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QRO Conversion for HF 2500DX for 10/11 Meter Operation????
The neat O thing about the DX2500 is that it uses the Soviet 4CX800 Tetrodes, in a grid driven circuit.
With a slight modification to the Control Grid Circuit a step up toroid transformer like the one in Pride DX300 can be used to allow a stock low power radio to drive the amp to its full output power.
The neat thing about Tetrodes in a grid driven circuit, it wont take any power to drive it. The power is applied to a 50 ohm resistor across the grid to allow the radio to see a perfect 50 ohm load.
This tetrode grid drived design allows a step up transformer and higher value load resistor to be used, just like in the Pride DX300 Amps.
I've been looking at the schematics for this amp; what happens when you switch it to the 10/11 meter position? Is the amp bypassed or does it switch into transmit but has no output?
Please advise me to what is a good replacement mic for my SR-497HPC... Answer: 497 is "wired like Cobra", so many choices available. That radio does not need a power mic, so purchase a stock "coffin style" mic with a decent cord, like the ones that Astatic uses. The Superstar DM-507 is my go-to. https://www.ebay.com/itm/3050474478...adANq91JSiEEnz8EGqPJRBloTgEyaVsBoCtoMQAvD_BwE $12.99 + .99 cent shipping.
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