Dirty PCB

[mayfly]

Hi Folks,

For those of you who roll your own PCBs (Printed Circuit Boards), may I introduce Dirty PCB.

http://dirtypcbs.com/store/pcbs

These guys run a no bullsh*t cut rate on-line board shop.  They send your board design out to cut rate Chinese PCB shops for not a lot of money.  They are also hilarious - Here's a quote from their FAQ:

Is my design safe?
Your board will go to a cut-rate prototype PCB factory in China. In all likelihood they have too much volume to give a crap about what's on your PCB, but if this is a concern PLEASE FIND ANOTHER SUPPLIER.

And another quote
We'll process your boards, but because most services are offered at-cost we have very little appetite for demanding or difficult people. We really don't care if you want to take your business somewhere else, and it's not worth our time to deal with stupid questions or asshats. Paypal fee reversals, annoying emails and the like will get you banned from the site. It's like Mitch Altman says, don't work with people you don't like.

Mostly because of this, I had to give them a try!  well, that and the super cheap prices.  I'm in the middle of designing my own micro live mixing desk (yes I know - I'm insane) so I sent the board for the mic pre strip out to them.  Below is what came back.

It's not bad actually!  I got the blue solder mask I asked for, the silkscreen is legible, the holes are a bit off but not that bad.  All in all a damn good board.  The only issue is that it took 7 weeks to get to me. I've got a lot of projects on the go so this was not really a problem, although now I have to refresh in my mind what exactly the design is...

I'll let you guys know how the board stuffing and fireup goes.  But for now, Dirty PCB looks like a winner! - especially if you're not in a hurry...

 

[Cagey]

Cool!

I used to make my own PCBs about 100 years ago when I was young and it didn't seem like an unrestricted sado-masochistic activity (even though it really was), and I'd have given anything to have a service like that available. Later on, I found much of the work could be automated with software (circuit design/test, layout, mask printing, etc.) but the cost of entry for the software was kinda painful. These days if I can't buy the widget I need already packaged and warranted, then I find something else to play with  :laughing7:

 

[Verne Bunsen]

I just love folks who say what they mean and don't give a rats a$$ who likes it. I don't happen to have need of their services but I have been enjoying their website. Hope your board checks out functionally!

 

[Logrinn]

That looks really impressive Mayfly. Will be exciting to hear how it turns out.

 

[mayfly]

Just a little update.  I stuffed the board, did some initial tests on the bench, did some tweaking to the circuit, then attached it to it's companion board that handles the bus mixing, master fader, balanced outputs and power supply.

Then I brought the works over to the rehearsal room, placed it on some non-conductive paper based substrate (cardboard) attached to a mic stand, plugged everything in...

... and it worked!  Well, pretty well anyway.

What works:
1 - there's no 60Hz hum, even in the open air
2 - mic pre sounds great!  I used the THAT corp mic pre chipset.  A solid choice - recommended.
3 - pan circuit (using a single linear pot and 1/2 an op-amp) works great.
4 - low cut filter on the mic pre (12db / octave Linkwitz - Riley centered at 80Hz) works really well.  Say goodbye to muddy live vocals!
5 - groovy 'lit shaft' mic gain control.  I have it set to turn green when there is signal present and turn red during overload.  That works great - and you have to admit it's pretty cool looking  :headbang:

what does not work so well:
1 - The THAT corp mic pre chips require a reverse-log pot for a gain.  I tried to be clever and devise one out of a linear pot and a 'slug' resistor.  Didn't work - I ended up with a log pot instead.  That is, exactly what I didn't want    The gain is a bit 'touchy' 
2 - There is too much gain in the master fader board.  The rig is pretty loud in the first 1/8 of a turn, and there's some hiss present when you put your ear up to the speaker even with all the volume controls off.  Might have to tone that down.

But other than that I'm very pleased! Might have to start a new thread on this little project...

 

[mayfly]

Update - I stuffed another mic pre board, made the same mods to it for the first, and hooked it into the bus.

Works great as well!  Now I've got a 2 channel mixer  :icon_biggrin:

 

[Budpixel]

I used dirtypcbs to get my PCBs made, my first experience getting PCBs. But now i use Seeed Studio Fusion pcb prototype service for it's much cheaper than dirtypcb now!

 

[fdesalvo]

:toothy12:

 

[fox]

I  visited the dirty pcb 2 month ago,  uploading the gerber file , no responsed. I don't know why. it can't support the zip format? I look their quote $11.

Recently , i found a pcb company , jlcpcb, it  support the zip. easy to use .
The  most important is 100*100 just cost $2 $2!! First i can't believe this, just tried. But the quality  is pretty .
I want share it with  us .
https://jlcpcb.com/

 

[Cagey]

Some wonderful stuff available these days. When I think back on the pitiful parts I used to make and then look at this stuff, it just makes me laugh.