Velleman-Kit HIGH-Q K8040 User manual

Total solder points: 299
Difficulty level: beginner 1 2 3 4 5 ⌧advanced
HIGH-END MONO MOSFET
POWER AMPLIFIER
ILLUSTRATED ASSEMBLY MANUAL H8040IP-2
K8040
K8040

3
Features & specifications
Features :
 no compromise high-end design
 ideal to place next to the speaker (short wires to the speaker)
 auto-power on possibility when input signal is sensed
 auto-standby function when no input signal is sensed
 exclusive, high finish, solid aluminium enclosure
 high quality D-MOS IC output stage
 total of 40.000µF power supply capacitors
 relay-less speaker DC protection
 Real Clipping distortion indication
 power output level indication with backlight
 bypass output to drive bi-wired speakers using separate amplifiers
 double overheating protection with LED indication
 high grade speaker and input connections
 overload protection
Specifications
 input:
• input sensitivity for maximum output:............. 0dBm (= 0.775Vrms)
• input impedance:................................................................ 15Kohm
• minimum auto switch on voltage:....................................... 5mVrms
 output:
• maximum RMS output power 4ohm:........................................ 90W
• maximum RMS output power 8ohm:........................................ 70W
• dynamic RMS output power in 4ohm: .................................... 125W
• minimum load impedance: .................................................... 4 ohm
• damping factor (ref. 8ohm 100Hz): ...................................... > 1000
 audio:
• signal-to-noise ratio (A-weighted ref. max. out): ................. >105dB
• total harmonic distortion:............................0.003% @ 1kHz ref 1W
• frequency response:......................... 9Hz to 120kHz (-3dB) in 50W
 power requirements:
• AC power: ....... 115Vac (110V to 120V) or 230Vac (220V to 240V)
• consumption:................................................................. 100W max.
 dimensions: ..................................290 x 165 x 68mm (11.4" x 6.5" x 2.7")
 weight (net):........................................................................ 3.4kg (7.5Lbs)

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Assembly hints
1. Assembly (Skipping this can lead to troubles ! )
Ok, so we have your attention. These hints will help you to make this project suc-
cessful. Read them carefully.
1.1 Make sure you have the right tools:
• A good quality soldering iron (25-40W) with a
small tip.
• Wipe it often on a wet sponge or cloth, to keep it clean; then apply
solder to the tip, to give it a wet look. This is called ‘thinning’ and will
protect the tip, and enables you to make good connections.
When solder rolls off the tip, it needs cleaning.
• Thin raisin-core solder. Do not use any flux or grease.
• A diagonal cutter to trim excess wires. To avoid injury when
cutting excess leads, hold the lead so they cannot fly towards the
eyes.
• Needle nose pliers, for bending leads, or to hold components in
place.
• Small blade and Phillips screwdrivers. A basic range is fine.
For some projects, a basic multi-meter is required, or might
be handy
1.2 Assembly Hints :
⇒Make sure the skill level matches your experience, to avoid disappointments.
⇒Follow the instructions carefully. Read and understand the entire step before
you perform each operation.
⇒Perform the assembly in the correct order as stated in this manual
⇒Position all parts on the PCB (Printed Circuit Board) as shown on the
drawings.
⇒Values on the circuit diagram are subject to changes.
⇒Values in this assembly guide are correct*
⇒Use the check-boxes to mark your progress.
⇒Please read the included information on safety and customer service
0.000

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* Typographical inaccuracies excluded. Always look for possible last minute
manual updates, indicated as ‘NOTE’ on a separate leaflet.
1.3 Soldering Hints :
1- Mount the component against the PCB surface
and carefully solder the leads
2- Make sure the solder joints are cone-shaped
and shiny
3- Trim excess leads as close as possible to the
solder joint
REMOVE THEM FROM THE TAPE ONE AT
A TIME !
Assembly hints
AXIAL COMPONENTS ARE TAPED IN
THE CORRECT MOUNTING SEQUENCE !

