The Passinwind Open Source Preamp

[Passinwind]

No, it doesn't do placement and doesn't have any specific knowledge about audio nuances. However, that's not as bad as it sounds and there are some workarounds:

• You can hand route important stuff (ex: grounds) yourself, then let it autoroute the rest
• It does try to optimize trace length and vias, which means component placement plays a large part in determining the routing. Putting related audio components next to each other will usually result in sane routing.

I have found that some iterative autoroute->move components->autoroute again cycles have really improved the routing. Because you can watch it work you get a sense for where there are too many constraints, and sometimes just moving a component slightly will fix congestion areas.

Like I said, it may not always be pretty but may be worth experimenting with.

Cool, just have to find the 100 hours that it always takes to learn new software! Maybe during my upcoming summer shop shutdown.

Edit: where the heck is the direct download link? I already hate it!

 

[Jeff Siddall]

Cool, just have to find the 100 hours that it always takes to learn new software! Maybe during my upcoming summer shop shutdown.

Edit: where the heck is the direct download link? I already hate it!

Hah, yeah, I hear you on new software. IIRC I followed their recommendation and installed the layout editor package, which came with FreeRouting. After that it didn't take long to get it going. I run Linux, but Windows packages exist too:

Download | LayoutEditor

Unfortunately I can only help with the Linux install process, but after that it is the same java app.

 

[Passinwind]

Hah, yeah, I hear you on new software. IIRC I followed their recommendation and installed the layout editor package, which came with FreeRouting. After that it didn't take long to get it going. I run Linux, but Windows packages exist too:

Download | LayoutEditor

Unfortunately I can only help with the Linux install process, but after that it is the same java app.

Thanks Jeff, this will go into the investigation queue, which is very very long at the moment. Hopefully I can get to it sometime this year.

 

[rumblinbass]

No, it doesn't do placement and doesn't have any specific knowledge about audio nuances. However, that's not as bad as it sounds and there are some workarounds:

• You can hand route important stuff (ex: grounds) yourself, then let it autoroute the rest
• It does try to optimize trace length and vias, which means component placement plays a large part in determining the routing. Putting related audio components next to each other will usually result in sane routing.

I have found that some iterative autoroute->move components->autoroute again cycles have really improved the routing. Because you can watch it work you get a sense for where there are too many constraints, and sometimes just moving a component slightly will fix congestion areas.

Like I said, it may not always be pretty but may be worth experimenting with.

Prolly just a matter of time before AI takes over PCB layout.

 

[SubSpec]

Prolly just a matter of time before AI takes over PCB layout.

DeepPCB | Pure AI-Powered, Cloud-Native PCB Routing

 

[Jeff Siddall]

DeepPCB | Pure AI-Powered, Cloud-Native PCB Routing

I figured I would give this a try with my Natural Tone Preamp board. More than 2 hours and 90 "solutions" in, it still hasn't managed to connect 7 of the traces:

Time Spent:
2h 9min
Status:
Running
Connected / Total
209/216
Number of Vias Used
176
Total Circuit Length
24673749

Seems inline with other AI tools: not quite there yet!

If it ever completes I am curious to compare it to the FreeRouting result.

 

[seanm]

As a software programmer, I am really looking forward to AI. Once I retire, I expect to make a lot of money fixing AI software that almost, but doesn't quite, works.

 

[SteveCS]

As a software programmer, I am really looking forward to AI. Once I retire, I expect to make a lot of money fixing AI software that almost, but doesn't quite, works.

As an assessor and certifier of high integrity safety-critical software it scares the living daylights out of me. IME the type of 'developers' that go this way are the types that have little respect for deterministic behaviour through safe design or the life cycle discipline and engineering rigour needed to accomplish it. YMMV

 

[DrummerwStrings]

As a software programmer, I am really looking forward to AI. Once I retire, I expect to make a lot of money fixing AI software that almost, but doesn't quite, works.

Ready, Fire, Aim….I might try AI for a (lower voltage) pedal design; I just hope in a rush to be 1st to market the consequences from mistakes are easily repairable.

