A look at my brand-new Boss Katana 100 MkII guitar amp.

As many of you might already know, I recently decided to buy myself a brand-new Boss Katana 100 MkII guitar amp, the main reason for buying it was so I would have a great sounding, easy to tote to gigs without hurting my back, guitar amplifier I could bring to the open mic nights at the Smoke and Oak club, located on the same street that my flat is on.

I've played two open mic nights with the Katana, and so far my experience with it has been a very happy one, it really does live up to all the hype, sounds great, and is more than loud enough to cut-through a full live band mix without being miced-up, I mostly had the amp set to the 50W output-power setting, and the master volume up half-way and it was plenty loud enough.


Okay then, let's give the amp a good look-over and see just what we get when we buy one of these, this one is the 1X12 version, that is, it has one 12 inch speaker, I'm not sure exactly what model the speaker is, it appears to be Boss's own design, but it definitely sounds good, here are some pics:


Firstly, here's a pic of the front of the amp:

Attachment 41105

And the back:

Attachment 41106

Next is a close-up of the various sockets on the back panel:

Attachment 41107

Pics of the control panel:

Attachment 41108

Attachment 41109

Attachment 41110

And pics of the optional GA-FC Foot Controller:

Attachment 41112

Attachment 41113

Okay, so, what is the Boss Katana 100 MkII 1X12?, it's a solid-state digital modelling guitar amplifier that Boss currently manufacture and sell, it is rated to put-out a maximum of 100W of audio power, but, using the Power Control switch located on the control panel, you can dial-back the maximum power-output to 50W, or .5W, the Power Control switch also has a Standby setting, when Standby is selected, the amp is fully powered-up but is silent, Boss's Katana range of solid-state modelling amps use a technology that Boss call Tube Logic, which they say digitally emulates the way a Tube amp behaves, the Katana 100 MkII Tube Logic emulates the behavior of an amp that uses EL34 power Tubes, personally I think they did a really good job of it, and this is coming from someone who owns a Marshall MA100C amp that uses four real EL34 Tubes.

If you look at the pics of the control panel I posted, you'll notice a knob labelled Amp Type, there are 5 different amp type settings to choose from, which are as follows.....

Input Socket: Self-explanatory.

Acoustic: Useful if you're playing an Acoustic/Electric guitar and need to plug it into an amp to get a good clean Acoustic sound so you can be heard.

Clean: Pretty self-explanatory, if you're after some clean electric guitar tones this is what you would typically use, I quite like the clean tones I'm getting so far.

Crunch: Again, pretty self-explanatory, if you want some slightly overdriven, edge-of-breakup tones, you'd use this setting.

Lead: Again, self-explanatory, if you want lead-tones, this setting is what you would use.

And finally....

Brown: This amp-type setting is all about that high-gain distortion tone most famously used by Eddie Van Halen.

There's also a small button just above the Amp Type knob, labelled Variation, pressing this little button gives you a variation of all the different Amp Type settings, to my ears it changes each Amp Type's voicing, so you've virtually got a total of ten different Amp Types to choose from.

Next you've got a knob marked Gain, no guesses as to what this does, it controls how much gain each of the Amp Types give, turn it up to get more gain and vice-versa.

Next is Volume, this works like a preamp volume control.

And then you have your three band (Bass, Mid, Treble) EQ/Tone controls typically found on most guitar amps.

Next, you have your Effects control section, two of the control knobs are actually dual-gang types.

Booster/Mod: The Booster control knob controls the level of boost, likewise, the Mod control knob controls the level of modulation effects.

FX/Delay: The FX knob controls the level of effects, such as for example Tremolo, the Delay knob controls the level of delay effects.

And then there's the Reverb control knob, this controls the level of Reverb effects.

Above each of the Effects controls are five small buttons, these are used to switch between different types of Booster, Modulation, FX, and Delay effects.

To the right of the Reverb control knob is the Presence control, this works the same way as the presence control found on most guitar amps.

Then there's the Power Control switch with four settings: Standby, .5W useful for practicing, 50W, and 100W, the three output power settings set the maximum output power you can get out of the amp.

And Master: This works like the master volume control found on most guitar amps.

Lets have a look at the back panel.

You have an IEC mains power socket, self explanatory.

Next, you have your FX Loop Send and Return sockets, you can use these if you want to add some external FX pedals, or processors to the amp.

Stereo Expand switch: This switch is used to enable the Stereo Expand feature of the Boss Katana 100 MkII, you can connect a second Boss Katana 100 MkII up to the amp to get stereo Delay or Reverb effects.

