Siegmund Big Boy 330 User manual

Big Boy 330
Owner’s Manual
330 Watt Bass Guitar Tube Amplifier

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Before you plug into your new amplifier, be aware of the following precautions:
• Practice common sense.
• Connect the amp only to a grounded AC power source, meeting the power supply
specifications, provided next to the AC power socket.
• nly use fuses with the rating indicated next to the fuse holder.
• Turn off the power, when changing fuse or tubes.
• Give tubes time to cool down, before replacement, to avoid burned fingertips.
• Never attempt to service the amplifier, unless you are a qualified technician.
DC current and voltages can be lethal!
• Do not expose the amp to moisture, water, direct sunlight or extreme temperatures.
• Do not use solvents to clean the amps covering or chassis.
Use a damp (not wet) soft cloth.
• When the amp is stored for an extended period, switch on both power and standby for
a few hours. At least once a year, to keep the filter capacitors from drying out.

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Contents
ContentsContents
Contents
Precautions 2
Contents 3
verview 4
Power-up 4
Controls 5
FX Loop 6
Preamp ut - Power amp In 6
Tubes 7
Bias Control 8
Tube Replacement Procedures 9
Speakers 10
Warranty 10

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verview
verviewverview
verview
The Big Boy 33
Big Boy 33Big Boy 33
Big Boy 330
00
0 is a Bass tube amplifier with high quality custom wound transformers.
Simplicity in design and function creates the purest and most musical bass tones made available yet.
The Big Boy
Big BoyBig Boy
Big Boy has silky smooth big warm lively tube sound packing a powerful tight punch.
The overdrive tone and crunch is rich with even-order musical harmonics.
Six KT150 power tubes in ultra-linear operation with Gain, 5-band EQ and Master Volume controls plus
parallel FX loop and Preamp output and Power amp input.
External bias and balance feature allows for easy adjusting and monitoring of the output tubes for ideal
performance and sound quality.
Power
PowerPower
Power-
--
-up
upup
up
Important : This power-up procedure should always be followed to substantially extend the tubes life.
Plug your Bass into the Input
InputInput
Input jack on the front panel.
Bring the Standby
StandbyStandby
Standby switch to the Standby position.
Turn the Power
PowerPower
Power switch on.
The pilot lamp will light up - an indicator that the tubes are being heated.
Each tube will emit a faint glow in its center. After about 1 minute
1 minute1 minute
1 minute, the elements inside the tubes have
been sufficiently heated for the tubes to operate properly without premature wear.
The Standby
StandbyStandby
Standby switch can now be turned off to supply voltage to the tubes.
The front panel will light up - an indicator that the amp is ready to play.

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Controls
ControlsControls
Controls
High / Low Z
High / Low ZHigh / Low Z
High / Low Z switches between high or low impedance pickups.
Passive pickups are High impedance and Active pickups are Low impedance.
You can also use the switch in either position regardless of pickups –
whatever gives the better signal and useful sweep range of the gain pot.
Gain
GainGain
Gain controls how much gain is sent to the following stages.
It also supplies the signal to the FX loop Send.
After the Gain
GainGain
Gain knob reaches the maximum clean headroom setting, any further rotation of
the knob will slightly raise the volume and make the distortion more saturated and compressed.
The EQ section of the Big Boy
Big BoyBig Boy
Big Boy is designed to suppress or boost certain frequency ranges in an
interactive manner.
EQ band ranges are 50, 160, 500, 1600 and 5000 Hz with 6 dB/octave roll-off between peaks
and flat below 50 and above 5000.
Sub
Sub Sub
Sub 50 Hz
Low
Low Low
Low 160 Hz
Mid
Mid Mid
Mid 500 Hz
High
HighHigh
High 1600 Hz
Bright
BrightBright
Bright 5000 Hz
Master
Master Master
Master allows for lower volume and a complex and natural overdriven tone at lower volume levels.
It is completely bypassed, when turned all the way up, for maximum clean headroom.

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FX
FXFX
FX Loop
LoopLoop
Loop
The Big Boy
Big Boy Big Boy
Big Boy parallel effects loop has a buffered low-impedance Send
SendSend
Send output.
It is capable of supplying both effects rack-mount and pedal inputs.
The DI output
DI outputDI output
DI output gives a low impedance Microphone level signal.
Adjust the Level
LevelLevel
Level control to get a good balance with the unit connected to Send
SendSend
Send.
Note: Rotating the knob will cause slight scratchy sounds, which are normal.
The Return
ReturnReturn
Return input is high impedance and accepts any kind of preamp, for dual channel operation.
A standard instrument cable or patch cord can be connected between Send
Send Send
Send and Return
Return Return
Return to create a
parallel secondary preamp channel.
The Mix
MixMix
Mix control blends the preamp with the signal from the Return jack.
Return jack.Return jack.
Return jack.
Always leave the knob turned all the way to Pre when no effect or other preamp is connected.
Preamp ut
Preamp ut Preamp ut
Preamp ut -
--
- Power amp In
Power amp InPower amp In
Power amp In
These jacks provide access to the Big Boy
Big BoyBig Boy
Big Boy Preamp and Power amp.
Preamp ut
Preamp utPreamp ut
Preamp ut taps the preamp signal.
EQ / FX Toggle
EQ / FX ToggleEQ / FX Toggle
EQ / FX Toggle selects if the Preamp ut signal includes the EQ of the front panel and the FX loop
Power Amp
Power Amp Power Amp
Power Amp In
InIn
In When plugged in, the preamp signal turns off and an external Preamp can be used.

