Custom Engraving Examples

Custom engraving is free with any new JDS Labs amplifier or DAC ordered through jdslabs.com. It’s a fun process, both for us, and for you.

When you click the “Engrave” button during checkout, our production staff receives and pastes your custom text or image into Adobe Illustrator, then prints to one of our two laser engraving machines. Here’s our new Trotec laser engraver in action:

A full image takes just 2-3 minutes, and custom text takes only seconds.

Engraving Examples

Engraving image quality is comparable to that of a black and white laser printer. The key difference is print media. With a laser printer, black toner prints onto white paper. With a laser engraver, the result is always white onto all anodized aluminum, regardless of aluminum color.

Like a laser printer, black and white images engrave perfectly:

A monochrome image with a black background needs to be inverted. Our production staff uses their best judgement and corrects images as necessary, for example:

Laser engravers handle shaded images acceptably. This customer did not realize his image contained shading, and was surprised to see the result. [Note: We use calibrated IPS monitors. Check your screen brightness if you cannot see shading in the dark images!]

A gradient test pattern reveals engraver shading limitations:

Color images and photographs can be engraved reasonably well even with limited shading:

In summary, custom engraving works best with monochrome images.

Fischer Headphones In Stock

We select a few fun headphones to display at each audio show to demonstrate our amps and DACs. Fischer’s FA-011 attract curious visitors, and have earned a spot on both my home and office desks.

So, we exchanged messages with Fischer and now stock their most popular models.

Fischer FA-011 Natural Wood
Fischer FA-011 Natural Wood

We’re extremely pleased with the FA-003Ti-W. Sound quality is exceptional. These are Nick’s go-to set to drown out the sound of coworkers on the phone:

FA-003TiW-bog-oak3-7df03ff728
Fischer FA-003TiW Bog Oak

And last for now, triple-balanced TBA-04’s:

Fischer Audio TBA-04
Fischer Audio TBA-04

How to Connect Android, iPad, or iPhone to a DAC

There are three basic requirements to connect a USB DAC to any Android or iDevice:

  1. Power: The DAC must not consume more power than the phone or tablet permits.
  2. Support: The phone or tablet must be able to stream digital audio over USB.
  3. Cables: You must use an appropriate cable for your device.

Below we’ll show how you can connect a USB DAC to most Androids, iPads, and iPhones.

Nexus 7 connected to C5D via OTG cable
Nexus 7 connected to JDS Labs C5D via OTG cable

Power Requirements

All iPad, iPhone, and most Android devices enforce a peripheral power consumption limit. If you have a self-powered DAC like C5D, this requirement is easily satisfied since the DAC only consumes power from its own battery.

Connecting a more common, power hungry DAC is still possible! USB devices declare their power consumption in software, during USB enumeration (connection). Therefore, it’s easy to trick a phone or tablet by connecting the DAC to a small USB hub. With the right USB hub, your phone only reads the low power consumption of the USB hub, and not the larger power consumption of the DAC.

For example, directly connecting ODAC to an iPhone or iPad does not work. ODAC consumes about 20mA, while iPhone/iPad permits a maximum current consumption of around 5mA in software. With a portable USB hub connected, ODAC now works!

iPhone 5S successfully connected to ODAC, employing a USB hub.
iPhone 5S successfully connected to ODAC, employing a USB hub.

Power consumption has not actually changed here since we’re using a non-powered USB hub; ODAC still draws power from the iPhone.

A powered USB hub would be more ideal, but this experiment shows it’s possible to fool the software power limitations. Also note that a USB hub will only work with your phone or tablet if it reports itself as “self-powered”. Not all portable USB hubs report their power consumption this way. We’ve had success with Plugable’s USB 2.0 2-Port hub, but it’s worth mentioning that some customers have received Plugable hubs that do not work. Again, a powered hub is the best choice.

History Lesson: It’s safe to bypass the tiny power consumption limit of your iDevice. Maximum power consumption of iPad was much higher in iOS4 and earlier, so most standard DACs worked out of the box with iPad back then. Apple later reduced the software power limit causing standard DACs and other peripherals to only connect when used with a powered USB hub.

Android Devices – DAC Connections

Cables: Any USB On-the-Go (OTG) cable will suffice. Android devices use a micro USB port, while most DACs rely on mini USB. A micro-to-mini OTG cable makes a perfect connection.

