This PCB can implement any of the AMT Legend Series II drive channels. Does not include the clean channel or cab sim. This will fit easily in a 125B case.

I also have a PCB that includes the clean channel and cab sim here: https://www.pcbway.com/project/shareproject/M2_Guitar_module_for_combo_embedded_projects_0a1b466c.html

Be warned... These PCBs use SMD transistors. PCBWay can mount those for you but each model has different ones populated. Populating them all is not the right thing to do. To do this yourself, I suggest a bit of solder paste lightly applied to pads with a tooth pick, stick the transistors onto the paste and then put the PCB on a hot plate until the solder flows. This is the hot plate I use:

https://www.amazon.com/dp/B07W1ZZH8T?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1

I have some videos showing how I solder SMD components here...

First Video is the application of solder paste with a tooth pick to the PCB.

This is using a very tiny amount of no-clean solder paste.

I’m careful not to leave any paste anywhere but where it is supposed to be.

https://drive.google.com/file/d/1lt_ZqyDOzroHl71-aa7eTO1sPOqIvmZi/view?usp=drive_link

Second Video is the application of solder paste with a tooth pick to the bottom of a TPA3118.

This ensures there will be enough solder and some flux on the IC to get a good solder flow.

https://drive.google.com/file/d/1sV1S1fdVRavs7U-p2nuOOFPRRwq1SbFu/view?usp=drive_link

Third Video is flowing the solder and adding the TPA3118.

Note, for transistors, stick them all to the paste at once while cold, then put the PCB on the hot plate.

The hot plate is already up to temperature, about 325 Fahrenheit.

The PCB is laid onto the plate and wait for the solder to all flow and wick onto the pads.

Then the IC is applied with some pointy tweezers and nudged into place.

Then the PCB is carefully removed from the hot plate and set aside to cool.

https://drive.google.com/file/d/1O_xk2ix7Je_61Z00tFmFoQ9teNyKT7G9/view?usp=drive_link

Fourth Video Buffing any little solder remnants with a tooth pick and brushing.

You can see some very tiny beads being knocked off by the tooth pick.

https://drive.google.com/file/d/1FRlDJYWNrmMDcHIsJxUTkVqsknLjimx4/view?usp=drive_link

Final Video is cleaning with 99% IPA.

Clean it all up with IPA and inspect for anything wrong under the microscope.

https://drive.google.com/file/d/18zwHHAlTBkC1kf13lI_0zVwgchezy74N/view?usp=drive_link

The following interactive BOMs can be used to populate some versions of the drive channel.

C2: https://paulamps.com/boms/AMTDriveOnly/AMT%20Drive%20Only%20C2.html

E2: https://paulamps.com/boms/AMTDriveOnly/AMT%20Drive%20Only%20E2.html

K2: https://paulamps.com/boms/AMTDriveOnly/AMT%20Drive%20Only%20K2.html

M2: https://paulamps.com/boms/AMTDriveOnly/AMT%20Drive%20Only%20M2.html

O2: https://paulamps.com/boms/AMTDriveOnly/AMT%20Drive%20Only%20O2.html

R2: https://paulamps.com/boms/AMTDriveOnly/AMT%20Drive%20Only%20R2.html

P2: https://paulamps.com/boms/AMTDriveOnly/AMT%20Drive%20Only%20P2.html

S2: https://paulamps.com/boms/AMTDriveOnly/AMT%20Drive%20Only%20S2.html

B2: https://paulamps.com/boms/AMTDriveOnly/AMT%20Drive%20Only%20B2.html

D2: https://paulamps.com/boms/AMTDriveOnly/AMT%20Drive%20Only%20D2.html

Step one: Use a sharpie on the PCB to mark out all the components labeled XXX in the BOM. These are not installed.

Step two: SMD transistors using solder paste and a hot plate.

Step three: Resistors. Save trimmed leads for jumpers.

Step four: Install jumpers for all components labeled LINK.

Then diodes, caps, 2n5458 and pots.

All POTs are Alpha 9mm:

https://smallbear-electronics.mybigcommerce.com/single-gang-9mm-right-angle-pc-mount/

These pots limit the height of ALL other components to 10mm or less for case clearance!

All resistors are YAGEO 1.9 mm x 3.4 mm 166 mW Metal Film:

https://www.mouser.com/c/passive-components/resistors/film-resistors/metal-film-resistors-through-hole/?diameter=1.9%20mm&length=3.4%20mm&m=YAGEO&power%20rating=166%20mW%20%281%2F6%20W%29&instock=y

Note that some resistors are underneath the pots, so you must use these small resistors there. But, you can use larger 1/4W resistors elsewhere standing up instead of laying flat. Resistors can also go on the back of the board but be careful not to block locations for input/output jacks in the case. The intent of this build is to install all components on the top side with only one exception: the current limiting resistor, RP64, for the LED so you can choose brightness after having built the pedal. This leaves room for jacks to overlap the location of the board in a 125B case. But, there is very little room. Even small resistors on the back of the board will not allow the jacks to fit.

Capacitors less than 1nf are ceramic:

https://www.mouser.com/c/passive-components/capacitors/ceramic-capacitors/mlccs-multilayer-ceramic-capacitors/multilayer-ceramic-capacitors-mlcc-leaded/?lead%20spacing=2.5%20mm&m=Vishay&instock=y

Signal capacitors from 1nf to 220nf are KEMET Polyester Film:

https://www.mouser.com/c/passive-components/capacitors/film-capacitors/?dielectric=Polyester&lead%20spacing=5%20mm%20%280.197%20in%29&m=KEMET&instock=y

Signal capacitors 330nf and above are MLCC to limit the height below 10mm.

https://www.mouser.com/ProductDetail/Vishay-BC-Components/K105K20X7RF53H5G?qs=DPoM0jnrROXWXcRVcoIT%2FA%3D%3D

Electrolytic caps must be under 10mm tall. These are suitable 10uf and 100uf caps:

10uf: https://www.mouser.com/ProductDetail/KEMET/ESS106M035AC2EA?qs=9RUIYXQlAdDELwYaBIsKWw%3D%3D

100uf: https://www.mouser.com/ProductDetail/Rubycon/35ML100MEFC8X7.5?qs=T3oQrply3y%252BVMudpVXVKFw%3D%3D

Semiconductor links:

2N5458 https://www.mouser.com/ProductDetail/Central-Semiconductor/2N5458-PBFREE?qs=u16ybLDytRbDLInQLnKe%252Bw%3D%3D

J177 https://www.mouser.com/c/?q=863-MMBFJ177LT1G

2SK208R https://www.mouser.com/ProductDetail/Toshiba/2SK208-RTE85LF?qs=iCzJi%2FIZBF52K9IBnicZ%2FA%3D%3D

BAT48 https://www.mouser.com/ProductDetail/STMicroelectronics/BAT48?qs=JV7lzlMm3yLztdLrSLKoPQ%3D%3D

BAT41 can also be used and might be a better match to the original real pedals. I've used BAT48 in all my builds and like them. BAT41 have a bit lower forward voltage, so a little more distortion in a drive pedal.

1N5817 https://www.mouser.com/ProductDetail/Micro-Commercial-Components-MCC/1N5817-TP?qs=KFo7JewZbUG5sQj%252BWAsavw%3D%3D