Problem with original Aleph P

Hello,

I own a original Pass Aleph P and I am having some problems with it. I brought it down to a drop of power from my wall sockets from the normal 220V to about 204V.

In the Aleph P is a 240V 30-0-30 transformer. However normal during the day (at at 03:00) I have about 223V on the wall socket. At evenings it drops to 204V-208V and when I am using the oven and the Aleph 2 it sometimes drops below 200V !!!

Now this is can be a problem of my power company; but the Aleph P starts to buzz the input/output relais when it drops... brrr...

at 204V I have about 54.4V AC (instead of 60V) and about 66V DC unregulated (instead of 80V).

66V-60V = 6V not enough for the muting circuit which is on a threshold when the AC rises a bit and the mute relais start to buzz (on/off/on/off etc.) ..

at 214V I have about 57.3 AC gives 71V DC unregulated??

What can I do?

1. Call the power company (lost case???)
2. Change transformer
3.??????

Nelson can you tell me why you used a 240V transformer??? Here in the Netherlands most house holds only get 220V !!!

Help,

Edwin
 
This is actaully a common problem in areas with poor power distribution. This is ultimately beyond your control, even that of the local power company for that matter.

What you can do is replace the toroidal with a 220V 2x35VAC secondary. This will deliver 60VAC or more when the input drops down to 208. Your output voltage will climb to 70 VAC at normal line voltage, this should not be a major problem as the FETS should handle the extra DC in the unreg circuit. You will need to check what happens in the regulated circuit, I am not sure what the higher DC voltage will do to it. The Preamp will run a little warmer.

Perhaps someone familiar with th cirvuit could answer to the effects of a higher DC rail voltage.

Anthony
 
You could build yourself an AC voltage stabilizer.
A friend of mine had some kind of a problem like yours with an ARSP10MK2 preamp (the preamp used to auto-mute and go to stand by mode each time the voltage dropped below 210 VAC).
He bought an APC 1.2 kVA stabilizer and solved the problem.
Nick
 
Edwin,

I think you should call the power company. It is their responsability to deliver good power. That is what you are paying for, right? :)... The fact that your power drops at evenings (when everybody turns on their lights) is probably due to a weak distribution net. Perhaps you should ask your neighbours if they have problems too. (they probably will, or they haven't noticed it was due to a weak net)

There was a time my neihbourhood was connected to a weak net. During a soccer match the voltage dropped below 180VAC!! Turning on my coffee machine (1000W) created another drop of 6V !!:bigeyes: Fortunately my equipment held, but that really was the limit. After extensive calling the power company (Essent) adjusted a few power lines and now all works fine :)