Bandwidth Audio Kaskode One User manual

Kaskode One –Phono Preamplifier
Owner’s Manual
www.bandwidthaudio.com
[email protected]

Kaskode One Rev 1.1 2
WARNING
Configuration of the Kaskode One will require removing the
cover of the unit. Before removing the cover for any reason,
make sure to power off the unit and unplug from mains wall
outlet.
Wait a minimum of 60 seconds for all voltage to dissipate before
opening the cover.
FAILURE TO READ OWNER’S MANUAL BEFORE FIRST USE CAN
VOID YOUR WARRANTY

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CONTAINS LETHAL VOLTAGES
High voltage can be lethal. Do not remove cover while preamplifier is connected to the
Mains power source. For service, contact Bandwidth Audio.
HIGH VACUUM TUBE TEMPERATURES
Vacuum tubes can get extremely hot with bulb temperatures capable of reaching 200ºC. Do
not touch or attempt to remove the tubes while they are hot.
DO NOT ENCLOSE
This preamplifier will get warm from use. Make sure to place the equipment in a non-
enclosed area with good ventilation and air flow.

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Table of Contents
1.0 Kaskode Connections and Setup .................................................................6
1.1 Phono Preamplifier Placement ........................................................................................................... 6
1.2 Mains AC Grounding ............................................................................................................................... 7
1.3 Powering ON & OFF................................................................................................................................ 7
1.4 Installing Optional (MC) Moving Coil Module........................................................................... 8
1.5 Moving Coil Input Connections......................................................................................................... 9
1.5.1 Balanced / Unbalanced Input................................................................................................ 9
1.6 Moving Magnet Input Connections.............................................................................................. 10
1.7 Kaskode One Input Wiring Diagram............................................................................................ 10
1.8 Tonearm and Turntable Wiring....................................................................................................... 11
1.8.1 RCA Connection......................................................................................................................... 11
1.8.2 XLR Connection (MC Only) .................................................................................................. 12
1.9 Subsonic Filter.............................................................................................................................................. 14
2.0 Cartridge Loading........................................................................................ 15
2.1 MM Cartridge Loading Options ..................................................................................................... 15
2.1.1 MM Input Resistance .............................................................................................................. 15
2.1.2 MM Input Capacitance........................................................................................................... 15
2.2 MC Cartridge Loading Options....................................................................................................... 19
2.2.1 MC Input Resistance................................................................................................................ 19
2.2.2 Selecting the MC Step-up Ratio ....................................................................................... 22
2.2.3 Selecting the Rsl value for Cartridge Loading........................................................... 25
3.0 Controls and Layout.................................................................................... 27
3.1 Front Features .......................................................................................................................................... 27
3.2 Back Features............................................................................................................................................ 28
4.0 Typical Specifications.................................................................................. 30
5.0 Notes:............................................................................................................. 32

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List of Figures
Figure 1: white markers indicate correct MC orientation................................................................................... 8
Figure 2: Input Wiring Diagram ................................................................................................................................. 10
Figure 3: Turntable Wiring for RCA Input.............................................................................................................. 11
Figure 4: XLR Pinout (Front View)............................................................................................................................ 12
Figure 5: Turntable Wiring for XLR Option 1........................................................................................................ 13
Figure 6: Turntable Wiring for XLR Option 2........................................................................................................ 13
Figure 7: Location of J3/J4 subsonic filter jumpers............................................................................................ 14
Figure 8: MM frequency response with input capacitances............................................................................ 15
Figure 9: Location of S2 and S5 switches for setting the input capacitance ............................................. 16
Figure 10: S2/S5 setting for 150pF........................................................................................................................... 17
Figure 11: Input Network for MC Input................................................................................................................... 19
Figure 12: Location of Step-up ratio switches ...................................................................................................... 23
Figure 13: Location of Rsl selection switches S1 and S4 .................................................................................. 25
Figure 14: S1/S4 Rsl setting for 10000Ω ................................................................................................................ 26

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1.0 Kaskode Connections and Setup
From the factory, the Kaskode One is configured as follows
•Subsonic filter is active
•MC Step up module (if installed) is configured for unbalance operation
•MC Step up module (if installed) ratio is set 1:10
•Input capacitance is set to 150pF
•Rsl Cartridge loading is set to 10KΩ= MC input resistance of 100Ω
Pre-Operation Checklist
•Before first use check that the Kascode One is configured correctly for your phono cartridge.
oTo set the input loading for MM cartridge, see 2.1
oTo set the input loading and step up ratio for MC cartridge, see 0
•If using MC, check input connection type (Balanced or Unbalance) to match your setup,
see 1.5
•If using MM, check input connection, see 1.5.11.6
•For turntable and tonearm wiring best practices, see 1.8
•Set Subsonic filter to your preference, see 1.9
1.1 Phono Preamplifier Placement
For best operation and longest life of components, the preamplifier should be set up and used in a
well-ventilated area with good air circulation. Do not use the amplifier in enclosed furniture as
overheating can damage the amplifier, diminish tube life and cause risk of fire.
Due to the extremely high gain, phono preamplifiers are extremely sensitive to vibration. It is
always recommended to place the phono preamplifier on a sturdy substantial shelf to help
minimize vibrations coupled in from the floor.
Radiating electromagnetic noise (EMI) from sources such as large transformers, cellphones and Wi-
Fi routers can also cause audible noise from the speakers if this equipment if placed too close to
phono circuitry. It is best to have this equipment located far away.

