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Frequently Asked Questions

Common Questions

Do you ship internationally?

Yes, JDS Labs ships worldwide. Please see our Shipping page.

Can you lower the customs value or mark as a gift?

We utilize an automated shipping system which enters accurate customs information on every package.

Customs agencies in some countries lookup products on the Internet to verify shippers' honesty. False customs information can create problems for both the buyer and the seller. Therefore, you should always abide by your country's customs regulations.

What payment methods do you accept?

You may checkout with any credit card or PayPal account. Contact us if you require an alternative form of payment.

Where is my order?

We ship very promptly--often within hours of receiving an order. Please check your e-mail (and junk mail folder!) for our automated shipment notification.

Please note that tracking information is not provided with First Class International or Priority Mail International shipments. Status information is only provided during package acceptance at the post office. There is no way for JDS Labs or the United States Postal Service (USPS) to track these orders. Delivery time of 2-4 weeks is typical for international packages.

Please see our Policies and Shipping pages for more information.

Can I have a sample for review?

Please contact us. A limited number of sample units are available each month to qualified reviewers. It's helpful to tell us about your audience, such as number of Facebook, Twitter, or YouTube followers, or the number of unique visits/month to your site or blog.

How do I request custom engraving?

Custom engraving is free with any new order of C5, ODAC, or O2. Text or images can be engraved onto any surface of your amp or DAC. Use the "Order Notes" field during checkout to describe your special engraving request.

If you wish to provide an image, please reply to our "Order Confirmation" email with your artwork. Image files can be provided in any format. Engraving an image is similar to printing to a common laser printer. If your image prints well, it will also engrave well.

Image Requirements:

• Color Depth: Black-and-white or greyscale
• Resolution: Vector, or minimum 600ppi (1 inch = 1*600 = 600 pixels)

Dark colors of your image will be engraved and white areas will be ignored. Therefore, we do not recommend images with a colored background.

Where are your products made?

All of our amplifiers and DACs are sourced and assembled in the USA! Most of our printed circuit boards (PCBs) are manufactured in Arizona. Our surface mount PCBs are assembled in California. We perform thru-hole soldering, final casing assembly, testing, and packaging in our own facility in Illinois.

A large portion of our facility is devoted to our machine shop, which allows us to perform 100% of aluminum CNC machining and engraving. Thus, we're able to competitively manufacture our products in-house, here in the United States.

cMoyBB Questions

Can the cMoyBB be customized? How?

Yes, the cMoyBB can be custom built upon request to match your headphones. To request free customization, please mention your headphones in the "Order Notes" during checkout.

Customization is strongly recommended for low impedance headphones (32 ohms and below), such as Grados and most in-ear-monitors (IEM's/earbuds). We adjust over 10 components to optimize the amplifier's gain, bass boost, input attenuation, and ground circuitry to best match your specific equipment. There is no need to contact us in advance. We will automatically make all beneficial adjustments based on your order notes.

The cMoyBB is built by default to work well with any audio signal, including headphone output signals and line-level signals. If you plan to use a line-output adapter (LOD) cable, please mention this fact as well as your headphones during checkout. LODs produce a very strong signal which may require additional attenuation.

Please see our DIY modifications page for an explanation of all modifications.

The following cannot be customized:
     • Opamp Chip
     • Input Jack
     • Output Jack
     • DC Jack
     • Bass Boost Toggle Switch

Different jack requirements (such as RCA or 1/4" stereo jacks) can be fulfilled using appropriate adapter cables.

What other tins/enclosures are available?

The cMoyBB PCB is designed only to accommodate rectangular mint tins. Other enclosure types are not offered.

All cMoyBBs are built in Peppermint (red) style tins by default. Alternative mint tins are sometimes available; the tins pictured below may be in stock. Out of stock tins are indicated by a red X. Contact us prior to ordering to confirm tin availability. Please note that our tin supplier restocks alternative tins at unpredictable intervals!

To request a specific tin, please mention the tin name during checkout with PayPal (Wintergreen, Cool Honey, Creme de Menthe, etc.).

_{Stock Last Updated: March 15, 2013}

   

What types of batteries can be used?

Rechargeable or non-rechargeable batteries (any) are safe to use in the standard cMoyBB. This includes alkaline, Li-Ion, NiMH, NiCd, etc.

You may use non-rechargeable batteries in the rechargeable cMoyBB v2.03R for listening, but never connect a power adapter to a cMoyBB v2.03R unless using NiMH 9V's!

Can the bass boost toggle switch be replaced with a knob?

This modification is only available to do-it-yourselfers, as described in the Assembly Guide. JDS Labs does not stock the required potentiometer for the modification.

Will the cMoyBB work well with my headphones?

With over 4000 owners worldwide, the cMoyBB has received positive reviews from owners of practically every brand and most models of headphones on the market. Chances are, someone has tried the cMoyBB with your headphones and enjoyed it.

However, I do not own every set of headphones in the world and therefore cannot provide you with an honest opinion. I personally use Sennheiser HD-280 Pros, Grado SR-60s, Beyerdynamic DT-880s, and a variety of earbuds. The cMoyBB sounds great with them all.

The cMoyBB is fully capable of driving headphones of all impedances. High impedance headsets such as Sennheiser HD-650's (300 ohms), Beyerdynamics DT-770's and DT-880's (250 ohm editions), etc. are easily driven by the cMoyBB; an 18-24V power adapter can help to achieve dangerously loud volume levels with such models. Moderate and low impedance headphones such as AKG K-701's, Grado SR-60/80/125/225/325's, Ultimate Ears Super.Fi and Triple.Fi's, and Shure IEM's are also commonly paired with the cMoyBB.

Please browse through the cMoyBB's extensive Customer Reviews and you will likely find comments specific to your headphones.

What kind of cable do I need?

The cMoyBB uses standard 3.5mm (1/8") stereo input and output jacks. You will need a male-to-male 3.5mm interconnect cable (also known as a mini-to-mini cable) to connect your audio player to the amplifier.

Choose a heavily shielded cable. Look for terms such as "shielded," "noise-rejecting," or "braided." These cables use an additional grounding wire and and/or shielding sheath to avert a small amount of electromagnetic interference. Additionally, every cheap interconnect cable we have used has worn out in under a month, causing static, popping sounds, or a broken signal when the cable is wiggled. Invest in a rugged cable! We stock fine interconnect cables in our Store.

Many audiphiles prefer line-output adapters (LOD's) for their generally superior signal fidelity. We offer no LOD brand recommendations, but the advice above can also be applied to LOD's. Sometimes line-level signals can overpower unattenuated opamp inputs. If you plan to use an LOD, the cMoyBB can be adjusted accordingly (simply mention your intended equipment usage during checkout).

How long is battery run-time for the cMoyBB?

Battery life depends on volume, headphone impedance, amplifier customization, and of course battery type. A typical 9V alkaline battery in a standard cMoyBB lasts approximately 25-30 hours under heavy usage. Other battery types are also safe to use (NiCd, NiMH, Li-Ion, etc.). Run-time can be calculated as:

Hours = (Battery Capacity, mAH)/(Current Drain, mA)

where Current Drain varies from 10-30mA. Battery Capacity of a name-brand 9V alkaline is about 500mAh; many NiMH 9V's have a capacity of 200-300mAh. The most inefficient configuration lasts 6.75 hours, while the best can last up to 50 hours.

The standard cMoyBB does not feature recharging capability. A NiMH battery and charger are worthwhile investments if the amplifier is to be used portably.

What is the benefit of higher voltage?

Voltage supplied to an operational amplifier sets the upper and lower signal boundaries for the opamp's output. When volume is increased beyond the maximum voltage boundaries, the opamp clips the signal and you will hear distortion. Therefore, higher voltage allows the opamp to produce higher volumes when driving high impedance headphones.

There is little benefit to increasing supply voltage for low impedance headphones (32 ohms and less). These headphones tend to demand more current rather than more voltage, so a 9V battery is adequate for most listening. Instead of extra voltage, the cMoyBB's maximum output current can be enhanced for low impedance headphones by adding a second virtual ground IC.

A summary of recommended cMoyBB configurations can be found under our DIY modifications page.

All opamps are limited to "swinging" within a fixed distance from the voltage supply rails. Rail-to-rail opamps are able to drive signals much stronger before clipping. Thus, a rail-to-rail opamp is another way to achieve higher volumes, without resorting to higher voltage.

Why can't a cMoy be powered from a vehicle's +12V accessory supply?

The power adapter warning mentioned in the instructions sheet applies to every cMoy, not just the cMoyBB.

Most vehicular audio systems use an audio ground which is directly connected to the vehicle's negative battery terminal. Let’s call this ground “V-“, and the vehicle's positive battery terminal "V+".

