Trying to understand Digital/modelling amplification directly into an Audio Interface

[Nightburst]

Been wondering one thing since using digital modeling technology in my home studio:

In a traditional guitar/amp setup you have the 3 main components that will make up almost all of the sound: guitar -> amp -> speaker
But when going digital/modeling I see a difference: guitar -> preamp/modeler -> audio interface -> DAW -> VST -> IR -> monitors/headphones.

Why is there no power amp needed in the later situation? Is a power amp only traditionally there to make the sound ready before going into the speakers? Surely it will add it's own flavour? What about using power amp pedals instead? They must be connected to speakers or the amp will blow up?
Is this why IR's are used? I thought these are only to replicate the feel/sound of a speaker and not the power amp?

 

[Adieu]

Monitors are usually powered (have own amps).

Headphones might be amped a little by your audio interface.

And in any case, with digital modeling, you want the flattest most neutral output you can find, you want your flavor from accurate emulations not from random components of your personal rig that the emulator creators couldn't have predicted


...unless of course you have no interest in sounding close to what the people who programmed the model intended, in which case all bets are off experiment away.

 

[ErikH]

In a traditional amp setup for recording there is normally: guitar -> amp -> speaker -> mic -> audio interface / mixer / recording device -> studio monitors or headphones.

When going modeling, it's this simple because the entire amp / speaker / mic is simulated in the modelling in many cases:

1. guitar -> modeller -> audio interface / mixer / recording device -> studio monitors or headphones.

OR

2. guitar -> audio interface -> modeller plugin -> mixer / recording device -> studio monitors or headphones.

I use the second option above myself for home practice / recording. I've got AmpliTube 4 with Reaper but if I want to just play and not worry about recording, Ableton Live is a good live mix setup for the plugin or I just launch the AmpliTube app itself and play. My interface is a Focusrite Scarlett Solo and I listen to it all through a pair of Sony MDR-7506 headphones. Sometimes I'll run a pedal or two between my guitar and interface but most of the time I plug straight in to the interface and use the AmpliTube app.

A power amp is needed when you want to hear it through non-powered speakers but most studio monitors these days are powered. Now, live, you have the option to run the modeller in to a FRFR speaker for your own stage monitor or just get signal from the PA pumped in to your stage monitor or in-ears. Most players I have seen have a FRFR speaker on stage usually set as a side fill.

 

[Mincer]

My Fractals also model the power amp. I would think things like the Helix and Headrush do, too. They do this through IRs or convolution.

 

[beaubrummels]

Any modeler is also modeling the power stage, and the better ones have options to model speaker cabs and microphone with mic placement. You are over thinking the chain. Just focus on the resulting sound and find the knobs to turn to get the right sound. Doesn't matter if the knobs are hardware or in-the-box software virtual knobs, just go with it and listen to the result you are hearing.

 

[devastone]

Depending on the modeler, the IRs are probably in it, or some other form of cabinet simulation, the cabinet and the power amp is modeled as part of the amp modeling. At least that's how most of them work, in the higher end modelers you can load IRs, turn cab sim on/off, position mics, etc... On my GT-1000 I have the cabinet sims on for the XLR outs and run those direct to the board/interface, I usually turn them off on the 1/4" outs and can run those through a clean power amp into guitar cabs. Although, I rarely use guitar cabs now days. I can turn them on if I'm using the 1/4" outs to a FRFR powered cab.

 

[AlexR]

The volume gain for the power amp section is not needed, as you are not trying to get enough signal to move a massive speaker cone.
But of course as stated the tonal aspects of both PA section and speaker/cab are incorporated.

 

[Nightburst]

Thanks for the reply's guys.

I'm asking because I am using a Boss GT-1 and it only models the preamp from what I can find about it.
I noticed that if i run it through a VST that simulates a poweramp, I get much better results, a more realistic tone.
But the signal chain now is sraining my pc a lot, I have a good pc and a good audio interface which should be able to handle a simple guitar signal but there is too much micromanagement involved now. I prefer a plug and play type of setup both through the pc or live.

Maybe what I need is the Seymour Duncan Powerstage 200, it has line out also. Too bad it's kinda pricey.

It's quite the rabbit hole now, all the different IR's and VST's I need to make it sound great as opposed to a real amp which is plug and play but much too loud.

I'm hoping there is a pedal out there that can do a power amp simulatiuon to give the GT-1 some more oomph. I am using valuble slots now to make PEQ's shape the sound I like it, leaving less room for effects. I sold my EQ pedals because it's noisy and I want to keep my board as small and portable as possible.

