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MOSFET Spec Build Notes

If you are building your Overdrive 2 kit to MOSFET specs, before you begin, you should

be aware that there are several spaces on the PCB that need to be left empty and several

component values that need to be changed from what is labelled on the PCB.

1.

Leave the one 1M resistor space, the two 511k resistor spaces, and the two red LED

clipping diode spaces highlighted in RED empty.  Do not add any components to

these spaces.

2.

Use 1M resistors in all the resistor spaces that are highlighted in orange.

3.

Change the 100k resistor highlighted in yellow to a 1M resistor.

Содержание Overdrive 2

Страница 1: ...lty upon arrival Please direct all warranty issues to sales buildyourownclone com This would include any missing parts issues Return BYOC LLC accepts returns and exchanges on all products for any reason as long as they are unused We do not accept partial kit returns Returns and exchanges are for the full purchase price less the cost of shipping and or any promotional pricing Return shipping is the...

Страница 2: ...dy be answered Here are a list of things that you should include in the body of your tech support thread 1 A detailed explanation of what the problem is not just It doesn t work help 2 Pic of the top side of your PCB 3 Pic of the underside of your PCB 4 Pic that clearly shows your footswitch jack wiring and the wires going to the PCB 5 A pic that clearly shows your wiring going from the PCB to the...

Страница 3: ...Build Notes page 7 8 MOSFET Spec Build Notes page 9 11 Populating the Circuit Board page 12 22 Assembly page 23 25 Wiring the Footswitch Jacks page 26 28 Installing the ICs page 29 Setting up the Internal Trimpots page 30 31 More Modifications page 32 35 Schematic page 36 37 ...

Страница 4: ... brown 2 1M brown black black yellow brown or brown black green gold Capacitors 1 51pf ceramic disc small orange cap 1 022µf 22n film 223 2 0 047µf 47n film 473 2 0 1µf 100n film 104 1 0 15µf 150n film 154 2 1µf 1µ0 film 105 or 1J63 2 10µf aluminum electrolytic 1 47µf aluminum electrolytic 1 100µf aluminum electrolytic 2 0 15µf tantalum 154 2 0 22µf tantalum 225 Diodes 2 1N914 or 1N4148 small oran...

Страница 5: ...ed 103 1 50k louder trimpot will be labelled 503 1 100k min trimpot will be labelled 104 IC s 1 JRC4558D 1 OP2134 1 DIP 8 socket Hardware 1 drilled enclosure w 4 screws 1 byoc OD2 circuit board 2 SPDT PC mounted on off on toggle switch 2 3PDT footswitch 4 knobs 1 AC adaptor jack 1 mono jack 1 stereo jack 2 red LED 1 battery snap hook up wire ...

Страница 6: ...black brown brown 5 1M brown black black yellow brown Diodes 6 1N914 or 1N4148 small orange glass Transistors 5 BS170 MOSFET these go in backwards from the transistor labels on the PCB IC s 1 CA3260 Dual MOSFET OpAmp Potentiometer 1 B10k linear tone knob ...

Страница 7: ...resistor spaces 6 diode spaces and 2 transistors spaces highligted in the diagram above that should be left empty Do not add any components to these spaces Omitt these components There are no component values that need to be changed from what is labelled on the PCB Just be aware of this for now You will be reminded throughout the populating the PCB portion of the instructions as we come to each re...

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Страница 9: ...veral component values that need to be changed from what is labelled on the PCB 1 Leave the one 1M resistor space the two 511k resistor spaces and the two red LED clipping diode spaces highlighted in RED empty Do not add any components to these spaces 2 Use 1M resistors in all the resistor spaces that are highlighted in orange 3 Change the 100k resistor highlighted in yellow to a 1M resistor ...

Страница 10: ...FET transistors need to go in backwards 5HSODFH WKH N WRQH SRWHQWLRPHWHU ZLWK WKH N SRWHQWLRPHWHU Just be aware of this for now You will be reminded throughout the populating the PCB portion of the instructions as we come to each relevant component All of the other typical tubescreamer mods will still apply to the circuit even after MOSFET conversion ...

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Страница 12: ...ed Be sure to matched the end of the diode with the stripe to the layout on the PCB The stripped end should go in the square solder pad Only add the diodes highlighted in yellow if you are building to MOSFET specs If you are building to standard specs leave them empty ...

Страница 13: ... green with blank values However one mod that people like to do is to increase the input impedence of the two transistor buffers You would do this be replacing the 511k resistors with 1M resistors MOSFET Specs a Add all the resistors highlighted in RED according to the values labelled on the PCB b Omitt the two 511k and one 1M highlighted in pink and leave these three spaces empty c Add 1M resisto...

Страница 14: ...e socket so that the u shaped notch matches up with the end that has a notch on the layout Only add the socket DO NOT solder the actual chip to the PCB DO NOT solder the chip to the socket Only the socket gets soldered You will never solder the chip s Installing the chips or IC s into the socket will be explained on page 26 ...

Страница 15: ...ad that is longer than the other The longer lead goes in the square solder pad hole The shorter lead goes in the round solder pad hole DO NOT add these if you plan on using the MOSFET clipping You cannot use both at the same time You can only use one or the other ...

Страница 16: ...STEP 5 Add the film capacitors These are not polarized so they can be inserted into the PCB in either direction ...

Страница 17: ...positive side The positive side goes in the square solder pad hole Use the 22uf 224 tantalum caps for stock tubescreamer specs Your kit also comes with a pair of 15uf 154 tantalum caps Some people like to use these instead of the 22uf because they say it improves the frequency response of the tone knob ...