Line Out/Power Amp In: You can use the Line Out socket with the Stereo Expand switch to get stereo effects if you plug it into the Power Amp In socket of a second Katana 100 MkII, or, if you set the Power Switch to Standby, you can plug from the Line Out socket into a mic/line in socket of an audio interface for silent recording, or into a live band P.A. mixing desk.

Next is a USB 2.0 socket, you can use this to connect the Katana 100 MkII up to a computer, Mac or PC, and use the amp as an audio interface (it has it's own ASIO or Core Audio driver), or, you can use a free app called Boss Tone Studio that Boss offers for free, to create your own tone presets, the Boss Katana 100 MkII amp offers a total of 8 tone preset channels, that can have up to 5 effects chained in series at once, the Boss Tone Studio app comes with 60 emulated effects, so you have quite a large range of tonal options to choose from, I'm starting to get the hang of using the Boss Tone Studio app to create my own tone presets, so far my experience is, it is actually quite easy to do so, I found it pretty intuitive.

Note that when you first try using the Boss Tone Studio with your newly-bought Katana amp, you may get an error message saying something about a wrong version, to fix this, you need to go to the Boss website and download the latest firmware update for your model of Katana amp, then follow the directions Boss give for updating the firmware, doing this got my Katana amp working with the Boss Tone Studio app, it was quite a painless thing to do.

Next, there's a little 3.5mm input socket labelled Aux In, you can use this to plug an mp3 player into the amp for a backing track for practicing, or jamming along to your favorite songs.

GA-FC: The Katana 100 MkII is fully compatible with the GA-FC foot controller that Boss also manufacture and sell, I would very strongly recommend buying one of these if you're buying a Boss Katana 100 MkII, makes switching between the 8 tone preset channels very easy to do during a live band performance onstage, while you're at it, consider also buying the protective amp cover Boss sell.

EXP Pedal: you can plug the optional Boss expression pedal into this socket to control volume, or Wah effects.

And Finally......

Phones/Rec Out: You can plug a pair of headphones into this for silent practicing, or you can plug this socket into an audio interface to record in a Daw (Digital Audio Workstation) software.

I'll have to get a foot controller for mine. They're a great amp though, particularly for the price

Quote:

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Originally Posted by JohnH

I'll have to get a foot controller for mine. They're a great amp though, particularly for the price

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I'll second that, on Boss Australia's website, the Katana 100 MkII 1X12 itself retails for around Au$600.00 or so, since I had the money, I elected to buy both the optional GA-FC foot controller (glad I did) and cloth amp cover as well as the amp, all up, it cost me just over Au$800.00, I'm very happy with what I got for my money, I was half-expecting the amp to be a little hard to get a good sound out of, given my prior experience with a Line 6 Spider IV 75W digital modelling amp, turns out the Katana is a lot more intuitive than the Spider IV was, and didn't have that hard to dial-out "Digital" sound to it, the Katana behaves a lot like how a Tube amp does, when you turn it up it gets louder, fatter, and bigger-sounding like a Marshall amp does when you crank it up, I also noticed that the amp's bottom-end doesn't get flabby as you crank it up either, it stays tight.

I'm strongly considering getting the 50 in the next couple of months, however the GA-FC isn't compatible apparently. So I'd be looking at the FS-6 or FS-7 (or apparently the compatible and significantly cheaper Hosa FSC-385).

Yes, the Katana is the top of my want list for a new amp. Not going to happen anytime soon though due to Renos and upcoming landscaping😢

There's an app you can download for iOS and Android phones, called Katana Librarian or something like that, you can use it to keep all your unused Katana presets, I'm interested in downloading/installing it on my Samsung Galaxy J2 Pro android phone (it supports USB to go), but, I need to go on eBay and buy a USB to go cable for my phone, going to see if I can get that sorted-out tomorrow.

That's a pretty comprehensive going over Doc!

My drummer just bought a Mk II... well a MkI but they ran out of stock and sent him a II instead. Interested to have a mess around with it this weekend.

Update:

Sorry to have to say this, but my Boss Katana amp decided to pack it in yesterday, and stopped working normally, here's what it is doing:

* Powers up normally.

* No sound from the speaker, even at full power and volume settings.

* I do get sound out of the Headphone/Recording Line Out socket on the back panel.

* Some of the channel buttons on the front panel do not respond when I press them.

* The GA-FC Footswitch seems to operate normally when plugged into the amp.


Here's what I have tried so far:

* Performed several Factory Resets, this only temporarily fixed the no-sound issue once and the amp reverted back to the no-sound fault condition after switch-off and then power up.

* Performed a few firmware re-updates, this did not fix it at all.

