Spider 3 Theory of Operation………………Line 6 Confidential..……………………………. Page 1 of 14
CONTENTS:
I. REVISION COMMENTS
II. DISASSEMBLY & ASSEMBLY TIPS
• Guitar Input PCBA Installation
• Speaker Cable Installation
• User Interface (UI) Installation
• Power Amp IC Replacement
III. POWER SUPPLY CONVERSION
• Transformer & Fuse Tables
IV. SOFTWARE MODES
V. THEORY OF OPERATION
• Main PCBA
¾ Front-End
1) Analog Signal Input Circuit
2) User Interface Circuit
3) FBV (Floorboard) Circuit
¾ Digital
1) Digital Processing Circuit
2) Digital Signal Detail
¾ Analog Outputs
1) DAC Output Circuit
2) CD/MP3 Aux Input Circuit
3) Headphone Circuit
¾ Power Supply
• Power Amp
• Power Supply
VI. TROUBLESHOOTING TIPS
• Additional Troubleshooting Tips
Spider 3 Theory of Operation………………Line 6 Confidential..……………………………. Page 2 of 14
I. Revision Comments
Revision Changes Date
A Initial Release Nov 9th 2006 - JB
Spider 3 Theory of Operation………………Line 6 Confidential..……………………………. Page 3 of 14
II. DISASSEMBLY & ASSEMBLY TIPS:
Main PCBA Removal & Installation:
Upon Removal of the Main PCBA:
1) All nuts from each POT shaft, both ¼”jack nuts, and a single 6-32 screw (shown
below) must be removed before the Main PCBA can be taken out of the chassis.
Upon Installation of the Main PCBA:
2) Make sure to only partially tighten the 6-32 screw shown above. Install both ¼”
jack nuts followed by the all POT nuts and then the fully tighten the Main PCBA
screw.
Power Amp IC replacement:
For the 1508 & 3012 models:
1) Install the Power Amp IC back on the chassis in the same order detailed below.
Make sure that the Sil Pad is completely isolating the Power Amp IC from the
chassis! It is recommended using a DMM to ensure no shorts exist.
Shoulder Bushing w
#4 x ½” Screw w
#4 Washer
Add Split
Lock-washer.
Add Hex
Nut
Spider 3 Theory of Operation………………Line 6 Confidential..……………………………. Page 4 of 14
For the HD75 model:
1) Make sure that the Sil Pads are completely isolating the Power Amp TDA7293 IC’s
(P/N 12-30-7293).
2) Make sure the support bracket is installed tightly and does not touch any of the
Power Amp IC pins.
III. POWER SUPPLY CONVERSION:
Use the table below to determine the correct fuse value and transformer to install.
Spider 3 Theory of Operation………………Line 6 Confidential..……………………………. Page 5 of 14
WARNING! TO PREVENT RISK OF FIRE REPLACE WITH THE SAME TYPE
FUSE AS IS CALLED OUT IN THE TABLES ABOVE.
If a Power conversion is completed, always make sure the unused transformer terminal is taped
and a zip tie added as shown below!
IV. SOFTWARE MODES
During Power up hold the following buttons:
• Channel A: Reinitialize
• Channel B: Firmware Rev # check.
For example, if the software version is 1.04 then the Channel B button will light
once, the Channel C zero times, and the Channel D button four times.
• Channel C: None
• Channel D: None
• TUNER: Self Test Mode = True audio bypass at full volume
No effects, amp models, EQ, etc.
Use for Button and POT functionality tests.
V. THEORY OF OPERATION
The Spider 3 1508, 3012, and HD75 Main PCBA are identical with exception to the
stuffing options.
• The 1508 has no crystal Y1, no crystal buffer U12, and no FBV circuitry stuffed.
• The 3012 has all components stuffed.
• The HD75 is identical to the 3012 with exception to:
All on-board Power Amp components have been removed, an external
Power Amp PCBA with Heat sink is attached to chassis rear instead.
Several Power Supply components have been “upgraded” to higher
power ratings.
Spider 3 Theory of Operation………………Line 6 Confidential..……………………………. Page 6 of 14
MAIN PCBA:
Front-End:
1. Signal Input Section (Main PCBA):
a.) Analog detail (guitar):
Analog guitar input signal enters the ¼” jack J1 and is referenced to ground by
R1, which establishes a 1M-Ohm input impedance. Maximum input signal
amplitude before clipping is approximately 5Vpp. The signal is then buffered at the
voltage follower U1-A, no pre-emphasis or de-emphasis is used! The output of U1A is split and sent to the input of U1-B as well as to the left input of codec U2. U1-B
increases the “low gain” signal by +16 and sends the resulting “high gain” signal to
the right input of codec U2.