6
Construction
The unit consists of one main PCB with all the components including transformer
and power supply.
 Tip: The pictures on the packaging can be used as a guideline.
However, due to possible modifications they are not 100% reliable.
Mount the components in the order described:
CONSTRUCTION
 J1
 J2
 J3
 J4
 J5
 J6
 J7
 J8
1. Jump wire
 R1 : 1K (1 - 0 - 2)
 R2 : 1K (1 - 0 - 2)
 R3 : 15K (1 - 5 - 3)
 R4 : 1K (1 - 0 - 2)
 R5 : 470R (4 - 7 - 1)
 R6 : 100R (1 - 0 - 1)
 R7 : 15K (1 - 5 - 3)
 R8 : 15K (1 - 5 - 3)
 R9 : 15K (1 - 5 - 3)
 R10 : 15K (1 - 5 - 3)
 R11 : 470R (4 - 7 - 1)
 R12 : 15K (1 - 5 - 3)
 R13 : 15K (1 - 5 - 3)
 R14 : 100R (1 - 0 - 1)
 R15 : 15K (1 - 5 - 3)
 R16 : 2K2 0.6W (2 - 2 - 2 - 9)
 R17 : 100R (1 - 0 - 1)
 R18 : 1K (1 - 0 - 2)
 R19 : 470R (4 - 7 - 1)
 R20 : 2K2 0.6W (2 - 2 - 2 - 9)
 R21 : 1M (1 - 0 - 5)
 R22 : 470R (4 - 7 - 1)
 R23 : 1K (1 - 0 - 2)
 R24 : 470K (4 - 7 - 4)
 R25 : 470K (4 - 7 - 4)
 R26 : 470K (4 - 7 - 4)
 R27 : 100K (1 - 0 - 4)
4. Resistors (check the color code)
R...
 ZD1: 20V / 1.3W
(Mount 5mm above the PCB)
3. Zener diode (check the polarity)
CATHODE
ZD...
2. Diodes (check the polarity)
CATHODE
D...
 D1: 1N4148
 D2: 1N4148
 D3: 1N4148
 D4: 1N4148
 D5: 1N4148
 D6: 1N4148
 D7: 1N4148
 D8: 1N4148

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 R28 : 2K2 0.6W (2 - 2 - 2 - 9)
 R29 : 2K2 0.6W (2 - 2 - 2 - 9)
 R30 : 0R
 R31 : 15K (1 - 5 - 3)
 R32 : 100K (1 - 0 - 4)
 R33 : 100R (1 - 0 - 1)
 R34 : 0R
 R35 : 680R (6 - 8 - 1)
 R36 : 15K (1 - 5 - 3)
 R37 : 100K (1 - 0 - 4)
 R38 : 470R (4 - 7 - 1)
 R39 : 10R / 1W (1 - 0 - 0)
 JGND: 0R
If long input signal wires are used a low
input impedance can be useful.
In this case mount for RX a 680R (6-8-1)
resistor.
Check if your pre-amplifier can drive low
impedance!
 Our K8021 is OK for low impedance.
 Our K8020 is not suited for low
impedance driving.
Rx is normally left open.
 C1 : 100nF (104)
 C2 : 100nF (104)
 C3 : 100nF (104)
 C4 : 100nF (104)
 C5 : 100nF (104)
 C6 : 100nF (104)
 C7 : 100nF (104)
 C8 : 100nF (104)
5. Capacitors
c...
 IC1 : 8p
 IC2 : 8p
 IC3 : 6p
6. IC sockets. Watch the position
of the notch!
7. 10W resistor
R...
5mm
 R40 : 4R7 (4.7, 4R7)
 C9 : 2n2 (222)
 C10 : 220n (224)
 C11 : 1uF
 C12 : 1uF
 C13 : 2.2uF
 C14 : 2.2uF
 C15 : 100n / 250V (104)
 C16 : 100n / 250V (104)
8. Capacitors
 T1: BC547
 T2: BC547
9. Transistors
construction

8
Construction
 SW1: TS-04PV
 SW2: KRS1243
11. Push button. Mount them
straight against the PCB surface !
 SK1: MJ-523AG/R
 SK2: MJ-523AG/B
Tip:
A red and a black type are delivered
with the kit, if you bought 2 amplifiers
for stereo then one amplifier can be
built with red connectors
(right amp.) and one with the black
connectors.
10. RCA connectors. Mount them
straight and against the PCB
 SK3: 3p "Mains in"
 SK4: 3p "Mains transformer"
 SK5+SK6: 2x 2 pole Transformer
output
 First slide these two
connectors in each other.
12. Terminal blocks
Check that the position
corresponds with the PCB
silk printing.
 SK7: 2 pole Temp sensor
 SK8: 2 pole Power meter
 SK9: LS+
 SK10: LS-
13. Terminal connectors

