[rogerjennings]

Can anyone recommend a good PCB fabrication house?
What is important to high performance audio circuits?

I'm thinking extra oxygen free copper is a must and thicker traces is better. Silver or gold plating plating rather than standard tinned? Are silver clad PCB available?

I'm using Eagle PCB, so accepting those files directly is a big plus - otherwise have to figure out how to export.

Thanks!

 

[linuxworks]

imagineering seems to be a high quality shop. not the cheapest but I find that cutting corners on boards is never a good idea.

 

[Juaquin]

It all depends on how many you need and in what time frame.

I use BatchPCB (which uses GoldPheonix) when I'm doing small projects and prototypes without a deadline or any urgency (takes 4 weeks or so). Extremely cost effective but slow. You could skip the middleman and go straight to GoldPheonix if you need/want a full panel ($100 for 155 sq inch, 5-day lead plus 3-day ship). The quality is very good too, from my experience.

Imagineering is also a great shop from what I've heard, but you're going to pay more for faster service.

 

[Nemo de Monet]

Quote:

Originally Posted by rogerjennings /img/forum/go_quote.gif I'm thinking extra oxygen free copper is a must and thicker traces is better. Silver or gold plating plating rather than standard tinned? Are silver clad PCB available?

You're not serious, are you?

Oh dear, you are.

"Oxygen free copper"? Um, no. I expect you'd like the fiberglass substrate, etchant, and soldermask to be cryogenically-treated, too?

Unless you manage to find a fab house that specializes in radio-frequency (RF) PCBs, what you get is perfectly serviceable everyday ordinary copper on perfectly serviceable ordinary everyday fiberglass. If you do find a fab house that specializes in RF PCBs, you'll perhaps be given the option of perfectly serviceable everyday ordinary copper on some slightly more exotic substrates.

There are a few places that will do silver plating over copper, but it isn't something I'd really worry about. In PCB fabrication, the final finishing (be it tin, silver, or gold plating, or an "organic solderability preservative") is generally only designed to protect the copper traces from atmospheric effects (i.e. oxidization and corrosion) which could affect solderability and thus assembly if the boards were to be stored for a period of time before assembly. Nobody designs PCB coatings for their, ahem, sonic benefits, if any.

98% of a good-quality PCB is all down to layout and design. Learn to make good layouts in Eagle, learn what design rules are and how to use them, and learn what the standard manufacturing specs for two- and four-layer PCBs are. Learn how impedance works with regards to differing copper and trace thicknesses. Learn what acid traps are and how to avoid them. Prototype your designs at the cheapest fab houses you can find, on 1.8mm FR4 with 1oz copper and lead-free tin plating.

Then you can, if you really want, spend extra for boards with 2oz copper on some exotic low-loss substrate with gold plating, or something. They'll look very pretty... probably. Whether you can actually hear the difference between them and the 1oz tinned FR4 boards in any sort of headphone application is something I'll happily bet money against. Small sums, mind, because some people are just nutterss and I am after all a penniless sod, but, still.

Cheap fab houses I like: BatchPCB, MakePCB, Seeed (under "prototyping services"), and Sure Electronics (on eBay, of all places - search "pcb service"). They're all overseas, and thus comparatively slow... but they're also very inexpensive, and geared towards small prototyping runs that many other places don't like to deal with.

 

[Fixz8]

I recommend 4pcb (a.k.a AdvancedCircuits), based out of somewhere in colorado. They have a special site: www.33each.com for 2-layer boards (you can write "student" in the comments section and then order just 1 board instead of the required 4 or 5 boards) and their turn around time is pretty quick. It usually takes them 5 days to build my pcb's, and then shipping is added onto that, so a week and a half, give or take.

the 33-each deal does lead-free plating on 1 ounce copper, with a max board size of 60 square inches. I think they'll do down to around 6 mil trace-width and up to as fat a trace as you can make, with anywhere between a 15 to 250 mil hole size for vias and whatnot.

I've used them for a tiny (like 2.5" by 2") fpga board and for a much larger mosfet-based current-source board (about 7" by 8") and both came out really well.

 

[cobaltmute]

Anyone use Sierra Proto Express?

 

[Pars]

I have used Olimex before, as they will panelize and most of the stuff I am interested in doing is low qtys (1-2) of several boards. You can send them a drawing of layout of different board files on a 160xx100mm (or 320x200mm) panel, and they will do them for you, including cutting them apart. Shipping was reasonable and it didn't take as long as I though it would. Boards were of very good quality... not quite as good as Imagineering, for example, but close.

 

[Robin W.]

I've had great results from pcbcore.com great quality, and didn't charge an arm and a leg for different silk screen colors etc.

 

[Steve Eddy]

Quote:

Originally Posted by rogerjennings /img/forum/go_quote.gif Silver or gold plating plating rather than standard tinned? Are silver clad PCB available?

Don't have any plating done. Go with a straight hot air solder level (HASL).

se

 

[deltaydeltax]

Quote:

Originally Posted by cobaltmute /img/forum/go_quote.gif Anyone use Sierra Proto Express?

NO NO NO NO NO NO NO NO NO NO NO NO NO NO!!!!!!!!!!! Sierra is nowhere near the quality it used to be.

I used them for a while, then they got really bad and are in the condition they are in now. I had them short all of the pads on the secondary side of a six layer board.

Use San Francisco Circuits. The guy who owns it used to work for Sierra Proto Express and left due to their poor quality standards. If you want to PM me, I'll give you the owner's name and my name to use as a reference. I buy all of my boards with them instead of wasting time with all of these "use our software" places.

 

[cobaltmute]

Quote:

Originally Posted by deltaydeltax /img/forum/go_quote.gif NO NO NO NO NO NO NO NO NO NO NO NO NO NO!!!!!!!!!!! Sierra is nowhere near the quality it used to be. I used them for a while, then they got really bad and are in the condition they are in now. I had them short all of the pads on the secondary side of a six layer board. Use San Francisco Circuits. The guy who owns it used to work for Sierra Proto Express and left due to their poor quality standards. If you want to PM me, I'll give you the owner's name and my name to use as a reference. I buy all of my boards with them instead of wasting time with all of these "use our software" places.

How is their pricing compared to Imagineering?

 

[deltaydeltax]

Quote:

Originally Posted by cobaltmute /img/forum/go_quote.gif How is their pricing compared to Imagineering?

I know nothing about Imagineering. Some of the boards I've laid out have been very dense, over ten layers and had requirements which were very tightly controlled. To give an example, one board I sent SF Circuits was a twelve layer with give BGAs and was about the size of to decks of cards laid side by side. The larger BGA had in the area of 288 ball. The pads for this BGA were all "via in pad" technology, so they were silver filled, sanded down, and plated. The cost of these boards I don't remember, it might have been something like $5k for ten of them.

I've done some smaller boards, only two sided with no special requirements which were far more affordable. One in particular was about 2" x 2" with standard plating and solder resist. I purchased a min/max quantity and the total came to about $300.00 for 50 boards. So, about $6.00/board.

 

[RLCrisp]

Quote:

Originally Posted by Nemo de Monet /img/forum/go_quote.gif You're not serious, are you? Unless you manage to find a fab house that specializes in radio-frequency (RF) PCBs, what you get is perfectly serviceable everyday ordinary copper on perfectly serviceable ordinary everyday fiberglass. If you do find a fab house that specializes in RF PCBs, you'll perhaps be given the option of perfectly serviceable everyday ordinary copper on some slightly more exotic substrates.

Good advice. People these are audio boards, not microwave PCBs that are going to be shot into space for use in a satellite. FR-4 is fine, thick traces for power, and a ground plane if you want to get really fancy. Use HASL for your boards unless you're going to have them sitting around for a year, then get plating so they don't oxidize and don't heat the hell out of them when you do build up since they've absorbed a whole bunch of moisture.

If anybody thinks that loss/crosstalk/anything is important for up to 30kHz signals, please state your reasoning (I love listening to ridiculous theories)

 

[tomb]

Just an FYI - but there is a slight, but measureable difference using 2 oz. copper vs. 1 oz. copper. It's worth another ~0.005mVAC (~10%) in ripple reduction in the power supplies on the Millett MAX/MiniMAX. For that reason, Beezar uses 2 oz. copper on MAX/MiniMAX production boards from Imagineering. Unfortunately, 2 oz. copper on low-rate prototype PCB's are way too expensive to order, so I go with the 1 oz. for prototypes. Since most of my own amps are prototypes, that means most everyone's MAX/MiniMAX has better performance than my own.

 

[rogerjennings]

Thanks for all the posts!

Hearing about people using teflon-silver internal wiring, audiophile solder, and complaints by some about the plating on the endcaps of smd resistors, I thought there might be concerns about pcb materials.

I do like 2oz for is extra physical durability, such as when desoldering and soldering replacement parts and a pad lifts up.