***Looking for some advice here please as I'm pretty non-existent when it comes to electronics. I want to use a mixer to 'blend' backing tracks with my guitar then send that to my amp.
You can definitely do this. You will get the blended sound amplified by your amp, along with whatever tonal characteristics your guitar amp provides.
I definitely would not do it. Because the sound coming out is very unlikely to be something that would sound good (to me - your opinion may vary):
Guitar amplifier input stages do not amplify sound cleanly like a PA would - they are not meant to. They are meant to be part of the sound of the guitar, so there are distortions, non-linear bits, overdriven bits etc. Which means what you get out is not like having a guitar sound and a backing sound - it will be almost certainly not blend like you imagine.
- get a PA of some kind for your backing to keep it away from your guitar gain stage, or
- insert your mixer in the FX return on your amp so it just goes to the power stage
***Thanks for your input, guys. First, here's what I hope to be able to do: Mix a backing track/sound track from laptop (or other source) with my pedal steel (pedal steel > volume pedal > mixer) then from mixer to my amp as I can get the benefit of amp effects (mainly reverb). Then, the mixed sound will either come through the amp's speaker, or if I'm trying to stay friendly with my neighbours, through my headphones via the H/phone output in the back of the amp.
Now, here's where I'm at. (I'm also posting this as it may be helpful to anyone else who is trying for something similar.) I have a borrowed Yamaha mixer and tried a few things with that. I first tried going from pedal steel to volume pedal to amp then from there into Line In on mixer -- that didn't work -- no sound whatsoever. I then tried volume pedal into Line In on mixer then from C-R Out(L) on mixer to amp -- still nothing.
I've posted a photo of what I did that eventually worked for me.
The yellow lead is from volume pedal; the 2 phono plugs into "2TR In" are from laptop and the black lead from "Phones" goes to my amp.
I first tried going from pedal steel to volume pedal to amp then from there into Line In on mixer -- that didn't work -- no sound whatsoever.
That would be the course you'd likely want to take for pure recording but you need to do it right, with a stereo-to-mono cable, TRS to TS. If you use a pure mono cable, you likely shorten out the amp's single headphone output (unless it has separate headphone amplification for left/right), if you use a pure mono cable, the mixer will interpret the identical L and R signals as one balanced signal and will try to reproduce their difference which again is nothing.
However, when you want to play a backing track through the amp, you don't want to pick your guitar off the headphone socket since then both backing track and guitar will get looped through the mixer.
Instead you want to go through the "effect loop" of your amp, putting FX send from the amp into one channel of your mixer and routing the mixer output to your amp's FX return.
If you get hum in that manner, you'll need one or two DIs in the respective sound paths.
Your own answer goes directly from the volume pedal into the mixer. That means that your volume pedal signal will get the same treatment by the amp as your backing track would. That will only sound moderately useful if your amp is intended to play clean, namely if your preamp section does not do things like adding overdrive or reverb or things that are bad news for your backing track. Also any coloring the preamp adds will not appear in your recording.
That's ok if you are actually using a clean amp like a keyboard amp (say) and all of your sound is generated by pedals. But particularly if you are using a "modeling amp" which tends to have a rather clean power amp and a processing preamp adding the individual distortions/sounds, you want to record after the modeling and want your playback tracks not to go through the modeling.
Yes, you can do this and it can sound excellent. Don’t bother using the headphone output, use the R and L main outputs.
You can blend the two inputs, pan the guitar all the way to a guitar amp only and the backing tracks to a powered monitor or stereo system, or go halfway. As a bonus, you can use the output to the guitar amp as an overdrive. The one thing I wouldn’t do is route other tracks to the guitar amp, it won’t sound good.