02-06-2015, 07:39 PM
I've had this for about a year but never used it in anger, simply checked that it did give a reasonable Output and that the insides looked clean and undamaged.
It's just as well I didn't really need it beacause a quick test with my new Load showed that it was way short of the supposed Output.
This is the Little Brother of the SR151. It's not regulated and has quite a simple Circuit.
As far as I can tell from several possibly unreliable Sources it should be good for 350 Volts at 100mA, 400 Volts at 50mA and nothing at 450 Volts - in my day that was called 'Derating'.
I hooked it up to my new Load with the following Results:-
O/C 400v
60k 340v
40k 320v
20k 280v
10k 220v
5k 160v
Clearly not good. However, it came with some Spare Valves so the obvious candidates for substitution were the Series Pass Valves - CV428.
In a nutshell they made not one iota of difference.
So, what about the Rectifiers? Put simply V1 was very Dead, so it was only Half Wave rectifying.
With the two spare Rectifiers installed the Output was much more impressive.
O/C > 450v
3k5 at 350 Volts (100mA) no problem.
8k at 400 Volts (50mA) no problem
In fact the Results were much the same with the old CV428s installed, perhaps needing the O/P Voltage to be turned up a bit more, but generally fine, so I've left them in.
I'll get a couple of new Rectifiers to be on the safe side but I suspect the current ones will see me out.
By the way, the Load was fine.
Alan
It's just as well I didn't really need it beacause a quick test with my new Load showed that it was way short of the supposed Output.
This is the Little Brother of the SR151. It's not regulated and has quite a simple Circuit.
As far as I can tell from several possibly unreliable Sources it should be good for 350 Volts at 100mA, 400 Volts at 50mA and nothing at 450 Volts - in my day that was called 'Derating'.
I hooked it up to my new Load with the following Results:-
O/C 400v
60k 340v
40k 320v
20k 280v
10k 220v
5k 160v
Clearly not good. However, it came with some Spare Valves so the obvious candidates for substitution were the Series Pass Valves - CV428.
In a nutshell they made not one iota of difference.
So, what about the Rectifiers? Put simply V1 was very Dead, so it was only Half Wave rectifying.
With the two spare Rectifiers installed the Output was much more impressive.
O/C > 450v
3k5 at 350 Volts (100mA) no problem.
8k at 400 Volts (50mA) no problem
In fact the Results were much the same with the old CV428s installed, perhaps needing the O/P Voltage to be turned up a bit more, but generally fine, so I've left them in.
I'll get a couple of new Rectifiers to be on the safe side but I suspect the current ones will see me out.
By the way, the Load was fine.
Alan