Godders

Green pre questions- PSU transformer hook up (230v)
« on: February 28, 2006, 05:24:47 AM »
I?m building a 2 channel green pre as my first project and I have the boards stuffed. Thanks to all the question askers and answerers who's previous posts have meant I haven't had to ask any questions of my own up to this point. :thumb:

I think I have everything else I need to wire it up and I have a few questions with this bit.

First- wiring the power transformer. I have an idea what I?m doing with this having read previous threads but most of the stuff I?ve read has been for US mains voltage (primaries in parallell) and I?m in the UK. Here?s the wiring diagram for the toroidal transformer I have:



Having looked at the diagram here:

http://www.diyfactory.com/data/transformer_connections.gif

I think I need to hook it up as follows:

Primaries

Grey- Live
Violet- neutral
Blue and brown- do these get connected together and then not connect to anything else?

Secondaries

Red- 15v on the psu pcb
Orange- other 15v on psu pcb
Black and yellow- 0v on psu pcb

So how right/wrong have I got this?  :green:

A few other hopefully straightforward questions- what amp rating should the fuse be?

For the on/off switch I have what I believe to be a DPST switch with four poles on the back. How do I hook this up?

Thanks for any help you can offer folks

Cheers

Nick


Green pre questions- PSU transformer hook up (230v)
« Reply #1 on: February 28, 2006, 06:02:35 AM »
The way I do it with blue and brown is to twist both into a crimp terminal
Crimp it - then cover it heatshrink
Otherways to do it - could be to use  a block terminal strip cut one  - bolt that to the bottom of the chassis - then feed each one into each side (like joining speaker wire)
Check here for suggested wiring
http://sound.westhost.com/psu-wiring.htm

Godders

Green pre questions- PSU transformer hook up (230v)
« Reply #2 on: February 28, 2006, 07:40:22 AM »
Quote from: "uk03878"
The way I do it with blue and brown is to twist both into a crimp terminal
Crimp it - then cover it heatshrink
Cheers, that sounds straight forward, thanks for the link as well that looks very useful.

Cheers

Nick

Godders

Green pre questions- PSU transformer hook up (230v)
« Reply #3 on: March 03, 2006, 05:48:06 AM »
Sorry for the shameless bump.  :oops: I think I have the wiring sussed and I intend to use a 10A fuse but I could still do with some help wiring the mains switch? Like I said it's an illuminated DPST switch with four poles.

Cheers

Nick

Green pre questions- PSU transformer hook up (230v)
« Reply #4 on: March 03, 2006, 07:02:29 AM »
Quote from: "Godders"
Sorry for the shameless bump.  :oops: I think I have the wiring sussed and I intend to use a 10A fuse but I could still do with some help wiring the mains switch? Like I said it's an illuminated DPST switch with four poles.

Cheers

Nick

10Amps - whooah!
I think Kev tested the current draw at idle and it was
18.4mA on positive rail and 18.1mA on negative rail.

I am not a expert - but the only thing consuming current I believe are those ICs and if you have the LEDs for the mter (ie not a lot!)

BTW Kevs pages on Peters project are now at
http://www.diyfactory.com/projects/green/green.htm

radiance

Green pre questions- PSU transformer hook up (230v)
« Reply #5 on: March 03, 2006, 08:04:26 AM »
Quote from: "uk03878"
Quote from: "Godders"
Sorry for the shameless bump.  :oops: I think I have the wiring sussed and I intend to use a 10A fuse but I could still do with some help wiring the mains switch? Like I said it's an illuminated DPST switch with four poles.

Cheers

Nick

10Amps - whooah!
I think Kev tested the current draw at idle and it was
18.4mA on positive rail and 18.1mA on negative rail.

I am not a expert - but the only thing consuming current I believe are those ICs and if you have the LEDs for the mter (ie not a lot!)

BTW Kevs pages on Peters project are now at
http://www.diyfactory.com/projects/green/green.htm


I'm no expert either, far from it actually. When I powered up my green power supply (nothing connected) for the first time I used a 125mA fuse. That one blowed so I tried 250mA, that one also blowed. 500mA did not blow and everything behaves normally. I guess that at power up the capacitors draw some currend or so.....
But 10A is way to high....
"Knowing that you are dreaming, however, does not automatically guarantee full rationality.
Then again, being awake doesn't ensure good thinking, either." -  Lynne Levitan

Godders

Green pre questions- PSU transformer hook up (230v)
« Reply #6 on: March 03, 2006, 08:10:03 AM »
Thanks guys, OK I'll go with 500mA.

Cheers

Nick

Green pre questions- PSU transformer hook up (230v)
« Reply #7 on: March 03, 2006, 08:25:30 AM »
Nick - try and make that an anti-surge/slow blow fuse as well

Godders

Green pre questions- PSU transformer hook up (230v)
« Reply #8 on: March 03, 2006, 08:27:30 AM »
Quote from: "uk03878"
Nick - try and make that an anti-surge/slow blow fuse as well
will do,  :thumb: cheers.