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Tubes
TubesTubes
Tubes
6x KT150 12AT7 12DW7 12DW7 EF86
Power Tubes Phase Inverter EQ Driver FX Loop Input Gain
Always use matched sets of KT150 power tubes.
The Left side and the Right side of tubes are in parallel with each other on their side.
The amp understands each side as one combined unit and what matters is that both Left and
Right side are equally strong and balanced with each other.
If a matched sextet of tubes is not available, you can also use…
3x matched pairs or
1x matched quartet + 1 matched pair

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Bias Control
Bias ControlBias Control
Bias Control
To achieve maximum performance while giving longest tube life, the Big Boy
Big Boy Big Boy
Big Boy features a complete easy-
access Bias Control
Bias ControlBias Control
Bias Control section, with test-points for DVM hook-up.
Here is a simple guide for adjusting bias:
No technical knowledge is required.
All we need is a Digital Volt Meter, which reads DC millivolts (mV).
L … Le t Tube G … Ground R … Right Tube
Bias:
1 Follow the power-up procedure.
2 Play the amp or about 30 minutes or until the tubes are completely warmed up.
3 Turn the Master volume all the way down.
4 Switch the DVM to the DC millivolts setting. (200mV on most units)
5 Insert the Black probe o the DVM into the G test-point.
6 Insert the Red probe into L and adjust the Bias trim below it to the number shown in the table on the next page.
7 Insert the Red probe into R and again adjust Bias trim below it to the same number.
8 Repeat steps 6 and 7 until both sides have stabilized at the same number.
Balance:
1 Insert the Black probe into L and the Red probe into R
The meter reading is now the di erence between L and R
2 Play one single note or chord with the amp in your avorite ront panel knob settings and adjust Balance
to a reading close to Zero.

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Use this guide to find the bias numbers for your desired configuration:
Speaker imp
Speaker impSpeaker imp
Speaker impedance
edanceedance
edance Bias
BiasBias
Bias Power
PowerPower
Power Peak
PeakPeak
Peak
2 ohm
2 ohm2 ohm
2 ohm 200 mV
200 mV200 mV
200 mV 330 Watts
330 Watts330 Watts
330 Watts 43
4343
430 Watts
0 Watts0 Watts
0 Watts
4 ohm
4 ohm4 ohm
4 ohm 200 mV
200 mV200 mV
200 mV 26
2626
260 Watts
0 Watts0 Watts
0 Watts 30
3030
300 Watts
0 Watts0 Watts
0 Watts
4 ohm
4 ohm4 ohm
4 ohm 240 mV
240 mV240 mV
240 mV 300 Watts
300 Watts300 Watts
300 Watts 350
350350
350 Watts
WattsWatts
Watts
nly bias to 240 mV with a 4 ohm load - Never with 2 ohm, or the tubes will wear prematurely.
Biasing tips:
Biasing tips:Biasing tips:
Biasing tips:
• Always do bias adjustments with the power tubes fully warmed up after playing.
• From time to time check the Bias
BiasBias
Bias setting of both L
LL
L and R
RR
R to make sure all tubes are
working properly.
• A dead or premature worn tube will give a noticeable lower reading.
In that case remove one tube at a time and look for none or the least change in the meter
reading and replace that tube. Then reset using the Bias procedure above.
• Readjust Bias
BiasBias
Bias as tubes wear down over time to maintain balance between L
LL
L and R
RR
R
• Reset Bias
BiasBias
Bias after replacing one or more power tubes.
• Balance
Balance Balance
Balance can only be adjusted when the amp is played and Master is at least half way up.
Tube Replacement Procedures
Tube Replacement ProceduresTube Replacement Procedures
Tube Replacement Procedures
1) Allow tubes to cool down before handling.
2) Pull off the tube retainer.
3) Gently pull out the tube by its base with a light circular motion. Don’t use excessive force
and take your time.
4) Inspect each tube before inserting, for straight pins and an undamaged locating pin in the
center.
5) Line up the locating pin with the socket, by rotating the tube until it locks into place.
Caution:
Caution: Caution:
Caution: Power tubes will be especially hot!
Power tubes will be especially hot!Power tubes will be especially hot!
Power tubes will be especially hot!
Never touch hot tubes with your bare fingers!
Never touch hot tubes with your bare fingers!Never touch hot tubes with your bare fingers!
Never touch hot tubes with your bare fingers!

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Speakers
SpeakersSpeakers
Speakers
Always use a combined speaker load of 2
2 2
2 -
--
- 4
44
4 ohms
ohms ohms
ohms to make full use of the output transformer and to
match impedances of the tubes and speakers for maximum musical response and performance.
An 8 ohm and 4 ohm cabinet in parallel has 2.6 ohm
2.6 ohm2.6 ohm
2.6 ohm
In this configuration, the 8 ohm cabinet gets twice the power from the amp than the 4 ohm cabinet.
www.SiegmundGuitars.com
Lifetime Warranty
Lifetime WarrantyLifetime Warranty
Lifetime Warranty
Chris Siegmund
Chris SiegmundChris Siegmund
Chris Siegmund guarantees this Amplifier to be an excellent unit, functionally and musically.
It is covered by a warranty to the original purchaser for life,
against any defect traceable to faulty workmanship or defective components.
Siegmund Guitars Amplifiers
Siegmund Guitars AmplifiersSiegmund Guitars Amplifiers
Siegmund Guitars Amplifiers agrees to repair or replace such defect.
This warranty does not cover any damage resulting from misuse, accidents or improper storage
and the normal wear of tubes, sockets, jacks, potentiometers and filter capacitors .