|  | 
			
				| 
			
				|   |   |   | 
					
						
							| HL4 | All purpose triode | 1935 | B5 |  
							| HL4+ | low microphony triode | 1936 | B5 |  
							| HL4G | low capacity triode | 1936 | B7 |  
							| HL4GS | as HL4G with P base | 1939 | P |  
							|  |  |  |  |  
						
							
								| 1 | 2 | 3 | 4 | 5 | base |  
								| f | g | f | a | k,s | B5 |  
					
						| 1 | 2 | 3 | 4 | 5 | 6 | 7 | tc | base |  
						| s | - | - | f | f | k | a | g | B7 |  
					
						| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | tc | base |  
						| s | f | f | k | - | - | - | a | g | P |  
					
						|  | Vf | Af | Va | Vg | mAa | Ra | gm |  
						| HL4 | 4 | 1 | 200 | -3 | 4 | 11,500 | 3.5 |  
						| HL4+,HL4G/GS | 4 | 0.65 | 250 | -4.5 | 5 | 11,000 | 3.5 |  |  |  |