‘Studio Diary’ is an occasional series where I talk about building a home recording setup for hobbyists and enthusiasts like us. I share my personal experiences, and the thinking behind some of the decisions that I’ve made along the way.
Fractal Audio have recently overhauled their amp modelling in the Axe-FX 3 / FM-9 / FM-3. And my recent dive into the Orange Getaway Driver has shown me that I need to revoice my signal chain. I’m taking this as an opportunity to re-evaluate everything about the pedal preset I’ve built for the Axe-FX 3.
Most pedals that interest me will work best into a clean amp – either my 65 Clean preset or (for many tweed-tone pedals) my 57 Vintage preset. Every now and then, though, I take a look at a pedal that’s designed to run into a dirtier amp.
That’s where my JTM preset comes in.
Series Tracker
This is the ninth blog post in this series.
You can see the full list of these blog posts over on the dedicated FW 25 Pedal Platform Preset page.
Table of Contents
- Series Tracker
- Preset Requirements
- Unfortunately, I’m Finding This Preset Harder To Do
- Dialling In The Amp
- Dialling In The Virtual Speaker Cabs
- Other Notes
- How I Auditioned This Preset
- Final Thoughts
Preset Requirements
Why Do We Need A Preset With A Dirtier Amp?
There’s three main reasons why:
- Some pedals are designed to tone-shape an overdriven amp.
- Some pedals are designed to add extra gain to an amp that’s already overdriving.
- Some pedals rely on an overdriven amp to tame the extremes of the pedal’s tone.
For the first two, think of pedals like the Tubescreamer or many of the boost pedals that are out there. They weren’t invented to be the main source of overdrive: they were invented to improve the sound of an overdriven amp in some way.
The third category is the one that I’m most interested in.
As I understand it, there’s an important difference between clean amps and amps that are already overdriving.
- Clean amps reproduce a wider range of frequencies than an amp that’s a little bit crunchy / dirty. They’ve got sufficient spare capacity (known as headroom) to reproduce all the frequencies that come from their input source.
- Amps that are already overdriving are bandwidth-limited: that overdrive prevents some frequencies from getting louder. Their signal is clipping; it’s hitting the limit, and cannot amplify those frequencies any further (at that stage of the amp, at least).
At least, that’s my experience to date.
A Marshall Sound Of Some Kind Would Be Great Too
Whenever I want a clean Strat neck (or neck and middle) tone, I’m going to do it in one of three ways:
- I’m going to run the guitar straight into my audio interface (no amp, no cab),
- I’m going to run the guitar into a clean(ish) Marshall amp (and corresponding cab), or
- I’m going to run the guitar into a Tweed Deluxe.
Now that last one is very new to me; it’s not something I’ve done before. But the first two? That’s how I’ve done it for decades.
Basically, that’s what I’m used to. And I’d like to have that option too with the JTM preset, so that I can use pedals like my Klon KTR to get the Strat tones that I’m chasing.
Unfortunately, I’m Finding This Preset Harder To Do
I Can Never Get Plexis And Marshalls To Sound Right For Me
No matter what I try, I can’t get my Axe-FX 3 to create the same plexi tones that others do.
Here’s a good example. I love the plexi tones that Jonathan Nathan Cordy gets out of his FM-3 in this video:
He’s using a stock preset too, one that I have on my Axe-FX 3. Should be no problem getting that tone, right? Or at least close to it?
No dice. The tone that I get has a lot more low-mid content, and is nowhere near as bright or as cutting.
And that doesn’t change if I build my own presets from scratch using any of the models of vintage Marshall amps. Compared to the Fender amp models that I use, it sounds like there’s a blanket over the speakers. That’s a characteristic that I really hate, loathe and detest.
I don’t know what’s causing this.
- I’m listening to the YouTube video through the same speakers that I’m using for my Axe-FX 3. If it was just a problem with the speakers, I’d expect the video to sound dull as well.
- I’ve recorded test audio directly from the Axe-FX 3 over USB, to completely bypass my audio interface. To my ears, it sounds exactly the same as when I record through my audio interface.
It does sound a lot closer when I listen to the Axe-FX 3 through headphones, though 🤷♂️
I’ve placed an order for IK Multimedia’s ARC Studio with my local guitar shop. It’s a hardware unit to do room sound correction. It’s out of stock right now, and I’m not sure when it will arrive. Won’t be any time soon.
When it does turn up, I’ll have to come back and revisit this.
Auto-Impedance Curves Are Bugged Right Now
There’s a strange bug in Firmware 25.04 that’s affecting the tone.
In the Amp block, there’s a settings page for how the amp interacts with the Cab block, called the ‘Speaker’ tab.
On the Speaker tab, there’s a setting called ‘Auto Dyna-Cab Imp’. When this is on, the Amp block should select a speaker impedance curve to match whatever speaker I’ve loaded into the Cab block (as long as I’m using DynaCab IRs in the Cab block, which I am).
Here’s a screenshot of my Amp block’s Speaker tab. You can see that I have ‘Auto Dyna-Cab Imp.’ set to on. But, for some reason, it’s gone and selected the wrong impedance curve.
Here’s my actual Cab block settings. You can see that ‘CAB 1’ is set to ‘1×12 Div 13 CJ11’, and not the ‘2×12 Class-A 30W’ speaker that the Amp block thinks is there.
I can get around this by disabling ‘Auto Dyna-Cab Imp.’ and choosing an impedance curve for myself, sure. But that’s a pain when I start loading different speakers into the Cab block for this preset.
Dialling In The Amp
Recreating The JTM45 ‘Bright’ Channel
I’ve got two models in the Axe-FX 3 to choose from:
- Brit JM45
- Brit JM45 Jumped
I’ve tried both, and I’m far happier with the sound that I got from the Brit JM45 model. I’m running it with the bright switch on, which hopefully emulates the ‘bright’ channel of an early Marshall JTM45 amp.
