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TEXT TO RACK SCHEMATICS

OCTAVE DOUBLER : Very good octave doubler! with a external LFO you can get Tremolo, Vibrato and really weird effects.
I got the schematic from a Practical electronic magazin-83. I've omitted the noise gate but kept the limiter(IC=570).
If you omit the 570(save your money!) then add break-jacks between 741'an and the resistor-divider 10k/1k before pin 10(1496) Now you can patch in a fuzz ,a compressor or whatever!

BI PHASER : Two phasers tuned differently.Got this scheme from a Elektor magazine-87. The nice phase effect occurs at slow speed setting. Match therefore the J-fets closely.Adjust trimpot=250k for maximum amplitude modulation with minimum distorsion. All this can be done with your ears! Use metall-film resistors!

CARLIN COMPRESSOR : All transistor design. This isn't the easiest effect to build but it's worth the effort!
It has more sustain(more than Craig A comp. which I used at first) and is more of a guitar compressor.
The fuzz is a bit limited in use i think.

ROCKY HEAD : With gain, drive, tone and volume. Uses red LED's to break all those nice sinewaves into good squarewaves! A modern sounding Fuzz-device. I've borrowed the Tone-circuit from a Marshall valvestate preamp! Now it's even better! Improved gain characteristics more filtering, changed the Tone pot to log. Now it has become a Heavy Metal Machine!

VCF : From the Formant syntheziser(Elector) With a few modifications it works really well with guitar. I use a volume pedal as voltage divider, sending a Control voltage to the filter. Uses a Transconductance amplifier=3080. You have to select the right resistors to the j-fets so they work properly! It has several Wha-tone options due to the many tone altering possibilities. Test it! With a smooth fuzz preceeding the wha and with a heavier fuzz at the output you can experience really fat sounds!

TREMOLO : With a mixing arrangement at the output,two different Tremolo sounds is possible! (This part I found in Everyday electronic-83) Be aware of that the VTL5C3 is heat sensitive. Remember that the LED-part of the VTL5C3 maximum current is 40mA! (I have burn one all ready!)

NOICE GATE : Easy to use. Extracted from a Compressor schematic by DOD. The led indicates when it's off. Very useful!

EQUALIZER : Five frequency band: 100, 500, 1k, 4k, 10k and a volume. Using coils(with core).
This is a quiet and a well working tool

MXR FLANGER : My favorite! Bought it -81 I think. This unit is slightly modified for dual supply,otherwise it's the original. The original scheme can be found at my effect site! Set the trimpots at midpoint. Use quality trim =Cermet. I will come back on the trim procedure. You can buy the SAD1024 from R.G Keen. E-mail to Mr Keen is: Keen@eden.com

PRE AMP/FUZZ : These two effects share the same frontpanel, but are seperable. They have seperate input/output-jacks too! If you use the Fuzz (a phone plugg in the fuzz jack)it automaticly breaks the connection to the pre-amp! Now they are seperate! Plugging into the preamp only gives you the option of using the Fuzz seperately. The panel switch is a DPDT switch. A sort of bypass switch (buffer-mode or effect) There is no microphone amp included because I have a seperate mixer (Ram 10-channels) with everything on it!

MIXER : Four channel with pan, gain, channel on/off switch and output-volume L and R.
The schematic shows one input channel and the complete output circuit.You need to add more channels.
This is a simple circuit and it works really good.The channel switches are really useful! You can patch different
sound configurations and switch them in and out while playing.Using 4016(4066)this can be done remotely with footswitches!
Don't use 4016/4066 in the signal chain though! Only use them to short the signal to ground.

BYPASS : This relay (Fabr.Meisei) pinouts correnspons to the measurements of integrated chip pins! That makes it simple to adjust to pcb. Remember to connect the bypass in the relays non-active position!
The picture shows effect on.The diode prevents the coile charging backwards(negative voltage)
Use quality relay's with low R on and low current consumption.Now when you now to use relay's the smile on your lips will never disappear again!

RACK REMOTE BOX : With all those goodies it would be fun to at least be able to switch between two different sound patches. Or using some form of remote control! My method is simple. This is a substitute for foot switches. With a 10 pole female and male connector and 2.5 metres 10 lead-cabel, at least 8 effects could be remotely switchable! The other two are one positive lead and a ground lead. I used my little collection of slide-switches, rarely used. Now they came to use! This is a very 'stone age' simple effect but very useable. There are two channels, A and B. I can switch between two preset arrangements or just remotely switch on or off any of the eight(8) effects.

1999-04-06
Stellan Lehrberg