CC2

The CC2 is a triode for low-frequency amplification and oscillation, indirectly heated at 13 V, 0.2 A. Philips permits AC or DC heater operation in series or parallel. Its 1935 description refers to AC2 construction, curves and connections, stating equality except for heater data; this does not allow replacing CC2’s 13 V with AC2 heating. The Tungsram booklet headed TCC2, indexed with CC2 in our sources, includes audio amplification after TCB2, oscillation with hexode TCH1 and combination with an RF pentode for frequency conversion.

Philips on 19 March 1940 gives plate 100 V, grid −2.5 V, current 2 mA, transconductance 1.8 mA/V and internal resistance 16 kΩ. At 200 V, −4 V: 6 mA, 2.5 mA/V, 12 kΩ; at 250 V, −5.5 V: again 6 mA, 2.5 mA/V, 12 kΩ. Amplification factor is 30; the 3.5 mA/V transconductance at zero grid must not be confused with biased operating points. Tungsram agrees at 200/250 V but gives normal transconductance 2.0 instead of 1.8 mA/V at 100 V; editions remain distinct. Curves show current versus bias at different plate voltages, without making the near-zero region a universal cutoff limit.

Audio use is documented by a complete resistance-coupled circuit. Philips 1940 at supply Vb 150 V, plate resistor 0.32 MΩ and cathode resistor 16 kΩ gives current 0.21 mA, output 14 V RMS, total distortion 2.4% and gain 16.3. At Vb 250 V with the same resistors: 0.35 mA, 14 V RMS, 1.8% and gain 13.2. Vb is circuit supply, not necessarily actual plate voltage after resistor drop. The circuit includes grid resistor 1.5 MΩ, following-stage load 0.7 MΩ, coupling capacitors 10,000 µµF = 10 nF and cathode bypass 25–50 µF. Tables also cover plate loads 0.2 and 0.1 MΩ: gain and distortion are circuit results, not constants of the triode alone.

Philips 1940 maxima are operating plate voltage 250 V, cold plate voltage 550 V, plate dissipation 2 W and cathode current 10 mA. Grid-cathode resistance reaches 1.5 MΩ; Philips 1935 specifies 1.5 MΩ with self-bias, 1 MΩ with fixed bias, also distinguished by Tungsram. Maximum heater-cathode resistance 20 kΩ and voltage 125 V. Philips 1935 and Tungsram require bypass capacitance at least 0.1 µF for cathode resistance below 1 kΩ, at least 1 µF above it; this note does not state the exact 1 kΩ case. Grid −1.3 V at positive current 0.3 µA is a test condition. Philips capacitances are plate-grid 1.7 pF, plate-cathode 4.5 pF, grid-cathode 4.9 pF; old µµF equals pF.

The base has eight side contacts, called 8B by Tungsram. Philips shows plate, cathode, two heater terminals and m, with grid on the top cap, without contact numbers. Philips 1940 specifies maximum diameter 37 mm, overall length 100 mm and base transverse dimension 30 mm in its maximum-dimension drawing. Tungsram gives overall length 100 mm, maximum bulb diameter 37 mm and dome diameter 24 mm; only bulb diameter is explicitly labelled maximum in that text. Mechanical observations retain the two sources separately.

Photographs show silver-coated Telefunken specimens with top caps, including a CC2-marked box. A retained test card specifies heater 13 V, plate 250 V and grid −6 V, with reading references 5 mA and 1.7 mA/V: these are card test conditions, distinct from nominal datasheet points, not a contradiction to remove by substituting values. Documentation: Philips CC2, page 60 of the 1935 description; Philips Miniwatt CC2, two pages dated 19 March 1940, 3321/1 and 3322/1; Tungsram Radio TCC2, pages 51–52; Telefunken application booklet, 1935/36 supplement referring CC2 to AC2; CC2 test card no. 153. The digital index added in 2000 is not an introduction date.