I have - based on very little electronics knowledge - built a preamp including an active filter. It contains a chinese-made pcm2311 volume control, that uses the one transformer, followed by a pair of CheffdeGars UGS's and the active filter, which share the other transformer.
The two transformers, their separate rectification and filtering are in a separate chassis. The chassis that contains the audio circuits also contain the regulation of both transformers. The thing actually works, but getting near my loudspeakers (within 30 cm.) I can hear a faint hum!
My first question now is:
Where should the grounds from the two transformers meet and which of the chassis should have the ground connection?
By the way, I'm from Denmark! We don't have safety ground in the outlets on the wall, so no use talking about that...
The two transformers, their separate rectification and filtering are in a separate chassis. The chassis that contains the audio circuits also contain the regulation of both transformers. The thing actually works, but getting near my loudspeakers (within 30 cm.) I can hear a faint hum!
My first question now is:
Where should the grounds from the two transformers meet and which of the chassis should have the ground connection?
By the way, I'm from Denmark! We don't have safety ground in the outlets on the wall, so no use talking about that...
Yes, there are a number of different connectors in Denmark including French and German. The system, as far as I can ascertain, is two phases of 115Volts with any grounding being the centre of the poles. I though the mains outlets had a ground lead and comply with SRAF 1962DB but if not I would expect all things should be doubly insulated.
generally ..... both cases need to be safety gnd-ed
regardless of lack of brain in Denmark (regarding sagety gnd) there is no need to make different arrangement than usual - chassis on safety gnd , audio gnd through NTC to safety gnd
two PSU grounds need to meet on most important audio gnd point ... which is UGS PSU
pictures will help
regardless of lack of brain in Denmark (regarding sagety gnd) there is no need to make different arrangement than usual - chassis on safety gnd , audio gnd through NTC to safety gnd
two PSU grounds need to meet on most important audio gnd point ... which is UGS PSU
pictures will help
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When you say "grounds from the two transformers" do you mean the transformer shield wire(assuming they are shielded) or the PSU grounds?
nash
The transformer does not have a ground.
The transformer secondary charges up the smoothing capacitor/s via the rectifier.
get that working first. Power that bit up via a Mains Bulb tester. Prove you have the wiring correct. The bulb should be off or glowling VERY dimmly.
There is no ground. Each smoothing capacitor will have a +ve terminal and a -ve terminal. Measure that voltage and prove you have this part wired up correctly and at your expected operating voltage.
The transformer secondary charges up the smoothing capacitor/s via the rectifier.
get that working first. Power that bit up via a Mains Bulb tester. Prove you have the wiring correct. The bulb should be off or glowling VERY dimmly.
There is no ground. Each smoothing capacitor will have a +ve terminal and a -ve terminal. Measure that voltage and prove you have this part wired up correctly and at your expected operating voltage.
TT is indeed what is required in any new installation in Denmark.
But even then the local earth wire is only installed to kitchens and wet rooms.
It only becomes really impossible when you live in a rented apartment that hasn't had its electrical installation renovated since the 1940'
Then you are stuck with no safety earth at all and no way to improve that situation.
If I read the Wiki correctly, it seems that RCD is compulsory.
That must be your first line of protection.
It seems you just have to be careful ensuring that all the LIVE side (L & N) should be well isolated/insulated, so that shorts to the secondary side can never occur.
That must be your first line of protection.
The Fuse, or MCB, stops the house burning down.
It seems you just have to be careful ensuring that all the LIVE side (L & N) should be well isolated/insulated, so that shorts to the secondary side can never occur.
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