User`s manual

FAQ's (frequently asked questions)
Q: What does "DC-Coupled" mean?
A: DC is an abbreviation for Direct Current. DC is an electric current which flows in a
single direction, as from a battery. In contrast, audio signals are AC or Alternating
Current. Typically, capacitors and transformers are used to form AC-Coupled circuits
which allow AC signals to pass while blocking DC. Most commercial preamps are AC-
Coupled. But caps and transformers are reactive components which produce frequency
dependent phase shifts. This can negatively influence perceived resolution and
transparency. In a DC-Coupled circuit these components are not present. Since Pueblo
Audio preamps are designed with DC-Coupled circuits, their phase and frequency
response remain linear and free of reactive distortions. In fact, they have no low frequency
cut-off at all; being flat down to zero hertz! This is one reason for their relaxed, effortless
sound.
Q: Will exposing the DC-Coupled inputs to phantom power harm the Preamp?
A: No. The preamp inputs are protected from exposure to phantom power, hot patching,
static discharge and other such casualties. During product development, a special test jig
was fabricated to zap a preamp's input with 60 volts sourced from 2,000uF storage
capacitors. The jig cyclically zapped the same preamp once every 90 seconds for 60
days: 57,600 zaps in total (each zap from the jig pulsed enough energy to spot-weld relay
contacts!) Afterwards, the preamp was tested and found to still be working perfectly. It still
performs beautifully today, many years later. Pueblo Audio's design dispels any concerns,
leaving the user worry-free.
Q: Are the Phantom channels and Preamp channels internally connected?
A: No. Each channel is a stand-alone module with no internal signal connections. A
number of considerations led to this configuration. First - most commercial preamps
which have ribbon mic inputs do not offer fully bypassed phantom circuits. Their
phantom circuit's "back end" is always tied to their preamp's front end. This can
negatively disturb the mic signal, which partially defeats the purpose of having a special
ribbon input. Since JR2/2 phantom channels can be patched completely out of circuit, this
issue is totally avoided. Second - all audio electronics, including mics, take an hour or
more to warm up and reach optimal operating condition. With Pueblo Audio, an
"idle" Phantom channel can remain connected to its mic, keeping it warmed up and ready
to go at all times. Third - many Pueblo owner's have remarked on the extra size, image
stability and natural timbre that Pueblo Phantom channels gives to their microphones, so
they requested the phantom channels be available to use with all their mic preamps.
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