Aleph 30 PS Help

[AndreaFx]

Hi, this is my firt post in this forum........sorry for my bad english

I've assembly the chipamp psu for Aleph30. I follow the istruction on the Brian's site but the voltage out is to high then i've expected.

I attach an immage of my work.

The trasformer have two secondary 20-0-20

It's ok or i wrong something?

Thanks for the answers
Andrea

[HIPCHECK]

just going to ask some questions to maybe help you. Is the transformer dual primary. Is it possible you have it wired for 115v and it is getting 230v if so that would maybe explain your output voltage.

20-0-20v after recitication should be 28v or so from 115vac
if wired for 115vac and its getting 230vac you would have 40-0 -40v after rectification 56v. this seems to be the easy answer for your problem.

I am no expert just looking at the numbers.

post better pic of the transformer and maybe someone else can confirm this

[AndreaFx]

The trafo is made from my specific request.
This is the specs:
Only one primary is 230vac
Two secondary are 20vac-0-20vac

This is the PS scheme:
http://www.diyamps.com/aleph/ps.shtml

And the component
http://www.diyamps.com/aleph/docs/ps-parts-list.xls

I've measure the output voltage from V+ and GND, but if you see the scheme AC0 (with bar) and AC1 go out to the GND........why? I will attach the GND to the GND trafo??

Sorry for my simple question but.........i'm not an electronic

[GRollins]

Not being familiar with the layout of the board, it's hard for me to tell what you're measuring. However, if you're measuring between the positive rail and the negative rail, then you're seeing exactly what you should see: 2 x 28V = 56V
If you measure between one rail and ground, you should get 28V, plus or minus a volt or two. If you measure both rails at the same time, then you'll see pretty much what you're getting.

Grey

[MEGA-amp]

By the picture it looks like he's got the black test probe on the ground terminal, if thats the case, something isn't right. The trafo looks like it has two primaries, and two secondaries, I could be wrong about the primary side. Take a closer pic of connections. You may have your secondaries connected wrong on the board.

You may want to try and connect it this way:

[AndreaFx]

Originally posted by MEGA-amp
By the picture it looks like he's got the black test probe on the ground terminal, if thats the case, something isn't right. The trafo looks like it has two primaries, and two secondaries, I could be wrong about the primary side. Take a closer pic of connections. You may have your secondaries connected wrong on the board.

You may want to try and connect it this way:

Ohhhh yessss, It's possible that i'd wrong the connect of the two secondary. This evening i try to connect while you suggest and retry to measure voltage output

Thanks MEGA-amp

[AndreaFx]

This morning i do these tests

First
AC0 20vac green
AC0(with bar) 20vac green
AC1 20vac red
AC1(with bar) 20vac red
Output 56V

Second (As MEGA-amp's suggest)
AC0 20vac green
AC0(with bar) 20vac red
AC1 20vac green
AC1(with bar) 20vac red
Output 56V

Third
AC0 20vac green
AC0(with bar) Ground
AC1 Ground
AC1(with bar) 20vac red
Output 28V

I suppose that the thind test is only correct, right?

[MEGA-amp]

If you get 28 volts from either rail to ground, then you got it. Go with #3. If possible, could you take another picture of the connections that worked, i'm just curious.

[Betterheart]

Hi

I plan to build the same board, but link to Aleph page on chipamp.com is disappear. I contact web site many time but no answer yet. If you still have PS and Amp schematic and part list it will be great if you can forward of leave link like zip file on this page.

Thank from Thailand

[AndreaFx]

The part list is here

http://www.chipamp.com/diyaudio