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Frequently Asked Questions
Is the cMoyBB in
stock? How quickly can you ship?
Yes, please check the
Store for
details. All items are in stock and ship in 1-2 business
days unless otherwise noted.
Do you offer
customization?
Gain can be customized upon request to match your
headphones, although this
is generally unnecessary. To request free gain customization, mention your headphones during checkout with PayPal.
Alternative mint tins are very rarely available.
The cMoyBB PCB is designed only to accommodate rectangular mint
tins. Other enclosure types are not possible.
The following cannot be
customized by JDS Labs:
-
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.
Can the bass boost
toggle switch be replaced with a bass boost knob/dial?
This modification is only available to
do-it-yourselfers, as described in the
Assembly
Guide. I generally do not stock the required potentiometer for
the modification.
Will the cMoyBB
work well with my __[insert model]__
headphones?
With nearly 1000 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, and
Beyerdynamic DT-880s, plus a variety of earbuds. The cMoyBB sounds
great with them all. Your headphones should be no different.
What kind of cable
do I need? What do you recommend?
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.
I have no specific brand recommendations. Instead, I offer the
following advice:
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 I 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!
*I occasionally stock interconnect cables.
Contact me for details.*
What is the
expected battery run-time for the cMoyBB?
Battery life depends on volume, headphone
impedance, and of course battery type. A typical 9V alkaline battery
should last approximately 25-30 hours under heavy usage.
A 9V NiMH battery and charger are worthwhile
investments if the amplifier is to be used portably.
Do you also design
or build DACs?
No, I do not. Please investigate the
Useful Resources
page if you are interested in DACs.
Why can't the
cMoyBB be powered from a vehicle's cigarette outlet (or hardwired to the
+12V supply)?
The power adapter warning mentioned in the
instructions sheet applies to all cMoys, 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 protect from 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 an external
audio player, such as an iPod.
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