I have a question regarding an audio output transformer I want to incorporate into a tube amplifier I am building.
The output transformers are taken from an old Northcourt Stereo Ninety-Five amplifier someone once gave me (an obscure UK amp?). Please refer to the attached marked up schematic I found online of a tube amp output stage, which shows the exact same color code as the transformer I want to use.
The primary (HV) leads are pretty straightforward and I understand the color code and how to connect them (colors are identical to the one I have). However, there are 4 output (speaker) wires at the secondary output. Based on the explanation in the schematic, I understand that a 15 ohm output impedance is available between the green and black wires, and that a 3 ohm impedance is available between the brown and orange wires. The original amp also had outputs for either 3 or 15 ohms, which I consider to be somewhat oddball impedances.
My question is if I want to configure the output for 8 ohms (or close-by), can this be obtained between, say, the black and brown wires (see red mark-up in attachment) or other combination? Is anyone familiar with this transformer or has some idea whether it is more flexible than shown on the schematic.
Any info or advice anyone can kindly provide on this matter would be greatly appreciated.
The output transformers are taken from an old Northcourt Stereo Ninety-Five amplifier someone once gave me (an obscure UK amp?). Please refer to the attached marked up schematic I found online of a tube amp output stage, which shows the exact same color code as the transformer I want to use.
The primary (HV) leads are pretty straightforward and I understand the color code and how to connect them (colors are identical to the one I have). However, there are 4 output (speaker) wires at the secondary output. Based on the explanation in the schematic, I understand that a 15 ohm output impedance is available between the green and black wires, and that a 3 ohm impedance is available between the brown and orange wires. The original amp also had outputs for either 3 or 15 ohms, which I consider to be somewhat oddball impedances.
My question is if I want to configure the output for 8 ohms (or close-by), can this be obtained between, say, the black and brown wires (see red mark-up in attachment) or other combination? Is anyone familiar with this transformer or has some idea whether it is more flexible than shown on the schematic.
Any info or advice anyone can kindly provide on this matter would be greatly appreciated.