 

[Jeff Siddall]

I figured I would give this a try with my Natural Tone Preamp board. More than 2 hours and 90 "solutions" in, it still hasn't managed to connect 7 of the traces:

Time Spent:
2h 9min
Status:
Running
Connected / Total
209/216
Number of Vias Used
176
Total Circuit Length
24673749

Seems inline with other AI tools: not quite there yet!

If it ever completes I am curious to compare it to the FreeRouting result.

Update: it eventually said it was "done" even though it hadn't routed 4 of the traces.

Time Spent:
1days 15min
Status:
Done
Connected / Total
212/216
Number of Vias Used
104
Total Circuit Length
24133785

It also used about 50% more vias than FreeRouting, and ignored the pre-routed traces I had given it. Sigh.

 

[Passinwind]

Update:

Progress has been slow here, hot weather and a nasty wildfire nearby have been keeping me out of the shop. SMD opamp adapter boards due in tomorrow, so I can finally get back to some v2 builds. Waiting to see if @dcoyle's v4 spec works as well for him as my very similar last build has been working for me. And a per-pickup filter pedal build is in the works for this new acquisition:

There's a contact pickup on the resonator, already broken out to a stereo jack that also carries the humbucker output. The piezo pickup cops all the whale noises the neck 'bucker misses when I'm in slide mode, I'm also thinking of wiring it direct to a little 2 x 4" cab I have on hand. This thing is tuned like a banjo but sounds more like a dobro, 12 string guitar, and jazz box all rolled together than a banjo. Super nice for acoustic practice at home, it's not loud and clangy at all. Good times!

 

[Passinwind]

Looks like @dcoyle's v4 build is up and running now:

Once we compare notes on my latest v4 build I'll be wrapping up the official design spec and will get the board shares, schematics, and BOMs posted on GitHub. More than ready to move on to other things now, but it's definitely been a fun ride!

 

[sunbeast]

Looks like @dcoyle's v4 build is up and running now:


View attachment 5137467


Once we compare notes on my latest v4 build I'll be wrapping up the official design spec and will get the board shares, schematics, and BOMs posted on GitHub. More than ready to move on to other things now, but it's definitely been a fun ride!

Looking forward to building one!

 

[dcoyle]

I'll have more to say as I spend time exploring it, but this is an extremely useful circuit, well worth the effort to build. It is clean and very musical, and the Hpf control affects the feel on the bass in ways other preamps don't.

I had never used a peaking low pass filter for treble. The treble peaks as much as you dial in, and then drops above that frequency, so a lot of the upper frequency clatter I'm used to hearing on a Bax treble is not here. You fit in the mix better. Or you can lessen the resonance and increase the frequency to get a broader amount of treble for playing solo..

Charlie's boards are well thought out and easy to use. They are definitely small enough to fit in an instrument.

More after I get some time in.

Nice job, Charlie.

 

[S-Bigbottom]

 

[Passinwind]

Just one pic won't really do justice to that enclosure's color shifting finish. Here's what the Neutron Star finish looks like in direct sunlight:

Stomp Box Parts have enough leftover powder to do another run, but they'll probably all be in 125B format this time around. Fine for v2 builds at least.

 

[Bemo9]

Oooh boy!

 

[Passinwind]

I finished up the pedal for my mutant banjo/dobro hybrid yesterday:

The lower switch is not wired up yet, I'm thinking that using it as a bass control frequency shift might be useful. An input impedance option might be cool too though.

 

[dcoyle]

What's the inside look like?

 

[Passinwind]

What's the inside look like?

Knew you were going to ask that. Waiting on a couple of wire ties, and then possibly some cable re-routing. May not be able to swing that for a few days due to social obligations, and I'll want to make sure the config is what I want before I button it up in any case. I'll email you a quick pic or two in the meantime though. Now that all three main PCBs are the same size I will be trying some 3-D printed sub-enclosures the next time around, as hand making them from Nomex or fish paper is pretty time consuming. I could also get Nomex or fish paper already laser cut to spec, fish paper is more environmentally friendly for sure.