9
This coil will have to be made by
yourself. Use the supplied copper
wire (1.5mm) with the kit.
Wind this wire round a 8mm drill or
other round object and make 8 turns.
You can snip off the remaining copper
Then remove (scratch) the isolation
from the connections using a knife.
Mount the coil and make sure to have
a perfect soldering.
 L1: 8 Turns dia 8mm
14. Coil
L...
 VR1 UA7805
16. Voltage regulator. The back
side corresponds to the thick line.
 C17: 10µF
 C18: 10µF
 C19: 10µF
 C20: 10µF
 C21: 10µF
 C23: 1µF
 C24: 10µF
 C25: 47µF/63V
 C26: 47µF/63V
 C27: 47µF/63V
 C28: 47µF/63V
 C29: 220µF/63V
 C30: 220µF/63V
15. Electrolytic capacitors.
Check the polarity !
C...
VR...
 TR1: TIC246 or eq.
17. Triac. The back side
corresponds to the thick line.
TR...
construction
 LD1: LED3RL (3mm LED)
 LD2: LED3RL (3mm LED)
 LD3: LED3RL (3mm LED)
19. LEDs
COLOR= 2...5
LD...
CATHODE
 BR1: RS603
18. Bridge rectifier.
Check the polarity !!

10
Construction
 C31: 10.000µF
 C32: 10.000µF
 C33: 10.000µF
 C34: 10.000µF
20. Power electrolytic capacitors.
Check the polarity !
C...
 IC1: VK8040 (PIC12C508)
 IC2: CA258 or eq.
 IC3: MOC3041 / KP3020
21. IC’s. Watch the position of the
notch !
First: Bend the leads exactly like the
drawing.
Next: Solder one lead, and check the
position, if necessary correct by
heating the soldering.
Last: Solder the second connection.
 LD4: L-424YDT
 LD5: L-424YDT
 LD6: L-424YDT
 LD7: L-424YDT
Meter backlight:
LD8 is a white LED serving as backlight
for the power meter.
 LD8: L5WD (5mm white)
22. Mounting front LED’s. Check the polarity !
Short lead = Cathode or - !
7mm
C
12mm
IMPORTANT
Mount these LED’s exactly like in the
drawing, otherwise some LED’s will
not fit correctly in the front panel.
Please also use the front panel as a
positioning reference.
CATHODE
LD...
CAUTION:
After bending the
leads the long
appearing lead will
be the cathode!
LD...
CATHODE
3mm
18mm

11
construction
 IC4: TDA7293
Mount the support plate onto the IC as shown in the drawing.
Put a drop of silicone compound on both sides of the mica isolator.
Also check the position of the plastic isolator A.
ATTENTION : The bolt should be inserted on the side of the IC holder with the
countersunk opening B !
DO NOT TIGHTEN THE NUT YET
1. Position the IC onto the PCB.
2. Make sure that the support plate is touching the PCB surface.
3. Tighten the support nut.
4. Check again that the plate is touching the PCB surface.
5. Solder the IC connections.
23. Mounting the Power IC
A
Drop of heat conductive
compound
A
B

12
Mount the transformer as in the drawing (see also the picture on the packaging)
Use the supplied straps (4 pcs) to fix the transformer.
Primary windings (MAINS) connection:
Check the table on the PCB for the correct voltage selection and connect
the wires :
For 230V (220V to 240V), edge orange, then brown and black.
For 115V (110V to 120V), edge brown, then orange and black.
Using a black marker, erase the not used voltage on the rear panel of the
unit!
Secondary windings connection:
Connect the Red, Yellow, Blue and Grey wire to the SK5/SK6 connector, check
the colors on the PCB.
24. Mounting the power transformer and mains voltage selection
Construction
230V 120V
ORANGE BROWN
BROWN ORANGE
BLACK BLACK

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 Cut the thread in the
holes for the enclosure
feet in one of the alu-
minum profiles, using
the supplied special
M4 screw as a tap.
 Mount the feet on the
aluminum profile, using
two M4 hexagonal Allen
screws. Use the supplied
Allen wrench. It is advis-
able to stick the protection
adhesive onto the feet.
 Cut the thread in the front
and back of the aluminum
profiles, using the supplied
special M4 screw (4 holes
per piece)
25. Enclosure preparation
Enclosure preparation
FIG. 1
FIG. 2
FIG. 3

14
 Position the main PCB in the aluminum profile that is prepared with the feet.
 Mark the center position of
the three fixation holes on
the aluminum. A reference
indication is also on the
PCB edge.
 Remove the pcb and use a knife or a screwdriver to scratch the paint from
the aluminum fixation, from the hole closest to the back end. This fixation will
be used later to connect the ground and earth.
 Mount the three 5mm (0.14”) spacers as shown in the drawing. Use three
hexagonal screws and 3 washer. Do not tighten the spacers yet.
 Position the PCB in the enclosure and check if the position of the spacers is
correct, if so, remove the PCB and tighten the spacers.
Enclosure preparation
FIG. 4
FIG. 5
M3 hex. nut
5mm M3 spacer
Washer
FIG. 6