The Boss GT-1 has potential but it needs some work to make it sound big the way I run it now through my PC but the downside is that the way I make it sound good now is eating up all my patch slots on the Boss and CPU strain on the Laptop (which is an I7, 32 RAM, etc)

I believe a power amp pedal can solve these issues and simplify my rig a lot, there is just not much out there besides the Powerstage 200?

 

[ErikH]

According to the Boss web site, the GT-1 has some amp modeling in it. Have you not enabled those?

 

[devastone]

Make sure you are using the line/phones output, that one will have the cabinet modeling. It should be the same models as the GT-100, I used one for years with great results.

 

[Top-L]

Thanks for the reply's guys.

I'm asking because I am using a Boss GT-1 and it only models the preamp from what I can find about it.
I noticed that if i run it through a VST that simulates a poweramp, I get much better results, a more realistic tone.
But the signal chain now is sraining my pc a lot, I have a good pc and a good audio interface which should be able to handle a simple guitar signal but there is too much micromanagement involved now. I prefer a plug and play type of setup both through the pc or live.

Maybe what I need is the Seymour Duncan Powerstage 200, it has line out also. Too bad it's kinda pricey.

It's quite the rabbit hole now, all the different IR's and VST's I need to make it sound great as opposed to a real amp which is plug and play but much too loud.

I'm hoping there is a pedal out there that can do a power amp simulatiuon to give the GT-1 some more oomph. I am using valuble slots now to make PEQ's shape the sound I like it, leaving less room for effects. I sold my EQ pedals because it's noisy and I want to keep my board as small and portable as possible.

The Boss GT-1 has potential but it needs some work to make it sound big the way I run it now through my PC but the downside is that the way I make it sound good now is eating up all my patch slots on the Boss and CPU strain on the Laptop (which is an I7, 32 RAM, etc)

I believe a power amp pedal can solve these issues and simplify my rig a lot, there is just not much out there besides the Powerstage 200?

I have a GT-one-hundred, and the trick to getting it to sound realistic is to use one of the FX blocks as a resonance processor. You can dial in the exact amount of cab thump. Idk if your model has the resonance block, but I bet its in there.

 

[LLL]

Great topic.

A true power amp is of course designed to power the speakers so that the small guitar signal from the preamp becomes... "embiggened" (a large signal which is easily audibly heard).

Power amps, whether part of the amp, or separate tube or SS power amp, do impart their own flavor on the tone. More so with guitar-oriented power amps vs. audiophile stuff.

I'd say with most speaker iRs you will get some poweramp texture (they had to audibly record the convolutions after all), but if you're going to use iRs, a power amp sim really adds a touch of "real amp" authenticity.

Hence why I acquired a Two Notes Torpedo CAB M. speaker iRs + power amp modeling + mic modeling (dual mics, even) + EQ + verb if you like.

 

[Artie]

Make sure you are using the line/phones output, that one will have the cabinet modeling. It should be the same models as the GT-100, I used one for years with great results.

I have the GT-001, which is simply the desktop version of the GT-100. One of it's cool features is that you can set the output to go into several different amps, or a hi-fi power amp like a Crown. So, you can configure it to go into a JC-120, guitar head, guitar combo, 4x12 stack, etc.

 

[devastone]

I have the GT-001, which is simply the desktop version of the GT-100. One of it's cool features is that you can set the output to go into several different amps, or a hi-fi power amp like a Crown. So, you can configure it to go into a JC-120, guitar head, guitar combo, 4x12 stack, etc.

The GT-1000 has those options too, but the OP was asking about going into a DAW.

 

[Nightburst]

Well I ended up purchasing a Two Notes Captor and I can crank my real tube Mesa amp now and just use IR's inside the DAW.
Amazing product, I highly recommend this, it's plug and play really, doesn't even need power. Just speaker out from the amp into the box and line out into the AI.

The master volumes are around noon - 1 o' clock now and I can play at bedroom levels . Even in the middle of the night with headphones on.

I have been used to playing this amp live so I know the sound very well and I can honestly say that I don't notice any tone suck. The ability to be able to turn the amp up loud probably makes up for that part.

The trick to get it sounding great is to use a high quality Impulse Response. No plugins needed further so I can operate at 7mS latency. I am totally fine with this.
I am using the Boss GT-1 to finetune the low end and amount of compression I want. I love this pedal, it's got the expression pedal and all the fx I need. Using it as an 'amp' I find it lacking in sound quality but to use it for adding texture/fx/comp/eq it's really good. Funny enough the presets with the Boss pre-amps engaged actually sound pretty good through the clean channel.

I'm getting both great cleans and distortion sounds, the perfect solution for home playing without any drawbacks that the VST's have!

Also, using an (analog) Klon type pedal really adds depth and character ( I guess the correct term here should be 'complex mids' ) to the sound.