5
4
The Desktop & Ultra Desktop Rear Panel
1. Analog Input Selector
You may want to plug more than one analog
source into your Desktop Amp. Whether you are using one input or both, you
will need to indicate which analog inputs you want to listen to by choosing
either ‘1’ or ‘2’ with the analog input selector.
2. Analog Inputs
There are two sets of analog inputs, both are RCA in-
puts, with the top connector being ‘left’ and the bottom connector ‘right’. The
left-most column is ‘input 1’ and the middle colum is ‘input 2’. The analog
inputs is where you will plug in your non-digital source, such as a stationary
or portable CD player. If your player has an 1/8” line out plug, you will use
a portable cable (mini-RCA); if it has an RCA out (left and right) then you will
use a link interconnect (RCA -RCA). See the ‘cables’ area in our website to
purchase some of these cables.
3. Analog Output
If you want to use your Desktop Amp as a preamplifier,
plug your outputs into a powered amplifier or powered speakers.
4. +/- 15VDC Power Input
Plug in your power supply here. The ‘brick’
power supply included with the Desktop amp, as well as the Desktop Power
Supply, will use this connector. See pg 9 for more info on the Desktop Power
Supply upgrade.
5. Source Selector
When using the DAC, you will need to choose whether you
are using a digital input or an analog input. The source selector switch allows you to
have both digital and analog sources connected at the same time, and you may change
between the two with a simple flip of this switch.
6. Digital Input Selector
When using the DAC, the digital input selector allows
you to choose which digital input you would like to listen to.
7. USB Input
The USB input gets its signal from a computer: laptop or desktop;
PC, Mac, or Unix.
8. Coaxial input
The coaxial input is your typical coaxial connector. We recom-
mend using a 75 ohm digital cable when using the coaxial input.
9. Optical Input
The optical input is your typical Toslink connector. You get this
input signal from the optical output of your player. Not so many portable audio players
have optical outputs anymore (call or check our web site for recommendations), but
many portable DVD players and some hard disk drive players do. Of course, you can
get this signal from many pieces of home equipment.
Desktop & Ultra Desktop Digital-Analog Convertor
8.
coaxial input
4.
+/- 15
VDC
power
input
1.
analog
input
selector
9.
optical input
5.
source selector
6.
digital input
selector
7. USB input
2.
analog
inputs
3.
analog
output
5.
6.
7.
9.
8.
DAC (see pg.5)
Desktop DAC
The Desktop Amp includes HeadRoom’s Home DAC. HeadRoom’s Desktop DAC option
starts to become a very seriously impressive digital-to-analog converter: not only does
it use the flagship Cirrus Logic CS4398 DAC, it also uses the hyper-spendy but oh-so-
sweet-sounding Burr-Brown OPA627 op-amps in constant-current “Class-A” bias as
output stage devices. The result is the kind of fully transparent and liquid audio clarity
usually found in multi-thousand dollar upscale CD players but at a mere fraction of
their cost.
Ultra Desktop DAC
The Ultra Desktop DAC is an apostolic work of digital upsampling art dressed in gold
& black. These four-layer, gold-coated, double-copper tracing circuit boards are cov-
ered edge to edge with the best parts serious audiophile money can buy, and right in
the middle of it lies an Analog Devices AD1896 192kHz Stereo Asynchronous Sample
Rate Converter. WHAT?!... Simply a screaming miniaturized gizmo that up-converts any
incoming digital audio signal into an ultra high speed, high resolution digital signal
without relying on the incoming clock timing, and then down-converts it into the slow-
er 192kHz word stream while interpolating (to get rid of digital ‘haze’) and re-clocking
(to get rid of jitter) before sending the data off to the DAC stage.
