Below are some results from bench tests carried out on a few of the SJS Interstage Driver and Line Output Transformers. These tests have been graphed out to 1MHz, in comparison with the more normal 100KHz, so any comparisons with other products should be carefully made.
For each test the circuit shown below was utilised, and the valve type and conditions are listed for each. These results probably represent best case, as the tube is always well driven by the 600 ohm output of the signal generator, while the secondary load is high impedance and low capacitance. The circuit used is in keeping with those used by other companies however.
Please note that for the Interstage Drivers Vin at the grid is Out of Phase with Vout. For the Preamp Transformers Vin at the Grid is In Phase with Vout.
IT103 1:1 interstage driver - high current
IT101 interstage driver used backwords to give 1.5:1 stepdown
pa101 5:1 stepdown line output transformer
pa102 5:1 stepdown line output transformer - high current