The series capacitors C6-7 on each ADC input are used as “DC blocking”
capacitors since the analog inputs of U2 are biased to approximately ½ of there
analog supply, or 1.65V.
On the right “high gain” channel input to U2, diode D10 is used to “clamp” the
voltage to a safe level of -0.6V to +(3.3VA+0.6)V since this channel is usually
clipping with a nominal signal present at the input.
The ADC of U2 converts the left and right analog signals into digital signals,
which are then sent to the DSP as ADC_DATA for processing. Only one of the
signals is chosen for processing based on amplitude. Max voltage swing before
clipping at the ADC inputs is approximately 2.0Vpp.
b.) Analog detail (CD/MP3):
An auxiliary CD/MP3 input is provided by 3.55mm jack J2. The Left and Right
input signals are equally summed to MONO per R45 and R47 and then summed
with the processed guitar signal at the LPF gain stage U9-A, at the DAC outputs.
c.) Digital detail:
The only “digital” signal on the input circuit is GUITAR_SENSE. See Section V:
Theory of Operation - Digital Processing Circuit for more detail.
d.) EMI & ESD Detail:
For the Guitar input:
C67, C72 with L9-10 and GF1 help to shunt HF noise to the chassis. D2 is a
voltage clamp, and helps insure that ESD will not exceed the voltage rails of U1.
R2 provides over-voltage current limiting for both D2 and U1. All components
combined provide a low-impedance HF shunt to chassis ground for ESD.
For the CD/MP3 input:
C47-49 combined with L1-2 and L8 provide both EMI and ESD protection.
2. User Interface PCBA:
Buttons & LED’s:
Only 5 LED’s and 5 Switches are located on the UI PCBA, each with a single
resistor for current limiting. All signals run directly to the ADC’s of the MCU U3 via
Spider 3 Theory of Operation………………Line 6 Confidential..……………………………. Page 7 of 14
the ribbon cable from H6 to H1. The +3.3V is used as the power source and the
MCU as the sink for all switches and LED’s.
3. FBV (Floorboard) Circuit (Main PCBA)*:
The floorboard includes one single–ended serial “receive” data line RXN and
differential serial “transmit” data lines TXP and TXN along with a +8V power line
(+VL) and ground, DGND. All data signals are buffered through U6 and tied to pins
17-18 of the MCU U3.
*Note: The 1508 model has no FBV components stuffed!
a.) ESD/EMI Detail:
Inductors L3-7 combined with C39-43 and diodes D25-27 provide both ESD
and EMI protection. R39 provides additional protection to prevent damage at U6.
4. JTAG Circuit (Main PCBA):
The JTAG port of the DSP is available through the uninstalled H2 header. This
connection is used for development and in-house software upgrades.
Digital:
1. Digital Processing Section (Main PCBA):
a.) Audio Signal Detail (ADC to DAC):
The ADC’s of U2 sample the left and right analog signals at a rate of 39 kHz.
The digital signals are then sent to the DSP U5 on the ADC_SDATA line for
processing. Only one of the input signals is chosen to be processed by the DSP
based on amplitude. The Codec Right input is chosen for processing if the signal is
approximately 200mVpp or less. After further DSP processing is complete, the
codec receives the processed digital audio signal at its serial data input
DAC_SDATA. The codec then converts the digital signal into two single-ended
analog outputs biased to half of the Analog Supply VA.
b.) Digital Signal detail:
Clocks:
For the 1508:
No crystal is stuffed, the master clock is generated internally by the MCU which
feeds the DSP via the MASTER_CLK line. All sub clocks are provided by the DSP
using MASTER_CLK and the PLL made up of the components connected to pins
31-32.
Spider 3 Theory of Operation………………Line 6 Confidential..……………………………. Page 8 of 14
For the 3012 & HD75:
The 12.000MHz master clock Y1 provides a highly accurate and stable
oscillator for the DSP. All clocks are generated from this master clock using the
PLL within the DSP, including the 100 MHz core clock. The filter for the PLL is
made up of the components connected to pins 31-32 of the DSP (U5), as in the
There are two memory IC’s connected to the DSP, the Flash U4 and the SRAM
U7. The flash memory U4 holds the system code and is loaded into the DSP after
the DSP is ordered to re-initialize by the MCU. The other memory, U7 is an SRAM,
and is used for buffering processed audio signals.
Control & Sense Lines:
Master_Reset: Generated internally by the MCU and is active when Low. All other peripheral reset and enable signals are provided by the DSP U5.
DSP JTAG: The JTAG lines to the DSP are available through the uninstalled H2
header. This connection is used for development and in-house software upgrades.
Development Midi I/O: All lines to/from header H3 are used to interface with the
MCU for development and programming of the MCU U3 and the Flash U4. The
only way to update or reload code on a Spider 3 is with a Line 6 programming
interface PCBA connected to this header. No updates should ever be necessary!
HP_SENSE:
For the 1508 & 3012:
At headphone plug in, R60 is left floating which introduces +HI at the + pin 7 of
comparator U10-A. The voltage divider created by R57 and R62 creates a
reference point that is below that of the + input when headphones are inserted.
This forces U10-A output High, thus HP_SENSE active High. The DSP then
registers the headphones are connected and incorporates cab modeling into
+AUDIO_L.
For the HD75:
At headphone plug in, R43 is left floating which forces a steady +3.3V
HP_SENSE active High signal. The DSP then responds by incorporating cab
modeling into the +AUDIO_L signal. When the headphones are removed, the
Power amp output is clamped to a max of 0.0-3.3V per D15 and current limited per
Spider 3 Theory of Operation………………Line 6 Confidential..……………………………. Page 9 of 14
R43 and R60. The DSP recognizes this reduced alternating signal and registers no
headphones are connected.
GUITAR_SENSE: GUITAR_SENSE is Low if there is no input. If a jack is plugged
into J1 the line goes High (+3.3V) per pull-up resistor R37. The line runs directly to
the DSP which “mutes” all guitar audio from the DAC if an input is not present.
Note that CD/MP3 audio bypasses the DAC and will reach the headphones or the
speaker (if headphones not present) regardless of the guitar input connection. The
Power Amp Mute line is never active during normal operation for the HD75 model.
Analog Outputs:
1) DAC/CD/MP3 Output section:
The analog outputs of codec U2 are single-ended and have a DC bias of
approximately ½ of the VA supply, about 1.65V. The left and right DAC outs pass the
DC blocking caps C14-45 and are then equally summed with the left and right
CD/MP3 inputs per R45 and R47-49, providing a 3dB boost in noise performance. The
resulting Mono signal passes to the negative input of LPF U9-A which provides a gain
of 4.13. The 3dB frequency cutoff for the LPF is well above the audio pass-band
(fc>20kHz) and is intended to reduce EMI. The resulting output of U9-A (+AUDIO_L)
is single-ended, and in-phase with the system’s input. R59 serves as an analog
volume control for both the headphones and the Speaker output. U9-B is configured
as a buffer between the master volume and the power amp input.
2) Headphone Output (Main PCBA):
The Power Amp output OUTPUT_L+ feeds the Headphone outputs. R65 and 66
reduce the output of the power amp to a level more suitable for headphones. When
the headphones are inserted the sleeve lifts the AGND_PA connection from
OUTPUT_L- line running to the Speaker, which in turn mutes all Speaker Output.
a.) ESD/EMI Detail:
C44-46 combined with L11-12 and ground finger GF2 act as high frequency
shunts to chassis ground for EMI and ESD. R43 and D15 are used to clamp the
Power Amp output signal between 0-3.3V and feed it to the DSP as well as
provide ESD protection.
b.) Digital detail:
The only “digital” signal on the headphones circuit is HP_SENSE. See
Section V: Theory of Operation - Digital Processing Circuit for more detail.
POWER AMP PCBA:
• The Power Amp PCBA is identical for the Spider 3 1508 and 3012 with
exception to the Power Amp IC U8. For the 1508 an 18W PA IC (12-30-2030) is
stuffed and for the 3012 a 32W PA IC (12-30-2050) is used, both have identical
footprints.
Spider 3 Theory of Operation………………Line 6 Confidential..……………………………. Page 10 of 14
• The Power Amp PCBA for the HD75 is assembled with a finned aluminum heat
sink external to the Main board and mounted to the chassis rear, it is NOT
similar to the 1508 or 3012 models.
•The HD75 is the only model with a Speaker-Out PCBA attached to the Main
PCBA header H4.
1) Input and feedback Circuit detail:
For the 1508 & 3012:
The Power Amplifier IC U8 has the mono +AUDIO_L signal fed to its negative
input at pin 2. C21 blocks DC while R41 and R46 determine gain. C20 and C29 on
the +/-HI_PA rails provide additional supply filtering. C24 in series with R52 helps
suppress oscillation in case a speaker is not attached. R43 provides a current
feedback path to help simulate the response of a tube amplifier. The ground of the
speaker output is connected to the headphone jack J3 so that the speaker is
disconnected when headphones are inserted.