15
 Using an ohmmeter, measure between the edge of the aluminum profile and
the back spacer, if there is a good electric contact (less then 10 ohm).
If not, repeat the above step to remove the paint under the spacer.
 Slide two M3 nuts and two
hexagonal bolts into the profile,
the nuts will be used for the
temperature sensor, the bolts will
be used for the IC support plate:
 Mount the temperature sensor,
check the exact position. Make sure
there is silicone compound between
the sensor and the enclosure!
 Solder the wires of the supplied two
pole connector onto the sensor.
There is no polarity.
Enclosure preparation
0.000
FIG. 7
FIG. 8
11cm
FIG. 9

16
Final assembly
RE-CHECK CAREFULLY THE PCB FOR MOUNTING AND
SOLDERING ERRORS!
 Mount the pcb into the enclosure, check the position of the power IC.
The IC support must fit onto the previously inserted hexagonal bolts.
Make sure there is silicone compound between the IC support and the
enclosure!
 Glue the included insert Cbetween the transformer and housing.
 Make sure the PCB is aligned with the back of the enclosure
 IMPORTANT: FIRST fix the IC support
 THEN fix the pcb using three 5mm spacers + washer.
DO NOT TIGHTEN THESE FIXATIONS YET.
 Note: Not all components are visible on the drawing.
26. final PCB mount
C

17
Final assembly
Prepare the wiring of the mains connector like in the drawing.
First mount the switch into the mains connector assembly.
Do not forget to isolate the soldering connections using a piece of shrink tube.
Use the supplied 0.5mm wire:
 Blue for Neutral
 Brown for Live
 Yellow/green for earth
Use 3 pieces of about 10cm for later connection to the PCB mains connector.
 Mount the speaker connectors onto the rear panel. (black = negative)
 Take care of the isolation washers, there are two different types!
See picture.
 Make sure the connectors are very tight fit, and do not make electrical
contact with the panel (check using ohm meter!).
27. Speaker and mains connector assembly
Yellow/green
Brown
Blue
Isolation washer !

18
 Solder a 15cm (2.5mm) wire to the LS connectors. Black = negative, Red=
positive, use a shrink tube to isolate the connection.
 Solder a spade terminal to the other end, do not forget the terminal isolation.
 Mount (insert) the mains connector onto the rear panel. Insert a 2A fuse into
the connector (there is also room for a spare fuse).
28. Final assembly and connection
Final assembly
15cm

19
 Mount the rear panel onto the enclosure, using two M4 Allen screws.
 Connect the speaker wires to the speaker output tabs. Check the polatity!
Black= LS-, Red= LS+.
DO NOT CONNECT THE MAINS WIRING WITH THE PCB YET!
Final assembly
!
 Connect the two wired connector to the meter, RED =
+, BROWN = - to the meter.
 Mount the power meter onto the front panel.
 Fix the meter using a piece of transparent adhesive
tape (four sides).
Make sure the meter is positioned straight.
 Connect the meter to the PCB (SK8)
 Mount the front panel onto the front, using two M4
Allen screws.
Check the position of the LED’s and check if the button is working correctly.
It could be that paint covering the holes, is preventing the buttons from
smooth operation.
 Now the three PCB fixations can be tightened.
Check the push button.
29. Preparing the front panel

20
 Connect a 10cm blue wire to the
point Nof SK12.
 Connect a 10cm brown wire to the
point Lof SK12.
 Connect a 10cm yellow/green
wire to the earth point of SK12.
Later these connection will be sol-
dered to the mains connector.
21. Mains voltage connection
preparation
Test
Check again all connections of transformer and mains
 Connect the mains wires to the mains connector SK3, Blue= Neutral, green/
yellow= Earth.
 Connect a 60W light bulb in series with the Live (Brown wire) and the Live
connection on the PCB.
 Mount both the fuse and the spare fuse in the fuse holder.
CAUTION: Some points on the PCB are connected to the
dangerous mains voltage.
Connect the mains AC voltage to the mains. See also the user manual about
the power cord.
 Normally after switching ON the amplifier, the light bulb should briefly light up.
 If the bulb glows constantly, disconnect the power immediately and
recheck all connections.
• Normally the standby LED on the front panel should light as should both 35V
power indication LED’s LD2 and LD3.
30. Test
!
!