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  • One Control BJF-S66 Guitar Amp Head

    A full-featured, giggable amp that can fit in a shoe box? 



    by Phil O'Keefe


    Bjorn Juhl is very well known in the effects world as one of the most talented pedal designers and builders on the planet, and his hand-built BJFE pedals are highly coveted. Recently One Control began a partnership with him to build pedals based on his designs on a much larger scale. We've reviewed a couple of Bjorn Juhl-designed One Control pedals on HC previously, including the Honey Bee Overdrive and the Tiger Lily Tremolo. This time we'll be taking a look at something a little different - not another pedal, but an amplifier; in fact, this is the first amplifier to ever be offered by One Control, but not the first to be designed by Bjorn Juhl…








    What You Need To Know

    • While he's probably most widely known for his pedal designs, Bjorn Juhl also has considerable history as an amplifier designer. He's designed and hand-built amps for numerous famous live and studio musicians for decades. However, the new BJF-S66 is the first all-solid state amplifier he's designed, as well as the first amp to be released by One Control.


    • The word is that Bjorn was inspired by the sound of classic mid-1960's era "blackface" amps when he was designing the BJF-S66.


    • The BJF-S66 is a two channel, solid state amp. The preamp and front end are all analog solid state, while the power amplifier utilizes a high-efficiency Class D design.


    • The BJF-S66 measures approximately 10.43" W x 4.63" D x 4.13" H (including the knobs and feet, and with the handle in the lowered position) and weighs 3.57 pounds. Despite its light weight, the amp appears to be made primarily of metal - most likely an aluminum alloy of some type. It's light, but outside of the rather exposed knobs, it still appears rugged and durable.




    • The top features a metal handle that can be folded flat when you're not using the amp.





    • The brushed aluminum front panel is where you'll find the input jack. Input impedance is 1M Ohm.


    • There are 13 knobs, arranged in two rows. The top row contains the main amplifier controls.




    • The rhythm channel has a Master Rhy(thm) volume control to set the overall output level for the rhythm channel.


    • There are also Master Lead and Lead Boost knobs for the lead channel, with the Master Lead controlling overall volume for the lead channel and Lead Boost providing more drive on the lead channel when desired. With the Lead Boost set to zero the sound is closer to that of the rhythm channel, while turning it pup adds extra gain and grind to it.


    • A small toggle switch between the Master Rhy and Master Lead volume controls allows you to switch between the two channels from the front panel when you don't have the optional footswitch connected.


    • Both channels share a common Gain control that sets the overall gain level for both the lead and rhythm channels. Typically this should be set at around 5-6 for clean rhythm channel performance, and closer to 10 to achieve grittier tones from the rhythm channel.


    • The top row is rounded out with three EQ controls. The Treble control is set at 2 kHz and provides +/- 20 dB of boost or cut, while the Bass knob is set at 70 Hz with +/- 20 dB of boost or cut available, while the Mid control gives you +/- 10 dB of boost or cut that's centered at 450 Hz.


    • The lower row of controls adjusts the amp's impressive built-in effects. Like the blackface amps that inspired it, the BJF-S66 has both reverb and tremolo onboard.


    • The onboard digital reverb has individual Reverb Level and Reverb Decay controls for both the lead and rhythm channel.


    • The tremolo is shared by both channels, and includes Speed and Depth controls. A small toggle switch lets you turn the tremolo on or off when you aren't using a footswitch. As with the front panel-mounted channel select toggle switch, if a FS-P3 footswitch is connected, it over-rides the panel switch, making it inoperative. A red LED on both the front panel and on the FS-P3 (if one is connected) will illuminate whenever the tremolo is active.


    • A Bright switch rounds out the lower row of controls and provides a 10 dB boost at 4 kHz when engaged.


    • Switching channels can be accomplished with the front panel switch or with an optional FS-P3 footswitch. When you do so, the two color LED directly above the channel select toggle switch changes from green (rhythm) to red (lead), and the LED indicator for the active reverb controls switches too, with the green Reverb Rhy LED lighting up when you have the rhythm channel selected, and the red Reverb Lead LED lighting up when the lead channel is selected. A two-color LED on the footswitch also turns from green to red to indicate which channel is currently active.





    • The footswitch also has buttons for turning the effects loop on or off (a red LED near the input jack indicates when it's active), as well as for activating the onboard tremolo. While there's no switch to totally disable the built in reverb, this is largely mitigated by the inclusion of two sets of reverb controls for the two channels. 




    • On the back panel of the BJF-S66 is where most of the rest of the amp's connections are located.




    • A DC Power In jack accepts the plug from the included computer (line lump) style 24V 2.7A power supply, and a toggle switch directly above it controls Power on / off for the amp.


    • There are three 1/4" jacks for connecting individual standard, single latching footswitches for switching channels, turning the tremolo on or off, and for turning the amp's built-in effects loop on or off.


    • A RJ12 jack is not something you find on guitar amps very often, but there's one on the back of the BJF-S66. It allows you to use a single RJ12 cable to connect to the optional FS-P3 three-button footswitch, which controls all of the functions previously mentioned. While RJ12 cables are rarely used on amps, they're widely available (just make sure you get a RJ12 and not the similar-looking but differently-wired RJ11) and in a variety of lengths, so even if you lose or damage the 3 meter (roughly 9' 10") cable that comes with the FS-P3, or want to use a longer one, it should be easy to find a replacement.


    • A single 1/4" Speaker output jack is provided. The One Control BJF-S66 can be used with 4, 8 or 16 Ohm speaker loads, making it compatible with a wide variety of cabinets. The speaker jack can be left disconnected when running the amp (for example, when using just the preamp output) but One Control strongly advises plugging or unplugging a speaker when the amp is turned completely off since, as with most solid state amps, shorting the speaker connector while the amp is powered up can fry the amp.


    • Output power depends on the speaker load you have connected, with the BJF-S66 rated at 30W into a 16 Ohm load, 66W into a 8 Ohm load, and 100W into a 4 Ohm load.


    • The Preamp Out jack is post Master Volume, so in addition to using it to connect to recording equipment, effects processors or the PA, you can also connect it to the power amp input on a second amplifier and still use all of the BJF-S66's controls to adjust the sound.


    • The final two jacks are Send and Return jacks for the onboard effects loop. Selecting the Effects Loop from the FS-P3 footswitch when nothing is connected to the loop will silence the amp completely.




    • It's a bit noisier than some other solid state amps. With the rhythm channel selected and everything set to the middle of its range (and with the effects loop and onboard effects turned off) there's a noticeable amount of hiss that is roughly equivalent what you'd expect to hear from a similarly powered, well-designed tube amp at idle.


    • Speaking of power, while I was unable to confirm it (I don't have a working oscilloscope on hand at the moment), when I was playing through the BJF-S66 I got the subjective impression that there might be less power on tap than the manufacturer's rating. I initially ran the head into a 2x12 cabinet wired to give an 8 ohm load, and it felt more like a 45W amp to me than a 66W one. Even with my highly efficient E/V EVM 12" speaker the output sounded a bit lower than I expected. It's certainly a powerful amp (especially considering its diminutive size) and it's definitely gig-able, even when driving a 16 Ohm load, it's just not quite as hair-raising as I was expecting.




    This is a delightful little amp! I really have enjoyed playing through it. For those who need to travel light are going to love it. You literally can drop it in a gig bag with your cables and a small pedalboard or multi effect pedal, throw the bag over your shoulder, grab your guitar in one hand and a compact, high-efficiency cabinet in the other and literally carry an entire, fully gig-ready rig in one trip from your car, or if necessary, on the subway. The amp design was tweaked with the Eminence Alessandro speaker in mind, but since I didn't have one available, I tried it with a variety of different cabs and speakers, including a 2x12 Fender cabinet with 16 ohm Eminence speakers, a highly efficient Electro Voice EVM 12 8 ohm, a Weber 16 ohm Blue Dog AlNiCo, and a couple of different cabinets loaded with 10" speakers.


    The BJF-S66 is extremely compact and lightweight for such a fully-featured and powerful amp head. The only complaints I have are minor, and one is unconfirmed since I was unable to test it due to not having a working oscilloscope on hand to measure the actual output power, but it does subjectively feel a bit lower than rated. The hiss issue is minor, and unless you're extremely sensitive, it's probably not going to bother you, and it's certainly no worse than what you'll hear coming from a good tube amp. It's still a bit surprising, considering the amp is entirely solid state. Other than the slight hiss, the sound quality is very good. I'm a longtime fan of tube amps, and it is only occasionally that a solid state amp impresses me. This one did. The channel switching is a big plus. You can dial up very different (or similar) sounds and levels for each of the two channels. If you need to go from clean to dirty (with or without a volume level boost) you can easily do so with this amp. While there's a reasonable level of dirt that can be coaxed from the BJF-S66, it's not a metal amp any more so than the blackface '60's era amps that inspired it are, although it does have more gain on tap than many of the amps from that era did. The overdrive sounds remarkably tube-like, and while it isn't capable of going into super hard rock or metal territory, it wasn't intended to. If you want to get that from this amp, you'll need assistance from a good dirt pedal, and the BJF-S66 is an excellent platform for that - it works extremely well with pedals, whether it's a distortion pedal running in front of the amp or a delay pedal inserted into the handy footswitchable effects loop. The quality of the onboard effects is, as you'd expect from Bjorn Juhl, outstanding. I really like having the ability to dial up different amounts of reverb with different tail lengths for each channel, and the tremolo is very amp-like in its character and response. The RJ12 footswitch cabling for the optional FS-P3 footswitch is a bit unorthodox, but in practice the switch itself worked consistently and reliably, and the added flexibility it provides makes it a must-have addition to the amp. If you'd prefer to have the amp without the switch, or can't afford it initially, it's available separately if you decide to purchase one later, although you do save a bit if you buy it bundled with the amp. Folks with a bunch of old-fashioned 1/4" latching footswitches, as well as people who use fancy MIDI switching systems can still use them to control the BJF-S66 since it also includes 1/4" jacks for switching too. One Control is a bit of a misnomer here, since there's more than one way to control the switching on this amp!


    All in all, this is not only an impressive amp that is fantastic for those who need to travel light, but also a terrific value. While Bjorn's previous amps have all been hard to find, and at $2k and up, relatively expensive in comparison, the BJF-S66 has a price tag that is very reasonable for everything you're getting, and it should be much more readily available for purchase. Like I said, I'm not normally a big fan of solid state amps, but the One Control BJF-S66 is a rare exception. It's just a very capable and great sounding little (and I DO mean little!) amp that is packed with features and comes in at a very reasonable price. I heartily recommend that any guitarist who likes that classic Fullerton sound check one out - especially if they want to cut down the size and weight of their rigs.   -HC-



    Want to discuss the One Control BJF-S66 Guitar Amp Head or have questions or comments about this review? Then head over to this thread in the Amp forum right here on Harmony Central and join the discussion!





    One Control BJF-S66 Guitar Amp Head ($599.00 "street", amp bundled with footswitch, $699 "street")

    One Control's product web page     

    BJF-S66 product manual (PDF file)     



    You can purchase the One Control BJF-S66 Guitar Amp Head from:


    American Musical Supply / AMS     

    Macdaddy Music     



    One Control FS-P3 Footswitch  ($159.00 MSRP, $119.00 "street")

    American Musical Supply / AMS   

    Macdaddy Music     





















    Phil O'Keefe is a multi-instrumentalist, recording engineer / producer and the Senior Editor of Harmony Central. He has engineered, produced and performed on countless recording sessions in a diverse range of styles, with artists such as Alien Ant Farm, Jules Day, Voodoo Glow Skulls, John McGill, Michael Knott and Alexa's Wish. He is a former featured monthly columnist for EQ magazine, and his articles and product reviews have also appeared in Keyboard, Electronic Musician and Guitar Player magazines.  

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