ive seen some other threads about this problem with amp blocks. But im just trying to use the QC as a straight effects pedal board into the front end of an amp. the outputs and inputs are all set to default and the master volume knob on max. its considerably quiter than plugging the guitar direct into the amp and hence the amp is not being pushed properly. any ideas? is this a problem?
closest I can get to it being transparent is +10db (max) on the output settings and +4db on the input settings. then its pretty similar. surely thats not right though. I would’ve thought the base point is like a helix or something where what you get out is what you put in.
I guess, you’re talking about unity gain here. There is an interesting article in the Fractal Audio Wiki regarding this topic: Connections and levels - Fractal Audio Wiki
There it is also noted that unity gain does not apply to all devices by default. For example, the FX8 is Fractal’s only device specifically designed with unity gain in mind. Devices, intended for amp modeling, which are running into mixing desks or power amps, don’t really rely on unity gain. If QC is used as an FX plattform only, I wouldn’t expect it to provide unity gain by default but it should be achievable by adjusting I/O settings, like you did. As always, I might be wrong.
ah ok. that makes sense I guess. shame though as you can’t effectively use it as a pedalboard only.
checked that fractal link. sounds like fractal have a special mode called unity gain. the article is more about dont push all the blocks volumes and overload the system. So I looked in the quad manual and it says you can use the quad as a pedal board and a 4CM and 7cm device. in my experience you can’t as it reduces the volume by so much. thats straight through without anything in the blocks. so 4 cm it will reduce the volume by even more as you are going in and out and in again… I will test this out.
It would be actually surprising if you couldn’t compensate for the reduced output by increasing the output levels. In 4CM you can increase the send level going into your amp’s preamp as well as the out level going into your amp’s power amp.
You can most certainly use it as an effects only platform - you just need to set your levels accordingly. Interestingly, I believe that it’s this very same thing that causes people to complain about captures not having enough gain (a misconception in my opinion). The key to this is the input level.
In order to achieve unity gain through the QC (including to the blocks in the grid - be it captures, amps, effects, whatever) you need a significant boost on the input. If you want to be accurate with it then the best way to make sure you have it set right is to use an A/B switch to toggle between going through the QC & going straight to your amp with nothing between it & the guitar (save for the A/B switcher of course). You can then use your ears to match it up. If you put in the effort to get your input level right then all blocks in the grid will behave correctly (including the gain levels of captures) & everything will sound better.
The ideal way to set the output level in your case is to just turn the big physical volume knob all the way up & leave it there (it’s best to only really use it for attenuation when using headphones or going FRFR).
I hope all that helps; good luck! 
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I agree with everything RavenVoice stated above and have found that gain staging is CRITICAL with the QC. It’s been designed with so much versatility in mind - so many different ways to use it, and it’s going to take a little (at least) tweaking to adapt it to each specific setup and user application.
It can definitely take a bit of experimenting to dial in your sweet spot, but the QC can cover such a range of usage, that has to be the case.
One thing I’ve found is that the fewer blocks you have on the grid, the lower your output is going to be, there really seems to be a cumulative effect volume-wise. If you’re not using amp or capture or cabinet/IR blocks, you may need to really boost your I/O stages, or even add a gain block
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so are you saying I should do the whole compensation on the input level. as I said in the reply before I have found that a plus 4db on the input and a Max 10db on the output to give a similar unity thing. should I be putting it all on the input then? and leave the output at default? wont that mess with the blocks a lot? my 4db on the in and 10db on the out was what I thought was a good compromise . But would be great to know from QC what the official idea is for using it as a transparent level FX board.
My advice would be to aim to get the level going into the grid (using the input level found in the QC’s I/O window) so that the blocks react the same way as the real-world devices would if you plugged straight into them. In my case I did this by using an A/B switch to compare captures that I made with the real-world devices that were captured. I don’t have my QC in front of me right now to check but; if memory serves, I believe it required a 10.2db boost. Once you’ve got your input level right then you should hook the QC up to your amp in the desired fashion (4CM I assume), load up the grid configuration that you want to use & then make any further tweaks with the output level if you feel it’s required.
