Power - too much?

[kt66se]

Hi,
I have been looking around at different SE designs, having a listen to a few amp in P/P & SE and have decided to go the SE path. I found a design based around PSE using either KT66 or equivalents and also a power supply.

I've decided to build the power supply, using 5u4 valves on a separate chassis and started last night. The design I am using runs off a HT rail of 450v, I got 495v with no load. I also noticed something else, I put my meter on AC and it indicated 1000v ac. Then onto DC and it read 495. I am using two 5u4 in parallel to provide enough current to drive to mono blocks. I also have used in order.

(365 - 0 - 365) 2x5u4 > 47uf cap > 2.5h choke > 47uf cap > 2.5h choke > 120uf cap

I may have this all wrong but went off the duncan power supply program and to be honest, I struggled with it a bit, but also got advise from Sowter transformers and came to the 365-0-365

So my question is, will the 495v level off to around 450v under load and is the ac meter reading of 1000v normal. (digital meter) Transformer HT rated at 0.3amps, SE amp draws 0.1 amps per channel.

Many thanks

Adam

[Deco-Doctor]

Originally Posted by kt66se

Hi,
I got 495v with no load.

So my question is, will the 495v level off to around 450v under load and is the ac meter reading of 1000v normal.
Adam

Adam

495V with no load sounds about right, don't forget what you have is essentailly an unregulated power supply so the output voltage will change with load.

I have been using the Duncan Amps PSU designer program for a few years and It has always given me very accurate results, especially if I make good measurements of the mains transformer characteristics (primary DCR, secondary DCR, off load AC volts and mains voltage).

Martin