Download User Manual F6

F6 USER MANUAL. Ver1.1E
F6 assembly instruction.
Attention!
This device is powered from the AC main that poses threat for life and
health. During the work with a high voltage it is necessary to follow
safety measures. The user bears full responsibility for the
consequences and possible loss as a result of all their actions.
0. INTRODUCTION.
This KIT is based on F6 scheme from Nelson Pass. Detailed information can be found on the
sites firstwatt.com and diyaudio.com
The scheme contains a number of the additions for the safe operation of the amplifier and
speaker. Clip and Ready indications are provided.
The offered MULTIKIT is very simple in assembly and tuning. Nevertheless, you must have to
possess elementary skills of installation and understanding of electricity. The order of an
assembled product is possible.
All risks of wrong adjustment, connection, assembling, insufficient
qualification of the assembler, force-majeure circumstances, are
completely accepted by the customer. Some parts or values can be
changed without notices. Claims in subjective parameters of products
are not examined. The fact of the order of KIT confirms full
acceptance of these conditions.
1. TOOLS, EQUIPMENT, MATERIALS.
For performance of assembly operations you need to have minimum: crosswise screw-driver,
nippers, six-sided key and soldering iron (60-100W).
For adjustment operations the multimeter is sufficient. Variac, oscilloscope and the
generator are desirable.
From materials the screened wire and an assembly wire (14-17AWG) will be required. Solder,
flux, shrink tube and plastic ties.
2. PCB ASSEMBLING.
Install according to the scheme and component placement card the demanded components
in the corresponding positions. Lastly install semiconductors, power cap, output transistors
and wires.
VD1 and VD2 can be replaced with two serial connected LED’s (white or blue). It is also
possible to use reverse-biased junction of low power transistor.
While soldering avoid overheating of components carry out the soldering for no longer than
3-4 seconds. Do not allow cold solder joints, short circuits. Do not inhale fumes of solder,
work in the aired room.
After assembling make sure there are no mistakes in the cold solder joints, or short circuits.
3. ASSEMBLY OF THE AMPLIFIER.
Before installation it is necessary to put on output transistors the insulating pad with thermal
paste. Use mica or ceramic only! Thickness of paste has to be minimal - surplus is extremely
harmful.
Attach PCB with four screws. Install transistors clips. Lock in the corresponding screws by
sufficient effort by means of a six-sided key.
Connect indication PCB, level regulators, input and output connectors according to the
assembly diagram.
On the chassis install the transformer (transformers) with the isolating gaskets. Connect a
main 220VAC according to the assembly diagram. Isolate solder places with help of shrinkable
tube. Do not connect secondary windings.
After completion of assembly works make sure of lack of mistakes.
Example of assembling:
4. ADJUSTMENT OF THE AMPLIFIER.
Before power up:
Connect the transformer to the adjusted channel.
Adjust R7 and R8 resistors in the minimum resistance position. Check resistance – values
must be no more than 1 Ohm.
Connect the voltmeter between XN9 (Out) and XN10 (GND). Power up the amplifier. Voltage
must be close to zero. Voltage on R23 and R24 resistors has to be close to zero. If is not
present - immediately power off and look for mistakes.
Slowly rotate the R8 resistor before appearing voltage in a point of XN4 (Out) of -50-100 mV.
Then slowly rotate the R7 resistor before reduction of voltage to 0 mV.
Measure voltage on R23 and R24 resistors- within 0.1– 0.14B (current 1.0– 1.4A)
Consecutive adjustments of R7 and R8 resistors achieve output voltage in limits +/-10mV and
the demanded voltage on R23 and R24 resistors. Final adjustment is made on heated-up
amplifier. Thermal changes of this voltage are normal.
Position of the R21 and R22 resistor defines structure of harmonic distortions and the
corresponding coloration. You can execute this adjustment depending on your preferences.
5. PROTECTION.
This KIT is equipped with output transistors overcurrent protection. There is an opportunity
to exclude protection. For a complete elimination of protection you need to remove VT5 and
VT5 transistors.
However, the system of protection has slight influence only on the tiniest nuances of sound
transmission. But the risk of damage of the amplifier and destruction of the speaker system
sharply increases. Therefore I do not recommend protection mechanisms eliminating.
© StD 2015