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15

L5 PREAMP

General Build Instructions

Build Order

When putting together the PCB, it’s recommended that you do not yet solder any of the enclosure-mounted 

control components (pots and switches) to the board. Instead, follow this build order:

1. 

Attach the 

audio jacks

DC jack

 and 

footswitch

 to the enclosure. 

2.  Firmly attach the 

pots

 and 

switches

 to the enclosure, taking care that they are aligned and straight.

3.  Push the 

LEDs

1

 into the hole in the enclosure with the leads sticking straight up, ensuring that the flat side 

is oriented according to the silkscreen on the PCB.

4.  Fit the 

PCB

 onto all the control components, including the leads of the LED. If it doesn’t fit, or if you need 

to bend things more than you think you should, double-check the alignment of the pots and switches.

5.  Once you feel good about everything, 

solder them from the top

2

 as the last step before wiring. This way 

there is no stress on the solder joints from slight misalignments that do not fit the drilled holes. You can 

still take it out easily if the build needs to be debugged, but now the PCB is “custom-fit” to that particular 

enclosure.

6.  Wire everything according to the wiring diagram on the last page.

1

 For the LEDs

: You can use a bezel if you’d like, but generally it’s easier just to drill the proper size of hole 

and push the LED through so it fits snugly. If you solder it directly to the PCB, it’ll stay put even if the hole is 

slightly too big. Make absolutely sure the LED is oriented correctly (the flat side matches the silk screen) before 

soldering, as it’ll be a pain to fix later! After it’s soldered, clip off the excess length of the leads.

2

 Note on soldering the toggle switch(es):

 It will require a good amount of solder to fill the pads. Try to be as 

quick as possible to avoid melting the lugs, and be prepared to feed a lot of solder as soon as the solder starts 

to melt. I recommend waiting 20-30 seconds between soldering each lug to give it time to cool down.

Sockets

Since double-sided boards can be very frustrating to desolder, especially components with more than 2 leads, 

it is recommended to use sockets for all transistors and ICs. It may save you a lot of headaches later on.

License / Usage

No direct support is offered for these PCBs beyond the provided documentation. 

It is assumed that you 

have

 

at least some experience building pedals before starting one of these. Replacements and refunds will not 

be offered unless it can be shown that the circuit or documentation are in error. I have in good faith tested all of 

these circuits. However, I have not necessarily tested every listed modification or variation. These are offered 

only as suggestions based on the experience and opinions of others.

Projects may be used for commercial endeavors in any quantity unless specifically noted.

 No bulk 

pricing or discounting is offered. No attribution is necessary, though a link back is always greatly appreciated. 

The only usage restrictions are that 

(1) you cannot resell the PCB as part of a kit

, and 

(2) you cannot 

“goop” the circuit, scratch off the screenprint, or otherwise obfuscate the circuit to disguise its source

(In other words: you don’t have to go out of your way to advertise the fact that you use these PCBs, but please 

don’t go out of your way to hide it. The guitar effects pedal industry needs more transparency, not less!)

Summary of Contents for L5 Preamp

Page 1: ...curately with a template you may not be ready for this one yet 4 YOU VE GOT TO BUILD IT AS IT WAS INTENDED I approached the project as though I was designing a completed product for market Everything...

Page 2: ...output straight into a power amp either a dedicated power amp or the return jack of an amp with an effects loop The main difference will be the volume you run it at This thing is capable of enormous v...

Page 3: ...is a patented Moog invention that uses a set of six fixed frequency resonant filters to add a very unique quality to an instrument signal that is unlike any other guitar effect sometimes described by...

Page 4: ...rovided only as a convenience You are responsible for checking through the parts to make sure they are the ones you want and Mouser is responsible for sending you the correct parts I tried to pick hig...

Page 5: ...220R R73 10k R74 3k3 R76 100k R77 15k R78 220R R79 220R R81 10M R82 820R R83 22k R84 6k8 R87 22k R88 3k3 R89 2k7 1 2W R90 33k R91 10k R92 10k R93 47k R94 47k R95 680R 1 2W R96 100k R97 10k R98 1k5 R99...

Page 6: ...resistors so the values have been modified but it is electrically identical 2 Optional I included these three resistors as an experiment to see if the inevitable LED switch noise could be cut down by...

Page 7: ...f the output with a multimeter black lead to the sleeve red lead to the tip The measurement was around 20mV AC I ended up at the 23 4dB setting in the app to get 30mV This probably varies widely depen...

Page 8: ...than 10mA but they are required if you want to test out the power section before inserting the ICs and transistors which is a good idea and they barely draw any power so you may as well leave them in...

Page 9: ...GND 22k 560R GND 390R 300R GND GND 22k 22k 22k 6k8 39k 18k GND GND 10n GND 100n 2M2 GND 10n 10n GND GND C11 C12 1 2 3 MID2 2 3 1 IC5A 6 5 7 IC5B 2 3 1 IC4A R24 R23 R25 R22 R27 R26 1 2 3 FREQUENCYA 1...

Page 10: ...k GND 15k 10n 6k8 33k GND CA3080 1k GND 470k 220R 10k 20k 220pF GND V 10n GND 2N5088 2N5088 3k3 2k 47k V 330R 10n GND 330n GND 100k 68n 2N5457 V CA3080 6k8 15k V 10M GND 820R 100pF 220R 220R GND GND V...

Page 11: ...the placement of the pots switches and other hardware inside the enclosure looking in from the bottom 1590X VOL1 2 5kA TREBLE1 50kA VOL2 25kA TREBLE2 25kB MULTI 25kA MASTER 25kA MID1 2 5kA BASS1 50kA...

Page 12: ...y reasonable so do whichever you think is best For always on LED operation run a wire from the CH pad on the channel switching board the one on the right hand side in the diagram above looking from th...

Page 13: ...ure to secure it while drilling Note that the holes are shown slightly smaller than they need to be so drill out the holes as shown and then step up until they are the correct size for the components...

Page 14: ...s is about 50 bigger than life size The main PCB measures 5 35 x 3 5 The smaller PCB on the left is the master bypass and the one on the right is the channel switching These both inclode on board LEDs...

Page 15: ...x later After it s soldered clip off the excess length of the leads 2 Note on soldering the toggle switch es It will require a good amount of solder to fill the pads Try to be as quick as possible to...

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