How do you model an amp's FX loop?

FullThrottle64

Inspired
How can you simulate FX being inserted into an amp's FX loop (which is basically between the preamp and the power amp)? In reviewing the blocks manual, I don't see where there is a FX loop provision. Am I missing something?
 
I don't think there's a way. I could be wrong. But I recall reading that FAS avoids any sort of separating of the power amp section because there are a lot of proprietary algorithms going on that could be analyzed when isolated. BUT you can always plop a few blocks between the amp and cab block so the effects sound like they're being sent through a traditional cab.
 
You could do it using two amps, with the first one’s sag at zero. But why? An effects loop has always been a compromise for live use.
Step one for me will be duplicating what I have, and my legacy rig is all FX in the loop of my amp.

There is also the point that a delay signal run through the cabinet has a different sound than a delay before the preamp or after the mic.
I don't think there's a way. I could be wrong. But I recall reading that FAS avoids any sort of separating of the power amp section because there are a lot of proprietary algorithms going on that could be analyzed when isolated. BUT you can always plop a few blocks between the amp and cab block so the effects sound like they're being sent through a traditional cab.
That makes sense...may try to find a workaround.
 
Step one for me will be duplicating what I have, and my legacy rig is all FX in the loop of my amp.

There is also the point that a delay signal run through the cabinet has a different sound than a delay before the preamp or after the mic.

That makes sense...may try to find a workaround.
The units are designed to maximize user experience, but of course they cannot replicate every scenario, especially ones that result in compromised tone.

Back when recording was occurring on tape, you’d record dry and add effects later (which people still do via re-amping).

Some artists had high tech rigss where they would slave their amp to line level to run the entire amp before the effects, but you had to have deep pockets. Most used a few pedals in their loop, in mono, because it was what they could afford.

At some point, you have to embrace the technology and accept the point is to improve your tone, not duplicate it.
 
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You are correct that there is a difference in sound placing the effects before the preamp or after the mic. However, the difference in sound between a virtual effects loop and placing your effects between the amp and the cab would be negligible. Especially on a MV design like the Legacy.

Unless there's distortion added in the Cab block then there should be no differences between before or after the Cab.

Do a search here on "Linear Time Invariant" to learn some more on that.
Umm...yeah. Now that I think it through, this makes sense.

Sorry for the stupid question, and thanks for the explanations!
 
the question is, why would you want to. an amps effects loop is a fudge...a compromise...placing your time based fx after the amp and cab (in stereo) as you would in a studio setting is much more desirable.
Hmmm... depends on the genre. I can't stand the sound of time based effects after the amp/cab.
 
How can you simulate FX being inserted into an amp's FX loop (which is basically between the preamp and the power amp)? In reviewing the blocks manual, I don't see where there is a FX loop provision. Am I missing something?
Man, just run them in front of the amp(s)... more like having them in the loop, that putting them behind the amp/cab.
 
Run effects in between amp & cab blocks.

That's what you want to do to get close to your setup.
Actually, that’s nothing like having effects in the loop and won’t sound the same. The loop is typically after the preamp and before the power amp, and will cause power amp clipping (dirty repeats).
placing an effect in front of the cab is identical to placing it after the cab (if the cab is stereo). there's no difference in tone.
The only difference being that the cab filters the effect placed in front of the cab.
 
The only difference being that the cab filters the effect placed in front of the cab.
you have to understand that placing a filter (which is basically what the cab block is) into a signal path will give you the same result no matter where you place the filter. fx in front of the filter is the same as fx after the filter
 
Actually, that’s nothing like having effects in the loop and won’t sound the same. The loop is typically after the preamp and before the power amp, and will cause power amp clipping (dirty repeats).
This is a legitimate point and something we can't replicate in the Axe. But I imagine most of those wanting dirty repeats would be happy just putting their time based effects in front of the amp block. I don't think there'd be much difference between having your delay out front vs in the loop, unless you're using a MV amp with lots of preamp gain and you have the master high enough to drive the power section.
 
I'm still not 100% convinced on pre/post cabinet effects being the same. I thought there are components of the cab block that introduce non-linearities, such as the preamp section (this came up in a different thread). And then thinking about resonant filters in modulation effects, drives and filters in delays, and added harmonics in pitch-shifted sounds, the results before and after a cab always seem different to my ears (if subtly so).
 
This is a legitimate point and something we can't replicate in the Axe. But I imagine most of those wanting dirty repeats would be happy just putting their time based effects in front of the amp block. I don't think there'd be much difference between having your delay out front vs in the loop, unless you're using a MV amp with lots of preamp gain and you have the master high enough to drive the power section.
Yep that’s what I do.
 
Actually, that’s nothing like having effects in the loop and won’t sound the same. The loop is typically after the preamp and before the power amp, and will cause power amp clipping (dirty repeats).

The only difference being that the cab filters the effect placed in front of the cab.
No that's not true. Having the effects after the amp vs the fx loop are much closer than you think. Having them in front of the amp is nothing like having them in the loop. Power amps on amps with fx loops really don't really produce audible distortion, if at all. They're aren't design to do that, and will sound like ass if you crank the master volume loud enough for that to happen.
 
you have to understand that placing a filter (which is basically what the cab block is) into a signal path will give you the same result no matter where you place the filter. fx in front of the filter is the same as fx after the filter
Ah, I’ll have to try that. That wasn’t the case when I had a helix.
 
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