This are custom built precision high-power resistors,
that I use as a dummy load for output power measurements of audio amplifiers (high-power / PA).

Available in 16Ω or 1.6Ω
By using Ohms law and series- and/or parallel-connection of several resistors combined
you are able to create high power dummy load for audio amplifiers with 1Ω, 2Ω, 4Ω, 8Ω and so on ...
(see table at the bottom)

In any case you need a huge heatsink (active or passive cooled) that is able to dissipate the resulting power (=heat) to the ambient air ! (you have to use thermal compound paste !)

Welwyn ALN-50 (Series RCL-SX) No.9201AG / 9201AB

manufactured year 1991 in the USA
old but never used

Technical data:

• 50W power dissipation (on a suitable heatsink)
• 1% resistance tolerance
• 20ppm/°C TCR (-55° to 200°C)
• wire-wound construction (welded to the caps)
• non-inductive ("Ayrton Perry") winding style (for lowest reactive components)
• aluminium housing (for direct mounting on a heatsink)
• isolation voltage 2000V
• NOT RoHS compliant / NOT lead-free
• physical dimensions --> see picture below

all other technical data are almost equal to the today's modern "WH50"-type of TT Electronics plc (the successor of Welwyn):
--> http://www.ttelectronics.com/.../datasheets/resistors/WH.pdf

Physical dimensions:

• A=70mm
• B=21.4mm
• C=39.7mm
• E=2.8mm
• F=30mm
• G=15.7mm
• H=3.25mm
• L=50mm
• M=7.8mm
• N=2.2mm
• weight = ~30g

Possible combinations

explanation to the table entries (examples):

• "1,6Ω: 5S = 8Ω" ==> use 1.6Ω resistors: connect 5 in series => then you get 8Ω
• "16Ω: 8P = 2Ω" ==> use 16Ω resistors: connect 8 in parallel => then you get 2Ω
• "16Ω: 2S/8P = 4Ω" ==> use 16Ω resistors: make 8 lines of 2 in series / then connect these 8 lines in parallel => then you get 4Ω
• "1,6Ω: 10S/2P = 8Ω" ==> use 1.6Ω resistors: make 2 lines of 10 in series / then connect these 2 lines in parallel => then you get 8Ω