J.Rockett Audio Designs Archer Review – Best “Klon Centaur/KTR” Pedal?

Reviewed by:
On June 9, 2015
Last modified:October 8, 2016



The J.Rockett Audio Designs Archer has been drawing a lot of attention lately from tone-obsessed guitarists. You might assume that’s only because the Archer is obviously another Klon Centaur inspired pedal. But the story of the Archer is a bit more interesting than that of any mere “Klone”. When Bill Finnegan at Klon decided to create the successor to the legendary Centaur, the Klon KTR, he sought none other than J.Rockett to bring it to life. After J.Rockett built the original Klon KTR units, the companies parted ways. To the dismay of guitarists everywhere, Bill refuses to build Centaurs again although several companies have stepped in to attempt recreating the iconic overdrive/clean boost pedal to fulfill demand. But among them all J.Rockett is arguably the most qualified builder to authentically replicate a Centaur thanks to their intimate knowledge of every aspect of the Centaur/KTR pedal design. After spending about a year re-creating the Centaur, carefully arranging spec-accurate components while measuring power traces at every turn, J. Rockett was finally satisfied that they had accomplished the unthinkable: creating a small, pedalboard-friendly pedal that can perfectly nail the Klon Centaur sound. Thus the Archer was born.

J-Rockett-Audio-Designs-Archer-Review-Best-Klon-Centaur-KTR-Pedal-02Mythical Diodes, Mythical Tone

Anyone who’s heard of the Klon Centaur has probably heard about the overblown hype surrounding this pedal. While Bill tried to hide the circuit in the beginning, the schematic was eventually discovered and cloning ensued. But the exact germanium diode used to achieve the Klon’s style of clipping was the one secret known to no one else… until now. While even J.Rockett themselves doubted the claims about the so-called “mythical diodes”, they spent months swapping diodes and discovered that no other diodes have the correct forward voltage as the specific NOS germanium diodes used in the silver Klon Centaur. Bill’s claims were accurate. Thus the J.Rockett Archer is the only Centaur inspired pedal that doesn’t deviate from the original schematic and contains the exact same diodes as the original silver Klon Centaur. It isn’t fair to call the Archer a mere clone of the Centaur. The Archer supposedly is the Centaur. But what is the Centaur exactly and why is it so sought-after? Here’s a brief history of the pedal from which the Archer draws its inspiration.

Along Came A Centaur

Although the Klon Centaur probably needs no introduction as being one of the most sought-after, valuable, and controversial stomp boxes out there, the fact that it’s actually a very simple yet useful pedal might have escaped some. The builder, Bill Finnegan, originally set out to create the ideal pedal to push an amp already at the edge of breakup into a musically pleasing and expressive overdrive. The consensus among dedicated Klon Centaur users is that he succeeded. Thus, where the Centaur really shines is in pushing your amp into overdrive by boosting the volume and emphasizing the ‘right’ frequencies while adding a slight amount of overdrive of its own for some extra grit and sustain if desired.

However, according to the opposite camp who don’t worship at the Klon Centaur altar, the pedal can be somewhat bland and disappointing (especially considering the prices today) when used as a standalone overdrive plugged into a clean amp (i.e. with the level at or below unity and the drive coming from the pedal itself).

This also means that the Klon Centaur cannot be easily judged on it’s own, since it’s highly dependent on the amp and the way it’s dialed in: when the amp is too distorted you might not notice much difference, and when the amp is too clean it will mainly make the signal louder, which is nice, but not something to get very excited about.

It has to be noted that when it comes to overdriven guitar sounds, drive pedals generally sound more natural when pushing an amp that’s already breaking up, so the Klon Centaur was nothing new in that sense (Tube Screamers were doing this for years).

And thankfully these days there are a good number of overdrive pedals out there specifically designed to do what the Klon doesn’t: completely change the gain structure of the sound when paired with a clean/neutral sounding amp (most of these are higher gain/distortion and ‘amp emulation’ pedals).

So in essence the Klon is a fairly humble drive/boost pedal, sharing a lot of it’s design with earlier classic drive pedals, but it does have a few key design elements that, especially at the time, were fairly unique and can be held partly responsible for the circuit’s success:

  • The gain control utilizes a so-called ‘dual gang’ potentiometer, relatively uncommon in guitar pedals. This means that when turning the gain control you are in essence turning two potentiometers, simultaneously controlling the amount of clean signal and overdrive, making for a very effective clean/dirty blend, which helps maintain some of the clarity and punch, especially on lower gain settings.
  • Upon entering the pedal, the voltage gets converted from 9v to 18v, via a charge pump, which results in more headroom and therefore more dynamics and available output.
  • The Klon Centaur is non-true bypass which means its buffer is always in the circuit, adding a little bit of color on it’s own. I like the added sparkle of this particular buffer design so much that I actually have a DIY standalone Klon buffer circuit mounted underneath my pedalboard for that reason, but it really is a matter of taste and might be ‘too much’ in combination with other pedals and also requires a little extra thinking when implementing into a pedalboard.
  • Not so much a design feature, but rather a matter of dedicated customer service, Bill Finnegan reportedly talked to potential buyers about their playing style and setup, helping them determine whether or not the Klon would work for them, and therefore decreasing the chance of disappointing his customers.

Although the hype and ridiculous secondhand prices would make you assume the contrary, there is no magic involved in the creation and production of this mythical pedal, but rather quite a bit of smart thinking and hard work. By now, 20 years after Bill sold his first Klon, the circuit has become readily accessible information, and there are a ton of builders and companies out there selling copies (aka ‘Klones’) to a varying degree of accuracy, which can be accounted to these factors:

  • Apart from the circuit clearly being the result of a lot of tweaking, Bill Finnegan, like most small builders today, reportedly was quite picky about the type of components used (there are quite a few different materials and manufacturing technologies used for each of the common components within a guitar pedal). These design choices are not considered as inherent to the circuit but rather the interpretation of the circuit, and this can account for the (arguably small) differences in sound between identical circuits.
  • The best example of this is in regard to the type of clipping diodes used, since those in the original Centaur pedals are unmarked and therefore somewhat of a mystery to everyone besides Bill and J.Rockett. Although their voltage has been measured and it is known that they are likely NOS (New Old Stock, not currently manufactured) and Germanium (a material type), a measurement and physical inspection didn’t provide all the info needed to identify this particular diode. (This is a big reason why no other “Klone” has a chance of being as 100% accurate as the Archer in achieving the Centaur sound.)
  • In order to maintain consistency from pedal to pedal, Bill likely also measured each part to be within spec, something which is often too time consuming when mass producing.

Obviously it must be noted that not every builder’s goal might be to exactly replicate the original Klon, as there is always room for modifications, mainly in regard to the buffer/true-bypass issue, the character of the clipping diodes, and/or the somewhat limited tone control.

Due to J. Rockett’s collaboration with original Klon builder/designer Bill Finnegan on the Klon KTR, I think it’s fair to say that they’re perhaps the only company out there outside of Bill himself who knows all the details and has the necessary skills required to execute a truly authentic Klon Centaur replica. This is why the J. Rockett Audio Designs Archer is perhaps the most noteworthy of the ‘Klones’ out there.

All that being said, for the rest of the Archer review I will primarily be judging the Archer by its own merits, since this review isn’t meant to be a comparison or shootout.

Archer Features:

  • Contains the same NOS Germanium Diodes and design schematic as the silver Klon Centaur.
  • Controls for Output, Treble, & Gain.
  • Built to accurately capture the playability, sound, and response of the Klon Centaur.
  • Internal charge pump converts 9 volts to 18 volts for added headroom.

Starting on the outside, I suspect the enclosure was specifically manufactured for J.Rockett, as is the case with their other pedals, and it has a couple of unique features:

I hadn’t noticed it from the photos online, but in person it is immediately apparent that the Archer is a lot smaller than most pedals, similar in size to the small MXR style enclosures. In contrast to its size it’s actually quite heavy and feels very solid.

The input/output jacks are top-mounted on either side of the 9v input, which can be a little tight depending on the type of connectors used (pancake jacks may not be ideal), but this does facilitate easier pedalboard positioning next to other pedals with top-mounted jacks.

J-Rockett-Audio-Designs-Archer-Review-Best-Klon-Centaur-KTR-Pedal-03The 4 screws to open the pedal up are on either sides of the enclosure, which means the entire bottom plate could potentially be covered in velcro or 3M Dual Lock, and it could stay attached to the pedalboard when replacing the battery (providing you’d allow for a way to get a screwdriver close enough and at the right angle) if you’d rather not rip the whole pedal off the board.

The status LED does not have a bezel, but is slightly recessed (although clearly visible when lit), so it can’t be accidentally pushed in.

The controls are laid out in a triangular array like most 3 knob pedals, although it must be noted that the order from L-R is Output-Gain-Treble as opposed to the original Klon and most ‘Klones’, where the order is Gain-Treble-Output (something to be aware of when comparing settings). This change is probably due to have to rearrange the components on the PCB to accommodate the smaller enclosure while remaining faithful to the original Klon Centaur schematic.

After living with it for a while I did notice that the silver/chrome finish is prone to scratching, but for what it’s worth, even when it doesn’t look new anymore it’s still a very classy looking pedal with the color scheme and knobs clearly referencing the original Centaur, a nice indicator of J.Rockett’s attention to detail.

On the inside the Archer looks like a work of art, with a classy black circuit board and very efficient use of space. From what I understand (without mapping out and comparing schematics) the Archer is an accurate replica of the original Klon Centaur, but one notable difference is that in order to make it fit in such a small enclosure the Archer uses a combination on through-hole and surface mount components (also referred to as ‘SMT’ or sometimes ‘SMD’, tiny, machine soldered components) which does make for complicated repairs should it ever break. The Klon KTR differs from the original Centaur in this regard as well with the Centaurs being 100% hand-wired. The Archer also uses smaller 9mm potentiometers which help this pedal achieve its significantly smaller size, and thus, make it much for pedalboard-friendly than the massive Klon Centaur.

In addition to this, the pots and jacks seem to be board-mounted, meaning that pulling on the cables or accidentally stomping on the controls could potentially cause stress on the PCB. This used to be a concern on cheaper mass produced pedals, but J.Rockett has a good reputation in regards to build quality, and this pedal feels remarkably sturdy. As always, time will tell, but I don’t expect any issues.

Also, although I wasn’t expecting it from the size, the Archer does actually have a 9-volt battery option.

Visit J. Rockett Audio Designs for more info about the Archer.

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Sound & Performance:

J-Rockett-Audio-Designs-Archer-Review-Best-Klon-Centaur-KTR-Pedal-04Here’s a brief evaluation of the Archer’s controls.

Output: Unity gain is typically between 8-10 o’clock (depending on the gain control setting), and it gets very loud at maximum, maybe not as much as a dedicated clean boost like the Keeley Katana, but definitely more than a Tube Screamer for example.

Gain: Clean when turned all the way down to a decent amount of drive when on maximum, again, more than a Tube Screamer and maybe even comparable to lower gain settings on many common distortion pedals.

Treble: This one is fairly limited but dialed in to a very musical range, so it’s hard to find a bad setting. Even at maximum it’s never shrill or piercing. In my experience its main purpose is to fine tune the inherent treble response of your setup as opposed to radically altering the frequency response. It’ll help you match the tone and response to single-coils or humbuckers, for example.

The classic ‘Klon’ setup would be with the Gain somewhere in between minimum and 11 o’clock, Output between 9 and 12, and Treble to taste while being plugged into a vintage-voiced tube amp which is just about to distort. My personal favorite sound was using either a Les Paul Standard for big beefy classic rock tones or a low output vintage style Telecaster for more roots type playing, both through a vintage Fender Champ dialed in to a slight crunch. The resulting sound is still honest and clear, with a nice touch of sensitive sparkle and typical roar when hit hard. No huge surprise there but lots of fun and very inspiring to play.

Using the Archer on higher gain settings through the same amp was more useable than I expected, with the amount of gain available clearly dependent on the output of the guitar’s pickups. Using the Les Paul, the character would be reminiscent of 70’s era hard rock, and when maxing out both Gain and Output it could get quite saturated, almost resulting in the so-called brown sound. Obviously the power tube is really cooking at this point, and it must be said that the somewhat looser and grittier sound wouldn’t be suitable for those heavier styles of music where tighter definition is required.

At all settings there is a slight but noticeable bump in the lower mids (focused somewhat lower and sounding less spikey than a Tube Screamer) which is part of the signature Klon sound and happens to be the range where guitars generally sound best. This also makes the Archer very useable for simply fattening up a clean sound when using it with the Gain control completely turned down.

The pedal is very quiet, partly due to the clean build and compact layout of the PCB, but like any other overdrive pedal there’s a slightly raised noise floor once you turn up the gain and some hiss with both Output and Gain controls maxed, although that’s also likely due to the rest of the setup being pushed so hard.

As previously mentioned, the pedal is non-true bypass, with the buffer being permanently engaged, which adds a noticeable coloration to the sound, mainly restoring the high end sparkle lost somewhere along the signal chain – which is simply what buffers do. It must also be noted, that like all buffered bypass pedals, it does not pair successfully with buffer sensitive pedals after it, mainly vintage style Germanium transistor fuzzes.

Using the Archer the way the Centaur was intended (with quite a bit of volume boost) can make it a difficult pedal to successfully integrate into your rig, and I certainly wouldn’t advise using it with high wattage (non-master volume) amps unless you play big stages or are using an attenuator and/or low sensitivity speakers. And of course, it wouldn’t be my first choice for players who like super aggressive or unconventional guitar sounds, unless paired with other effects, since the Archer’s primary strengths are enhancing and fattening your original sound, pushing your amp into sweet overdrive, and coloring your sound with a sweet overdrive of its own if called upon. But if that’s what you’re looking for, you’d be hard pressed to find another pedal that does those things better.

J. Rockett Archer vs Klon Centaur

J-Rockett-Audio-Designs-Archer-Review-Best-Klon-Centaur-KTR-Pedal-05This is perhaps the one thing every guitarist really wants to know, and I’ll make this short. While the most notable apparent difference at first seemed to be that the Archer evoked a generally more ‘open’ sound, slight tweaks of the knobs (Treble in particular) helped dial in sounds that made the pedals indistinguishable from each other. If you simply set the knobs to the same positions, you’ll most likely notice slight variations in mid-range and treble response, but remember, the smaller, 9mm pots of the Archer have a slightly different response. (For example, you might notice the Klon’s Gain knob producing slightly higher output at the same Archer setting.) But when simply following our ears, we easily dialed in tones on our Archer and a 2007 silver Centaur that made it impossible for us to even tell the difference when switching between pedals when using a Free The Tone ARC-53M effects switcher (Using a switcher was necessary when A/B testing to prevent the pedals’ buffers from interfering with each other). If you bought a Klon Centaur at its original retail price, you got a sweet deal. If you were recently ‘hype-baited’ into paying an exorbitant price for that ‘unattainable’ Klon sound, you might want to pick up an Archer and hear the truth for yourself. Then consider trying to flip that Klon for around what you paid for it while you still can.

The Archer is the king of “Klones” and dare I say, perhaps even better than the venerable Centaur thanks to offering that authentic Klon sound in such a small and affordable pedal. Let’s see the final result.



The J. Rockett Audio Designs Archer is your chance to own a very faithful rendition of a legendary and proven design. It offers great boutique value for relatively little money and has a small footprint that makes it a very practical addition to any pedalboard. However, because it is meant to work together with an amplifier that is at the edge of break up, which might not be desirable/practical in some rigs, the Archer, like the Centaur, is certainly not for everybody or every situation. But pair the Archer with the right amp, and it’s unlikely you’ll be putting your guitar down anytime soon. If the authentic Klon sound is what you’re after, the Archer delivers it flawlessly and at a much more reasonable price. The Centaur is dead. Long live the Archer.

That concludes our J. Rockett Audio Designs Archer review. Thanks for reading.


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  1. I bought one today, after trying one Zendrive version after another in search of tone like Sonny Landreth’s. I get all the gain, and beautiful overtones, without ever causing my Strat-into-clean-Fender rig to sound like something other than what it is. The gold Archer sounded more midrangey in comparison.

  2. Try this pedal with some of the newer Supro amps and you won’t be disappointed. the Archer does offer quite a bit of head room and if you were to set the volume level on you amp at that just breaking up point and use the Archers gain and output controls to fine tune it, you’ll find that all you friends will be calling you The tone master.

  3. Hi,
    I play metal through an Orange Rockerverb 50 head. I’m looking for a petal to boost my Dirty Channel for solos. I have my volume and gain on amp at 2 o’clock. When I’ve tried other boost or OD pedals in front, I just get more distortion, but no volume boost. Would this pedal fit the bill? In front? Through FX loop?
    Any suggestions are appreciated. Thanks.

  4. It should be mentioned in any review of this pedal that its voltage pump circuit is set up in such a way that it does not play well with a number of popular pedals, such as the big box Strymons. The Archer’s pump causes “heterodyning” .. or pew pew laser sounds and whining in the other pedals in certain modes. This is a drag and will mean that some folks cannot use it on their board. I don’t know if this is something that J Rockett will address. Time will tell. I certainly hope so, because otherwise the pedal is fabulous, sounding better to me than my ARC Klone V2.

    • so that’s what I’ve been hearing through my rig… I have a couple small box Strymons, recently added an Ola and I can totally hear the pew pew sounds :/ damn

  5. I’ll take a guess:

    PS1 was the J. Rockett and PS2 the Klon… Top and mids are exact;y the same but I did notice a a bit more low end on one of the pedals that I *think* was only apparent on the Klon, but I hope I’m wrong!


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