Страница 18: ...Step 7 Add the ceramic disc cap These are not polarized and can go into the PCB in either direction ...

Страница 19: ...mmer will affect the amount of minimum distortion Originally it was a 51k resistors so setting this trimpot to exactly halfway will give you stock TS808 specs MAX trimmer This trimmer will affect the amount of maximum distortion Originally it was a 4 7k resistor so setting this trimpot to exactly halfway will give you stock TS808 specs LOUDER trimmer This trimmer affects the gain of the second hal...

Страница 20: ...yellow are for MOSFET clipping transistors If you are using the clipping LEDs do not used the MOSFET clipping transistors You cannot use both at the same time MOSFET specs Add the BS170 transistors to all the spaces highlighted in RED and YELLOW Be sure to put the BS170 s in backwards from the PCB layout Do not add the clipping LEDs if you will be using clipping MOSFETS highlighted in yellow ...

Страница 21: ...m electrolytic capacitors These are polarized The positive end will have a longer lead and should go in the square solder pad The negative end will have a shorter lead with a black strip running down the body of the capacitor ...

Страница 22: ...ugh the under side of the strain relief holes Insert the stripped ends of the battery snap wires into the topside of their respective solder pads Solder on the bottom side where highlited in blue Remember the red wire goes in the hole and the black wire goes in the hole ...

Страница 23: ...tor jack to the eyelet on the PCB with 2 inches of hook up wire Connect the SLEEVE of the DC adaptor jack to the eyelet on the far right side of the PCB with 2 inches of hook up wire Connect the battery disconnect terminal of the DC adaptor jack to the eyelet more towards the center of the PCB with 2 of hookup wire ...

Страница 24: ...d holes and the two toggle switch into the bottom side of the PCB DO NOT SOLDER There are only two ways in which the toggle switch can fit into the PCB Either way is fine Each LED will have one lead that is longer than the other The longer lead goes in the hole of the square solder pad Remember to replace the 25k tone pot with the 10k if building to MOSFET Specs ...

Страница 25: ...em with your fingers You do not want them very tight yet Be sure to keep your hand on the PCB so that it does not fall off the PC mounting posts of the pots and toggle switch Step 5 Turn the entire pedal over so that the component side of the PCB if facing up Lift the PCB up off the pots and toggle switch about 2mm just to make sure that the back of the PCB does not short out against that pots Mak...

Страница 26: ...g the footswitch and jacks Step 1 Install the 1 4 jacks to the enclosure Be sure to turn the OUT jack a 1 4 turn counter clockwise so that solder terminal for the tip does not short out against the enclosure ...

Страница 27: ...ch on the left and lugs eyelets 1 2 7 8 of the footswitch on the right Cut 4 x 1 pieces of wire Strip 1 8 off each end These will be used to connect lugs eyelets 2 5 of the footswitch on the left and lugs eyelets 5 8 of the footswitch on the right Cut 2 x 1 5 peices of wire Strip 1 8 of one end Strip 1 2 off the other end ...

Страница 28: ...he IN jack to the ring eyelet on the PCB Step 3 Solder the wires for the footswitch Step 4 Remove the PCB assembly from the enclosure Solder the open ends of the wires that you just soldered to the footswitch to their respective eyelets on the PCB Load the wires in from the top and solder on the bottom side Step 5 Reinstall the PCB assembly to the enclosure Install the footswitch to the enclosure ...

Страница 29: ...Installing the IC ...

Страница 30: ...it was a 51k resistors so setting this trimpot to exactly halfway will give you stock TS808 specs Turning it up will give you more drive turning it down will give you less drive MAX trimmer This trimmer will affect the amount of maximum distortion Originally it was a 4 7k resistor so setting this trimpot to exactly halfway will give you stock TS808 specs Turning it up will give you more drive turn...

Страница 31: ...ount of drive and overall output Turning it up too much may cause squealing or self oscillation on certain settings Particularly if you turn the tone knob up all the way full turn clockwise This mod does not work very well if you built your pedal to MOSFET specs It will add a lot of noise so if you built your kit to MOSFET specs you should turn it down just about as low as it can go and still give...

Страница 32: ... other You can build some of the circuit to MOSFET specs and some of the circuit to standard specs The parts of the circuit that can be built to either MOSFET or standard specs can be broken down into 5 different sections the input buffer the op amp the clipping section the output buffer and the boost circuit The various components specific to each section are mapped out in the diagram below Input...

Страница 33: ...in this case If you wanted both you d need to get rid of the stock silicon diode clippers and put the LEDs in their place adn then leave the spaces for the LEDs on the PCB empty Boost Circuit highlighted in green The standard silicon boost will sound fuller and will be louder but cannot run at more than 9V The MOSFET boost will not be as loud as the silicon boost but it will have some sparkle to i...

Страница 34: ...0k resistor highlighted in yellow Try a 15k resistor This mod will not work with MOSFET build specs Modifying for Bass Guitar 1 Make the 22n input cap larger to allow more low end signal through Try a 100n or 1uf 2 Make the mids caps larger for fuller bottom end The 47n highlighted in red would be your center position position2 on the toggle switch cap Try a 100n or 1uf cap here The 47n cap highli...

Страница 35: ... a little tricky Because the standard spec overdrive circuit can run just fine at 18v But the standard silicon boost circuit cannot 18v will not hurt it but it will be distorted The MOSFET boost can run at 18v But the MOSFET overdrive circuit cannot Anymore than 9v will fry the MOSFET op amp So if you want to run the pedal at 18v you d need to build the overdrive portion of the circuit to standard...

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Страница 37: ...Please visit http buildyourownclone com board for any technical support copyright 2009 B Y O C LLC ...

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