I have kept the component references as close as possible to ones used in the original schematics.
Resistors
Reference | Value | Tolerance | Rating | Notes |
RV1 | 500 kΩ | – | 0.25 W | Logarithmic potentiometer dual 24 mm M8 |
R3 | 10 MΩ | 5 % | 0.5 W | Carbon composition |
R4 | 82 Ω | 5 % | 0.5 W | Carbon composition |
R5 | 1 MΩ | 5 % | 0.5 W | Carbon composition |
R6 | 6.8 kΩ | 5 % | 0.5 W | Carbon composition |
R7 | 390 kΩ | 5 % | 0.5 W | Carbon composition |
R8, R14 | 1 kΩ | 5 % | 0.5 W | Carbon composition |
R9 | 22 kΩ | 5 % | 0.5 W | Carbon composition |
R10 | 150 Ω | 5 % | 0.5 W | Carbon composition |
R12 | 2.2 kΩ | 5 % | 0.5 W | Carbon composition |
R13 | 560 Ω | 5 % | 3 W | Wire wound |
R15, R16 | 33 Ω | 5 % | 3 W | Wire wound |
I have kept (whenever possible) the same type of resistors as in the original: of carbon composition. But the rating has been chosen to be at least 0.5 W for carbon composition resistors because these are a little bigger than the 0.25 W ones, and more similar to the 1960 and earlier 0.25 W ones. In this way, even if there are a little too large for the power they need to dissipate, they will support a higher working voltage as the 0.25 W ones.
In case I couldn’t find a 0.5 W carbon composition resistor for a defined value, I could use a carbon film 1 W resistor instead.
The carbon composition resistors used are from the following manufacturers:
- Ohmite – Little Demon, OF Series (0.5 W ±5 % 350 V) – Datasheet
- Stackpole Electronics, Inc. – RC Series, RC12 (0.5 W ±5 % 350 V)
- TE Connectivity Passive Product – CBT Series, CBT50 (0.5 W ±5 % 350 V) – Datasheet
- Multicomp from element14 – MCRC Series, MCRC1/2 (0.5 W ±5 % 350 V)
The carbon film resistors used are from the following manufacturers:
- Yageo – Carbon Film Resistors, CFR Series – Datasheet
- Xicon – Carbon Film Fixed Resistors, CF-RC Series 294 or 293 – Datasheet
The wire wound resistors used are from the following manufacturers:
- Ohmite – Vitreous Enamel Wirewound Resistors, 20 Series – Datasheet
- Ohmite – Silicone-Ceramic Wirewound Resistors, 40 Series – Datasheet
- Vishay Draloric – Cemented Leaded Wirewound Resistors, AC Series – Datasheet
The 24-mm potentiometer is made by Alpha.
Capacitors
Reference | Value | Tolerance | Rating | Notes |
C1 | 0.022 µF | 5 % | 250 V | Polyester film, CDE Cornell Dubilier / Mallory, Type 150 – Datasheet |
C3 | 0.22 µF | 10 % | 400 V | Polyester film, Vishay / Roederstein, MKT1813 Series – Datasheet |
C4, C8 | 25 µF | 20 % | 50 V | Aluminium electrolytic, Vishay / Sprague – Datasheet |
C5 | 390 pF | 5 % | 500 V | Mica Stardard Dipped, CDE Cornell Dubilier, Type CD15 – Datasheet |
C6, C9 | 40+40+40 µF | – | 525 V | Aluminium electrolytic, CE Manufacturing |
Transformers
Reference | Type | Model | Datasheet |
TR1 | Mains transformer | Hammond Manufacturing 370DAX | Datasheet |
TR2 | Output transformer | Hammond Manufacturing 125BSE | Datasheet |
Vacuum tubes / Valves
V1 EF86 – Datasheet
V2 EL84 – Datasheet
V3 EZ81 – Datasheet
Miscellaneous
Part name | Quantity | Notes |
Valveholders | 5 | Belton Engineering, VT9-ST-1 – Datasheet |
Mains input socket | 1 | Bulgin, PX0580/28 – Datasheet |
Fuseholder | 1 | Bulgin, FX0455 – Datasheet |
Fuse | 1 | 5 mm x 20 mm, 500 mA (1 A for 120 V) |
Mains switch | 1 | Honeywell, 12TS115-2 – Datasheet |
Indicator light | 1 | Arcolectric, neon red L104100NAA – Datasheet |
Input socket RCA | 2 | Neutrik, NYS367 white and red – Datasheet |
Output socket | 4 | Hirschmann, PKI 10 A Au black and red – Datasheet |
Impedance switch | 1 | TE Connectivity, FTN0904 – Datasheet |
Terminal strip 2 way | 2 | Keystone 810 – Datasheet |
Terminal strip 6 way | 2 | Keystone 825 – Datasheet |
Solder terminal lug | 4 | Keystone 7327 – Datasheet |
Grommet 8 mm | 6 | Keystone 742 – Datasheet |
Insulator for FP Cap | 1 | AES S-H120 |
ON-OFF plate | 1 | NKK Switches AT214 |
Chassis steel black | 1 | Hammond Mfg. 1441-16BK3 |
Chassis bottom cover | 1 | Hammond Mfg. 1431-16BK3 |
#6-32 Screw 6 pack | 1 | Hammond Mfg. 1421J6 |
Bumper / Feet | 4 | 3M SJ-5744 BLACK |
Machine Screw, M3, 10 mm, Steel, Bright Zinc, Flat / Countersunk Head Pozidriv | 2 | M3 10 KRSTMC Z100 |
Machine Screw, M3, 10 mm, Steel, Chemically Blackened, Pan Head Pozidriv | 14 | M3 10 PRSTMC B100 |
Washer, Shakeproof, 3.2 mm, 6 mm, Steel, Zinc | 16 | DM3 ITST Z100 |
Nut, Hex, M3, Steel, Bright Zinc Plated | 16 | M3 HFST Z100 |
Machine Screw, M4, 10 mm, Steel, Bright Zinc, Pan Head Pozidriv | 8 | M4 10 PRSTMC Z100 |
Spring Washer, Steel, 4.4 mm Internal, 7 mm External | 12 | DM4 DSSSTWA Z100 |
Nut, Hex, M4, Steel, Bright Zinc Plated | 8 | M4 HFST Z100 |
Insulated hook-up wire, solid, 1 mm² (17 AWG) black, 300 Vrms min. | ||
Insulated hook-up wire, solid, 0.5 mm2 (20 AWG) black, blue and red, 300 Vrms min. | ||
Audio signal wire 2 x 0,14 mm² single shielding, black | ||
Pointer knob | 1 | (see text) |
The original pointer knob still exists today (Bulgin, KX0370), but I have preferred to use another model, chosen among those appearing in the following picture.
I have tried them all to see the look of the prototype with the different knobs: