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In the Forum: Melquiades Amplifier
In the Thread: The one-stage Melquiades.
Post Subject: Single-stage 6E5P: more notes in dairy.Posted by Romy the Cat on: 4/27/2007
Dima and I spent today quite a time experimenting with different operation of the Single-stage Milq. We drove it from my Fluke 409D with resistor bias, loaded with 12.8:1 into 12R.
Playing with bias, voltage and current we tried to find an operation with reasonable power, to have identical current and voltage clipping and absolutely symmetrical (V vs. A) halves of the wave. In the end we concluded that with my 15-16Ohm the 170-200V and 30-40mA is near ultimate operation (for single stage). We were able to get whole 2Watts with very sympatric V vs. A clipping. Probably in my case I will stay with 1.6-1.7W..
I also, tried the Zero base operation as ML8 suggested. Sure, I lost a lot of power and the amp began to operate in very severs voltage deficiency. Here is 4V overload with 115V on plate:
Another interesting test: trying to bypass the resistor between plate and screen. I was not able to detect with my scope any oscillation but I have a slow scope – juts 100MHz. hat I detected that with moving my heads neat the tubes and stressing the tubes the plate current was fluctuating within 3-4mA. With 4R resistor between plate and screen the problem did not manifest itself and the tube had a complete immunity to it’s environment. Over the weekend I will be loading the thing to the real drivers, find the V vs. A against the real load and listen the Sound...Rerurn to Romy the Cat's Site