How to set up external Channel Strip bypassing QU-24 Preamp?

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This topic contains 11 replies, has 9 voices, and was last updated by Profile photo of Giga Giga 6 years, 1 month ago.

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    Profile photo of Salislore


    I’ve been trying to figure this out for quite some time and have read the manual and searched through other posts, but I’m not sure if I understand what I need to do correctly. Here’s my goal: to set up one high level external channel strip (mainly for vocals), run it through my A&H QU-24 while bypassing the QU-24’s Preamp for that one channel and then into my DAW. This way I get the pure signal from the Manley directly into my DAW.

    My setup:

    QU-24 Mixer (using for audio interface & preamps for everything else, I/O with DAW).
    Logic Pro 10.2.4
    (I have an Akai MPK224 Controller as well)

    Will be purchasing: Manley Core Channel Strip.

    From what I’ve gathered, I think I can bring the Manley in via the ¼” input on one of the channels using a TS ¼” cable. This will bypass the QU-24’s preamp for that channel and send the Manley’s signal unprocessed in any way by the QU-24 to my DAW.

    Is my understanding correct?

    As always, any feedback would be much appreciated. 

    Profile photo of cornelius78

    You can bring the signal from the external pre into the Qu using the line inputs (above the preamps.) From what I’ve read, your Manley will be outputting a balanced signal over XLR, and the line-ins on the Qu are balanced, so an XLR-TRS cable would be best. NB that the line-ins on the Qu have a 10dB pad c/f their associated XLR inputs, so you might have to run the output of the Manley hotter, or increase the trim on the line ins to compensate.

    Once the signal is in the Qu, it can be passed out to your DAW via the USB-B socket. Setup>IO Patch>USB Audio to ensure that channel is being fed to the DAW (p75 of the manual.) I recommend using the “insert point” send option to keep as much of the Qu’s processing out of the DAW as possible.

    Then it’s just a matter of the DAW seeing a multi-channel interface, and assigning a track to an input of that interface.

    Profile photo of Andreas

    If the plan is to circumvent the Qu’s preamps, you’ll need an additional ADC and feed that one directly into your DAW.
    Whether you use the XLR or TRS of the Qu, your signal still went through the Qu’s input stage and ADC. The TRS just have some additional damping resistors compared to the XLR sockets (check out the block diagram at the end of The Manual).
    In don’t see a reason to not just plug the XLR outputs from your external strip right into the XLR inputs of the Qu.
    From a high-end perspective the XLR sockets normally should provide much better electrical contact than a TRS could.

    Profile photo of DoctorG

    If you’ll look at the functional diagram for the mixer, you’ll see that Andreas is correct – you don’t bypass the preamp by using the Line-in jacks.

    I usually kinda laugh when I hear something like this – using a thousand-dollar device to do something a $20 device does just fine. (A single preamp in the QU probably costs less than that.) I’ll guarantee you could not tell the difference if you could set up a controlled A/B comparison. This is a case of the old analog vs digital argument. The differences, if any, are at frequencies or signal levels that you cannot hear. The distortion that occurs if you overdrive the Manley will not be as harsh as with a digital preamp, but when operated within their limits, the two devices will sound the same, in my opinion.

    Perhaps you desire some of the other features of the Manley, but if the sound is the issue, you’re wasting your money. One review of the Manley stated that it has a “character.” That usually means that you can “hear” it, which means it adds something to the signal. If you want that, fine, but if it is the pure sound of the source you’re after, you may need to look elsewhere.

    Compare the specs of the QU to the Manley. The Manley specs are given at 0.5% THD. Of course, this is for high signal levels. The QU distortion is 0.001% or less. What %THD do you think you can detect by listening? The dynamic range of the Manley is given as >90 dB. For the QU, it’s 112 dB for the system. Of course, it’s difficult to compare specs like this, since so many variables are involved, but this should give you some perspective on the matter.

    There are folks that will sell you $100 3-ft power cords or USB cables, if you think you can hear the difference compared to the $10 cables. Some guys believe they can hear the difference!

    Profile photo of Salislore

    Thanks cornelius78, Andreas, & DoctorG for your responses.

    I’m glad to learn that the preamps are not bypassed when using the Line-in jacks. And by the way, I should have looked at the diagram. I’m currently recovering from Quadruple Bypass surgery, so my brain isn’t all there right now. 🙂

    I have a degree in Electrical Engineering, so I understand the differences between discrete circuitry components and how vintage and various components can effect outputs. And while I agree I would not be able to hear the difference of a direct A/B of the preamps, you have to take the unit into consideration (compressor, EQ). Not just the preamps. That’s where the coloration of a given box comes in.

    I have two main reasons why I want a high end Channel Strip like the Manley Core: 1) I am looking for a different “colored” sound than what I get going through the QU-24 preamps. It givee me more options to match individual voices to the right equipment. And a sound that is easier to get to sit in the mix properly and quickly. 2) Having industry standard names in my arsenal like Neumann, Manley, Neve, etc. is attractive to clients. How much these industry standard products make to the actual sound is totally subjective. I’m sure there are numerous plugins that will get the sound very close, but many clients don’t have an understanding how good some plugins can be. They just want to see the “name” of the hardware.

    Profile photo of [XAP]Bob

    You need a DFA fader on your desk then…

    The empty channel fader you can use when someone at church says it’s too loud. You turn down the DFA fader and they go away happy…

    Profile photo of anui

    Maybe Use STEREO INPUT Line Input (ST1/ST2) bypass preamp

    Profile photo of Lee7

    The DFA is the best fader/switch on the desk, FACT!

    I have seen so many happy faces over the years when I make minor adjustments with the DFA.

    Profile photo of Giga

    Haha, I’m thinking real hard about what DFA fader means but can’t come up with anything


    Profile photo of [XAP]Bob

    Does Faff All

    Although the F is often referred to by less courteous expansion.

    Profile photo of

    Cut and pasted from a forum somewhere on this global planet:
    A really snotty a… once asked me, “so what IS this DFA fader?” In a flash of lightening-quick inspiration (unusual for me!) I replied with a straight face, “why it’s the Digital FOH Assembly, of course”. And before I even had time to wonder if the guy would buy it, he just tweaked the fader and said, “Yeah, cool. That sounds so much better now”. Needless to say, I didn’t book that particular shower again.

    I had a bass player so loud [off the stage] in a concrete room as the drapes had been removed because the Theater was closing for renovations..
    I had the bass fader up in the mix but not turned on.
    The guy paying me [for the show] came over and said, “any way to turn that bass down?” “its a bit loud isn’t it:” I said yes feel free to adjust it. so he did pull it right out and said “oh that sounds better now.” Thanks Dave. You’re wonderful to work with.

    There is no way to bypass the inputs.
    However 3rd party gadgets can colour a signal wonderfully.

    Profile photo of Giga

    😜 thanks guys, I’ll have two of those thank you very much….


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