Components List Of 6 Valve VHF/FM Tuner
Components for the power supply circuit
Resistors. All carbon film 1 Watt except RV1
RV1 5K Preset Horizontal mount type.
R2 240R
Capacitors
C1 1000uf 63V Electrolytic
C2 to C3 100NF 50V Ceramic disc type
Semiconductors
BR1 W10 1 Amp Bridge Rectifier
LM317T 1.5 Amp Regulator IC
Mains Transformers
T1 18V 12VA to give 25V HT. Primary must be 240V for UK AC Mains.
T2 6V 24VA to give 4 amps headroom for valve heaters when adding a power amplifier. Primary must be 240V for UK AC Mains.
FS1 1 amp maximum anti surge fuse. NB Must be a ceramic type not glass.
FS2 100 milliamp maximum anti surge fuse. May be ceramic or glass.
Miscellaneous Items
Mains Switch. Double Pole 10 amp toggle switch
Mains Input Socket. 10 amp European type plug preferably with built in fuse holder for FS1
Mains Lead. 10 Amp European type which is used on electric appliances such as kettles to fit above item. NB Plug fuse must be rated at 3 Amps.
Cables
6 Amp white stranded or preferably single stranded tinned copper wire for 6.3 Volt valve heaters.
Red and black HT wire. About 1 amp single stranded tined copper wire for 25 volt HT wiring and inter connections to tuner.
Mains Cables
1 metre of 3 core 3 Amp amp mains cable for mains wiring
Solder Tags, Nuts, Bolts, Washers and Spacers.
4BA or M4 type for earthing and T1 and T2. 6BA or M3 type, for heater and component earths in tuner chassis and for mounting components in tuner chassis.
Terminal Posts And Sockets.
2 Red and 2 Black for 25 Volt HT Supply.
4 White, rated at 6 Amps for 6.3 Volt heater connections.
Circuit Board
Plain Veroboard. NB, Do not attempt to use copper stripboard
Vero Pins for connections on circuit board
Case
Suitable metal instrument case designed for housing power supply units with suitable ventilation.
Components for the FM Tuner
Resistors. All 1/4 Watt or 0.5 Watt carbon Film
R1 220R. R2 2K2. R3 2K2. R4 R5 R6 R21 R24 R25 R28 R30 R31 4K7.
R7 R9 R12 R14 R15 R17 R19 R22 R29 1M.
R23 10K.
R26 R27 47K. R8 R10 R12B R13 R17B R18 R20 15K.
Capacitors. Ceramic disc type 50V rating for 25V HT line or 100V when using 65 Volt HT line.
C1 2.2NF.
C2 C4 C8 C11 C13 C16 C21 C22 C24 C29 C33 100NF.
C34 100NF NB, Must be rated at 500 to 1000V for coupling to other valve amplifiers for safety reasons I mentioned in the text.
CX. This capacitor is the V1A Anode signal coupling capacitor that links to the L2 aerial and oscillator coil of V2B frequency changer. This value may be 2-10PF. The maximum value is 10PF but may need decreasing if you find oscillation is not very reliable on the low frequency end of the FM band. A trimmer may be preferable.
C9 C10 C12 C14 C15 C17 C18 C20 470PF.
C7 C26 1000PF.
C27 100PF.
Electrolytic Capacitors. 50 Volt minimum rating for 25 Volt HT Line or 100 Volt rating for 65 Volt HT Line
C14 C23 C32 10uf.
C28 100uf. C31 47uf.
RF Tuning and trimmer capacitors
TC1 TC2 10-30PF.
VC1 15-30PF Air spaced variable.
Valves
V1 V2 V3 V4 V5 ECC88 or 6922 RF triode.
V6 6AL5 or EB91 Double discriminator diode.
V7 ECC82 or 12AU7 AF triode.
Valve Holders
6 B9A Chassis mounting type.
1 7BA Chassis mounting type.
Chassis
Maplin Electronics still stock the following 2 items which I will describe in short detail. The first item is Code KR56L PC25 and this is the same chassis as I used to assemble my tuner and would be suitable for everything except the power supply components. KR57M PC26 is slightly larger and should enclose everything including the power supply components although there will be the hazard of live parts exposed and a wooden cabinet with a ventilated back cover would be required when the tuner is in normal continues use.
Other Miscellaneous Items
SK1 FM Antenna Socket 75 Ohm coaxial. Please also refer to the power supply components list as all the other items are already included such as wire and sockets.
RF Coils L1 and L2
18SWG Tinned copper wire or 1 metre of 1.5mm UK Mains lighting cable works fine.
Component Suppliers
Maplin Electronics Suitable for obtaining all components except the valves, valve sockets and tuning capacitors.
Cricklewood Electronics CCTV and Electronic Components Still an excellent UK supplier and stocks everything including the valves and holders except V6 6AL5 or EB91 and the tuning capacitors.
Watford Valves UK supplier, Stocks all the valves for this tuner at the time of writing including 6AL5 or EB91 and is a speedy delivery service and simple online ordering.
Chelmer Valve Company Another UK valve supplier and should have all the valves available for this tuner. There is no online shopping facility and inquiry request by telephone or email is required.
Jackson Brothers - Variable Capacitors and Drives The only company I know that still I think make variable capacitors for radios. Quote by telephone or email is required. No online shopping facilities
Antique Electronic Supply A USA based company and stocks everything. Vary good and secure online ordering facility's. Depending on your state of location, allow at least a month for shipping and delivery of goods.
Components List For Optional EL84 Output Stage
Capacitors. Ceramic Disc 100V Rating
C37 C39 100NF
Capacitors. Electrolytic
C35 10uf 100V
C36 47uf 50V
C38 47uf 50V
C40 1uf 100V
Resistors 0.5 Watt Carbon Film Except Where Stated
R32 47K. R33 R34 4K7. R34 1K. R35 680K. R36 150R 2 Watt. R37 6K8.
Valves
V7B Already included as 1/2 ECC82 with V7A line driver stage of FM tuner.
V8 EL84 Output Pentode.
Valve Holder B9A Chassis mounting type.
Output Transformer 100V 2 Watt Line Transformer available as Code N85CC from Maplin Electronics
Speaker 8 Ohm, bigger size the better sound quality, choice is up to you.
67 Volt HT Power Supply Components list. NB. Needed for powering EL84 Output stage only
Capacitors Electrolytic
C4 C5 47uf 450V
Resistors
R3 100R 3 Watt Wire Wound.
Bridge Rectifier
BR2 W10
Mains Transformer
Input 240V. Output 24.0.24V 6VA wired in series to give 48V. Available from Maplin Electronics as code N98CC.
Fuses.
FS3 Mains fuse 250ma antisurge ceramic type and panel mounting fuse holder to suit.
FS4 HT fuse 100ma antisurge ceramic or glass type and panel mounting fuse holder to suit.
Back to-6 Valve VHF/FM Pulse Counting FM Tuner Using Safe 25Volt DC HT Line