If you watch That Pedal Show regularly you will have heard Dan and Mick saying that Harmonic Tremolos are pretty rare and few and far between, but there are probably a few more out there than most people would have thought. I’ve had several requests recently to do a feature on purely Harmonic Tremolos so this is it! Harmonic Tremolos first appeared on amps like the early Magnatones and Supros as far as I understand, and have a very vibey tonality to them based on how they modulate the signal. To such an extend that Mick Taylor is currently using the Supro Tremolo in place of a Uni-Vibe. Standard Tremolo is frequently called Volume, Amplitude or Bias Modulation, while Harmonic Tremolo is rather Frequency Modulation.
My own knowledge of the genre comes mostly via use of my own favourite tremolo - the Chase Bliss Audio Gravitas - and for me, Tap-Tempo is a must for all my time-based modulations. I also personally have a significant preference for compact enclosure pedals - possibly a stretch to vertical medium enclosures if I must - so it’s immediately evident which of these pedals is likely to find favour with me. That is not to say some of these single footswitch pedals don’t sound great - as for many the Supro is the best sounding tremolo ever. But for me it’s always a combination of tone, feature set and form factor.
Some other well-known harmonic tremolos include Strymon’s Flint TremVerb and Walrus Audio’s Monument - which has recently been shrunk to my ideal form factor in its recent V2 incarnation. Each of the pedals featured here will do the job nicely - and several here have some very unique features - so it really depends on what your criteria are and usage preferences. I personally would be very unlikely to buy a tremolo which did not include tap-tempo. I would also likely dismiss what I determine to be over-sized pedals for a single effect - so I would not really want to go beyond a medium vertical enclosure as mentioned. That still leaves me with 7 options in the running from the above.
I so like my Gravitas that I’m not likely to abandon that any time soon, but there are a few more here that I have some significant interest in - for rotation purposes. The Strymon Flint has been on my wishlist for the longest time - and it really makes sense for my rig for occasional rotation / swap-out of the Source Audio Ventris - so I can have Tremolo after the delay. I’ve long intended to get the Flint - but it’s not happened yet. I also really like the extended functionality of the recently relaunched Drolo Twin Peaks Tremolo - so I definitely have that in my sights. Finally, I also really like the additional features added to the V2 Flower Pedals Dandelion Tremolo - so that’s up for consideration too.
Pedals are listed alphabetically by brand:
This was my first Chase Bliss Audio pedal and I use all of its 3 modes regularly - Standard, Harmonic and Combined. It also does all those really interesting bounce/ramping features which give you more textured rhythmic output. I still feel that Chase Bliss's analog effects are genius in how they work - with the wave-shaping, onboard presets, dip-switches and tap-tempo. And I know lots of players who really love this pedal too. Even though I'm considering getting additions here and alternatives like the Subdecay TremCoder - I still feel that the Gravitas will remain as my principal tremolo pedal of choice.
This medium enclosure tremolo has some cool features onboard - not least the 4 different modes - Tap (Tempo), LoFi (Bass-cut), Dist (Max Grit) and DBL (Double rate). There are also 4 wave-shapes and a rather unusual Grit knob for more lo-fi textures. The final cool feature is how the rate LED changes from yellow to red when you switch from standard to harmonic mode. This particular tremolo is just a little out of the ordinary - so it may be the one for you - while for me it's a touch over-sized in its format. Nonetheless a pretty cool addition to this genre.
This has just been revised and re-launched, and of course the first batch sold out almost immediately. But as is the way with Drolo - there will be another batch along soon enough - roughly one per month. This is a really smart 4 mode harmonic tremolo - Volume Modulation (Classic) | Frequency Modulation (Harmonic) | Bass Modulation Only, fixed Treble | Treble Modulation Only, fixed bass. You also get 8 wave shapes, a Symmetry knob, 3-way Tap Tempo multiplier switch and 3-way Envelope Mode switch - Middle deactivated Enveloper detector, Up increases rate as signal increases, Down decreases rate as signal increases - you also have the Envelope knob to adjust the sensitivity of the envelope detector / trigger. All in all a quite unique take on the format - and one what I'm very interested in acquiring at some stage.
EQD usually has its own unique take on the format - and the Night Wire is no exception. The key elements here are the two toggle switches - the upper of which controls the Tremolo portion - Attack or Manual - meaning the former allows you to ramp up tempo by degree of pick attack. The second switch controls the envelope filter portion with Manual, LFO (sweeping) and Attack modes. If you roll the depth back the Night Wire will act like a fixed filter, phase-shifter or envelope-controlled-filter depending on the Frequency mode selected. Of the 4 dials the Frequency control is the unusual one - and with the combination of features here this makes for a really feature-rich experience. I would have still like tap-tempo to really though!
The Tre-Verb to me has always seemed to be Fender's take on the Strymon Flint - they're not identical - but superficially they are very similar - 3 Reverb modes - '63, '65 and Plate and 3 Tremolo modes - Opto, Bias and Harmonic. You also get the typical controls you would expect for each of those effect types - Blend, Dwell and Tone for the Reverb, and Level, Depth and Rate for the tremolo - it's a decent take on the format and pretty reasonably priced - but does not have some of the extra bells and whistles these others have!
