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.
C1 1000uf 63V Electrolytic
C2 to C3 100NF 50V Ceramic disc type
BR1 W10 1 Amp Bridge Rectifier
LM317T 1.5 Amp Regulator IC
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.
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.
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.
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.
Plain Veroboard. NB, Do not attempt to use copper stripboard
Vero Pins for connections on circuit board
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.
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.
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.
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.
V1 V2 V3 V4 V5 ECC88 or 6922 RF triode.
V6 6AL5 or EB91 Double discriminator diode.
V7 ECC82 or 12AU7 AF triode.
6 B9A Chassis mounting type.
1 7BA Chassis mounting type.
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.
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
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.
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
C4 C5 47uf 450V
R3 100R 3 Watt Wire Wound.
Input 240V. Output 24.0.24V 6VA wired in series to give 48V. Available from Maplin Electronics as code N98CC.
FS3 Mains fuse 250ma anti surge ceramic type and panel mounting fuse holder to suit.
FS4 HT fuse 100ma anti surge ceramic or glass type and panel mounting fuse holder to suit.
Components List For AM/FM Version Of The 7 Valve Pulse Counting Receiver.
Components for receiver and AF amplifier stage
Resistors All 1/4 Watt cracked carbon except where highlighted
R1 220R. R2 R3 2K2. R4 4K7. R5 R6 4K7 0.5W. R7 220K. R8 1K.
R9 1K. R10 R11 33K. R12 220K. R13 47R. R14 1K2. R15 150K 0.5W. R16 100K 0.5W.
R17 47K. R19 220K. R20 1K. R21 R22 33K. R23 1K. R24 220K. R25 1K. R26 33K.
R27 1K. R28 220K. R29 1K. R29 15K NB Sorry duplicate numbering on diagram, This is the limiter decoupling resistor.
R30 33K. R31 4K7. R32 R33 47K. R34 4K7 1W. R35 330R 2W. R36 10K 0.5W.
R37 470K 0.5W. R38 100K 0.5W. R39 4K7 1W or 2W when using audio amp with 200V HT Line. RV1 AM Local Oscillator Regeneration Control 470K Lin preset pot.
RV2 IF Gain Control 470K Lin Pot. RV3 AF Volume Control 1M Log Pot, See text.
Capacitors Ceramic Disc. Maximum Voltage 50V except where stated
C1 2.2NF. C2 C3 100NF C5 10PF See Text. C6 47PF. C7 1000PF. C8 100NF. C9 470PF
C10 C11 C12 100NF. C13 470PF. C14 100NF. C15 470PF. C16 100PF or 100PF Trimmer, See text. C17 100NF. C18 100NF.
C19 100NF. C20 100PF. C21 10PF. C22 100NF. C23 470PF. C24 C25 100NF. C26 470PF. C27 100NF. C28 470PF. C29 C30 100NF.
C32 470PF. C33 C34 100NF. C36 22 or 47PF See text. C37 100NF. C38 1000 or 100PF For stereo decoder, See text.
C39 100PF. C40 100NF. C41 100N 500 - 1000V if used with high power valve amplifier. C46 100NF 100V NB This capacitor must be a polypropylene type with a voltage rating of 500 - 1000V if audio power amplifier is used on a 200V HT line.
Capacitors Electrolytic. Minimum working voltage 35V except where stated
C4 10uf. C35 22uf. C42 C47 47uf. C46 10uf 100V NB This capacitor must be rated at 450V Minimum when HT line of 200V is used.
Tuning And Trimmer Capacitors
VC1 10 - 30PF Air spaced VHF type.
VC2 VC4 Dual Gang 200 - 365PF Variable or alternatively 2 single gang units may be used.
TC1 TC2 10 - 30PF Trimmer. TC3 TC4 65PF Trimmer.
RF Coils And IFT1 Transformer
The L1 and L2 VHF coils are home constructed in the same way as the earlier version and will be described in the main text. As the AM RF coils are not easy items to find, These are also home wound and there will be full detail in the text on how to wind these. IFT1 is made by connecting 2 transistor type 455KHZ IF transformers back to back and are available from the following link Mouser Electronics - Electronic Components Distributor and you need to refer to the main text regarding connection of these components.
T1 Audio Output Transformer
The transformer is a 100V 4W line output transformer used in the earlier version but please note the following point. If you intend using the audio amplifier circuit with a 200V HT line to give an output of 3W I am afraid to say that these type of transformers are not suitable and may overheat. A proper valve transformer with a primary load impedance of 5K is available from the following link Amp Maker: Guitar amp kits and parts and prices at about £22 at the time of writing. Also this transformer is suitable for the EL84 version of the earlier amplifier and has a very high sound quality.
Valves. Available from the following link Watford Valves
V1 V2 V4 V5 ECC88.
V6 EB91or 6AL5.
V7 ECL82 or 6BM8
6 X B9A Chassis mounting type, Available from the following link Amp Maker: Guitar amp kits and parts or Watford Valves
1 B7A Chassis mounting type, Available from the following link Watford Valves
LS1 AF Speaker 8R NB If using high power version of ECL82 amplifier with 200V HT line, This component must have a power handling of 5 Watt minimum or more
Components List Of HT Power Supply For AM/FM Tuner Section
C1 C2 1000uf 63V Electrolytic.
R1 100R 5W Wire wound.
W10 1 Amp.
T1 Low HT Transformer
500 Milliamp minimum. Primary 240V for UK AC Mains. Secondary 18 or 20V AC to give 25V DC HT Line.
FS1 250 Milliamp A/S Mains Fuse.
FS2 100 Milliamp HT A/S HT Fuse.
S1A S1B Double Pole 240V 10 Amp Toggle Switch
Components List Of HT Power Supply For Audio Amplifier
C3 C4 47uf or 100uf 450V Electrolytic.
R2 100R 5W Wire wound. NB If you intend building the high power 2 Watt version of the ECL82 Amplifier please refer to the text regarding the mains transformer.
W10 1 Amp.
FS3 100 Milliamp HT A/S Fuse
T2 Amplifier HT Transformer
6VA 100 Milliamp minimum. Primary 240V for UK AC Mains. Secondary 40V AC to give 56 to 65V HT Line. NB Please see special note below regarding this item
I have some great news for those who would like to have an even more powerful audio amp similar to the Mullard 2 Watt Stereo Version. The following link Amp Maker: Guitar amp kits and parts :: Power transformers :: 0-190-275V 20W power transformer is suitable for powering the entire heater chain if one mono block amplifier is used. This transformer will also power a stereo version of the ECL82 Power amplifier providing a separate heater transformer is used for the tuner section. The R2 Smoothing Resistor must be increased to 1K8 and must be rated at 7 Watts minimum to drop 66V at 0.036 Milliamp to give a 200V HT line. The 190V tapping is used and gives 266V DC at 160 Milliamp. This version of the amplifier involves the use of very lethal high voltages and must not be attempted by inexperienced constructors. Please see the main text for more details.
T3 Heater Transformer
24VA 3.5 Amp minimum. Primary 240V For UK AC Mains. Secondary 6 Volts
For all other items such as hardware, That includes nuts, Bolts, Chassis and wire please refer to the components list of the earlier version as it is basically only the AM front end and a slight modification to the IF stages that have been added to this design.
Back To-6 Valve VHF/FM Pulse Counting FM Tuner Using Safe 25Volt DC HT Line