Thought i would ask this here since it may be of interest to others.
I am wondering if this regulator’s output voltage can be raised?
It is lower, at 15 volts, than what is allowed by the battery supply and both are lower than the 18 volts that has been mentioned on the old lamented threads at the other forum as being better than 15 volts.
Wondering why 15 volts was chosen. Using just one rail for the clock.
Is there a way to raise it simply?
In addition, I would prefer to have transformer and rectifiers close together and neither close to the circuit. I presume it would be simple to bypass the rectifiers on the board and take the DC voltage direct to the capacitors – if nothing else wiring directly to the capacitors. In addition I have lots of suitable chokes around and would use one in the supply.
What voltage does the raw supply need to present the 15 volts version?
There is no phase noise difference when powering the DRIXO oscillator with 15 or 18V.
We have measured the phase noise with the TWRPS-UGL at 15V, with the TWRPS-pp at 15V and 18V, with the TWRPS-LBS-M battery at 16V5. Always the plots overlapped.
The TWRPS-UGL is designed to output 15V. In order to get 18V one or more zener diodes should be replaced. Not recommended.
15V was chosen because the phase noise of the DRIXO is exactly the same in respect to power it with 18V.
Bypassing the rectifiers is enough simple, then one can provide DC directly to the board.
The the raw supply has to be 18 to 20 VAC.
Suitable transformer is the Bel Signal DP-241-6-20 Mouser part