I hear you regarding it being a little bit of a pain in the arse to get right at first; however, it’s kind of necessary as we’re dealing with a digital product & it’s important that we don’t get clipping at any of the various stages. Most guitars are passive & will require a significant boost for optimal signal-to-noise ratio & the unity gain thing is only really important to those of us who are either using the QC in specific ways alongside analog gear (like you) or those of us whom are extremely anal about getting the very best results when it comes to block behaviour, tonal characteristics & dynamics (like me 
). The vast majority will likely just be using the QC standalone & dialling in sounds using the inbuilt modelling & so long as there’s no clipping or too high a noise floor they won’t pay it a second thought.
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I guess it depends where the drop occurs. we dont know do we? - is it the input thats low or the output? I just managed to get a proper loop switch and compare - and its more like a 4db input and 4db output gain needed to be the same sound. but would be good to know where the drop occurs.
If you want the blocks to behave the same way as the real-world devices then a significant boost needs to be dialled in at the input - this makes sense as it allows one to dial in their signal for a more optimal signal-to-noise ratio (remember this is a digital device doing AD/DA conversion so it needs to be thought of more like the input on an audio interface than the input of a piece of analog guitar gear).
You may potentially find that a little more of a boost is also required at the outputs in order to achieve what you’re looking for though. This is because the outputs will have been designed to work satisfactorily with the inputs of an audio interface, a FOH mixing desk or FRFR monitors where clipping is an absolute no-no.
For you this is a two-prong issue - firstly you want to get the input level right for correct block behaviour (this is the only part that concerns me personally as I’m using an FRFR rig); secondly you may then want to tweak the outputs afterward to suit you amp.
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I’ve had similar experience and my only advice is to just crank the levels. The downside is you might not be able to “boost” the amp as well as with a real pedal.
In my case a 10 dB boost was also necessary for my guitar to max out the input meter without clipping. However, with this input boost, my own captures of pedals felt to have way more gain than the real pedals at similar settings. But maybe I was doing something else wrong. Based on this experience, I keep the input level adjustment on the QC at 0.
Here’s a quite extensive video about gain staging the QC for capturing. Maybe there’s some valuable information on how to trace down “the drop” @jonhollis : https://youtu.be/BQAEXIcCHVA
FYI l, I originally had my input level set to +19.3db as that gave me the best signal-to-noise ratio (although it may have been a tad too hot perhaps); I then reduced it to 10.3 (just checked my QC & that’s what it’s actually at so my memory wasn’t far off ) because all of my captures needed too much gain reduction & amp blocks were needing to be set with lower gain levels than their real-world counterparts would. At +10.3db things behave correctly for me (note - I have low-output pickups).
The other thing to point out is that, with the 10.3db boost, I’ve found that the gain levels of captures match up with their real-world counterparts without any post capture tweaking when it comes to high-gain or clean tones. If I’m trying to capture something with a mid-gain/crunch tone then I do need to reduce the gain in the capture block afterward. This is the best compromise for me though because if I set the input gain so that captures match up for crunch tones then the high-gain tones need a gain boost & the stock amp or dirt pedal models don’t offer enough gain.
I’d imagine that the exact amount of boosting required is going to vary depending on the user’s guitar & their specific usage requirements. It’s definitely something that needs to be experimented with by the individual; however, I think it’s safe to say that most users should expect to boost their input to some degree.
Also note that the amount of gain that’s produced by a pedal block will vary greatly depending on the level coming from said pedal block & into the amp block that follows it. I believe that most people have obtained best results by setting the capture return to 0.0db when capturing pedals (if you boost the capture return for optimal volume levels like you would when capturing an amp then you will need to drastically reduce the level of the pedal capture afterwards when placed in the grid or else the signal going from it to the subsequent blocks will be far too hot).
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Some good tips here but a comment. Many of us may be familiar with Rhett Shull on YT. He is currently using a QC on tour as an effects unit only. He is pretty good about talking about these kinds of issues and I haven’t heard him comment on this. Would be good to ask him what he did. Maybe he is watching this!
Pete Thorn has used one on tour as well, but I am
Pretty sure he is running sims/IRs into the board.