HammondWiki - Diff: LineBox

Differences between current version and predecessor to the previous major change of LineBox.

Other diffs: Previous Revision, Previous Author

Newer page: version 3 Last edited on January 27, 2009 9:56 am. by StefanVorkoetter
Older page: version 1 Last edited on February 15, 2003 8:11 am. by
@@ -1,6 +1,11 @@
-Electrical Waves fed into the line are shifted in phase by each line section ( the amount per section being proportional to the frequency) , so that at any tap on the line, the phase is retarded relative to the previous tap. 
+The vibrato line box consists of a sequence of 18 (for the console models) or 16 (for the spinet models) second order low-pass passive LC filters. One side effect of low-pass filtering is a time delay, which manifests itself as a phase shift in the output. Audio signals fed into one end are delayed by each stage of the line box , so that at any tap along the line, the phase is retarded relative to the previous tap. 
- [Scanner] 
- VibratoChorus  
- [DelayLine ]  
- VibratoSmall 
+The vibrato [Scanner] samples the outputs (taps) of the line box from one end to the other and back again, resulting in a frequency modulated signal at the scanner's output due to Doppler shift. Because of the attenuation caused by the low-pass filtering, there is also somewhat of an amplitude modulation.  
+Like the ToneGenerator, the capacitors making up the filters in the line box can degrade, which results in larger delays which gives more frequency modulation, and also more high frequency attenuation giving more amplitude modulation. Replacing the capacitors will restore the original factory levels of vibrato.  
+It is also possible to rewire the connections to the line box to change the "shape" of the vibrato effect.  
+See also: [Scanner ], VibratoChorus, and VibratoSmall  
+Overhauling and optionally rewiring the line box is described in this article by StefanVorkoetter [http://www.stefanv.com/electronics/hammond_vibrato_mod.html].  

The content of this page is Copyright (C) 2000, 2001, 2002 Geoffrey T. Dairiki and the other authors of the content, whoever they may be.
This is free information and you are welcome redistribute it under certain conditions; see http://www.dairiki.org/HammondWiki/opl.html for details.
Absolutely no warrantee is made as to the correctness of the information on this page.