How sound the Green Ringer with "Null carrier" and "Filter switch" mod?

[gigimarga]

Hello,

I've built an Green Ringer using Tonepad's project (http://www.tonepad.com/getFile.asp?id=90) and after i made these mods, but i had some problems:

1. Null carrier mod: http://www.generalguitargadgets.com/pdf/ggg_gro_sc_null.pdf - the turn of the pot don't affect very much the sound. I didn't change the values of the Q1's resistors (560k, 160K, 18k and 6.2k) to 470k, 120k, 15k and 4.7k because i understood that they are alternatives, not compulsory values. Also, i didn't have 2N5210 and i used the BC549C.

2. Filter switch mod: http://www.generalguitargadgets.com/pdf/ggg_gro_sc_filter.pdf - it sounds very strong, but it seems to me not to help the octave very much...the sound is muffled...

Have anyone some clips with these mods?

[gigimarga]

 

[gigimarga]

Nobody has a soundclip?

[Processaurus]

Hi, I don't have a sound clip of the original pedal I tried the lopass filter mod on, but it sounds like the fullwave rectification of your GR isn't working quite right, there should be a position on the "null" pot that balances the two halves of the waveform and brings the octaveness in.  With that imbalance taken into account, it makes sense that the filter isn't useful, it sounds muffled, because that's what it does: removes all high end from the signal before the rectifier.  With even full wave rectification it makes the octave sound cleaner, though, like when you turn your tone knob down.  The harmonics added by the rectification make up for the now toneless, muffled signal on the input.

You might try looking at the wiring on the null pot, as well as double checking the orientation of the PNP transistor.  Maybe try it following the original schematic, without the null pot and/or maybe some different transistors?

[gigimarga]

Hi, I don't have a sound clip of the original pedal I tried the lopass filter mod on, but it sounds like the fullwave rectification of your GR isn't working quite right, there should be a position on the "null" pot that balances the two halves of the waveform and brings the octaveness in.  With that imbalance taken into account, it makes sense that the filter isn't useful, it sounds muffled, because that's what it does: removes all high end from the signal before the rectifier.  With even full wave rectification it makes the octave sound cleaner, though, like when you turn your tone knob down.  The harmonics added by the rectification make up for the now toneless, muffled signal on the input.

You might try looking at the wiring on the null pot, as well as double checking the orientation of the PNP transistor.  Maybe try it following the original schematic, without the null pot and/or maybe some different transistors?

Thx a lot...i will try to use an oscilloscope to set the "null" point...anyway, it's works ok (the PNP is oriented ok) without the filter mod "on"!

[Mark Hammer]

I think that optimizing the GR, or any phase-splitter-based octave-up unit, will probably be easier using not only a scope but a signal generator that lets you keep the input signal constant.  I imagine it is very hard to hear the effects of signal nulling adjustments when simply strumming a guitar.

[gigimarga]

I think that optimizing the GR, or any phase-splitter-based octave-up unit, will probably be easier using not only a scope but a signal generator that lets you keep the input signal constant.  I imagine it is very hard to hear the effects of signal nulling adjustments when simply strumming a guitar.

I tried to do something using Visual Analyzer.
This is what i obtained with my "no mods" Green Ringer on the 12th fret of B:



It is OK? It is "nulled"?

[gigimarga]

The image don't work, so i put a link to it:

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/gr.gif.html?g2_imageViewsIndex=1