wiring two transformers to two dual rectifer units

[larryg]

I'm using the 3886 from chipamps.com. I have two transformers
(dual primary-dual secondary-24v) I have two rectifer boards(each have two rectifers), and two amp boards. I'm not sure how to wire these. Better to ask for help. Can someone provide help?
Thanks, larryg

 

[Atilla]

Each transformer will power one rectifier board. Get one transformer's secondaries and wire one pair to the AC1 pads and the second pair to the AC2 pads on the power supply board. Those are the holes between the diodes.

The transformer should have markings for which the secondary wires are. For example, mine are marked Red+Green and Brown+Blue. So in my case - red and green go to the AC1 holes on the left side of the board and brown and blue go to the AC2 holes to the right side of the PSU board.

The primary windings are connected either in series or paralel depending on the mains voltage. What is yours - 115V or 230V ?

 

[snknby123]

what type and MD of transformers are you using?

 

[larryg]

mains ac transformer

Hi Atilla, the main Ac is 117 (U.S.)

Hi snknby123, my trans are toridal, made by Toroid. They are 100 VA.

Thanks for your help, larryg

 

[snknby123]

looking at their website now. What's the actual Model Number (MD) or just link the data sheet so we can see it.

 

[larryg]

model #

The model # is: 711.242.
Thanks, larryg

 

[wakibaki]

2 rectifier boards. Link?

w

 

[larryg]

rectifiers

Hi wakibaki, I have two rectifier boards. Each have two rectifiers.
I got these from chipamp.com--(BrianGT)
Thanks, larryg

 

[snknby123]

I thought the minimum was around 160VA? 100VA is pretty low isn't it? May strain the transformer...

Here is the link to the data sheet.
http://www.toroid.com/standard_transformers/rectifier_transformers/DataSheets/711.242_M4.pdf[/URL]

Someone with more experience correct me if I'm wrong but it looks like white/orange will go to AC Neutral and Black/Yellow will go to AC Hot.

As far as secondaries looks like brown/red for AC1 and orange/yellow for AC2.

Let someone else chime in to confirm b4 hooking it up.

-BB

 

[larryg]

volt amps

Hi snknby123, would two 100va equal one 200va?Each channel
its own transformer.
Thanks, larryg

 

[AndrewT]

would two 100va equal one 200va?

no,
the regulation of smaller transformers is generally worse than bigger transformers.

But 100VA will work.
Each transformer can power between 50W and 100W and perform reasonably well.
Your 28Vac transformer will allow about 60W into 8ohm speaker.

 

[larryg]

100va transfomer

Hi AndrewT. Thankyou for your help.
larryg

 

[wakibaki]

Looks like Atilla and snknby123 have the right of it, so you are going to build 2 independently-powered LM3886 channels with dual rails (positive and negative supplies).

Your mains voltage is 117v so your primaries will be connected in parallel; white paired with orange and yellow paired with black for both transformers.

Brown/red to AC1 and orange/yellow to AC2 in the case of both rectifier boards, build them both exactly the same.

Have you read up on fuses and safety grounding? 117v is not low enough to be treated casually.

Be careful with toroidal transformers not to inadvertently create a shorted link.

w

 

[larryg]

3886 dual mono

Hi wakibaki, yes to the dual mono. I've read up on grounding and wire pairing for 117. I'm still not sure about the 0volt wire.
Thanks,larryg