Finished Project - Linda Looper

[mfunky]

I just finished this project (I called it "Linda") and wanted to share some information and images with you guys; if somebody is interested in building one yourself, just PM me– I had to order a minimum batch of PCBs and I still have a couple left and could send you a programmed microprocessor as well. If required, I can write documentation as well, provide drill templates, shopping list for components etc. to help you with the build.

What it is – in one sentence: Linda is a versatile on-the-fly programmable, highly customizable DIY-Arduino-based effects-looper for external or on-board effects with floating send/return, amp-channel-switching and A/B/Y-Amp-selection capabilities and one-button-access to presets, amps, amp channels and effects.

Now, that was a complicated sentence, therefore now explained in more detail:

Versatile: Linda's configuration can be changed with external switches. Use it a fx-pedal looper, as a stand-alone multi-fx-unit or use it to control your four-channel amp. Or all of the above. 8 functions, 14 presets.

On-the-fly-programmable: Select the desired combination of internal effects, external effects, amp and amp channel. Hit the write-footswitch and select the preset, where you want to store the setup. No need to kneel down.

Highly customizable: The PCB's have a lot of pads for jumpers and switches to adopt Linda's configuration and external access to options such as polarity toggle to your needs and your gear.

Arduino-based: Uses an ATmega328.

External or onboard effects: External effects are connected with insert cables (stereo plug on one side, two mono-plugs for input and output on the other side). If a jack remains empty, internal effects of your taste can be added (as long as there is enough room in the enclosure).

Floating send/return: The send/return breakout can be jumpered to be anywhere in the effect chain. So, Linda works for you, if you want two wahs and five drives before the preamp and one chorus in the fx loop, but also, if you prefer to use one boost (before the amp) and seven flangers (in the fx-loop of the amp) (for the latter, please send me a demo tape  ). Of course, you can have everything in front of the amp as well.

Amp channel switching: Loops 3, 4, 5 and 6 can be assigned to switch amp channels rather than add effects to the signal chain. Linda has two additional stereo (TRS) jacks for that. Polarity of the channel switching can be changed (so that the LED turns ON for the HOT channel of the amp, not vice versa. Some amps ask for that...)

A/B/Y Amp selection: If you have two amps, the signal can be routed to either the one or the other (A/B-switching, can be realized if you assign it to ONE footswitch/loop). If you want to add the "Y" (both amps active), you need to sacrifice a SECOND loop/footswitch for that.

One-Button-Access: 8 footswitches for loop control, up to 7 switches for presets, one A/B-bank-button. No "Mode"-Switch to change between Preset-Mode or FX-Mode, like many commercial loopers have (to save on expensive switches and room, guess). More the oldschool-bradshaw-kind-of-approach. So, if you like the preset but would like to add a bit of delay, simply tap one button.

[Cozybuilder]

One nice looking bit of kit, great job!   

[mfunky]

Yeah, Cozy. After a couple of 1590A-builds, I was longing for something more... well... BIG!!!

[mfunky]

If somebody needs the documentation, check here: http://www.madbeanpedals.com/forum/index.php?topic=22999.0

[mfunky]

Update - I found some minor issue today that I want to fix before giving away remaining PCBs and Chips... everything works fine except for one relay, so I have to debugg this next weekend...

Good news is, I ran a full setup today with the follwing functional setup:

1. "Naughty Fish" envelope filter
2. - empty (relay broken?)
3. Boost on my Engl Ironball
4. Lead on the Engl
5. Zendrive
6. Reverb on the Engl
7. Arion Chorus
8. T.C. Alter Ego Delay

Everything except stomp #2 worked fine, so changing presets from clean-chorus-reverb to zendrive-boost-naughty fish-delay works with the press of one button.