General behavior I/O settings

Beforehand I have to tell that I’m using the QC only with electric basses (active & passive).

In my opinion the input setting (e.g. Input 1) of the QC must be that high, that the meter quite reaches the thin marker line if I play my maximum signal. This way the QC uses the maximum dynamic range of my instrument. It seems that even after the line marker the QC will not clip immediately, so there is enough headroom.
This is what I do at my real world amp to get the best signal and it will result in a fully clean signal. After that (in real world) comes the drive option to get some overdrive or distortion. Earlier this days one would have used the master volume to let the amp/tubes distort.

With the QC it seems that especially the older Ampeg amps (6464, 6466) are hard to play clean, one has to reduce the master extremely. Could be the natural behavior of this amps.
It seems that a lot of QC users struggle with clean signals from QC amps and I read some recommendations to reduce the input level to get a clean signal. But as far as the QC amp should normally deliver a clean signal this would be the wrong way.

What do you think about this topic ?
Maybe it’s a problem with other users presets which are designed with a much lower input range ?
Or is it an error in the QC signal chain design ?

Although I don’t play bass, I do think you should lower the input gain.
Feeding the amp with a hot signal will push it to earlier breakup, hence the need to lower the master.
It’s not just the dynamic range that is determined by the input gain, it really is how hot the signal is as far as the amp blocks are concerned, just like the effect of adding a clean boost in front of the amp.

Regarding dynamic range, I would worry about it mostly at the output stage - make sure your output is near clipping with just enough headroom for later DAW use.

Try adjusting the impedance. The default 1M might be too hot for your bass etc.

to me, it’s the difference between digital models and signal chains vs analog/real amp.
Since beginning several years ago w/ NDSP plug-ins, I noticed (and learned thru official videos) that for clean tones a much lower input level is required and because of the digital nature of the signal chain, that works fine as opposed to analog gear where you want a max safe level at input.
It’s not what we’re used to, but it that’s what it takes to really clean up the NDSP tones

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I am playing guitar. Most clean models I tried out resulted in overdriven sounds, even with gain VERY low. I set impedance to 1 MB, input to 0 db, even if the signal is far from clipping, gain down to sometimes less than -10db. This works but overall these models distort way to fast imho.

I’ve found the same thing - even for some distorted models and overdrive pedals too. I’ve found the best solution is to set your input like you would for tracking (below clipping levels) and then the first block I would add in a preset is a gain block. Here is where I would turn down the gain before going into an amp/pedal/etc. This changes the sound dramatically and gives you more control over the input gain control. I’ve found my sweet spot is about -15db for clean amps. This also dramatically affects the OD pedals, high gain models, and captures.

I like the higher gain for high gain amps but I’ve found rolling back the gain going into the amp can help it feel more dynamic. The nice thing about the gain block approach is that you can customize multiple amps in a preset to have different structures; the downside is that it uses an extra block, even if it’s very low CPU usage.

I’m not sure if this is a bug or intended behavior but the models sound very very different with this approach. The clean amps sound better IMO with this.

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I agree. Many models of overdrive pedals are not usable for me because they are so overblown and I wont achieve some low to mid gain sounds if I don’t dial the gain down to -15db or so. But then they sound dull to me. I wondered more than once if that may have to do with the DSP crew and their customers being more on the heavier side of guitar tones in general. I am just the opposite. However, I will try out what you suggested, but I question why it makes a difference to first turn up the IN signal (below clipping) and then turn the signal down again in before it hits amp and pedal blocks or just lower the input gain, keep the signal lower in the first place (and save a gain block). Thank you for the idea still.

For me I found that I’d rather deal with a gain block when switching guitars so I can fine tune the gain going into a specific amp block specifically instead of globally. I also found on hotter guitars using a gain block allows for more control and lower gain vs the input. And finally, I can control how hot I want my sound to be, regardless of guitar. Sometimes I want that hot signal- other times I don’t.

Also, getting the full range of your guitar signal on input to me sounds better. Then using a gain block after turns down that signal instead of a lower input in the beginning. The input section is still converting and boosting the analog signal to digital so this stage, IMO, is important to get a full healthy signal.

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Against all odds I set the input gain just to 0db, the signal meter barely reacts.
I tried all my own presets and the downloaded ones. It seems /sounds that indeed there’s the full dynamic range of my bass. All the amps and presets could be handled much more easily.

Obviously the input level doesn’t matter much, except it’s too high.
I’ll examine the following settings:

  • input/output values of an empty preset in comparison to the bypassed signal
  • comparison of these settings with my active Musician Stingray and maybe the use of gain block (which one best ?) the adapt the signal strength

I’ll be back.

I did some experimentation.
I left the input and the output level at 0 dB, and tuned the volume knob full open.
Empty preset.
Guitar into LEHLE Bypass switcher and either direct into audio card or insert of the QuadCortex.

  1. This way the guitar signal is nearly the same (+/- 1 dB) with or without the QuadCortex.
  2. I cannot detect any differences by ear or visual audio recording between the pure or the QC-signal.
  3. If I max out the input level up to thin bar I have to reduce the output level by nearly the same amount to get similar results.
  4. f I max out the input level up to thin bar and leave the output at 0 dB I have to reduce the volume knob to 36/100 to get similar results. (I’m not sure wether here is a real difference).
  5. The latter method shows correct levels in the I/O screen, but it seems that the resulting signal is the same. I do not know how to examine the signal in more detail to suggest any of the methods.
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