Center tap toroidal transformer

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fschris

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Joined 2011
#1
Where in the heck do I buy a toroidal transformer with a center tap... so it would have a ground .... I have look all over the internets...
i need something like a 45v-0-45 and and a secondary 15v-0-15v.. it is for that mono style amp plate i have been yapping about... i already have it (the amp plate) on ebay but i am still baffled i cant find one for it...
 
#3
fschris said:
Where in the heck do I buy a toroidal transformer with a center tap... so it would have a ground .... I have look all over the internets...
i need something like a 45v-0-45 and and a secondary 15v-0-15v.. it is for that mono style amp plate i have been yapping about... i already have it (the amp plate) on ebay but i am still baffled i cant find one for it...
Click to expand...

Couldn't you use one of these? Antek - AS-4445
and wire the two 45V secondaries into a 45-0-45 and the two 15V ones into 15-0-15?

I know, I didn't really answer your question, but maybe that's a workable workaround?
 
#8
fschris said:
I bought this... but at the the risk of killing my self or my amp I am not sure how to hook it up... Antek - AN-5445
Click to expand...

Hmmm, that doesn't really fit your requirements for the low voltage (15V), since one secondary is a little too low and the other one a little too high. Besides, it only has one 45V secondary.

Let's assume you get the one that has two 45V secondaries and two 15V secondaries. Now lets 'label' the wires H1/H2 for the first 45V secondary, H3/H4 for the second and L1/L2 and L3/L4 for the 15V secondaries.

You would connect L2 and L3 to form your center tap, now labeled L23. You'd have 15V between L1 and L23, and 15V between L4 and L23, no?

You would do the same with the two 45V secondaries, but it sounds like your board has hookups to connect those directly. Is there a picture of the board or a circuit diagram you could share?

It would also be useful to know what your current requirements are for the secondaries. The AS-4445 puts out 4.4A on 45V and 2A on the 15V secondaries.
 
#10
So from looking at the PCB traces in the pictures it seems that the 15V side would work as said before. L23 to the middle pin of the small connector and L1 and L4 to the other two. Judging by the size of that bridge rectifier (since the type is unreadable), my GUESS is that a 2A secondary is probably about right.

The 45V side is less clear, because
a) there seem to be two bridge rectifiers
b) they seem to be mounted on the aluminium panel for cooling
c) not all relevant traces to figure this out appear to be on the bottom side of the PCB

This makes any further thoughts nothing more than WILD GUESSes, so I am going to abstain, especially since that rail seems to me sized for at least 5A, given the wires used and the PCB traces being fattened with solder.

Unless you can find someone who has one of those subs and is willing to pop it open and take a look, you are probably not going to get satisfactory results by 'trying' things. Any searches for schematics for this panel also came up empty for me. How do you even know you need 15V and 45V...?
 
#12
the panel shows 120Vac & 6.3A fuse, along with 240Vac and 3.15A fuse with a change over switch.
It also shows 600W or is it 650W as the equipment rating.

These bits of information are compatible indicating probably around 500VA to 600VA transformer with twin primaries each rated for 110/120Vac operation.
The switch puts them in parallel for 110/120Vac or puts them in series for 220/240Vac operation.

If the 15+15Vac windings are ~2Aac then that is ~10% of your VA rating accounted for.
The other ~90% must be in the 45+45Vac windings. Assuming the lower 500VA rating then ~440VA are available from the 45Vac windings. This indicates that these HV windings are probably ~10Aac.

This is all based on the back panel and the 15&45Vac data. Very much guesswork, but it gives you a starting point.

BTW,
10Aac requires a secondary winding of ~3sqmm or about 2mm diameter. Can you check this?

45Vac windings will give ~65Vdc at the smoothing capacitors. Expect to see 75V or 80V capacitors here. Can you confirm this?
 
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