0355st parts

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:

  • Xicon – Carbon Film Fixed Resistors, CF-RC Series 294 or 293 – Datasheet

The wire wound resistors used are from the following manufacturers:

  • 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: