the DI, or through the real cab.
A cab sim on the DI is a very nice feature by the way.
Personally I probably wouldn’t use the effects loop much myself. The reason it exists at all is to provide a place to put effects that you want after the amp’s preamp. You can put all the effects you want in front of the preamp very easily, of course, but there is no other way to get a post-preamp without the effects loop.
Personally there are only a few things I would ever see myself putting there and I doubt I would use it much at all. But it would be a good place to put modulations (like chorus) that you want to have effect the amp preamp too, and it would be a good place to put reverb (which I like to put absolutely last). Additional amp/cab sims would work well there too.
But to me, it’s the least important “additional” feature for an amp. I really doubt I would use it much.
Then again, I have three preamps in my chain before the amp on a normal day
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Ooh, it has one on the headphone out too, that’s just really nice of them.
Cab sims make direct signals sound so much better. Less flat, more natural.
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You will I run the XLR straight into my mixing deck
Sound is much better, for reasons already pointed out here.
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I understand why one should use the Line out by now.
I don’t understand why according to @PamPurrs the FX return input does not work to add in the other instruments with the DAI. As its purpose is to modulate the signal after preamp and before cab sim I don’t understand why the returned signal with added instruments from the DAI does not work at all.
As I understand the drawing I posted the signal should get modulated and returned.
What am I missing/misunderstanding?
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Ahh, I see what you’re asking, sorry. I misunderstood.
So, if the signal coming in to the effect return is not being played through her amp but the same signal works through Aux In, I can think of two possibilities - either the effect loop is switched off (sometimes there is a switch/footswitch for it as shown in the schematic) or maybe she has a bad effect return jack.
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Thanks for the answer. However… My thirst for knowledge/understanding is still not satisfied, because…
As is indicated in the schematic and also described in the manual: The footswitch is for the internal overdrive that you can also activate on the amp.
As for the faulty cable: I just assumed Pam would have used an adapter for the aux-in with the same cable.
Just to make sure: So it should work but it might be possible the FX is turned off somehow or the cable is defect.
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@DaveT Once again thanks for that thorough explanation and your immeasurable patience explaining all this stuff here as I understand your explanations better than anything I find online (including music forums). Often what I read online it confuses me even more.
Still got a question though.
The Effects Send is specified as balanced output with 1db impedance in the manual. So it can be a balanced output with an 1/4" jack and has the same positive effect?
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I’ve ordered the XLR cable, and it should be here tomorrow. I’ll give the XLR out a try.
Meanwhile…
This is my current setup (see photo)
My bass is plugged into the pedal board, and from there to the input of the amp. The Effects Loop Send (from the amp) goes to Input #1 of the DAI. The drum machine goes to Input #2. My guitar is plugged into input #3. Input #4 is open.
I have a dual RCA cable going from the Line Out on the DAI, with an adapter on the other end of it so I can plug it into the AUX IN on the amp. This is the only way I can hear the other instruments (drum machine, etc.) through the amp.
As you can see in the photo, I also have another adapter to change the tip to 1/4. I tried plugging that into the Effects Loop Return, but I get no sound at all.
Alternatively, I COULD plug my bass directly into Input #1 on the DAI (via the pedal board) and eliminate the need for the Effects Loop, but someone in another comment/thread mentioned it would be better to do it this way.
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I’m glad it’s useful and it’s a pleasure. I’ve dedicated a considerable part of my career to education and I’m happy to be able to help. I often teach classes at the Infocomm convention in the US and have in the past taught at Integrated Systems Europe. When I was at Sennheiser I wrote and taught their Installed Sound Academy classes.
I understand the confusion of reading stuff online. I just minutes ago read a FAQ by the people with the compressor review site that contradicts something I said. They are also correct in the context which they gave the answer, but that distinction is easy to miss.
Here it gets funny because we are in mixed worlds between the tradition of processing an instrument signal from another era and modern circuit design. The output impedance of the effects send should be given in Ohms rather than dB. What model number device are we talking about? I’ll look it up and try to determine what it’s doing. A pedal loop wouldn’t traditionally be balanced, but that doesn’t mean this one isn’t. Buffering up to a low impedance output balanced line level in the design would mean that It could drive either pro gear or a traditional pedal next in the chain.
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My bad! It’s Ohm of course! I did not even notice my mistake until you pointed it out. I even made more mistakes as it’s 1k Ohm impedance.
I have the same amp as Pam and a lot of others here: Rumble 100 - Manual link to page with specs
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GAH! Sorry, you’re right. I had thought I remembered seeing one on the effects loop too.
I didn’t mean a bad cable, I meant a bad effects return jack. The socket, not the plug.
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see what you are doing
if you are using the XLR cable to go to your DAI, you theoretically should not connect the output of the DAI to the AUX-IN again
In order to hear the drum machine/music, you might better connect it to another set of speakers diretcly from the DAI
Or if the quality is sufficient through your computer on a set of (computer)speakers
To give you an idea of my setup
I use a soundcard in my computer to record
I use a mixing panel, to receive music/drum computer/XLR from Rumble and what ever I want to plug in
My Rumble only rumbles my bass
A set of speakers takes care of the rest
when recording I can choose mix it at the deck (basically what you can do on your DAI)
or only record my bass and mix it in the computer
strange that the FX loop does not work
can you try to loop it with 1/4" cable, just one plug in each end, if no sound there is something wrong with the connector
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I would agree with this. If you plan to run a DAI output back in to the amp you should not be running an input into the DAI from the amp.
If you want to run the output of the DAI into your amp I would literally do just that; plug all the instruments into the DAI, and run the line out from the DAI into the normal amp input, where you would normally plug in your bass. Be very careful with levels if you try this. This is what I do myself (though just into a headphone amp, not a bass amp.)
Otherwise, what Marcel suggests would be the most advisable. Run your bass into the amp, a DI out from the amp to the DAI, and the line out from the DAI to another set of speakers. The only weird thing there is you’ll hear the bass through both the Rumble and the other speakers.
One other thing to point out: your other instruments may not sound good through your bass amp, at all. I would absolutely not run a synth through a bass amp myself, for example; high freq square and sawtooth waves would probably not be super good for the speaker and would sound like garbage.
And note this is true for other things you are playing back through the DAI as well.
So, given all that, using the bass amp just for your bass and its DI out and running the other audio to some other speakers via the DAI out should work better than any other plan here.
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