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HELIODOR AMP OVERDRIVE

11

LICENSE & USAGE

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

 It’s assumed 

that you have at least some experience building pedals before starting one of these. Replacements and 
refunds cannotbe offered unless it can be shown that the circuit or documentation are in error. 

All of these circuits have been tested in good faith in their base configurations.

 However, not all the 

modifications or variations have necessarily been tested. 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 

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 without prior arrangement

, 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 industry needs more transparency, not less!)

DOCUMENT REVISIONS

1.0.1 (2022-02-01)

  

Corrections to capacitors in parts list. C1 was listed twice, and the capacitor types were switched 
around. (All values were correct.)

1.0.0 (2021-11-26)

  

Initial release.

Summary of Contents for HELIODOR AMP OVERDRIVE

Page 1: ...OSS OD 3 Overdrive The final entry in a series of legendary pedals using BOSS s discrete op amp topology that overdrives more like an amplifier than traditional drive circuits JFET overdrive 1 0 1 2022 02 01 BUILD DIFFICULTY Intermediate Actual size is 2 3 x 2 42 main board and 1 78 x 0 86 bypass board ...

Page 2: ...result the OD 3 was released under the Overdrive umbrella Regardless of what went on in the product development meetings the OD 3 does borrow ideas from both the OD 2 and BD 2 and manages to improve on both of them from a design standpoint The Blues Driver may get more attention but the OD 3 remains the crowning achievement of BOSS s discrete op amp topology The Heliodor is a direct adaptation of ...

Page 3: ... 4W R9 220k Metal film resistor 1 4W R10 220k Metal film resistor 1 4W R11 2k7 Metal film resistor 1 4W R12 6k8 Metal film resistor 1 4W R13 470R Metal film resistor 1 4W R14 3k3 Metal film resistor 1 4W R15 2k7 Metal film resistor 1 4W R16 100k Metal film resistor 1 4W R17 33k Metal film resistor 1 4W R18 10k Metal film resistor 1 4W R19 1k Metal film resistor 1 4W R20 2k2 Metal film resistor 1 4...

Page 4: ...x 2 5mm C10 1n2 Film capacitor 7 2 x 2 5mm C11 470n Film capacitor 7 2 x 3mm C12 10uF Electrolytic capacitor 5mm C13 12n Film capacitor 7 2 x 2 5mm C14 1uF Film capacitor 7 2 x 3 5mm C15 10uF Electrolytic capacitor 5mm C16 6n8 Film capacitor 7 2 x 2 5mm C17 18n Film capacitor 7 2 x 2 5mm C18 33n Film capacitor 7 2 x 2 5mm C19 22n Film capacitor 7 2 x 2 5mm C20 1uF Film capacitor 7 2 x 3 5mm C21 1u...

Page 5: ...T transistor PNP TO 92 Original uses 2SK184 GR 2SK209 GR is the SMD equivalent Q7 2N5088 BJT transistor NPN TO 92 Substitute Original uses 2SC2458 GR IC1 JRC4558D Operational amplifier DIP8 Substitute Original uses M5218AL IC1 S DIP 8 socket IC socket DIP 8 DRIVE 100kA 16mm right angle PCB mount pot TONE 10kB 16mm right angle PCB mount pot VOLUME 100kB 16mm right angle PCB mount pot LED 5mm LED 5m...

Page 6: ...y Using old stock transistors Toshiba has not manufacturered through hole transistors and JFETs in many years but it s still possible to find the 2SK184 GR and 2SK117 GR as well as the four types of BJT transistors used in the original However be aware that these follow the Japanese pinout conventions whereas the PCB layout is set up for USA conventions since there are a lot more widely available ...

Page 7: ... VB GND 47uF GND JRC4558D VA GND 18n 100k VB 2SK209 GR 2SK209 GR 10k VA GND 1uF 100kA 1uF 220k GND GND 100k 1n2 GND GND 2k2 GND 10uF GND 10k 470n 4k7 12n 1uF GND 47k 150k VB 6k8 1k 10uF GND 6n8 4k7 12k 18n 4k7 12k GND D1 C23 TONE 1 2 3 VOLUME 1 2 3 C24 RPD R1 C1 R2 Q1 R3 Q3 R9 Q4 R12 R11 R13 Q5 R14 R15 C8 C7 C4 R8 R6 C5 R7 D2 D3 D4 D5 C9 R17 Q6 R19 C18 C19 6 5 7 IC1B R30 Q7 R31 R33 R32 C20 C21 R34...

Page 8: ...es the use of closed frame jacks like the Switchcraft 111X If you d rather use open frame jacks please refer to the Open Frame Jack Drill Template for the top side LED hole drill size assumes the use of a 5mm LED bezel available from several parts suppliers Adjust size accordingly if using something different such as a 3mm bezel a plastic bezel or just a plain LED ø3 8 ø1 2 0 385 0 625 0 625 x 0 y...

Page 9: ...HELIODOR AMP OVERDRIVE 9 ENCLOSURE LAYOUT Enclosure is shown without jacks See next page for jack layout and wiring 125B ...

Page 10: ...HELIODOR AMP OVERDRIVE 10 WIRING DIAGRAM 125B IN V GND NC NC OUT PCB IN GND V V JACK GND JACK OUT IN GND GND PCB OUT ...

Page 11: ...ay be used for commercial endeavors in any quantity unless specifically noted 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 without prior arrangement and 2 you cannot goop the circuit scratch off the screenprint or otherwise obfuscate the circuit to disguise its source In other words yo...

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