Transcript 5687-based preamp

5687 based simple preamp
Basic layout
DIY Paradise
9 January 2003
6X4
Schematic
Signal circuitry courtesy of
[email protected]
5687
Output
RCA jack
IEC socket
Input RCA
jack
Power
transformer
6X4
50+50uF/ 500V
electrolytic
capacitor
Stereo
volume pot
5687
Chassis Layout Top View
Input RCA
jack
IEC socket
Output
RCA jack
30H chokes
50+50uF/ 500V
electrolytic
capacitor
Few points to note here.
Power circuitry is kept at
center.
Signal comes in from the
input RCA jack, goes to
volume pot, then tube, then
routes to output RCA jack.
Coloured wavy line shows
signal path.
6X4
The purpose of doing the
layout is to avoid stray flux
(from transformer, chokes)
from coupling into your
signal and also to ensure
components are not too
cramped together to the
extent that there isn't
enough ventilation.
Stereo
volume pot
5687
Chassis Layout Bottom View
The following wiring diagrams are meant to aid you in the sequence in
wiring this preamp. Of course, you can do it some other way. Any other
way, actually.
Please note that layout of components is not to scale, so when you plan
your chassis, don’t simply “follow” what you see here.
Remember basic rules still apply:
• keep signal wires far away from filament wires transformer, chokes and
tube rectifier.
• cross only at 90 degrees.
• twist tightly the heater wires, place close to chassis.
• maintain star ground.
SAFETY FIRST: REMEMBER TO SOLDER IN BLEEDER
RESISTOR! REMEMBER TO “EARTH THE CHASSIS”!
You “earth the chassis” by wiring Earth of IEC socket to chassis, through a
nut. THEN confirm the resistance between Earth of IEC and chassis is as
close to zero as possible.
Input RCA jack
short to chassis
Output RCA jack
insulated from chassis
6X4
1
2
3
4
7
50+50uF
500V
6
5
Using tube socket
spigot as ground
Using tube socket
spigot as ground
9
Gnd Out In Unused
Alps stereo pot
1
8
2
7
5687
3
6
5
4
Ground layout
3.15-0-3.15V
1
2
3
4
7
6
9
Gnd Out In Unused
Alps stereo pot
5
1
8
2
7
3
6
5
4
Wiring of heaters
3.15-0-3.15V
350-0-350V
1
2
3
4
7
6
5
Bleeder resistor.
Very important!!!!!
270kohm 2W
Tap B+ from here
9
Gnd Out In Unused
Alps stereo pot
1
8
2
7
3
6
5
4
Wiring of power supply
L / R Input
L / R Output
350-0-350V
1
2
1 Mohm
3
4
7
6
5
0.47uF
9
Gnd Out In Unused
Alps stereo pot
1
8
2
7
3
6
5
4
Wiring of In/Out circuitry
L / R Input
3.15-0-3.15V
L / R Output
350-0-350V
1
2
3
4
7
6
5
10kohm
10kohm
470ohm paralleld
with 470uF
9
Gnd Out In Unused
Alps stereo pot
3.15-0-3.15V
1
8
2
7
3
6
5
4
470ohm paralleld
with 470uF
Wiring of signal circuitry