Micro-to-Mini USB OTG Cable
JDS Labs Micro-to-Mini USB OTG Cable

Support: Digital audio support with Android continues to improve. While only some Android devices support digital audio out of the box, nearly all Androids can connect to a DAC using USB Audio Player Pro. And if you’re adventurous, Cyanogenmod is known to enable streaming digital audio systemwide (all apps) for most devices.

Tip: Even with the proper cable and support, Android sometimes needs a reboot. Make sure to turn your DAC on and connect it to your phone/tablet, then reboot Android. This will give Android a chance to initialize the DAC.

For more background information on Android digital audio support, see our C5D release article.

Android Summary

  • Power – Use a self-powered DAC. For other DACs, you can use a self-powered USB hub.
  • Support – Varies with Android device. If default Android does not work, use USB Audio Player Pro or Cyanogenmod if needed.
  • Cables - Use any USB OTG cable.

iDevices – iPhone & iPad DAC Connections

Apple unlocked digital audio support under iOS 7, so all iPhone and iPad  devices painlessly connect to self-powered DACs. Support is excellent.

Unlike Android, Apple’s proprietary cables are the only point of confusion. There are presently four possible connections, and only three of four work.

Lightning to USB Cables

The best solution for now is Apple’s Lightning to USB Camera Adapter, part number MD821ZM. This cable conveniently provides a USB port from your iPhone/iPad, allowing you to connect a short mini-USB cable to your DAC.

One might expect that Apple’s Lightning to Micro USB adapter (MD820ZM) and a short USB cable would also work. We’ve confirmed this adapter is NOT usable with DACs! Apparently it was made only for charging.

Apple 30-Pin to USB Cables

For iPhone and iPads with an older 30-pin dock connector, you’ll need Apple’s 30-pin Camera Connection Kit (CCK), Apple part number MC531ZM.

Note that iOS 7 is mandatory to use a DAC, meaning these adapters are suitable for iPad, iPhone, and iPod Touch running iOS 7. There’s currently no standard digital audio support for iPod Classic or iPod Nano, as they do not support iOS 7.

If you already have a 30-pin CCK and a Lightning-to-30-pin Adapter (MD823ZM), it’s possible to pair these two connectors together to form a bulky Lightning to USB adapter:

Lightning to 30pin --> 30pin to USB --> mini USB --> JDS Labs C5D
Lightning to 30pin –> 30pin to USB –> mini USB –> JDS Labs C5D

Addendum: You can use any mini USB cable with the above Apple accessories. The stock, 1.5ft cable provided with C5D will work, or you may choose a shorter cable. Some users also prefer to strap their devices together with silicon bands for better organization:

Generic Lightning Cables

Now you’re probably asking yourself, “Why doesn’t someone make a short Lightning to mini-USB cable?!”

It was a quick task for us to find a great manufacturer for our custom Android OTG cables. Sourcing the equivalent Lightning-to-mini-USB cable is vastly more challenging. Apple controls the accessory market under its MFi Program. JDS Labs has applied twice in the past 3 years and has yet to receive a go ahead. This leaves us with three options: We can either source generic Lightning cables from non-MFi certified manufacturers, or we can partner with an MFi approved developer, or we can continue to wait for our own MFi certification.

We’ve found several overseas vendors willing to product custom Lightning cables, but we have no interest in breaking Apple’s MFi agreement or distributing cables which may not always work. So, generic cables are not an option. We’ll continue seeking a path of MFi approved production.

iDevices Summary

  • Power – Use a self-powered DAC. For other DACs, you can use a self-powered USB hub.
  • Support – iOS7 fully supports streaming digital audio!
  • Cables - Use Apple Camera Connection Kit cable + mini USB cable

 

Questions?

Cyber Monday 2013 @ JDS Labs

After a busy Black Friday sale, we bring you Free Shipping this Cyber Monday. All amplifiers and DACs ship free today, including international orders!

  • Free shipping applies to all orders weighing 3+ ounces
  • Orders placed with free shipping will be mailed via USPS First Class or USPS First Class International. If your order is too heavy for First Class mail, we will upgrade your shipment to the next fastest shipping method.
  • Shipping insurance remains mandatory for international orders over $75 USD
  • Offer applies only to orders placed on Cyber Monday, December 2, 2013 from 12:00AM to 11:59PM Central Standard Time (UTC-6).

C5D Shipments Continue

This morning we’re glad to resume production of C5D! UPS delivered parts at 10am and I’ve been listening to C5D for more than two hours with a smile on my face.

C5_Intro2

In case you missed the drama, we caught a tiny error in the first batch of C5D and temporarily halted production. Our terrific engineers, George Boudreau and Ken Mathews, collaboratively resolved the mistake in less than 48 hours. We owe them many thanks.

Customers

A few C5D’s shipped on Monday and Tuesday without the correction. We’re emailing affected customers today and will offer an easy exchange.

Distributors

C5D shipments to distributors resume next week:

  • Headphone Bar / Canada
  • Munkong Gadget / Thailand
  • Headsound Audio / Germany
  • Kingsound Audio / Hong Kong
  • Noisy Motel / Australia

C5D samples also ship to reviewers by Monday.

Technical Explanation

If you’re curious, C5D is a complex device that makes use of 12 highly regulated, onboard power supplies.

C5D Printed Circuit Board
C5D Printed Circuit Board

Prior to the production fix, the first batch of C5D exhibited an extremely low level hum under USB data transfer. Hum vanished while music was not playing over USB, so it was easy to miss while listening. And by nature of its presence, it could never appear in Noise measurements, and was simply a tiny component of THD measurements (all excellent). This type of problem could only be found by an engineer actively looking for it. Conclusion: Subjective results matter as much as Objective measurements!

Working backwards, we disabled individual power supplies in C5D to isolate the issue. We found that when the USB controller placed its heavy load during data transfer (0.5W), it brought the primary +7V rail to 60% capacity. The +7V rail has been stable in C5, and the amplifier and DAC measure well independently. While powering both amp and DAC, the higher power draw pushed the rail slightly out of regulation. Line ripple increased by a factor of 10.

The solution was shockingly simple–we added a larger capacitor to the +7V rail (this capacitor will be hand soldered on the first batch of C5Ds). Ripple decreased more than 10x, to levels better than ever. Performance is restored. Low level hum is gone.

Introducing C5D, Amp+DAC

Today we’re pleased to release our new C5D Headphone Amplifier + DAC:

C5_Intro2

On a related note, we pushed a major site update to JDSLabs.com last night. Please call, email, tweet, or reply below if you encounter any browsing issues.

C5D Production Status

  • Design: 100% Complete
  • Benchmarks: 100% Complete
  • Production: Ships by November 22

C5D is entirely complete and ships immediately! We temporarily paused production to make a final tweak. Shipments resume no later than November 22.

Design Priorities

C5D adds an outstanding PCM5102A DAC and extra bass boost level to our C5 headphone amplifier. Both C5 and C5D are built for portable users who demand exceptionally low noise, sufficient output power, and a super fine volume control to handle sensitive headphones and IEM’s.

Our goal for C5D is simple: Merge a reference grade DAC with C5, valuing performance and compatibility over superfluous features. C5D works natively with iPhone, iPad, and all devices and operating systems which support UAC1.

Going UAC1

USB Audio Class 1 (UAC1) is the widely compatible standard for transmitting digital audio over USBUAC2 is required to go beyond 24/96 audio, but UAC2 support remains limited and requires special drivers for Windows XP/7/8, etc. In other words, connecting a UAC2 DAC becomes more involved and potentially buggy.

It’s easy to understand why audiophiles develop specification wish lists such as 32/384kHz PCM via UAC2, or DSD, or asynchronous operation. The numbers and algorithms look really impressive. But ultimately, you can’t utilize 32/384 audio when your music collection is the bottleneck. It makes perfect sense from a marketing standpoint to enable the latest features on a new device. Fortunately, we’re engineers and not marketers.

C5D’s hardware actually supports DSD and 32-bit audio. We disabled both. UAC2 breaks compatibility with many portable devices, and C5D needs to work out of the box with phones and tablets. Plus, transparency is achievable through UAC1 and fully utilizing 24-bit depth can be unrealistic.

So instead of giving C5D compatibility limiting UAC2 features, it’s configured for awesome performance under UAC1. And we still managed some interesting characteristics–galvanic isolation, asynchronous operation, and a low latency jitter filter.

Reference D/A Conversion

C5D’s new DAC circuitry fits in previously unused space beneath the battery, so size remains identical to C5. The PCM5102A DAC and SA9027 controller pack incredible performance in this small space.