Do you have the circuit diagram? Can you separate the pre- from power-amp parts? It sounds like you have a malfunction that may be after the pre- but is either in the power amp circuit board or after. I don't know what to make of the fact that it works briefly after a reset then cuts out. If this is a class-D amp, I wonder if there is some problem in the power-amp, but I don't have a clue as to how you'd diagnose it!

Quote:

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Originally Posted by fender3x

Do you have the circuit diagram? Can you separate the pre- from power-amp parts? It sounds like you have a malfunction that may be after the pre- but is either in the power amp circuit board or after. I don't know what to make of the fact that it works briefly after a reset then cuts out. If this is a class-D amp, I wonder if there is some problem in the power-amp, but I don't have a clue as to how you'd diagnose it!

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I was actually pretty lucky, I managed to find a set of Service Notes for the Katana KTN-100 series of amps online from Scribed in PDF form, fortunately I managed to download a copy before Scribed deleted it, the Service Notes contained full schematics and PCB layouts so, it'll be very helpful, I also have a couple of oscilloscopes and signal generators too, last night the amp did seem to come good all on it's own for a short time, so, that suggests that most of the circuitry is working in a fashion, the amp has a muting circuit and also a muting signal line from the amp's CPU to the power amp IC, so, I'm thinking that maybe the amp's CPU is muting the power amp when it shouldn't be muting it for some reason, what makes me think that is that I do seem to get signal through the headphone/recording line-out socket on the back panel when there's no signal coming through the speaker.

The amp uses a dedicated power amp IC that's located on a big heatsink, it is soldered to a separate little PCB, looking at the schematic, I noticed that one of the connector pins is labeled CPU Mute or something like that, it's possible that the amp is suffering from some kind of CPU controller issue, maybe caused by bad supply filtering on the supply rail/s that power the CPU, my forte is in analog electronics, I'm not that great with complex digital circuitry, but I do know some digital electronics theory, hmmmmm....maybe once I get the amp put back together again, I could use my FNIRSI digital scope to check the noise-levels on all the amp's supply rails, I stripped the amp-chassis down to the bare chassis in order to clean-out some dirt, and insect detritus that had accumulated in the amp chassis, the Service Notes detail how the Katana is disassembled and put back together again, so I should be okay.

Fortunately, the amp uses an old-school linear power supply, rather than a more modern SMPS, so I don't have any high voltage caps to deal with, the highest voltage rated caps in the amp are a couple of 4700uF/63V can caps in the power supply, which would be the supply filter caps for the power amp IC.

I understood just enough of that for it to be clear that I should never attempt such a thing. Will be interested in the eventual diagnosis and what you end up doing about it! Also my blood pressure spikes when I hear expressions like "big caps." Do you think you can repair the wayward circuit board--or will you be just popping in a new one?

Quote:

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Originally Posted by fender3x

I understood just enough of that for it to be clear that I should never attempt such a thing. Will be interested in the eventual diagnosis and what you end up doing about it! Also my blood pressure spikes when I hear expressions like "big caps." Do you think you can repair the wayward circuit board--or will you be just popping in a new one?

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Unfortunately, Boss don't sell replacement pcbs for the Katana, to Katana owners, or even licensed service techs, so, there's not much of a chance in me being able to buy replacement ones, Boss really designed these amps with built-in planned-obsolescence, as a way for them to maintain their healthy profit-margins, I have two options left, I can either fix it myself since the amp is most likely out of warranty already, or, I can fork-out another Au$999.00 to buy a brand-new Boss Katana 3rd gen amp.

I'm going to have to opt for the first option and get busy with my new FNIRSI Digital Scope, and see if I can fix the amp myself.

Do you at least have a good schematic to work from? The other thing I wondered about is if there is a way to find a busted Katana. If it's not busted in the same way as yours, maybe you could use it for parts. There must be a gazillion of them around, particularly if they break down and Boss won't support them when they go out of warranty...

Quote:

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Originally Posted by fender3x

Do you at least have a good schematic to work from? The other thing I wondered about is if there is a way to find a busted Katana. If it's not busted in the same way as yours, maybe you could use it for parts. There must be a gazillion of them around, particularly if they break down and Boss won't support them when they go out of warranty...

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Yep, I managed to find a Service manual for the Katana KTN-50/KTN-100 series of amps online after doing some searching on Google, it contains schematics and test procedures.

I can use my new FNIRSI Digital Scope and XR2206 function Generator to do some signal tracing, but I need to build an 8 Ohm 100W dummy load first.

Can you do it cheaper than this?:

https://www.parts-express.com/8-Ohm-...gaAmzuEALw_wcB

Parts have gotten expensive enough...although, I am guessing you have stuff around the house/lab/lair that will to make one :cool: