music first audio Baby Reference Preamplifier User manual

Baby Reference Preamplifier
Owners Manual

Baby Reference Preamplifier user manual
Introduction
Congratulations and thank you for purchasing the Music First Audio Baby Reference Preamplifier.
his original device controls up to six sources and attenuates level. It sits between stereo source
devices such as CD players, turntables etc. and power amplifiers. A rotary switch on the front
panel selects inputs and level is controlled by another rotary switch.
Level is controlled by a custom designed and made transformer via the front panel mounted
ELMA 24 position switch. his method offers many advantages over other attenuation solutions.
Conventional passive volume attenuation relies on resistive networks selected via multi way
rotary switches. Introducing transformers also introduces considerable physical and therefore
audible improvements:
•ransformer isolates components, breaking ground loop problems and reducing noise
•ransformer matches impedance between components.
•ransformer affords superior transfer of musical energy
he effects of the unit are obvious from the first listen, the sound flows from source to destination
without any colouration allowing music to be heard as it was intended without any interference
from active components.
Music First Audio introduced the Classic Preamplifier in 2003 and it went on to receive
widespread critical acclaim. Glowing reviews and many awards followed and it became the
standard by which others are judged.
In the years since we designed our original preamplifier, we experimented with many different
approaches and techniques. We discovered that we could improve on our original design, but
only by ignoring the usual manufacturing constraints of time and expense.
he Baby Reference Preamplifier is a true ‘cost no object’ design. We have used only the finest
possible components and each unit is built by hand in our Hastings, East Sussex workshop.
he Baby Reference Preamplifier takes the multiple-award winning performance of our original
product to another level and offers unparalleled sonic performance together with an extraordinary
range of features.
In order to get the most out of your Baby Reference Preamplifier, please take a little time to read
through this user guide.
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Baby Reference Preamplifier user manual
Unpacking and Installation
he Baby Reference Preamplifier comes supplied in a professional flight case. his ensures that
your preamplifier arrives with you in the same condition as it left us. Please keep this flight case
in case you ever need to return the unit to us (for modification for example).
Connection
he rear panel houses all input and output connections. Inputs are situated to the right and
outputs to the left (when viewed from the rear). he inputs should be connected to the outputs of
source devices (CD player, cassette player etc.) at line level. he phono/ RCA inputs are for
connection to unbalanced equipment, while the XLR inputs are for connection to balanced
equipment.
As a general “rule of thumb” if the output of a piece of source equipment is on XLR sockets then
it is balanced and if it is on phonos/ RCA sockets, then it is unbalanced. his is not always the
case, but should give a good starting point.
he outputs of the unit are located on the left hand side of the back panel. hese can be
specified at the time of ordering as two XLR, two RCA or one XLR and one RCA.
he XLR outputs are balanced and the phono/ RCA outputs are unbalanced. Because the
transformers convert balanced and unbalanced signals, these outputs are always the same,
regardless of which input type is used.
If you are in any doubt about connections, please contact us via email [email protected] and
we’ll be very happy to help.
WARNING - Connection of faulty equipment to the unit will cause malfunction,
ensure all devices connected are in good orking order.
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Baby Reference Preamplifier user manual
The Ground Selector S itches
Once equipment has been connected as described, it is necessary to select grounding options
with the rear-mounted switches. hese two position switch controls whether each output ground
is lifted (unconnected) or connected to the internal ground reference (and to input ground).
If both outputs are XLR then the switches select whether pin 3 of each XLR is lifted (LIF ) or
grounded (GRND)
If both outputs are RCA then both switches must be set to LIF in order to lift the ground. If either
switch is set to GRND then both outputs will be grounded.
If there is one XLR and one RCA then the XLR output switch will allow either grounding or lifting
of pin 3 on the XLR. he RCA output switch will allow either grounding or lifting of the RCA
output. Please note: If the RAC output is grounded then pin 1 of the XLR will also be grounded.
he setting of these switches is entirely dependent on the rest of your system. A simple
procedure will deduce how it should be set.
