wiring up a transformer (brian gts kit)

fusion

Member
2005-09-15 7:37 pm
After soldering up the kit i bought from chipamp.com im pretty eager to test the power supply boards and see if I get the right output from em.

problem is i bought the dual mono kit and have two psu boards... and one transformer with 3 sets of 2 wires. blue and brown are input then i have the pairs of red and black then yellow and orange.

im not sure how to wire these to the ac1 ac2 inputs of BOTH boards. did i need two transformers or does the 3 sets of 2 wires mean i can use both boards with one transformer?

officially confused,
richard
 
Hi,
yes, wire up both PSU boards to BOTH sets of secondaries.
The power ground coming from each PSU board will be separate from each other.
I suggest you keep the dual mono set-up and retain the separate audio ground between the channels as well.

When you get around to making this dual mono set-up safe to use you will need to connect the two separate channel audio grounds to the Safety Earth.
I suggest you try using two independent disconnecting networks to make the safety connections. If this fails to give low noise, then direct connection between the audio grounds and Safety Earth may be better but this relies on very close/very short grounding connections between the channels and this can be difficult to achieve.

If all these options/solutions fail to meet your standards then twin transformers is your next route.
 
fusion said:
so negative and positive of one secondary go to one ac. (ac1) then the other to ac2...

erm ive got two psu boards which is where i get confused....

thanks again

In that case, its perfectly fine to use just one PSU board. Do, however, make the cables to amplifier 1 exactly the same length, and exactly the same length as to amplifier 2. ;)
It isn't necessary to braid, but do keep the hot lines within 1/4" or closer to the ground lines (close to each other).

I have absolutely no idea how to wire the common ground to the case if using a stereo pair and a torrid transformer. Can someone help out here?
 
fusion said:
so negative and positive of one secondary go to one ac. (ac1) then the other to ac2...

erm ive got two psu boards which is where i get confused....

thanks again


I have attached a picture which should give you a clue how it could look..
There should be a picture on the side of the transformer which you should use to check the colours are the same..
The metal case (if you use one) should connect direct to the mains earth. Both of the ChG's (channel Grounds), should also connect to earth . If it hums then check other threads for info.
Please follow info about safety posted by AndrewT..
 

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audio1st said:
If it hums then check other threads for info.

Nice chart!

Hey, there's less hum if you use same length leads for both power supplies. Also good is same length leads for both amplifiers.

Another fix for humming is to avoid metal to metal contact of potentiometer or signal terminals, with a case that is already grounded. This option that may stop a hum. I mean, use just one ground for the case--not several.

Oh, and do make the signal cables same lengths for both right and left amplifiers. That way you can plug in a common ground source like a computer, ipod, most CD players, etc. . .
 

fusion

Member
2005-09-15 7:37 pm
omg lmfaoooo i think i just fried my psu components. hooked up the transformer to onee of my psu boards (brians snubber) as shown attached...

the board started humming and the blue light came on then faded. now the capacitors are wayyy too hot to touch... i got another psu board but i dont wanna do this again... any advice?



[IMGDEAD]http://img112.imageshack.us/my.php?image=photo0046ju7.jpg[/IMGDEAD]

:bigeyes:

:dead:
 
If it was really hot then part or all of it was backwards. One or the other.

So now just check the caps and see if there's any deformities.
Check the diodes for conductivity (they're just like light bulbs inside).
And just replace any bits that got fried.
Its probably none, or maybe a diode expired.

Howabout putting a nice 100w light bulb in-series with the AC input (bulb in-series with mains power cord) before testing again?

It might help to view your torroid as two transformers. Each powers half of the power supply.

;) P.S. I knew that I would do that very same thing so that's why I use a CT, made the mod, plugged it in and never gave it a second thought.
That's because I took one look at a torroid, thought: "I'm going to pay extra to get really confused?" No way. I'm already confused enough. ;)
 

fusion

Member
2005-09-15 7:37 pm
i appreciate the help. caps were hot for ages but no deformities... multimeter thinks diodes are fine.... ok my electronics knowledge isnt non existent but i just ... tend to do silly things.

im in the process of building a bulb holder ... should be interesting.

ill post how i get on. thanks
 

MJL21193

Disabled Account
2007-03-10 1:20 am
fusion said:



one transformer with 3 sets of 2 wires. blue and brown are input then i have the pairs of red and black then yellow and orange.


My guess is red/black is one secondary and yellow/orange is the other.

Connect the transformer to the mains (through the light bulb limiter, don't ignore good advise) without connecting the PS board.
Use your meter to read the AC volts across the red/black pair. Assuming this is a dual secondary transformer, the same voltage should show at the yellow/orange leads.

EDIT: An illustration:
 

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