Brownie - Harmonic Tremolo

Hi everyone!

I got into Pure Data about 1 1/2 months ago and have just uploaded my very first patch.

It’s a probably not 100% correct take on Fender’s Harmonic Vibrato which has been included in many of their early 1960s so-called “Brownface” amps.

The incoming signal gets split up into a high- and a low-passed signal, modulated by two identical but 180° out-of-phase LFOs and then added together again.

This description of the schematic by David Morrin helped me a lot: Fender Harmonic Vibrato -

Usage is pretty much self-explanatory and fairly basic - just two parameters for speed and depth. Footswitch and Aux switch between effect and bypass.

It sounds almost identical to the “brown” setting on my White Whale - White Whale — Crazy Tube Circuits - which has been my reference point.

Hope it’s of use for anybody interested. Works well on guitars and basses but I don’t know about synths as I don’t currently own one to test…

Open to any feedback! Thanks!


I really like it! I was bummed that it was only available as a stand alone patch but it sounded so good with my guitar, I ported it over to Orac for use with other modules! Also, it does sound great with synths :wink:


Thanks a lot for the feedback. As mentioned above I have just started out with pd about 1 1/2 months ago and still consider myself a beginner.

I have tried Orac a while ago but it felt so overwhelming, that I haven’t spent any more time with it - which I should definitely change. Porting to it is way beyond my current ability - in fact I wouldn’t even know where to start but it makes of course perfect sense as a module in a digital pedalboard - so thank you for taking care of that! Hats off! :brown_heart:

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In my honest opinion, it’s much easier to write a module for Orac than the regular Organelle. Especially complex patches that use multiple pages. A lot of the interface has already been designed and taken care of for you, you just have to define your parameters you will be using in a separate .json file. In fact, the Orac version is a smaller program than the stand alone version. I’m in the process of getting a livestreaming setup going so I can help answer questions about Orac and help further it’s development. It definitely has it’s quirks for developers however but I want to help be able to grow the community so everyone can make more modules for me to use :smiling_imp:

Orac can be a little overwhelming at first but ever since I’ve been digging into it over the past year, it is practically the only patch I use and I have based my entire live set around it with the modules I’ve developed. I put together what I think is some what thorough documentation on Orac in a different thread called Orac beginner resources if you want to check that out. I think there is also a video tutorial that I put together that might also be in either that thread or the Orac 2.0 thread.


Perfect, just wanted to ask you for some pointers in the right direction. I will check that definitely out! Thank you!

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Great patch! Thank you! We made a quick video with it:


Wow! Thank you so much for this. This made my day! :heart:

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Just a quick note that Brownie just got a whole lot cooler, as it now includes a spring reverb as well. The spring reverb was realized via convolution/impulse responses. This brings us a bit closer to the real thing. In case this ticked some boxes for you, you can find the updated version on Patchstorage.


Another update of Brownie is up on patchstorage. With version 0.5 you’re able to sync the tremolo speed/rate with an external MIDI clock.

C#3 toggles MIDI clock sync → LED turns cyan and blinks if an external clock is detected, stays static when it’s armed but no clock has been detected. Knob1 values will change from Hz or BPM to rates from 1/2 dotted to 1/32 note length. Press again to switch back to free tremolo mode. The last selected values will be saved and restored.

D#3 allows you to switch between Hz and BPM on the OLED display (works only if MIDI clock sync is not active)

I’ve reduced the hi-pass filter presets from 10 in the previous version to 5. Check the link below for a graphical overview of the new controls.

Controls v0.5

Enjoy, or not and as usual please let me know in case you encounter any bugs or have questions.
Thank you! :slight_smile:

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