How to Maximize Your Tube Amp’s Harmonic Saturation

Have you ever recorded a clean guitar track only to notice it sounds remarkably fuller and slightly more overdriven after it runs through the preamp and plug-ins designed to accentuate natural frequencies? Harmonic distortion is playing a big part in this phenomenon. What if you could accomplish the same thing through your tube guitar amplifier?

 I’ve been doing a lot of experimentation with maximizing harmonic saturation lately. I removed a few “harmonic sucking” pedals from my pedalboard and tuned everything in my signal chain to accentuate the 2nd, 4th, and even 6th generation even order harmonics produced by my tube amp. The odd order 3rd, and 5th generation harmonics play an  important part too, but it’s the even octave ones I’m working to bring out due to their musicality.

Note: I’m using a Bad Cat Stella with their patented K master circuit that’s explained here: Bad Cat Cub III Review. When turned up above noon this master circuit has the ability to boost the EL34 power tubes without stressing them in the least. The result is a massive amount of harmonically rich power tube saturation. The pentode EF86 in the V1 position and dual triode 12AX7 tone stack buffer in the preamp also abound with harmonics.

How’d I get here?

I’ve been heading in this direction after noticing how some of the P&W guitarists I work with are able to cut through the mix in a concert setting much better than others. The ones that rely on multiple stages of EQ altering boosts and grainy overdrives set at high gain tend to get lost in the drummer’s cymbal wash with all of their unnatural artifacts. While the ones who use their pedals to accentuate frequencies rather than distort them (James Duke is a great example) are able to introduce new frequencies that cause their tube amps to respond in natural ways that are full of harmonic saturation and just plain beautiful at even the highest gain settings.  They don’t get more distorted, just more saturated with rich harmonics. When using ethereal and modulated effects they tend to cut through the mix better too, sounding more like a 3D orchestra than a one dimensional horn section.

Where do we start?

Well, at the source of course! The most important contributor to great guitar tone is a harmonically rich instrument. If a guitar sounds good unplugged, it is most likely capable of sounding great amplified. An amazing sounding instrument will give the harmonics produced by analog circuits, high quality processors, and vacuum tubes along the way more to work with.

Many of the tips mentioned in my previous article A Few Inexpensive Ways to Improve Your Tone can help bring out desirable frequencies very early in your signal chain. A perfectly intonated instrument, hardware, nut, strings, pickups, pickup height, wire loom, switches, pots, tone/treble bleed caps, and instrument cables are all inexpensive but very crucial contributors to a full sounding signal.

Adjusting Your Pedals

Anything added to your chain after the signal leaves your guitar should act to accentuate the frequencies you want to hear. I recommend that you get your fundamental tone dialed in where you want it before you start adding pedals. Plug your guitar lead straight into your amp and follow the steps in my previous Tonesmiths Report entitled How to Quickly Dial In a Tube Amplifier. This article explains how to set up your tube amp in a way that increases touch sensitivity and note bloom. After all, if you don’t like your basic tone then no amount of effects pedals is going to help.

Remember this is rock-n-roll, so these aren’t rules just suggestions for increasing the presence of harmonic distortion in your signal chain. There are no rules when it comes to pedals designed to intentionally produce crazy noises or massive amounts of gain. Use whatever gets you the sounds needed for the music you play. Just be sure to choose pedals made from quality components that sound natural when engaged and bypassed. Beware of the “tone suckers” and don’t get too caught up in the true bypass thing (the Klon should’ve debunked that snobbery long ago). Here are some pointers for selecting and dialing in a few of the most commonly used pedals.

 Compressor/ Expander/ Sustainer- These can both act to accentuate desirable frequencies. Just be careful not to squash your signal to death. I abandoned my onboard compressor since my tubes provide enough natural compression and the sound engineer generally compresses my signal in the house mix. I replaced it with The Schaffer Replica by Solodallas. This compressor in this pedal is followed by an expander that removes unwanted squash and pump while still allowing for dynamic leveling. It also increases sustain and introduces tons of rich harmonic content. My best discovery in recent years. You can read about it here in our Tonesmiths Report entitled  The “Schaffer Sound” is Back!

Clean Boost- The trickiest part is finding a transparent boost with a perfectly flat response. That will allow you to push the tubes in your amp into natural saturation and work well as a lead boost without messing with your EQ every time you step on it. Boosts shouldn’t be left on to make your amp sound fuller. If this is needed then just turn up the volume and adjust the EQ to achieve the same thing without it.

Overdrive- Finding a overdrive that introduces low mid to treble frequencies that cause the tubes in your amp to react in a musical ways isn’t easy either. Try setting your overdrives on the edge of breakup with the EQ set as bright as you’re comfortable with. Other ODs with different colors can be used independently or added in stages to introduce as much harmonic distortion as you like.

Distortions and Fuzzes- Believe it or not there are distortion and fuzz pedals that generate harmonic distortion that’s very musical. Sometimes those pedals nail the “bad tones” perfectly. Other distortion pedals use a controlled mix of even and odd order  harmonics to produce smooth amp-like overdrive that doesn’t sound or react like a pedal.

A lovable fuzz pedal can be hard to find. Silicon fuzz pedals tend to be smoother sounding, whereas germanium based fuzzes produce a grainier square wave frequency that is nearly made up of all even order harmonics.

Reverbs-  reverbs are more important in this equation than you may think. They contribute ambient overtones that can either make your overall harmonic structure artificial sounding or become the harmonic icing on the cake. Try adjusting the tone knob to a resonant frequency that complements the uppermost frequencies produced by your amp.

Other Pedals- There’s an ever-growing sea of amazing (and not so amazing) effect pedals out there to choose from. Too many to cover here. Just have fun experimenting and discovering new sounds. You may want to consider a signal buffer if you run more than five pedals though.

This YouTube video does a pretty good job of describing the basics of how harmonics and harmonic distortion are generated:

Frequencies & Sound explained #4 : Harmonics & Harmonic Distortion

Tonesmiths is a gear consultation service. We offer free tone-shaping advice to touring and aspiring guitarists. Please contact us below if you need any help designing your sound.

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2 Responses to How to Maximize Your Tube Amp’s Harmonic Saturation

  1. ejangi says:

    So, out of interest, which pedals did you find produced these harmonics?

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