FX Loop Mod for AX2

[KaZoom1618]

Here's a replay of my 2013 post with 2015 updates:

 

I added an Effects Loop to my old AX2!

by KaZoom1618 on 2013-01-13 14:37:44

So I have an Line6 AX2 that I luv, but I got a looper for Xmas, and it's the one effect that the AX2 is missing...

 

Now if I place the looper between the guitar and AX2, the guitar is recorded 'clean' so that any effects that I set are applied to all loops as well as the live soloing. Not nice.

 

I downloaded the schematics, and wow - this is the easiest modification to make! I didn't even have to cut any traces - Line6 ran a multiwire jumper from the main board to the master volume pot break-out board that I can hack!

 

So the 'splice out' to a loop-out/loop-in pair of 1/4" jacks can be made right on the cable that links up to the master volume pot.

 

Since the AX2 is in stereo (and my looper isn't) - I only spliced in to the Left channel - but with stereo jacks, you could splice both wire 1 and wire 4 just as easily.

 

I also used a 1/4" jack with a switched contact on the receive jack (it switches as you push in the plug) - so that the receive defaults to getting the 'shorted' send signal - if you don't plug anything in the the loop.

 

This way the amp runs normally with no loop cords plugged in.

 

But plug a cord into the (upper) new 'loop-out' jack on the back panel to connect to the looper input, and another cord from the looper output to the (lower) new 'loop-in' jack on the back panel, and its magic!

 

Uh, here's a few pics along with the schematic mod:

http://www.ad-ons.com/AX212/loop-mod.zip

 

If you need more info (if anyone on the planet is still using this paradigm-breaking amp, and wants to mod it), just ask - I'm an EE :-)

 

BTW, it works great! I can record a loop with rhythm guitar effects on, and then play the loop back to the power amp while I solo (in stereo) with lead guitar effects!

 

 

 

Re: I added an Effects Loop to my old AX2!

by KaZoom1618 on 2013-01-14 14:16:18

I forgot to mention - to remove the amp chassis from the case, you remove 2 screws from each side of the amp, and 4 from the top (including the 2 that hold on the handle).

 

Then slide the chassis out of the back of the case - no need to remove any knobs, but of course, you unplug the AC cord, speakers and floorboard first!

 

Then remove the 'bottom' plate to access the circuit boards by removing the 9 screws.

 

Enjoy!

Edited July 5, 2017 by Line6Tony
Removed links to schematics

[Musicmannetje]

Thanks for the info on this. I have build a stereo fx-return in my AX2, to be able to connect my POD HD to it. 

[peterjanwilbrink]

Hi Kazoom,

 

thank you very much for this post. I'm gonna do this mod too, (as I'm already opening the amp to eliminate the digital rattling noise that comes from the speakers even when the master volume is turned all the way down.)

 

So the schematics will help me with that too!

[Thub]

Does anyone have the AX2 schematic that KaZoom1618 linked?  Those links unsurprisingly no longer work.

[jmgtr]

K-

I was a little disappointed that this amp didn't have an FX loop, but now...

That's it? 2 shielded splices between the outs on the FX board and the stereo master pot before the power amp section?

And there's PLENTY of room to do it?

This is the best mod since the casters I screwed into it.

I plan on making it a normalled L/R IN, L/R OUT (4 jack) configuration.

I bought this AX2 for $200 including a 3 year replacement warranty from GC, so it will void that $50 warranty, but WORTH IT!

Of course, the levels will need to be adjusted from the inserted unit (Sony HR-MP5), but not a big deal. Simply adjust the input volume so that you get a nice, clean signal to send back to the loop return. The Sony has a programmable realtime output volume via MIDI, so it'll go past 11.

I'd be willing to bet these FF guys just popped a less user-friendly Alesis Quadraverb in there after the modeler, because the block diagram and effects are virtually identical.

Way more versatile than a used JC-120, and a hell of a lot cheaper.

[KaZoom1618]

Hey jmgtr - yes the mod is really that easy!  You don't even need to cut a track!

 

I wonder - why 4 jacks? Why not just use 2 stereo jacks?

 

Once you 'get' the control metaphor that FF used in the AX2, its incredibly versatile. 

Most guitarists just want a knob they can turn up to 11 and let 'er rip.

So FF had to dumb-down the interface in the spyder amp for just that reason, to appeal to guitarists and not just Engineers.

It lost a huge amount of versatility in my opinion.

 

Your comment about the Alesis Quadraverb circa 1989 got me looking... The TMS320 DSP family was started in 1983, so I'm sure every audio engineer was clambering to design a processor at that time.

Now AFAIK, FF holds the patents to digital amp modelling, so they probably just reached into the public domain for effects and 'modelled' existing DSP effect processors, like the Alesis.

Either way, the 212 holds a thousand different 'setpoints' to let you tweak a sound just right, with no need to lug around a board full of little effects boxes!

 

KaZoom

p.s. After straining to move my 212 after my last gig, I seriously thought about adding some casters. LOL.

[jmgtr]

The AX2 isn't a backbreaker - my Kitty Hawk M1 has that distinction. Imagine a JCM800 with a 1X12 cab bolted to it...

Wheels over heels for sure.

This was supposed to be a cheap practice amp. When I tried it out, it was decent and cheap. All I need is a good clean sound, and the AX2 clean is really good.

After fiddling with the gainy sounds, I was surprised to discover that some are not bad.

Some are unusable as programmed, but a little tweaking gets 2 good gain sounds. After that, a few distortion pedals take care of the rest. The FX are best used minimally.

I recommend this amp highly.

It's durable, flexible, transportable, and cheap. It's also super-uncool. Perfect for me. I hate fake vintage, whether in gear or in actual music.

As far as the 4 jack setup - I despise breakout cables. There's always an extra patch cable in my bag - a stereo cable is convenient, but it kind of locks you into its way of doing things.

Best to all,

J