How much headroom do you need? Pedal platform amplifiers explained
Headroom! If you’ve been anywhere within the world of guitar amps and effects, you’ll have heard this term – but what does it mean? How much headroom do you need? Is it always a good thing?
The term is mostly used when talking about tube amplifiers, but it’s still something that you can apply to any signal chain. So regardless of whether you’re playing analogue overdrives into tube amps or a digital direct rig, it’s good to have an understanding of what it means – so let’s dive in.
Already got your head around headroom? Skip to some examples.
What is headroom when talking about guitar amplifiers?
Headroom is, generally, a way of describing how cleanly an amplifier will respond to an increase in signal. In terms of guitar amplifiers, it’s used in two main ways – how much signal a preamp can handle before limiting, and how loud you can turn an amp up before it starts to distort. Let’s look at preamp headroom first. Imagine, if you will, a simple signal chain of an overdrive pedal running into a clean amplifier. Turning the overdrive’s volume up will of course increase the level of signal coming out of the pedal. So the louder you turn that volume pot, the louder the amp will go, right? Yes – at first. If the overdrive is loud enough, there will ultimately be a point where increasing the volume of the signal going into the amp doesn’t increase the volume coming out of the amp.
Instead, things will just get more compressed and distorted, because you’ve hit the preamp’s headroom. It’s not an immediate hard ceiling, but there is ultimately a limit to what any preamp can handle, even on the cleanest setting possible. Tube preamps will distort differently to solid-state preamps, but both have their limits on how much incoming signal they can handle cleanly.
And so amplifiers with more preamp headroom are traditionally viewed as good pedal platforms – because they’re able to cleanly handle the output of your favourite pedals, without imparting too much of their own distortion and compression. Amps like Fender’s Deluxe Reverb and Hot Rod Deluxe are classic tube combos for this application – wallpaper-strippingly loud and as clean as you like most of the way up the volume dial.
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One really easy way to avoid overdriving a tube preamp is to, well, eliminate the tubes. The Roland Jazz Chorus amps – such as the JC-120 – are excellent solid-state options with extremely high-headroom clean sounds on tap. Solid state amps are, in general, better at staying clean – obviously, this has given them their reputation as more ‘sterile’ than their tube counterparts, but for super-clean high-headroom applications, that’s no bad thing!
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Obviously, the thing to keep in mind here is that pushing a preamp can sound really good. It’s basically the whole principle behind overdrive pedals – our ears generally like the extra compression and harmonic overtones that result from a signal being even slightly limited, especially by tubes. This is also essentially the basis of tube amplifiers with dedicated overdrive/distortion channels – these channels are set to already overload themselves by amplifying the signal to the point where the tubes can’t cleanly amplify it anymore.
So what’s the benefit of a high-headroom preamp, then? Firstly – as good as it sounds, you may not be playing the sort of music that requires the sustain and compression that comes from overloading a preamp. Funk, for example, needs loud transients percussively establishing a rhythm – you’ll need your amp to have enough headroom to let those clean transients through! There’s a whole other discussion there about guitar-friendly compressors and attack times, but that’s something for another day.
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Another musical consideration is overall dynamic range. You might want to be able to play softly in the verses and then open things up for a chorus – this will fall a little flat if you’ve already hit your amplifier’s headroom. You’ll have nowhere to go when you need to gun it. Relatedly, what about solos? If you’re at your amplifier’s headroom before your big moment, it can be hard to then give yourself a lift to stand out from the rest of the band.
Say you’re using effects like reverb and delay – if your amp doesn’t have an effects loop, you may want to keep the delay repeats and reverb trails clean, even if they’re being applied to an overdriven sound. A good pedal platform amp in this case is one with enough headroom to handle your dry signal – clean, dirty or anywhere in between – and the wet signal from your delay and reverb pedals. Alongside delays and reverbs the same goes for any other pedals that kick out a lot of extra information – freezes, loopers, synth and organ pedals and so on.
Headroom and volume
When people talk about high-headroom clean amps, they’re not just referring to the preamp. It also refers to an amplifier’s ability to stay clean while turned up to gig or rehearsal volumes. Like a preamp, an amp’s power amp – the part of the circuit that gets things to speaker-driving levels – will only be able to be pushed so hard before it also starts to distort.
One of the most important determining factors as to when this will happen is the amp’s wattage. A 15-watt tube amp and a 100-watt tube are actually not that far away from each other in terms of their maximum volume, measured in dBs. However, in general, a 100-watt amp will be able to stay clean while turned up much louder than the 15-watt one.
Image: Electro-Harmonix
What does this mean in practice? Well, say you’re playing a gig and you’re competing with an extremely heavy-handed drummer, and the sound engineer isn’t bothering to mic up the guitar amps. So you set your 15-watt amplifier to absolute maximum, go to play a clean part – hey, did you leave a distortion pedal on? Nope, it’s just that the amplifier cannot stay clean when set this loud. The power amp tubes are working as hard as they possibly can, and so have started to overdrive – just like preamp tubes might.
This can still be a problem even if you’re using a deliberately overdriven sound. Once the power amp is at its limit, you’re effectively running anything that’s in the effects loop into another distortion stage – which, in some ways, defeats the point of the loop. Power amp distortion can smush reverb trails and delay repeats into a much less articulate, smeared-together howl. This can be great fun to play with, but it’s not ideal for all musical settings.
The traditional solution, of course, is to get a higher-wattage tube amp. This will get you to the same physical volume earlier on the dial, and keep the power amplifier well within its headroom for amplifying any clean sounds and/or delay repeats.
However high-wattage tube amps are heavy and expensive. Another solution is to explore the solid-state path. We’ve already mentioned the JC-120, but for sheer head-blown-off volume, it’s hard to beat Orange. The Orange Pedal Baby 100 is utterly pristine and clean with an absurd amount of headroom, plus it’s portable and pretty affordable – and if you want something in the same form factor but don’t want to use a pedal preamp, the Tour Baby 100 uses the same solid-state power amp but includes two great-sounding channels for clean and dirty playing.
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Is headroom always good?
There’s an argument to be made that an amplifier is simply an extension of your instrument. Hence asking if headroom is always good is a bit like asking if seven strings are always better than six – it all depends on what you want to achieve musically!
High-headroom amplifiers are great but there’s a reason attenuators exist – sometimes, if you want to get certain amps sounding their best, you’re going to have to be playing at absurd volumes. Not great if you’re recording at home, or if you want to reduce your stage volume to something reasonable. Here, a lower headroom option is great – tiny, low-wattage combos like the Supro Blues King 8 or 12 are great ways of getting the sound of an amp pushed well beyond its limit without waking up the neighbours on the other side of the street.
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If you still want to reach gigging volumes but want to really get gnarly, amps around the 15-watt mark are, in general, more than loud enough to compete with a drummer – but will start properly cooking up some serious power-amp distortion when turned up. Personally, I’ve used an Orange OR15 for this purpose many years – but keep in mind that at full whack, it’s basically like having a fuzz pedal permanently at the end of your chain!
Another option is the venerable Fender Blues Jr, which has a bit of a cleaner preamp but still sounds absolutely killer when turned up high!
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But even if you want to stay pristine and clean throughout a set, it’s worth remembering that…
Volume is complicated
This is all a bit of a simplification, as there are many, many things that determine how ‘clean’ you sound at different volumes. Different amp designs all respond differently to being cranked – just because two tube amps have the same wattage, they definitely won’t have the same amount of headroom. Guitar speakers also have an upper limit which varies between them, and will distort and compress even the cleanest of sounds when driven hard enough.
With vintage-style tube amplifiers, a lot of them have certain volumes where they just sound their best – they strike a balance between working their preamp and power amp valves a little bit, while still giving you more than enough room to work with your own pedals and playing.
The Fender Deluxe Reverb, for instance, is only 22 watts. Piddly, you might think, compared to some 100-watt behemoth, but if you’ve ever heard a Deluxe Reverb on 3, you’ll know that it’s got a hell of a lot of volume and headroom at this point – most likely more than you’ll ever need in most gigging situations! So headroom, and how well an amp will work as a pedal platform, will depend on the specifics of the amps and pedals in question, as well as what you’re aiming to achieve with them. So let’s dive into some specific examples that might be helpful in getting towards your sonic goals.
High headroom, gain-stacking overdrives
A traditional approach for those who like pedal-platform tones is to stack a few overdrives before a cleaner amplifier. This gives you a palette of different sounds at your feet – cascading one drive into another will obviously increase the amount of distortion happening, but it also means you can mix and match for different levels.
It’s worth noting that, like amplifier preamps, overdrive pedals will have their own levels of headroom – so gain staging traditionally goes from lowest-gain to highest-gain to keep from any low-gain pedals getting overwhelmed.
The aforementioned Fender Deluxe Reverb is absolutely fantastic in this regard, as is the slightly more affordable Hot Rod Deluxe.
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Solid-state solutions
As already mentioned, Orange’s recent Baby series – plus the original Pedal Baby – are all great options for hassle free headroom.
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Plus there is that old reliable of the Roland JC-120 Jazz Chorus – it’s sworn by as an utterly excellent pedal platform for a reason!
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More affordable still is Blackstar’s recent Debut 100R, a solid-state combo that’s capable of being set very loud and very clean, and does wonderful things when paired with your favourite overdrives or distortions.
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Digital modelling
Early digital modelling amps weren’t fantastic at handling lots of input signal from loud pedals. When analogue-to-digital conversion clips, it’s not normally a pleasing sound. However, more recently digital modelling amps have much more sophisticated input stages and therefore are much more capable of responding well to pedals.
The latest generation of the venerable Boss Katana amplifiers – Gen 3 – adds a brilliant new amp model called ‘pushed’ – it’s really, really good at responding like an edge-of-breakup Fender to overdrive pedals.
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Speaking of digital models of edge-of-breakup Fenders, there’s a whole range of digital modelling amps dedicated to doing just that! The Tone Master combos are brilliant digital models of specific Fender tube amps, and their input stages are just as happy accepting fuzzes and drives as the real deal. Plus, thanks to some speaker design choices and the lack of any heavy transformers, these combos are featherlight compared to their tube counterparts.
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You might also want to explore other digital paths – we’ve spoken a lot about stage volume today, but what if you want a silent stage? The direct choice is more viable than ever these days, and one amplifier pedal stands out as a particularly good high-headroom clean option for this application – the Universal Audio Dream. There’s a reason you see it at the end of massive ambient and worship pedalboards!
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