C5D Circuit Board
C5D Printed Circuit Board

Galvanic Isolation

The large chip next to the USB jack is an Analog Devices ADuM3160. This IC serves two functions:

  • Enhanced ESD protection at the USB jack
  • Galvanic Isolation

Also next to the USB jack is a new toggle switch. Flipping this switch right allows C5D to charge. Flipping the switch left makes use of the ADuM3160’s air core transformer technology to operate C5D in self-power mode*. That is, the DAC runs from its own battery when connected to a portable USB audio player. This is known as galvanic isolation, and it cleverly prevents the DAC from being subjected to noise on the USB +5V rail.

Self-power mode also gives C5D maximum flexibility with portable devices since most smartphones and tablets disable USB devices that consume too much power.

* Full isolation is utilized with low power USB devices. C5D enters a hybrid self-powered mode when connected to strong USB devices, only consuming extra power. DAC performance is identical in all power modes.

Asynchronous Mode

Just weeks before we approved C5D for production, I received word that a code update could convert C5D from adaptive to asynchronous operation. Features are always second to performance at JDS Labs, so we repeated all benchmarks.

C5D jitter already measured extremely well in adaptive mode. We want to see a sharp signal in this test, with minimal sidebands (especially near the signal). Keeping the sum of matched components below -100dBFS prevents an audible impact. C5D in adaptive mode far surpasses this reference goal at -111dBFS:

Jitter in Adaptive Mode, -3dBFS, LLF High
Jitter in Adaptive Mode, -3dBFS, LLF High

Running asynchronously, jitter improves little more than the measurement’s margin of error:

Jitter in Asynchronous Mode, -3dBFS, LLF High
Jitter in Asynchronous Mode, -3dBFS, LLF High

Jitter measures slightly better at -112dB in async mode, and is the only standard test that revealed any difference from adaptive mode on C5D. All other benchmarks returned identical results. Thus, C5D ships in asynchronous mode.

Technical Specifications

Asynchronous mode and galvanic isolation together make C5D a rare UAC1 DAC. These features make it highly self-reliant, generating its own clock and power.

DAC Specifications

Frequency Response +/- 0.14 dB
THD+N 100Hz 0.0014%
THD+N 20Hz 0.0015%
THD+N 10kHz 0.0025%
IMD 19/20kHz, -7dBFS 0.0015%
Noise, A-Weighted -103 dBu
Dynamic Range > 109 dB A-Weighted
Linearity Error, -90dBFS 24/96 0.2 dB
Crosstalk -10dBFS -80 dB
USB Jitter, Marked Sum -112 dB
Maximum Output 2.0 VRMS

DAC measurements were obtained by hardwiring a line-output jack to C5D’s PCM5102A output for connection to our dScope Series III audio analyzer.

Frequency response is excellent, with negligible rolloff of 0.1dB in the final octave of human hearing.

C5D Frequency Response
Frequency Response of C5D’s PCM5102A (direct DAC output signal; amplifier bypassed)

THD+N measures well below our reference goal of 0.005% at all frequencies:

THD+N @ 20Hz
THD+N @ 20Hz
THD+N @ 100Hz
THD+N @ 100Hz

A-Weighted noise exceeds expectations with components at -110dBu, and overall noise better than -100dBu:

Noise, A-Weighted
Noise, A-Weighted – C5D DAC line output

Dynamic range measures quite well at 109dB:

Dynamic Range
Dynamic Range – C5D DAC line output

The DAC’s line output crosstalk measures at -86.1dB, outperforming our reference requirement of -80dBFS. Note that crosstalk is limited by 3.5mm cables in actual use (still excellent).

Crosstalk
Crosstalk (C5D DAC line output)

The IMD CCIF test checks DAC performance during simultaneously playback of 19kHz and 20kHz tones. C5D returns excellent results here, with minimal blurring between the high frequency signals (noise below -120dB). Total distortion measures well at a very low 0.0013%:

IMD CCIF: 19kHz + 20kHz, -7dBFS.
IMD CCIF: 19kHz + 20kHz, -7dBFS.

Low Latency Filter

The PCM5102A DAC used in C5D features a configurable low latency filter. In testing, we’ve observed no significantly audible difference. C5D ships with its Low Latency Filter set High.

C5D’s firmware is released freely under the Creative Commons BY-SA 3.0 license. Refer to line 55 if you wish to experiment with the PCM5102A’s LLF feature. Note that a programmer and pogo pins are required for DIY tinkering.

Amplifier Performance

C5D’s amplifier and supporting power circuitry is identical to that of C5, with the exception of an additional bass boost level and smaller output resistors. Output impedance of C5D has improved to 0.62Ω. This specification change minimally impacts overall performance, and ensures neutral operation with low-impedance balanced armature IEMs.

Amplifier Specifications

Frequency Response +/- 0.1 dB
THD+N (20-20kHz, 150 Ω) 0.0015%
THD+N (20-20kHz, 32 Ω) 0.0045%
Noise -105 dBu
Crosstalk @ 150 Ω -67 dB
Inter-channel Phase @ 1kHz +/- 0.01 degrees
Channel Balance +/- 0.55 dB
Max Output @ 600Ω 4.146 VRMS
Max Output @ 150Ω 3.580 VRMS
Max Output @ 32 Ω 1.182 VRMS
Power Supply 14.0 Vpp
Output Impedance 0.62 Ω
Battery Run Time 7-12 Hours
Charge Time 2-4 Hours
Operating Temp 0°C to 60°C
Operating Humidity 0 to 85% Relative
Dimensions 99.5 x 61.5 x 14.0 mm
Weight 4.2 ounces

Triple Bass Boost

C5D’s bass boost has three positions: Off / Medium / High. The High position is identical to C5’s bass boost, with the Medium level residing audibly halfway between off and high. Below are C5D’s bass boost curves in low gain:

C5D Bass boost reponse at Low Gain
C5D Bass boost response at Low Gain (2.3x)

These curves relax at high gain, in effect producing four unique bass boost curves:

C5D Bass Boost Response at High gain
C5D Bass Boost Response at High gain (6.5x)

DAC Compatibility

Compatible Requirements
iPhone Yes Camera Connection Kit and iOS7
iPad Yes Camera Connection Kit
Windows XP/Vista/7/8 Yes
Linux Yes
Android Some ROM and OS must support UAC1
Mac OS X Yes

Android

We considered developing C5D for fully native operation with Android, and discovered the goal is presently futile. Even a DAC designed for native functionality via Android’s Open Accessory Protocol remains limited to 16-bit, 44.1kHz operation. And even then, support is not 100% guaranteed across all Android devices! Only an app like USB Audio Recorder Pro unlocks full 24-bit digital audio, by utilizing alternative drivers.

C5D works with every Android device we’ve tested under USB Audio Recorder Pro. We met a few Android users at the 2013 CanJam who successfully used C5D natively (i.e., with any app). Some Android phones and tablets output UAC1 natively. Others require special ROMs or apps.

Guaranteeing DAC operation with all Android devices is currently not realistic. Since Android is opensource, it’s definitely possible to enable 24-bit digital audio output on any Android device. Hopefully Google will make UAC1 output standard in future Android updates to simplify the user experience.

The good news: C5D is self-powered, so its power consumption is not a limitation. You’ll only need to enable digital audio output on your device if it’s not already available.

iPad and iPhone

C5D works out of the box with iPad and iPhone! Apple has finally enabled UAC1 output as of iOS7. You simply need a Camera Connection Kit cable. C5D is self-powered, so power consumption is of no concern.

iPhone connected to C5D at CanJam
iPhone connected to C5D at CanJam

Questions?

 

 

 

Machining an Audio Company

We build amazing headphone amplifiers and DACs. Obviously, this niche market appeals to owners of nice headphones. More interesting is a look at Google Trends for the search phrase “headphones”:

Google Trends - Headphones

It’s clear that headphone popularity has grown in the past 3-4 years (and the average consumer searches for Beats by Dre…). Easy to explain is the annual spike in headphone interest around the December holiday season, followed by a return to normal interest by summer.

Since interest in headphones directly correlates to interest in headphone amps and DACs, we’ve learned to use summer for two things:

  1. Building our company
  2. Enjoying the summer!

Upgrading our Office

We moved into a 950 sq. ft. office in May 2012. We knew orders were growing at 300% annually in 2011, and hoped that our 2012 office would be large enough to last for 1-2 years. We ran out of space in 3 months. Our inventory room was packed full, our soldering benches were feet away from our CNC machine (noisy and messy), our shipping station doubled as an assembly table, and we had no room for additional desks in our front office. Our product display table and couch turned into a lunch table and conference “room” for visitors. We even resorted to storing an engine hoist in our restroom. At least the rent was low!

