Hammond scanner guitar effect project released..

[jpdesroc]

Hi List,

Introducing my new electronic project,
It's a Hammond scanner Chorus/Vibrato guitar effect
using its original vibrato line and a bunch of electronics
to support it. All this put inside a small cabinet
stolen from a scrap 15w guitar amp.

You can hear it on this youtube link:
https://youtu.be/UMf6ya3Ayyo

You can also have a look at a group of detailed pictures
showing most of the steps involved in the building process here:
http://www.arcenson.com/projects/Hammond_Scanner_Chorus_Vibrato_Effect/Pictures/

It's a one year project I'm proud of.
Cheers !

J-Pierre
Quebec City, Canada

[Mark Hammer]

Félicitations!

Sounds very nice.  But a LOT of work.

[jpdesroc]

Thank you !

And YES a lot of work..
But that has been fun to build and discover..

JP

[Mark Hammer]

How does the Hammond scanner work?  I am unfamiliar with that technology.

[jimilee]

You should be proud, looks and sounds phenomenal


Sent from my iPhone using Tapatalk

[jpdesroc]

The complete eplanation of Hammond scanner working
would be a long one but I can give you this web link
that explains the 'inner' of that technology.

http://modularsynthesis.com/modules/DJB-scanner/scanner.htm

You can also hev a look at all my schematic files here:
http://www.arcenson.com/projects/Hammond_Scanner_Chorus_Vibrato_Effect/Specifications/

This guy also made a project out of a Hammond Scanner:
http://www.stefanv.com/electronics/hammond_vibrato_mod.html

*****************************************
Hammond Vibrato/Chorus short explanation:

The vibrato and chorus settings are V1,V2,V3 and C1,C2,C3.

Vibrato is the periodic raising and lowering of the pitch,
and is thus fundamentally different from tremolo
which is a variation in only the loudness of the pitch.
The Hammond vibrato is implemented using a tapped delay line, really a low-pass filter.
The signal is applied to the delay line and a rotating scanner,
attached to a small motor (DC motor in my case),
picks the signal off of the delay line at the tap points.
The scanner, a single-pole 16-throw air-dielectric capacitor switch,
is wired so that the tap point will traverse the entire delay line twice,
once up the delay line and once back down, for each scanner rotation.
As the delay line is traversed phase is added-to and then subtracted-from the signal.

The chorus signal is produced by adding non-pitch-shifted signal to the pitch-shifted signal.
The three settings each of vibrato and chorus correspond to different amounts
of total delay thus different amounts of total pitch shift.

In addition to the pitch shifting function, the vibrato, as implemented in the original Hammond organ,
also acts as a sweeping low-pass filter.
There is some frequency response and amplitude variation as the tap point of the filter is swept.

The Scanner:

The scanner is used in the organ as a single-pole 16-throw rotary switch.
It is constructed as a multi-plate air-dielectric capacitor with 16 stator poles and one rotor.
It is used, in conjunction with the vibrato delay line, to create the chorus/vibrato.

[stonerbox]

God.. that is tasty! 

[287m]

woohooo, mentioned stefanv make me remember first build batt charger for my 1:10 RC car 

btw, good work!