voltage on the 1st cap of the aleph-p 1.7 power supply

[jarthel]

Before I begin, let me first say that I have searched the forums, passdiy and the net in general and nothing came up.

But my search criteria may have missed it, so I apologise in advance. I would appreciate it if you could tell me the correct search criteria.
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If you are using the power supply as designed by Mr . Pass, can please measure the voltage across the 1st cap on the power supply and let me know?

I am building the preamp using the same/similar board sold in the group buy. BUT I'll be using choke input instead of cap input (which is the default on the power supply) and choke input requires larger secondary.

Thank you for help

[jarthel]

Can you also include the resistance on the secondary windings?

Thank you very much

[GRollins]

The voltage on C28 and C30 will be a little over 80V. I could point out that it's noted on the power supply schematic, but that would silly of me (please do your homework...please?) so let's do it the hard way.
It works like this:
The transformer is an Avel Lindberg D4007 (on the schematic as AL D4007)
A quick trip to the Avel Lindberg website shows that the secondary is 30-0-30V
Note that the two secondaries are in series, so that's 60Vac
A quick tickle of my calculator's tummy then tells me that 60V * 1.4 = 84Vdc
After subtracting diode losses and allowing for the fact that the transformer probably isn't going to deliver exactly 60Vac (due to variations in the line voltage and the manufacture of the transformer itself), it's just easier to say 'a little over 80V.'
The characteristics of the D4007's secondary are useless to you because you're going to have to use a different transformer--one with a higher secondary voltage--if you intend to use an LC filter.
It's not worth getting too worried about anyway. All you need to do is to make sure that you have sufficient voltage for the regulator to run efficiently (about 65Vdc minimum, but 70V would be better) and you'll do just fine.

Grey

[GRollins]

Come to think of it, depending on the inductor, you might still be able to use the D4007.

Grey

[analog_sa]

Jarthel

I couldn't help but notice you have started a myriad threads with different questions about the 1.7. That most of your questions can be answered by either searching, looking at the schematics or with a basic electronics text is besides the point. What i really don't understand is why do you need a new thread for each tiny query that comes to your mind?

As these threads are not likely to benefit anyone else and only reduce the S/N ratio of the forum i can only hope a moderator will combine them into a single thread: "Jarthel fighting the Aleph"

[GRollins]

Originally posted by analog_sa


"Jarthel fighting the Aleph"

Bookies stand ready to take your bets as to the winner.
I second the motion to combine the questions. Tidy this stuff up a bit. Granted it'll take time to track down all the threads, but it would cut through the clutter. Sadly, the problem is ongoing.
Gawd, I'm glad I'm not moderator anymore. Thankless task.

Grey

P.S.: Jeez, saw recently where almost 10% of people in some locale (don't remember where...England, maybe?) were willing to bet that the world would end by 2010 or so.
And you guys think I'm pessimistic?
I think the planet will make it. I'm not so sanguine about humanity's chances, though.

[analog_sa]

Originally posted by GRollins



willing to bet that the world would end by 2010 or so.

Definitely no bets placed in South Africa. Everyone here is expecting to cash in big time on the soccer world cup in 2010. I need a place to hide.

[jarthel]

I know the math but obviously with only 2000uF as cap input, you won't get the full 1.414 factor. Hence the reason for this thread

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if you can't read, I will repeat it again. I have searched the forums, passdiy and the net and nothing came up.

[jarthel]

Thanks GRollins. I apologise that some of my threads were created hastenly without any effort.

But I believe this time I put in effort (searching first and simulating in PSuD2) before I created this thread.

[Magura]

Originally posted by analog_sa



Definitely no bets placed in South Africa. Everyone here is expecting to cash in big time on the soccer world cup in 2010. I need a place to hide.

Feel free to drop by for those couple of weeks......I promise, no football what so ever around me or my place

Magura