Most Controls Around 1:30
Bass, Mid, Treble, Presence and (on the Ideal controls page) High Treble … I’m running all of these at around 1:30 (or around 6.25-6.5 out of 10).
To my ears, this is the sweet spot for getting a rich sound that still has the cutting note attack that I’m chasing from a Marshall-style amp.
Not As Crunchy As Led You To Believe
The gain control is on 3.07 / 10.
I’d love to run this amp with more crunch (that’s my original goal!), but I found that the amp very quickly lost its cutting note attack and became quite messy on the low E string.
Unfortunately, I couldn’t fix that by turning the Bass control down. To my ears, turning the Bass control down caused a huge EQ shift in the final tone. I didn’t like how the mid-range sounded at all – especially when hitting it with pedals – so I put it back, and decided to live with the lower gain instead.
Throwing In A Second Channel
I decided to fill the rest of the preset with a bit of an experiment, by trying to recreate the JTM45’s second channel too.
I managed to dial in a smoother tone by making the following changes to the Amp block:
- drop the value of the bright cap down to 47 pF (a common mod to Marshall amps, I believe?)
- drop the Input gain down to 0.8 (to sort-of emulate plugging into input 2 on a real amp)
- drop the Depth control down to 0 (to help keep the low-end from farting out with humbuckers)
- take out a little bit of 62 Hz in the Output EQ (to clean up the low-end a bit more)
- raise the Amp block’s output volume (to make it sound as loud as my original JTM preset)
Does it accurately create the sound of the JTM45’s other channel? Almost certainly not. But I like it, and it gives me a nice option when working with some guitars and some pedals.
Dialling In The Virtual Speaker Cabs
Non-Authentic Speakers Worked Best For Me
I own a 1×12 cab fitted with a Celestion G12M-65 Creamback. It’s the speaker and cab that I used with my Marshall Origin all the way back when the blog first started. I also have Celestion’s official impulse response pack of the Celestion G12M-65.
That gives me two useful reference sounds to help me dial in a set of DynaCabs on the Axe-FX 3.
We don’t seem to have an actual G12M-65 modelled as the Axe-FX 3 DynaCab at this time, not in a 1×12 cab anyway. But I did get damn close by using the ‘1×12 Car Ambler’ DynaCab model.
The documentation here isn’t great: we’re not told definitively what speaker this model uses. To my ears, though, it sounds like my two G12M-65 references, and that’s good enough for me.
Both Amp ‘Channels’ Use The Same Cab Block
The preset contains 6 scenes in total:
- 3 for ‘CH1’, and
- 3 for ‘CH2’
Normally, each set of scenes would use their own Cab block (that’s what my 57 Vintage and 65 Clean scenes do, inside my USA Pedals preset).
Here, though, I want both sets of scenes going through the same Cab block. For example, ‘CH1 4 Most Guitars’ and ‘CH2 4 Most Guitars’ use the exact same virtual mics with the exact same settings.
The virtual mics were all dialled in for the three ‘CH1’ scenes, and then I dialled in the ‘CH2’ amp settings to work with the ‘CH1’ virtual mics.
Too Much Low-End? Make The Ribbon Mic Quieter
This is a reminder for me as much as anything.
Each channel in the Cab block uses a virtual SM57 dynamic microphone and a virtual R121 ribbon microphone. If I’m having trouble with too much low-end, and I’m running out of things to try, then I need to go into the Cab block and lower the volume of the virtual ribbon mic.
That normally sorts it out, without drastically shifting the EQ balance of the tone.
Other Notes
Has A Tendency To Sound Narrow
The biggest challenge that I had with this preset is that pedals can sound very small and very narrow through it. They can sound like they’re missing both low-end and high-end, especially when compared to the Fender-voiced presets I’ve built.
I must have spent a fortnight just on this, trying to understand it and trying to stop it happening.
In the end, I came to the conclusion that the preset is fine: it’s just revealing how bandwidth-limited some of these pedals really are. Some of these pedals are specifically designed to tidy up the top-end and bottom-end of cranked, messy Marshall amps and the like.
It’s not a fault; it’s a feature.
Has A Tendency To Make Pedals Sound Similar
Both the virtual amp and the virtual speaker cab in this preset play a large role in the overall sound. Much more than with my 65 Clean preset. As a result, different pedals can sound quite similar with this preset.
This isn’t a surprise to me. I don’t think it’s a problem, and it doesn’t make all pedals sound identical.
This preset is for pedals that are designed to interact with an opinionated amp. These pedals aren’t for clean, neutral amps. They’re not meant to be the only source of dirt in the signal chain. They’re built to go into a dirty Marshall amp.
So, once again, it’s not a fault; it’s a feature.
How I Auditioned This Preset
I did the vast majority of my initial testing with BOSS pedals and my Wampler Ratsbane, using my PRS Silver Sky and Paoletti Loft super-Strat style guitars.
Once I was happy with the amp and virtual speaker settings, I then threw TS-style and more generic drive/boost pedals at the preset, with a few more guitars. I’ve owned most of these pedals for years; this was the first time that I liked what I could get from them.
Sadly, though, I still can’t make the TC Electronics MojoMojo sound good to my ears. That’s the one failure from my testing.
Final Thoughts
Building this preset has driven me absolutely crazy.
I’ve honestly lost count at the number of days that I’ve walked away from this preset, only to come back the following day with fresh ears and go “it doesn’t need changing” … and then try tweaking it anyway.
It was worth it.
I can now take those pedals that never worked for me through a Fender-style clean tone and enjoy them for the first time.