We began looking for a larger facility as soon as the 2012 holiday rush ended. There was a slight difficulty: We require an unusual mix of office and warehouse space. Large machines, dock access, and concrete floors are normally found in huge warehouses. We needed all of this, plus professional office space in a relatively small space.

In March, we were pleased to find a 2500 sq.ft. office just days away from undergoing a construction makeover. We signed a lease and moved into our fully customized facility on June 1st.

New Assembly & Shipping Benches
New Assembly & Shipping Benches

Frequently accessed inventory is now footsteps away from our two main soldering benches. Nick also spent a laborious weekend assembling a massive table for assembly and a 7ft tall shipping station.

Not pictured: About 60% of this room is unused for now. Room to grow!

Laser Engraving Station
Laser Engraving Station

Soldering and laser engraving stations are equipped with 4″ industrial fume exhaust lines.

A Soldering Bench
A Soldering Bench
Front Office
Front Office
New CNC Room
Dock and CNC Machining Area

Building a Machine Shop

Last year we bought a Tormach PCNC 770 as our first foray into the world of machining. Within 12 months, we’d machined over 5000 parts on the Tormach. Notice it’s absent from the picture above.

As much as we valued the ability to machine our own parts, the PCNC 770 turned into the weakest link of our production process. We frequently found ourselves waiting for parts to be machined. It struggled to keep up with our busiest weeks, so Nick was forced to work 12+ hour days in December and January.

Plus, moving a CNC (even the entry level Tormach 770) is no trivial matter. Industrial movers quoted 10% of the cost of the Tormach just to relocate it from our old office to our new facility. I didn’t want to invest more in a machine that was holding us back.

Nick found a lightly used 2012 Haas Mini Mill 2 the week before our move. At 7.5x the horsepower and 4x the speed of a Tormach, we placed the PCNC770 for sale and upgraded to a Mini Mill 2.

Our new CNC (Haas Mini Mill 2)
Our new Haas Mini Mill 2, CNC

The Tormach was capable of producing about 45 Objective2 front plates per day. We’re now able to machine 135 of these parts in the same amount of time (3x faster).

To give you an idea of how quickly the Mini Mill 2 moves, here’s the first 30 seconds of machining a batch of endplates

And here’s the entire, 3-step process compressed into less than 3 minutes:

Fixing Objective2’s Power Jack

** We’re moving to a new office on Friday, May 31st. Orders placed after 10am CST tomorrow (5/31) will ship Monday! **

If you’ve assembled NwAvGuy’s Objective2 in the past year, you must have noticed that its power jack is discontinued. Alternatives to Kobiconn 163-7620-E do not fit.

One of many alternative 2.1x5.5mm DC jacks -- Does not fit!Substitute power jack for O2. Does not fit.

NwAvGuy last reached out to us on July 1, 2012 before mysteriously disappearing. Two months earlier, he’d discussed revising the O2 PCB. The discussion is archived for those interested: NwAvGuy Emails

From:Northwest AvGuy
Sent: Tuesday, May 01, 2012 12:30 PM
To: John Seaber
Subject: John: O2 Power Jack

Have you found an alternate power jack for the O2, are you modifying jacks to fit, or do have enough of the old ones for now? I’m getting more questions about the discontinued jack and trying to decide what the best solution is.

If I revise the PCB artwork I would fix the jack footprint and move the via under the corner of the gain switch. Are you aware of any other necessary board revisions?

On Tue, May 1, 2012 at 11:57 AM, JDS Labs Inc. wrote:

We source unique parts in large quantities, so we have enough power jacks to last all year.

Kobiconn 163-179PH-EX is close. Dimensions aren’t a perfect match to 163-7620-E, but it should fit existing O2 boards and front plates [Edit: 163-179PH does not fit]. Breaking mechanical compatibility with the original board/plates would be a mess.

No other revisions should be necessary!

On Tue, May 1, 2012 at 2:08 PM, Northwest AvGuy wrote:

Thanks for the reply. Yeah, I have a sample of the 179PH already and, as I posted on the O2 Summary comments, two of the tabs are a bit too big. A revised board shouldn’t change form, fit, or function of the assembled board.

