Aside from switching phase inverter type, does it count as a 5E9A if you don't inject the trem into the cathode of the paraphase? I don't see how the oscillator signal is connected to anything once you're out of fixed-bias mode.
Also not clear on the purpose of the 50k resistor connected to the 220kΩ plate loads for the 5E9A paraphase.
I'm curious to find out how different you find the results to be in each mode. I once had a '55 5E9 Tremolux, and it had quite nice, swampy trem. It also broke up at a nice low recording volume.
Nope, once you switch the PI to a 5E9a you do not get any trem as you figured out. I thought of how to get it in the cathode but then I would have to compromise on the 5G9 oscillator, running out of switch contacts. Figured I wanted a paraphase amp with a LTP to give a wider difference in the tone of the amp. I could have done it with the trem on the 5E9a position but most people like the output tube biased version. Haven't been able to hear any good recordings of the 5E9a trem, might have to try both now to hear the difference.
50k resistor is just a bit of a load on the power supply filter, the 5E9a runs at a lower voltage and I thought since I had the contact there I might as well drop some more current through the 10k resistor. I would have liked to drop more voltage at the screens on down but again, lack of available switches did me in. I was going to put a choke and then a resistor in series with it and short the resistor when going in LTP giving more headroom. I do have some nice old Russian rotary switches with enough contacts but I wanted to make something that anyone else can do picking up common parts.
I did do a small Princeton type amp with a switch to go between different PI types, I really liked how the paraphase sounded with some imbalance when driven clean and slightly dirty. It did not fair too well when you hit it real hard, thought the LTP would be more suited for that. I already have a design using a cathodyne and a LTP in the works, thought this might be a fun amp to try.
Topic: Shaking up some Tweed tremolo circuits (Read 2611 times)