Manley JUMBO SHRIMP - Manual (Page 6)

MOVING RIGHT ALONG...
Why can’t I have balanced ins or outs?
Like we said earlier, since the whole guts of the Jumbo Shrimp are inherently single-ended, adding balanced
I/O would require additional circuitry, transformers, or IC’s which would inevitably color the sound.
If you have some gear that you are trying to hook up to the Jumbo Shrimp that offers both balanced and unbal-
anced connectors, in many cases, you will find that the XLR balanced jack does indeed go through extra stuff just
to become balanced, and in many cases this was done purely for marketing reasons because sometime in the 1990’s
somebody started telling everyone in the Hifi biz that “balanced was better” and everybody started banging on extra
balancing thingies and all the cable guys got to sell everybody new cables. (end of cynical rant...) Balanced runs
are indeed mandatory for very long runs of cable, and certainly there are benefits of Common Mode Rejection and
cancellation of odd harmonics in balanced circuitry, especially fully differential circuitry. However, to pull this off
in tube-land with no coupling transformers or extra “stuff” to have to listen through is quite a challenge and in our
experience, the purity and elegance found in low-level single-ended tube circuits just can’t be beat. In the quest for
The Ultimate Good Thing, we adopt the “Less is More” mantra. Try it and see.
If you have other gear that only has balanced ins or outs, check its owner’s manual to see how it prefers to be
hooked up to a single ended device. Some equipment, especially transformer coupled gear, must have something
always hooked up to both legs. Presuming the convention of Pin 2 = HOT, one would wire an RCA to XLR cable
as follows:
RCA PIN to XLR Pin 2
RCA Outer Shield/Ground to Pins 1 & 3
If the device you are trying to interface with the Jumbo Shrimp prefers to NOT have anything hooked up to Pin
3 in an unbalanced interface, (some IC gear is like this) then hook up: RCA PIN to XLR Pin 2
RCA Outer Shield/Ground to Pin 1 only, leaving Pin 3 empty and neglected.
Check with the manufacturer of your other balanced equipment to see how best to hook it up. It can be done.
NOW THAT YOU HAVE ALL YOUR CABLES PLUGGED IN, you may now connect the IEC power cord to
the preamp and to an energized power outlet.
(Unless you live in California and are in the middle of a Rolling Greyout ®™ .)
Set the VOLUME control to about 9 o’clock. Choose an active input, as necessary, with the INPUT control. Place
the balance control at the center detent position.
Place the preamp’s mains power switch in the ON position. The MUTE switch lamp will start flashing and the
MANLEY SHRIMP badge will light up. The winking MUTE lamp indicates the beginning of a 30 second warm-up
mute delay, during which time the muting relay is engaged; no output will be heard from the preamp. As soon as
everything is settled down inside, the MUTE will go off and stop winking at you. If the MUTE light is still steadily
illuminated, then push it so the MUTE will go off and tunes can play.
DURING OPERATION
Once audio is heard from the JUMBO SHRIMP the exploration for comfortable volume and balance control
settings can begin. Notice that it takes about 45 minutes of warm-up time for the system to reach thermal equi-
librium. During this warm up time, go walk your dog, make dinner, or play some lite pop music. The Monkees
would be a fun choice. Or even Tom Jones.
POWER DOWN
At the conclusion of your listening session rotate the power knob to the OFF position to cut power to the preamp.
Notice that effort has been made to keep power engagement and cessation noise generated by the preamp to a
minimum. Nevertheless it is wise to remove power mains and signal feed to your power amps when the preamp is
undergoing a power state change. As a rule, power up your amplifiers last, power down them first so they do not
amplify any stray noises which could occur upstream from source components powering up or down. Additionally,
it is best to cut power to the JUMBO SHRIMP when not in use rather then leaving the power on indefinitely. This
will enhance tube and system life. The tubes should last thousands of hours under normal conditions.
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