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1.2 Mains AC Grounding
Always share the same AC mains ground circuit with all other audio equipment.
For lowest noise, it is always recommended to share the same AC mains ground circuit between all
audio equipment in a system. The easiest and best way to achieve this is to share a common wall
and use a quality power strip to power all pieces of equipment. This is most desirable to insure the
ground reference of all audio equipment is at the same potential.
Ground is used as a safety voltage reference and should not have any current flowing. However, It
is likely that any 2 ground circuits in buildings wiring will have a small voltage differential across
them. If these grounds are shared by audio equipment, a ground loop is formed and the small
voltage differential can now drive a current through the audio ground, causing noise.
Faulty equipment on the AC line can also be a source of ground noise.
1.3 Powering ON & OFF
The Kaskode One is designed with a time delay start sequence to insure all operating voltages are
stabilized and the preamplifier is ready to play audio before the output is active. This removes the
chance of any pop and noise during power on and off. The Kaskode One can be turned on and off
without any need for power sequencing with other equipment. The “Active” indicator on the front
panel shows the status of the power on sequence. The preamp output will be active approximately
60 seconds after power on.
The power on sequences is as follows:
The Kaskode One “Power” indicator will illuminate. The “Mode” and “Mute” settings will also
illuminate with their status. After a delay of approximately 60 seconds, the “Active” inductor
will illuminate indicating that the phono preamp is ready for use and music can be played.

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1.4 Installing Optional (MC) Moving Coil Module
The Kaskode One features optional plug in transformer modules to also support MC type
cartridges. If your preamp was ordered with the MC option, these transformers have already been
installed at the factory.
To install the MC modules:
Align the MC modules so that the white orientation markers are aligned on both the main preamp
PCB and the PCB of the module.
After the correct orientation has been found, carefully plug the modules into the female header pin
sockets on the main PCB. Be careful not to misalign the pins. Press gently until the MC module is
fully seated.
Figure 1: white markers indicate correct MC orientation

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1.5 Moving Coil Input Connections
For MC input mode, additional gain is provided by optional step-up transformers. With the step-up
module installed, the either the RCA or XLR inputs labeled “MC” on the back of the unit can be
used, provided the input “Mode” switch on the front is set to “Moving Coil”. If no MC module is
present, the MC inputs cannot be used.
1.5.1 Balanced / Unbalanced Input
Jumper J3, located on the optional MC module, is used to select between balanced or unbalanced
input. Balanced input is achieved with jumper J3 removed by isolating the primary and secondary
ground of the MC transformer. In balanced operation, the MC transformer will provide a high
degree of common mode rejection, helping to remove noise picked up in the cabling between the
preamplifier and turntable. Always disconnect the power cord before making any adjustments to
the phono preamp. (See Figure 2: Input Wiring Diagram)
In balanced input mode, either the RCA or XLR input can be used, however, the XLR input is
recommended. When using a high quality 3-conductor XLR cable, the positive (+) and negative (-)
signals are a twisted wire pair covered by a metal shield. The +/- pair connects to the MC
transformer and the shield is connected to the preamp chassis. Not only does the shield provide
hum rejection but the +/- twisted wire pair is naturally balanced such that any noise that
penetrates the shield, is removed by the common mode rejection of the MC transformer.
In contrast, an RCA cable is a 2-conductor unbalanced cable. The positive (+) signal flows through
the center of the negative (-) shield. Therefore, the geometry and surface area of the + and –
conductors are not identical and noise will not couple uniformly on both conductors. Therefore, the
transformer’s common mode rejection will not help remove noise.
•When using an RCA cable for the MC input, unbalanced connection is recommended.
•When using an XLR cable for the MC input, either unbalanced or balanced connection
can be used.
•Remember to set J3 on both MC module boards

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1.6 Moving Magnet Input Connections
For MM input, the RCA connectors labeled “MM” on the back of the unit should be used. These
inputs bypass the MC step-up module as well as the resistive loading. Moving Magnet type
cartridges will require setting the capacitive loading.
1.7 Kaskode One Input Wiring Diagram
Figure 2: Input Wiring Diagram
Figure 2, above shows how the inputs for the MM and MC sections are wired. Notice that both the
MC RCA and MC XLR inputs can be wired as unbalanced or balanced by connecting or removing
jumper J3.