Help/advice/guidance translating schematics onto a pcb

[Cqwet Dbdfte]

Hello again everyone!!

Been working on this almost constantly since my last reply! Here is my update and where the project stands at the moment!

Got the pcb's from JLC, VU from Aliexpress, and a blank L-bracket and faceplate from CAPI. Got everything installed and finally got brave enough to plug it in last night aaand it works!! Mostly! Input gain is good, pad is good. However, my polarity wasn't working nor was the low cut! Also my output attenuator is working but opposite than I intended?? Currently clockwise rotation attenuates which my brain absolutely hates but it's working so still a win!

It was so hard to wrap my head around how to layout and drill out the L bracket and faceplate! I didn't pay much attention to the physical laayout dimensions when designing the pcb so that took me a good few days. This iteration is mucked up but I saw it through for the practice. I have a new bracket and faceplate en route and thanks to my jeweler roommate i now have the tools to cut and polish up the holes real nice.

Sadly though, I think just one more PCB iteration is needed and that should do it. I'm going to scrap the Lowcut filter since it didn't work and the button is kind of taking up too much space. I think it'll be a bit better overall to scrap it and free up some more real estate. That'll also allow me to move the 2 remaining buttons down (they were rubbing against the input knob) and move the input down (It was too close to the VU meter). Also found that I need to space my resistors out a bit more for it to sit flush and look nice (the vishay resistors I used are thicker than most). Oh and I did some looking at other polarity schematics and I think I just had it wrong in this iteration so I need to fix that as well.

The VU also wasn't working. It was lighting up just fine but wasn't responding to signal at all. Did some fiddling and the TL072 IC started to smoke lmao so that'll be a little something to figure out!

Overall though, I'm super excited. The fact that it passed signal was so gratifying and seeing it physically come together felt like I had won a boss fight in a video game! I just need to iron out some wrinkles and it'll be ready for a life in the studio. Huge thanks to everyone here for helping me through this!! Hope y'all get some joy out of seeing it come together because I'm ecstatic!!

Also for anyone that's curious about the cost, this comes together for right around $200 top to bottom! Not bad considering the current API iteration is around $800 new.

You can also order aluminum PCBs from JLC, for your front panel.
Use the "copper" side with black solder mask, and you can use silkscreen for text, or use Stop layer, to reveal the goldplated metal or HASL, which is very nice looking. Holes will be cut with very high precision.
If 1.6 mm is not thick enough, double stack them. Holes can be sized for selftapping screws.

 

[djmiggymigz]

You can also order aluminum PCBs from JLC, for your front panel.
Use the "copper" side with black solder mask, and you can use silkscreen for text, or use Stop layer, to reveal the goldplated metal or HASL, which is very nice looking. Holes will be cut with very high precision.
If 1.6 mm is not thick enough, double stack them. Holes can be sized for selftapping screws.

Whoaaaa that is an incredible idea thank you!! I've been banging my head trying to figure out an affordable way to get the front panels made. I was looking at Front Panel Express but it's super pricy!! The second I pop any sort of printing on the price skyrockets to like $60-80 just for one. Let me look into thiss!

 

[merlin]

Very interesting. I've made whole enclosures from PCB material before, but aluminium clad is new to me!

 

[ccaudle]

aluminium clad is new to me!

I have never designed anything with that substrate yet, but I found some high power LED modules using alumin(i)um core PCB.
I think some high density power supplies may use that. I am surprised that GPU have not started using it yet, but likely it is only useful in cases where the PCB can be bolted to something to transfer the heat, so cards inserted into an edge connector would not benefit. Just a guess based on seeing them in places where the PCB is bolted to a metal enclosure of some kind.

But that doesn't mean we can't use them for low or no power applications if it eases case construction.
I think technically it may be possible to make double sided PCB, but which are actually just two non-connected single sided PCBs glued to the same thermal substrate.
Maybe not commercially available, but I was thinking that might be a way to get e.g. a faceplate with nice epoxy soldermask and silkscreen for colored exterior face, and also a PCB back face for mounting e.g. a microcontroller and some LEDs to make a front panel display.

 

[Cqwet Dbdfte]

I have never designed anything with that substrate yet, but I found some high power LED modules using alumin(i)um core PCB.
I think some high density power supplies may use that. I am surprised that GPU have not started using it yet, but likely it is only useful in cases where the PCB can be bolted to something to transfer the heat, so cards inserted into an edge connector would not benefit. Just a guess based on seeing them in places where the PCB is bolted to a metal enclosure of some kind.

But that doesn't mean we can't use them for low or no power applications if it eases case construction.
I think technically it may be possible to make double sided PCB, but which are actually just two non-connected single sided PCBs glued to the same thermal substrate.
Maybe not commercially available, but I was thinking that might be a way to get e.g. a faceplate with nice epoxy soldermask and silkscreen for colored exterior face, and also a PCB back face for mounting e.g. a microcontroller and some LEDs to make a front panel display.

You could use reverse mounted SMT LEDs for indicator on a frontpanel, and/or use it with aluminum side out and a full single layer circuit on the "other" side.

 

[ccaudle]

and/or use it with aluminum side out

Yeah, aluminum side out is the more obvious approach, but then you don't get the nice UV cured epoxy coating (i.e. soldermask), you have to paint it yourself, which can sometimes be a pain with aluminum (not all paint sticks well to aluminum oxide so it can scratch easily).
At least it looks like they will silkscreen the aluminum side for you, if you are OK with bare metal instead of painted.

 

[Cqwet Dbdfte]

Yeah, aluminum side out is the more obvious approach, but then you don't get the nice UV cured epoxy coating (i.e. soldermask), you have to paint it yourself, which can sometimes be a pain with aluminum (not all paint sticks well to aluminum oxide so it can scratch easily).
At least it looks like they will silkscreen the aluminum side for you, if you are OK with bare metal instead of painted.

Aluminium is not anodized, and you can order a second PCB for the "front" with silkscreen, and have the cake on the backside. It is really low cost.

 

[ruffrecords]

Very interesting. I've made whole enclosures from PCB material before, but aluminium clad is new to me!

I tried this type of PCB as a front panel a few years back. At that time you could only silk screen on the copper side so the panel colour was that of the solder resist. However, looking at that video it is clear you can now silk screen on the metal side which looks pretty good to me. Ideal for prototypes and small tuns.

Cheers

Ian

 

[arthurdb]

I've used FR4 pcbs for front panels. Aluminum might be stronger but FR4 is already very tough...

 

[Cqwet Dbdfte]

I tried this type of PCB as a front panel a few years back. At that time you could only silk screen on the copper side so the panel colour was that of the solder resist. However, looking at that video it is clear you can now silk screen on the metal side which looks pretty good to me. Ideal for prototypes and small tuns.

Cheers

Ian

Those AL PCBs do not connect the aluminum to the copper layer, if you need this some other method would be needed, maybe a screw. Holes can be drilled to a root diameter to a screw and a self-tap a machine screw thru it to a ground pad.
JLC claims 3kV dielectric strength, dissipation factor and epislon not stated, last time I checked.
While silkscreen on the aluminum may be possible, the surface finish on the aluminum is not certain, I would not take a chance on it. Better to design a second sandwich PCB for the front, if you want to keep parts on the inside of the enclosure. Some secondary finishing steps would be needed to keep the aluminum eye-friendly.