Just beware before ordering a large number of PCBs the artwork may be revised so you might want to check in with me first.

We believed NwAvGuy would eventually update O2. Now that almost a year has elapsed, we can only hope he’s doing okay.

We’ve spent the past few months seeking substitute power jacks. No success. Jack manufacturer Kycon quoted a custom part, with tooling and minimum order quantity totaling $25k-$100k. Not worth it! The last thing we want to do is violate NwAvGuy’s work by disregarding the O2’s no-derivatives license. We’ll gladly respect any wishes he may have if he’s able to return in the future. Until that time comes, we’ve decided it’s time to proceed with NwAvGuy’s intention of sustaining O2 as a viable DIY project. That means the O2 PCB must accept common power jacks.

NwAvGuy only supplied Gerbers for the O2, which makes the design nearly impossible to modify without re-drawing the schematic and PCB from scratch (definitely unacceptable).

O2 v1.1a PCB Gerbers
Original O2 v1.1a PCB Gerbers

Zooming in on the power jack (J1), you can see that plenty of copper surrounds its 2.3mm holes:

O2_original_zoom
Original O2 v1.1a PCB Close-up

Most power jacks have pin widths of 3.0mm, instead of the small 2.3mm pins used by 163-7620-E. So, we only need to increase hole diameter at J1 by 0.7mm.

NwAvGuy left us with wonderful documentation. You can find this table in the O2 readme, and tool “T8″ looks like the drill bit relevant to jack J1:

Tool Hole Size Hole Type Hole Count Plated
T1 28mil (0.7112mm) Round 104
T2 32mil (0.8128mm) Round 44
T3 42mil (1.0668mm) Round 23
T4 53mil (1.3462mm) Round 24
T5 55mil (1.397mm) Round 8
T6 62mil (1.5748mm) Round 12
T7 68mil (1.7272mm) Round 12
T8 91mil (2.3114mm) Round 3
T9 125mil (3.175mm) Round 3
Totals 233

To test this idea, I searched the drill file for “T8″. The first instance occurs at line 13, where this table is defined explicitly in Gcode:

M48
;Layer_Color=9474304
;FILE_FORMAT=2:4
INCH,LZ
;TYPE=PLATED
T1F00S00C0.0280
T2F00S00C0.0320
T3F00S00C0.0420
T4F00S00C0.0530
T5F00S00C0.0550
T6F00S00C0.0620
T7F00S00C0.0700
T8F00S00C0.0910
T9F00S00C0.1250
%

Tool names gain a prefix of ‘0’ throughout the rest of the drill file, and T08 appears with three coordinates on lines 250-253:

T08
X017Y-005452
Y-00305
X015189Y-00431

To confirm that T8 is the appropriate drill bit for the DC jack, I set T8 to an arbitrarily large size on line 13 and checked the visible result:

Changed drill size in NC Drill file to use arbitrarily large holes
Arbitrarily large T8 drill size confirms T8 is only related to O2’s DC jack

This test proved that T8 only affects holes at the DC jack. Thus, I changed T8 in the drill file to our desired hole diameter of 120mils (3.05mm). Here’s the visible result, showing successful 3mm, plated holes at the power jack:

O2 v1.1b PCB: Equal to NwAvGuy's v1.1a, with J1 holes enlarged from 2.31mm to 3.05mm
New O2 v1.1b PCB: Equal to NwAvGuy’s v1.1a, with J1 hole sizes increased from 2.31mm to 3.05mm

O2 v1.1b PCB fabricated and confirmed perfect!

Fits
CUI PJ-002A power jack (3.0mm pins): Fits new v1.1b PCB
O2 v1.1a in Green, O2 v1.1b in Purple.
Original O2 v1.1a in Green, Modified O2 v1.1b in Purple.

AVAILABILITY

Modified O2 PCBs are Now in Stock. You may also download the v1.1b Gerbers for your own use.

SUMMARY

O2 v1.1b is a straightforward manufacturing alteration to the O2 v1.1a circuit board. Specifically, holes of the power jack, J1, have been enlarged to accommodate standard power jacks. All aspects of the Objective2 remain unchanged from NwAvGuy’s work. The PCB layout is identical. Performance is identical. Even the silkscreen still shows “v1.1a” (admittedly confusing). The O2 v1.1b PCB merely allows builders to assemble O2 without encountering frustration from the DC jack.

 

How to Finish Aluminum

Disclaimer: This article has no audio related content. We hope the following manufacturing information will be useful to others.

A couple years ago, we naively expected that aluminum manufactures would perfectly interpret our engineering drawings and produce beautiful, black parts. After rejecting 4500+ aluminum cases in these past two years, I can tell you with certainty that this guy gives a false impression. There’s much more to fabricating a nice aluminum product than simple anodizing. Photos below are a chronicle of our progress.

Raw Aluminum

Our raw cases arrive from the aluminum manufacturer looking something like this:

Raw Aluminum
Raw aluminum extrusion for C5, “mil” finish (i.e., no finishing)
Scratch on right -- oops!
Right-most part was scratched prior to anodizing

Rough, huh? Sometimes we see deeper scratches and dents, and parts can even arrive covered in grease and oil.

Anodizing fixes none of this! Any scratches or defects visible before anodizing will remain visible after anodizing.

Brushed + Anodized Aluminum

We added brushed finishing to c421 after realizing that we couldn’t expect aluminum manufacturers to deliver parts in perfect condition:

Similar case w/brushed texture and black anodizing

Brushing solved the immediately visible problem in our first manufacturing attempts, but created new issues. The texture of production parts was rougher than samples. And here’s what happens with a heavy brush intensity:

Brushing can remove too much material, altering the case profile
Heavily Brushed piece at Left, Original piece at Right.

Pros:

  • Relatively fast to perform
  • Generally low cost
  • Brushed appearance is popular

Cons:

  • Since brushing a part is essentially like rubbing sandpaper against its surface, brushing can alter part tolerances (see above image).
  • An aggressive brushed finish can create a rough, undesirable texture.

Bead Blasting

When we began designing C5, we knew that enclosure quality needed to match the awesome new circuit board. Brushed cases had to go. Our local anodizer suggested a very fine bead blast (aka, “peening”).

Bead blasting is essentially like a pressure washer that uses “abrasive media” instead of water. Any media can be used: walnut shells, sand, and glass beads are common. Pick a media, a pressure, a distance from the part, and then blast the surface. Most shops say it’s an art.

Ultra fine glass beads produce a soft appearance similar to Apple’s Macbook:

Same part with bead blasting
Bead blasted extrusion (C5 case)

Bead blasting dulls the part finish. While appearance is excellent before and after anodizing, surface texture oddly changes after anodizing. In some cases, the texture is comparable to a chalkboard.

We also noticed that black parts turned out especially dull, unlike other colors.

Same bead blasted parts in Red and Black anodizing
Same bead blasted parts in Red and Black anodizing

Pros:

  • With the right bead blasting media and pressure, a bead blasted part looks excellent
  • Part tolerances are not altered

Cons:

  • Requires significant sampling/experimentation from your metal finishing shop
  • Cost is 50-100% higher than brushing
  • Most shops manually blast parts, which can lead to surface inconsistencies
  • Especially rough parts must be tumbled prior to blasting (even higher cost)
  • Anodizing yields a matte appearance, especially unsuitable for black

Bead Blasting + Bright Dipping + Anodizing

Aluminum parts are normally caustic etched immediately prior to anodizing. If you substitute etching for a process called Bright Dipping, dullness is magically replaced by a brilliant appearance and pleasant texture.

Bead blasted parts at top; bead blasted + bright dipped parts at bottom
Bead blasted parts at top; bead blasted + bright dipped parts at bottom

The bright dipped parts shown above are not actually brighter. At another angle, you can see instead that light reflects more brilliantly at all angles. Notice the bright dipped pieces appear darker in this photo:

Bead blasted pieces at Top; bead blasted and bright dipped pieces at Bottom
Bead blasted pieces at Top; bead blasted and bright dipped pieces at Bottom

Pros:

  • Excellent surface appearance
  • Excellent surface texture
  • Cost is comparable to standard anodizing

Cons:

  • Bright dipping is extremely corrosive, so it’s rarely offered in the United States
  • Carries all other downsides of regular bead blasting (see above)

Hopefully this helps someone in their manufacturing adventures. Special thanks to Tom at Archway Anodize for making our experiments possible!

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