For the HD75:
The TDA7293 Power Amp IC U2 has a mono +AUDIO_L signal fed to its’
positive input at pin 3. The 0.22-Ohm resistors on the output help create a current
feedback topology that provides a more tube like experience to the user. The input
and feedback resistors made up of resistor network R10 are put in parallel to
achieve values with less than 1% tolerance. The positive feedback 47pF cap and
the negative feedback 68pF cap create LP filters to eliminate chances of high
frequency oscillation. The 2.2-Ohm 2W resistor R6 and in series with C9 helps
suppress high frequency oscillation in case a speaker is not connected. Minimum
impedance for external speaker cabs is 8-Ohms per side.
a.) ESD/EMI detail:
For the 1508 & 3012:
C50-51 shunt high frequencies to chassis ground while C22 and C26 act as
bypass caps.
For the HD75:
C20 and C24-26 shunt high frequencies to chassis ground at the Speaker
Out jacks via GF1-2. C14-15 are bypass caps.
2) Speaker Out detail (HD75 only):
Both external Speaker Out jacks J5-6 are fed from the same OUTPUT_L+
signal. Inserting a second speaker only reduces the output impedance seen by the
Power Amp.
b.) ESD/EMI detail:
Ground is provided by SPK_GND. GF1-2 provide a high frequency path to
this ground via C20 and C25 for both ESD and EMI control.
Spider 3 Theory of Operation………………Line 6 Confidential..……………………………. Page 11 of 14
POWER SUPPLY:
• The Power Supply is identical for the Spider 3 1508, 3012, and HD75 with
exception to D28 and C35-36 on the HD75. The components on the HD75 are
the same value as the 1508 and 3012 but are rated at higher power levels.
1) Primary Power Supply:
From the IEC AC connector input, the AC main ties directly to the rocker Power
Switch and transformer primaries. No components are used for high frequency
removal on the primary. Current is limited for safety fuse F1.
! Note that for continuous safety protection, all components connected to
the AC main voltage must be replaced with Line 6 approved parts only; this
includes the power switch, fuse, and all primary cables.
For the appropriate transformer, which primary cable to connect to, and the
correct fuse values see Section III: Power Supply Conversion.
The transformer contains a thermal fuse, which will open the primary winding if
the transformer core gets too hot. This fuse is not accessible; if it blows the
transformer will need to be replaced. This should not happen under any normal
conditions and the cause of the over-heating should be investigated before
replacing the transformer.
The “hi-volt” secondary of the transformer provides approximately +/-15.2 rails
for the 1508, +/-16.5 rails for the 3012, and +/-27.4 rails for the HD75, with
grounded center tap. The lower voltage secondary for all three models is 7.2VAC.
2) Secondary Power Supply (Main PCBA):
All power for the 1508, 3012, and HD75 is supplied directly from the local
power supply on the Main PCBA. There are 4 supplies derived from the Hi-volt
secondary, they are the +/- HI rails and +/- VA. From the low volt secondary the
+VL and +3.3V supplies are created. The +VL power line is approximately
+10.5VDC depending on line levels and load currents.
The +/-Hi rails are rectified by the full-wave diode bridge made up of D16-17
and D19-20 and filtered by C35-36. For the HD75 the bridge is replaced with an
all-in-one diode bridge D28 and C35-36 are rated at 50V instead of 25V. The 47kOhm resistor R12 serves as a path for stored cap charge to “bleed” after power
down. The +/- HI rails are filtered a second time at the Power Amp by C20, C22,
C26, and C29 on the 1508 and 3012 and filtered by C14-15 on the HD75. The +/HI rails directly supply the Power Amp IC’s only.
+/-VA are supplied by the +/-HI rails and are regulated to approx. +/-9V by Q1-
2 on the 1508/3012 and by Q3-4 for the HD75. D13-14 provide +/-10V at the base
of each transistor, ensuring both are always ON. R53 and R55 limit current and
R54 and R61 help protect the collectors. C30 and C34 values were chosen in
conjunction with R53 and R55 to provide a slow ramp up on power up to minimize
turn-on pop at the speaker output. C31-32 are used for filtering only.
Spider 3 Theory of Operation………………Line 6 Confidential..……………………………. Page 12 of 14
+VL is formed from the low volt secondary via the full-wave diode bridge made
up of diodes D21-24 and filtered by C38. This directly supplies the optional foot
controller for the 3012 and HD75 models only.
+3.3V is produced by U11, an adjustable voltage regulator supplied by +VL.
The output of U11 is determined by resistors R63 and R64. D18 provides overvoltage and under-voltage protection while C28 and C37 provide filtering.