1. Ensure your power amplifier is turned off and connect it’s input to the output of the Baby
Reference pre amplifier.
2. Connect all your source equipment as described above and switch it on (do not play any
music at this point).
3. Set the Ground Selector Switches to the (LIF ) position and the Baby Reference pre
amplifier level control to 1 (minimum)
4. urn on your power amplifier and turn up the volume control (if there is one) a little.
5. Gradually increase the level control on the Baby Reference Preamplifier. You should here
nothing (a little “hiss” from source devices is normal). If you here a loud “buzzing” or
“humming” sound, turn down all level controls and switch your power amplifier off.
6. Set the output grounding switch GRND.
7. Repeat steps 4 and 5. he buzzing should now have stopped.
You might find that the switch requires a different setting for each piece of source equipment and
amplifier. It is worth trying the above procedure for each separate piece of connected equipment..
Please note:
he input grounds are connected to the internal reference via resisters (this is to drain static
voltage on source equipment ground which prevents “clicks” and “pops” when switching sources).
Input F is hard grounded (no resister); this input is best suited to sources that are particularly
noisy (e.g. digital television receivers etc.).
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Baby Reference Preamplifier user manual
Operation
1. Before use ensure the level control is set to ∞ (minimum level)
2. Switch on the source devices (CD player, tuner, turntable etc.)
3. Switch on the amplifier and set the amplifier volume control (if there is one) to the
maximum necessary listening level.
4. Select the source device.
5. Set the Baby Reference Preamplifier level control to the desired listening level
Please note:
•If the source is to be changed always return the level control to ∞ (minimum level) before
changing the source to avoid damage to loudspeakers and amplifiers
•Always turn amplifier levels down and power off before powering down sources, again to
avoid damage.
Burn in
o obtain the very best results from the Music First Audio Baby Reference Preamplifier a period
of “burn in” is necessary. Simply put, this means you will find the sound of the unit improving over
the first 100 hours or so of use. If possible, we recommend the following procedure:
1. Connect source and amplifier as described
2. Set the level of the Music First Audio Baby Reference Preamplifier to 0 (maximum). his
ensures the transformers entire winding will be “burnt in”
3. Play music through the Music First Audio Baby Reference Preamplifier for 100 hours
(using the amplifiers volume control to set level)
If you need further help or advice you can e-mail us at: [email protected]
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Baby Reference Preamplifier user manual
Maintenance
he unit should be cleaned with a soft dry cloth. NEVER use abrasive cloths or cleaning solution.
For stubborn stains, slightly dampen the cloth with water.
Contacts and connectors can be cleaned with proprietary contact cleaners (Servisol, DeoxI etc.)
although the use of switch lubricants is not recommended.
Specifications
Inputs 4 x Stereo unbalanced
2 x Stereo balanced
Outputs 2 x Stereo outputs
Controls Level (24 position rotary switch)
Source (6 position rotary switch)
Grounding (two 2 position toggle switches)
Z out:
0db volume setting Source Impedance + 600 R
(1k Source=1600 R)
+6db volume setting Source Impedance x 4 + 900 R
(1k Source = 4900 R)
-20db volume setting Source Impedance / 100 + 33 R
(1k Source = 43 R)
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Baby Reference Preamplifier user manual
Troubleshooting
Symptom Problem Solution
No Sound No source playing/ selected Ensure the source is playing
Ensure the correct source is
selected
Pre amplifier level too low/ off urn up the level control on the
Reference Preamplifier
Amplifier not on/ level too low Ensure the amplifier is on and
any volume control is up
Loud “buzzing or “humming”
sound
Ground selector incorrectly set Check that the grounding
switches are correctly set (see
“ he grounding switches”)
For any further advice, please contact us at [email protected]
WARNING
•In no event shall the manufacturer be liable for any damage, direct, indirect or
consequential of any type or any expenses or losses resulting from the use of this product.
•Contains no user serviceable parts, refer servicing to qualified personnel only.
•Do not expose the unit to moisture, excessive heat or cold.
•he contents of this manual are correct at the time of going to press. he manufacturer
reserves the right to change the specification and features without prior notice.
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