Mad Bean Pedals Green Bean, Быстрый старт

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threshold of the “warmth” frequency range, which tops off at around 400Hz. If you do not have a 120n cap, use
a 100n. You could go higher up to 150n but it will start to get a bit muddy at that point.
The
AS/Sym switch lets you choose between asymmetrical clipping and symmetrical clipping. The vintage TS
unit used two small signal diodes back to back for symmetrical clipping. A common mod for TS builders is to
change one of those diodes to two diodes in series to create asymmetrical clipping. Some purport this makes it
behave more like a tube amp, but nah, it doesn’t. It just makes it sound a little different. Trust me on this. Why
would I lie to you? There is no switch that suddenly makes guitar pedals sounds like amps. That’s just
marketing.
Anyway, it is a good mod so you have both options. The BOM does not list any particular diodes to encourage
experimentation but I will tell my personal choice: in my builds D1-D3 are 1n914 and D4, D5 are 3mm red
diffused LEDs. The LEDs are louder and crunchy, where the 1n914 are smooth and quieter. But, feel free to try
as many varieties as you can stand. For this reason, it is a good idea to socket those diodes until you are sure
you have the combination you want.
BTW: If you use an On/Off/On SPDT for the As/Sym mod, the center position will be no clipping diodes. This is
the same as the “Comp Cut” mode on the Fulldrive 2™.
The two toggle switches, while better located now, as still fairly close to the Gain knob. For this reason,
I
suggest not using HUGE knobs
for this build. 1/2" - 3/4" diameter should be fine.
Lastly, you can go up to 1MA on the Gain pot for more overdrive. This tends to make less difference on the
1n914 diodes since they are fairly saturated at 547k (gain pot + stopper resistor) but if you do use LED's the
extra resistance will help drive them a bit harder for more saturation.
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You can run the Green Bean at 15 or 18v provided you use caps and an IC rated accordingly. Rail to Rail op-
amps typically have a lower max voltage threshold. IOW: look at the datasheet and use the appropriate
voltage.
There are many op-amps to try in the Grean Bean besides the 4558. Here are a few: JRC4580D or DD,
TL072, LF353, LM1458, TLC2272, OPA2134, LF442, OPA2604, NE5532, JRC3404 and on and on.
For a thorough analysis of the Tube Screamer™ circuit design, please read R.G. Keen’s article on the subject:
http://www.geofex.com/Article_Folders/TStech/tsxtech.htm
You should read his “Technology of…” articles about once a year. You will learn something new each time.
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IC1 DC Q1 DC
1 4.48 C 9
2 4.56 B 3.92
3 4.48 E 3.58
4 0 Q2
5 4.48 C 9
6 4.48 B 3.58
7 4.48 E 3.27
8 9
Voltages - 9.42v supply
VC: 9.0 VB: 4.49