VI. Troubleshooting Guide:
This section outlines some common problems that may be encountered when
troubleshooting a Spider 3 1508, 3012, or HD75.
1. Test points are provided on the SMD Components Side of the Main PCBA for all
power supply voltages and clocks. Verifying these test points in the same order
listed should always be the first step in troubleshooting. Next, all “sense” signals
should be verified by probing at the correct nodes using a schematic.
2. The board powers up, the UI is displaying the correct items, the buttons and knobs
work, but there is NO AUDIO.
• First, check the audio input circuitry and make sure audio makes it through the
input op-amp U1 all the way to the CODEC U2 inputs.
• Second, make sure that the CODEC has the appropriate clocks driving it. In
particular, make sure data exists on the ADC_SDATA and DAC_SDATA lines
between the CODEC and the DSP U5.
• Third, check the audio path from the output of the CODEC to the power amp
and the headphone circuitry.
• Fourth, check that the GUITAR_SENSE signal is HIGH when a jack is plugged
into the guitar input. If this signal is not HIGH then the input jack J1 or the
support circuitry for the sense line is faulty. If the system thinks that a cable is
not plugged into the guitar jack it will automatically mute the audio from the
CODEC. Audio from the CD/MP3 Input J2 bypasses the CODEC and runs to
the headphone outputs without a guitar plugged in.
• Fifth, if the audio is correct all the way to the CODEC, the clocks are correct,
and the DAC_SDATA line is transmitting data when an input signal is present
then it is possible the CODEC is malfunctioning. If the DAC_SDATA line is not
OK than it’s possible the DSP or an item on its bus is malfunctioning. At this
point check for faulty soldering on the DSP or other items on its bus.
• Sixth, the audio is correct all the way to the power amp but no audio out of the
speaker. The headphone jack J3 mutes the Power Amp output to the speaker
by removing the ground and should be checked. Note that the HP_SENSE line
only changes the +AUDIO_L by enabling cab modeling for the headphones and
does NOT change the audio level.
For the HD75 model only, if the +VA line is low, then the AMP_MUTE line
will be active Low and mute Power Amp output. In this case the +HI supply as
well as the +VA circuitry should be checked.
Spider 3 Theory of Operation………………Line 6 Confidential..……………………………. Page 13 of 14
3. The LED’s, POT’s, and/or Buttons do NOT work.
First, check if you can get into Test Mode by powering up the unit while
pressing the TAP TEMPO button (see Section IV: Software Modes). If you are able
to get into Test Mode than any button pressed should have it’s corresponding LED
turn on. Each Pot movement should correspond to a particular LED surrounding
the AMP MODELS POT lighting up and a unique pair of channel buttons turning
on. Use the Test Mode to isolate any defective or damaged switch’s or POT’s.
If you are not able to get into Test Mode, check that the circuitry for the
switches is functioning properly. In particular, check the ribbon cable from H6 on
the Switch/LED PCBA to H1 on the Main PCBA. All lines from the LED’s, POT’s,
and Buttons go directly to the MCU U3 ADC’s on the Main PCBA. Check for bad
soldering on U3 and that clocks/signals to/from the MCU are OK.
4. The board is running but the RJ-45 interface to the floorboard (FBV) does not
work.
Check for faulty soldering and or defective SM resistors, inductors, and caps
attached directly to the RJ45 lines. Next check the +9V power lines to the FBV.
Verify that the signals are passing trough the buffer/inverter U6 properly. The MCU
U3 should be checked next.
5. The Pots and Channels change by themselves.
Try to isolate pot and channel changes using the Test Software Mode
described in Section IV: Software Modes. Next check the +3.3V line, if any ripple
exists on this line the MCU will believe it is seeing command changes from the UI.
The 1000uF C37 and 3300uF C28 caps on the +3.3V, all SMD caps on the Pots,
and C29 and C65 on the MCU +3.3V line should be inspected for thorough
filtering.
6. The Amp starts up and the LED’s function properly but the version checking
doesn’t work and No audio passes.
The serial flash may not be programmed properly.
7. Settings are not being saved.
The FLASH memory on the Spider 3 MAIN PCBA is updated with any knob or
button setting changes that occur at any time. If settings are not being saved,
check for faulty soldering or components on the DSP’s memory bus including the
DSP U5, the FLASH U4, and the SRAM U7.
Additional Troubleshooting Tips:
• Pay attention to the fact that there is a bi-polar electrolytic cap C12 on the
Power Amp PCBA of the HD75.
Spider 3 Theory of Operation………………Line 6 Confidential..……………………………. Page 14 of 14