10-10-2016, 06:50 PM
(10-10-2016, 06:14 PM)ppppenguin Wrote: Oh well, I would have probably stuck in some old fashioned 2N918 from the spares box to see what happened. I'm sure they would work but the HF gain woul have been a bit low. With the feedback design there might have even been nyquist instability due to the lower fT.
At higher frequencies, depending on the value of the choke, it would work with a choke instead of a resistor.
Hi Jeffrey.
Yes a couple of 2N918's might have worked especially as I intend to use the pre amp from long wave up to 7mhz max! The choke was fitted when the pre-amp was on loan and TBH I doubt the best component down at long wave frequencies, it would upset the DC conditions too.
I've ordered the correct transistors and once fitted will get on with yet another project that has been on hold for a while