The negative DC power input of the cMoy is not connected to its audio ground. Instead, the cMoy's audio ground is electrically biased halfway between the battery/DC input voltage. Let's call the cMoy's positive and negative voltage supply connections "Vp" and "Vn", respectively. In other words, a cMoy power circuit creates its own "virtual ground" equal to 0.5*Vp.

When you wire a vehicle’s +12V supply to a cMoy, you are connecting the vehicle's V+ supply to the cMoy's Vp, and V- to Vn. This immediately presents no problems. Plug in a set of headphones and an iPod and your music will sound great. However, as soon as you plug the cMoy into your vehicle's auxiliary radio input, you are effectively shorting “Vn“ to the “virtual ground”. This instantly fries the cMoy’s power circuitry (the cMoyBB v2.02's optional "D2" diode can sometimes prevent this damage).

Thus, if you wish to use a cMoy with a car/truck/motorcycle’s auxiliary radio input, you must use a 9V battery to avoid shorting out the “virtual ground.” The other option is to power the cMoy from the motorcycle’s battery and only use headphones and a battery powered external audio player, such as an iPod. Never use an audio source powered by the vehicle!

How do you change the operational amplifier chip?

Changing the opamp is simple: Remove the old chip, then insert the new chip in the same direction. Semi-circle notches can be found on the socket and chips to indicate proper orientation.

The chip sits in a socket from which it can be removed. If you do not own an IC extraction tool, use any thin, flat tool to pry the chip from its socket. A flathead screwdriver works well; needle nose pliers can also be used.

The above method applies to opamps in the standard DIP-8 package. To install a surface mount opamp, the chip must first be soldered to an appropriate SOIC-8 to DIP-8 adapter. The adapter can then be inserted into the amplifier as described above.

What other opamps do you recommend?

The stock OPA2227 opamp is an excellent chip. If you wish to experiment, several alternative chips are recommended in the Bill of Materials page. Because opinions vary from person to person, it is best for you to perform your own research and audition several chips. These discussions may help:

     • Head-Fi -- Best sounding opamp...
     • Tangentsoft.com -- Notes on Audio Op-Amps
     • Blog.JDSLabs.com -- SOIC Opamp Rolling and New Kits

The cMoyBB requires a dual operational amplifier chip in the DIP-8 package. Most dual-opamp chips (regardless of package style) will work in a cMoy. It is also important to choose an opamp with an acceptable minimum supply voltage. The cMoyBB supplies +/- 4.5V when running on a fresh battery. Therefore, an opamp with a minimum supply voltage of +/- 5V or more would be unacceptable when powered from a 9V battery. This limitation can be overcome by using a higher voltage power adapter.

It's also possible to use SOIC-8 (surface mount) opamps, or even pairs of single-opamps in conjunction with an appropriate BrownDog^™ adapter. We sell such BrownDog^™ adapters in our store for your convenience. Again, it's wise to research an opamp's compatibilty with the cMoy before dropping it into the circuit.

Finally, you may have noticed that we haven't recommended any specific chips. That's because audio is a subjective topic. What you enjoy hearing may differ the opinions of others. I personally enjoy the AD823, AD8620, AD825, OPA2604, and many other chips. Each opamp is unique and enjoyable in its own respect, so try as many as you can afford!

Why do nice amps have low volume imbalance?

This is a minor side effect of a high performance analog volume control. Any amplifier which relies on an analog potentiometer to control volume will exhibit some degree of channel imbalance at the lowest threshold of knob rotation. Imbalance is audibly resolved normally by 10-20% rotation of the knob.

So why do amplifier designers still use analog potentiometers? Performance! A digital potentiometer can control volume with great resolution and balance at all volumes. However, digital pots introduce unwanted capacitance, which directly degrades total harmonic distortion and noise (THD+N). Not exactly audiophile grade! High-end digital potentiometers with sufficiently low THD+N do exist, but implementation in a headphone amp would more than double the cost of a cMoy.

Thus, entry-level amps still use analog potentiometers. You get better THD+N at the slight expense of channel imbalance at very low volumes. If you're unable to listen to your headphones at the desired volume level, there are two solutions:

1) Use a standard interconnect cable to reduce audio player volume.
2) Reduce gain of the amplifier. Contact us for help.

Instruction Guides

cMoyBB v2.03

cMoyBB v2.03R

Objective2

O2+ODAC Combo

Standalone ODAC

c421 v1.01

C5