I liked this when it first came out - but the new V2 version is killer - with its smart Dual tremolo mode and Ramping functions. You can do all manner of secondary / alternative settings by holding down the On/Hold button - setting a secondary tremolo and fine tuning settings a la Alexander Pedals and Meris. On the surface it does not look like there's too much going on - but if you check out he above demo video you will see what really makes this pedal special. I always had the Walrus Audio Monument above this in my own compact tremolo pecking order - but these new features have elevated the Dandelion to second place here! It's been up and down my wishlist for a while - but I think I may just add this for rotation duties in the next few months.
This is another pretty cool take on the format - with just 3 knobs - Intensity | Shift | Frequency, 2 modes - Pulser | Panner and Presets! What you initially think is a tap-tempo footswitch is actually rather a Preset selector. This is actually a really gorgeous sounding tremolo which really uses the stereo field well - I would probably still have preferred tap-tempo here too!
This was actually the very first Tremolo pedal I intended to get - before I came across the CBA Gravitas and Stone Deaf FX Tremotron and settled on those two instead. But the Flint has never left my affections - it features high amongst John Mayer's favourites too if that is any significant endorsement for you. As I've mentioned above - the Fender Tre-Verb is really very similar to this, albeit with different selections - you still get 3 Reverb and 3 Tremolo modes - for the latter - '61 harmonic | '63 tube | '65 photocell. I'm a big fan of Strymon so I would obviously pay the premium for the Strymon. I have intended to get this pedal for the longest time - and is still makes sense now - as I can have the Tremolo at the end of my chain (after stereo delay) - using a TRS splitter cable for stereo in here. This is obviously a digital effect and some purists are adamant about only having analog modulations - but I mix mine up fairly regularly - to it's not an impediment here. There are two Strymon pedals that have been on my wishlist forever - this one and the Lex Rotary - neither is really a current priority - but I feel both will be added to the Tone Library eventually - it's always good to have options and alternatives.
A relatively simple but effective all analog harmonic tremolo - you can still flick it to standard / Bias mode courtesy of the mode switch - otherwise you have just 4 controls - Speed | Intensity | Envelope Drift | Volume. There's no frills here and no tap-tempo which is obviously a big deal for me, but may not be for other players wanting a simpler and more straightforward experience.
The Supro is the simplest Harmonic Tremolo featured here - just a mode switch for - Amplitude (Standard) / Harmonic - and then 3 dials - Depth | Gain | Speed. Yet is has a huge number of fans - and you will see it on quite a number of pro pedalboards. Mick Taylor (TPS) obviously loves his and uses it as a substitute for a Uni-Vibe. I love the sound of this, but would love it more if it also came with a tap-tremolo. I'm also a tweaker at heart - which means there are several other pedals listed here which are more suitable to my preferences. For those though looking for the simplest great sounding harmonic tremolo - this is likely your best candidate.
The V1 forerunner was always one of my favourite sounding tremolos - but a little on the large site for my needs - so it was good news all-round when Walrus shrunk down their formidable Monument to compact size - with all the feature set fully in tact - you just get the same great sounds with tap-tempo in a much more convenient enclosure size. This was for a while my second choice for Harmonic Tremolos - after the Gravitas - but the recently revamped Dandelion from Flower Pedals just pips it in its own updated version. Each does a slightly different thing - and they're both wholly worthwhile trialling to see which you like the best - you may find the hidden features of the Dandelion a little tricky to use - while everything on the Monument is straight up and straightforward - one of the best of its kind.
This is a glorious sounding full-featured harmonic tremolo - available both in DIY kit and fully assembled editions. I have no qualms about its extended feature set or how fantastic it sounds. It is a rather large pedal though. You do get 7 knobs, 2 mode switches and several internal trim-pots and dip-switches - and of course the obligatory tap-tempo footswitch. My only issue here is one of size really - as you would be sacrificing a lot of pedalboard real estate to a single effect - however good. And there is plenty of competition from several of the more compact versions here. The Quaverato has been very well received - it's just a little larger for my preferences!
My readers are getting pretty good at spotting and recommending overlooked pedals - and one such on this occasion is Source Audio's 3-Mode Vertigo Tremolo. You get Normal, Harmonic and Bias Tremolo options alongside 4 control knobs - Depth, Speed, Shape and Level. This is another great sounding tremolo - but I could have really done with a tap-tempo here too. Somewhat under the radar at the moment and therefore very reasonably priced - should be worth a gamble!
When I started the longlist I had a lot more pedals on it - some turned out to not really be proper harmonic tremolos while others were sort of inconclusive. Some of those that missed out include the Bigfoot FX Magnavibe Harmonic Tremolo, the Coldcraft Harmonic Tremolo V2 which is likely discontinued now, and the Keeley Monterey - from which you can extract a sort of Harmonic Tremolo from - but it's not necessarily official as such. As with any categories there are numerous small batch boutique pedals and many that are no longer in circulation for various reasons.
As to where my own tastes lie - I feel each pedal here has its own advantages, but all my favourites have to come with tap-tempo - and of course the more compact the better! So my own top 3 here are Gravitas, Dandelion and Monument. While I also like and will actually most probably be acquiring the Drolo Twin Peaks and the Strymon Flint - although there is not pressing priority on those.
Other players may have other requirements and preferences and prefer some fo the simple non-tap-tempo pedals here. If you are in the market for a Harmonic Tremolo than I believe I've pretty much got you covered with this selection - and you should be able to select from this list. If you feel I've overlooked something that should be here - please let me know!