Nick

Green pre questions- PSU transformer hook up (230v)
« Reply #9 on: March 03, 2006, 08:28:52 AM »
And also read Mark Burnleys bit on keeping yourself alive
http://www.groupdiy.com/index.php?topic=44699&highlight=electrical+safety+concerned#44699

(I am still trying to get you a decent picture of the DPST wiring - I don't want to describe it in case you read it wrong - so I am trying to find an onlline piccie)


radiance

Green pre questions- PSU transformer hook up (230v)
« Reply #10 on: March 03, 2006, 09:22:26 AM »
Quote from: "uk03878"
.....(I am still trying to get you a decent picture of the DPST wiring - I don't want to describe it in case you read it wrong - so I am trying to find an onlline piccie)


I had exactly the same thought when deciding what to write as reply....
"Knowing that you are dreaming, however, does not automatically guarantee full rationality.
Then again, being awake doesn't ensure good thinking, either." -  Lynne Levitan

Godders

Green pre questions- PSU transformer hook up (230v)
« Reply #11 on: March 03, 2006, 12:56:05 PM »
Quote from: "uk03878"
And also read Mark Burnleys bit on keeping yourself alive
http://www.groupdiy.com/index.php?topic=44699&highlight=electrical+safety+concerned#44699

(I am still trying to get you a decent picture of the DPST wiring - I don't want to describe it in case you read it wrong - so I am trying to find an onlline piccie)
That'd be very much appreciated. I'm very grateful for all your help.

Kev

Green pre questions- PSU transformer hook up (230v)
« Reply #12 on: March 03, 2006, 06:07:12 PM »
Quote from: "uk03878"
The way I do it with blue and brown is to twist both into a crimp terminal ...

NO
brown and blue are the main input
It   WILL   still work OK
BUT
it is the brown (active) and blue (neutral) that is the usual mains coding
join the Violet and Grey


Quote from: "radiance"
... first time I used a 125mA fuse. That one blowed so I tried 250mA, that one also blowed. 500mA did not blow and everything behaves normally. I guess that at power up the capacitors draw some currend or so.....
But 10A is way to high....

yes 10 A is WAY too high

the reason the lower value fuses blew is the in-rush (start-up) current for the Torroid
USA a SLOW BLOW fuse and you will be fine with 250mA and perhaps even 125mA for a Dual Green Mic-pre
Kev
DIY Factory

radiance

Green pre questions- PSU transformer hook up (230v)
« Reply #13 on: March 03, 2006, 07:02:52 PM »
Quote from: "Kev"
.....the reason the lower value fuses blew is the in-rush (start-up) current for the Torroid
USA a SLOW BLOW fuse and you will be fine with 250mA and perhaps even 125mA for a Dual Green Mic-pre


Ahh, so it's the torroid who's drawing current during power up... I always thought it where the capacitors....and yes, I probabely use "fast blow" (what are they called anyway) fuses instead of slow blow ones....

Thanks for clearing that up  :thumb:
"Knowing that you are dreaming, however, does not automatically guarantee full rationality.
Then again, being awake doesn't ensure good thinking, either." -  Lynne Levitan

Godders

Green pre questions- PSU transformer hook up (230v)
« Reply #14 on: March 04, 2006, 04:58:54 PM »
Quote from: "Kev"
Quote from: "uk03878"
The way I do it with blue and brown is to twist both into a crimp terminal ...

NO
brown and blue are the main input
It   WILL   still work OK
BUT
it is the brown (active) and blue (neutral) that is the usual mains coding
join the Violet and Grey


Quote from: "radiance"
... first time I used a 125mA fuse. That one blowed so I tried 250mA, that one also blowed. 500mA did not blow and everything behaves normally. I guess that at power up the capacitors draw some currend or so.....
But 10A is way to high....

yes 10 A is WAY too high

the reason the lower value fuses blew is the in-rush (start-up) current for the Torroid
USA a SLOW BLOW fuse and you will be fine with 250mA and perhaps even 125mA for a Dual Green Mic-pre


Cheers Kev. :thumb:

Nick

Green pre questions- PSU transformer hook up (230v)
« Reply #15 on: March 06, 2006, 04:55:59 AM »
Ah - yes - sorry for me getting it wrong - I saw the two coils and without thinking mentioned to join the two middle ones together without checking to see the numbers next to them

Godders

Green pre questions- PSU transformer hook up (230v)
« Reply #16 on: March 07, 2006, 05:05:59 AM »
Quote from: "uk03878"
Ah - yes - sorry for me getting it wrong - I saw the two coils and without thinking mentioned to join the two middle ones together without checking to see the numbers next to them
No worries, you've been very helpful. :thumb:

Wiring the switch is the last piece in the jigsaw, I spent much of yesterday googling for DPST wiring but with little joy, of course I've searched this site as well.

If someone could try and describe it to me it would be much appreciated. The top 2 poles are marked 1 and 2 and the lower 2 poles are marked 1a and 2a.

Cheers

Nick

Green pre questions- PSU transformer hook up (230v)
« Reply #17 on: March 07, 2006, 06:24:07 AM »
I am still hesitant to say anything...
But I would have a go at
Live in    1
Live out  1a
Neutral in  2
Neutral out  2a
But I would have a go at pushing DC via a  battery lead and a bulb to on/off to check first - through each side

Godders

Green pre questions- PSU transformer hook up (230v)
« Reply #18 on: March 08, 2006, 04:38:37 AM »
Ok thanks, I'll give that a try.

Cheers

Nick

peterc

Green pre questions- PSU transformer hook up (230v)
« Reply #19 on: March 08, 2006, 08:42:32 AM »
Before connecting the switch to mains, check with a multimeter which is the on/off pair of poles. Use that pair to switch the Live feed from the mains.

I've never used a 4 pole illuminated switch, the ones I use have 3 connections on the back.

Make? Model no? Pic from RS or Farnell catalogue?

Regards
Peter
If opportunity doesn't knock, build a door.


 

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