Stancor 515:1 [4100 Ohms] Voice of Music 12521 Vintage Output Transformer OT Tested 130:1 515:1 Tube Amp Audio 1955-1958

One (1) fully 1.00 kHz AC tested and guaranteed vintage tube amp output transformer. AC testing using an oscilloscope allows us to find and reject transformers with noisy outputs, which a simple resistance or continuity test will not reveal. Made in USA in 1955-1958 by Stancor for Voice of Music. IEA date code may vary, since this is a bulk listing of the OEM specification. Please offer $2 extra if you'd like us to poke through inventory to select a certain manufacturer or year. Otherwise, we'll grab the first one on the shelf. A typical IEA code for this model is 138713. Weighs 1 lbs 5 oz. Center-to-center bolt spacings 79 mm, and height of casing is 58 mm. Quantity sometimes available - please enquire.
This transformer was orignally used to connect a 6V6 output tube to a speaker.

Please see the image of an original schematic using this model, for one possible application!

Using a 10V_pp, 1.00 kHz input to the primary coil, we have verified these connections for this vintage transformer:

The turns ratio (pri:sec) is 23:1, leading to an impedance ratio for the main secondary coil of 515:1. This winding of the transformer would provide a 4100 ohm load resistance to the tube plate if you hook it to an 8 ohm speaker. This model has multiple secondary taps. Additional impedance ratios of 130:1 (via the black-green connections), and 515:1 (via the black-yellow connections), and are available as options.

SKU O-V521.