Return to Answer

So I'd probably add another \$5\:\text{V}\$ to reach the unloaded estimate for the transformer. Therefore, I think around \$15\:\text{V}+4.6\:\text{V}+5\:\text{V}=24.6\:\text{V}\$, unloaded, as a very rough guess, after the bridge has had its bite. Adding in the bridge, I'd go for \$26\:\text{V}\$. Since this is a bipolar supply, that doubles. So now we are at \$52\:\text{V}\$. Turning that into RMS, I get about \$\ge 37\:\text{V}_\text{RMS}\:\text{CT}\$. I would want windings capable of perhaps \$250\:\text{mA}_\text{RMS}\$, so a rating of about \$9-10\:\text{VA}\$.

So I'd probably add another \$5\:\text{V}\$ to reach the unloaded estimate for the transformer. Therefore, I think around \$15\:\text{V}+4.6\:\text{V}+5\:\text{V}=24.6\:\text{V}\$, unloaded, as a very rough guess, after the bridge has had its bite. Adding in the bridge, I'd go for \$26\:\text{V}\$. Since this is a bipolar supply, that doubles. So now we are at \$52\:\text{V}\$. Turning that into RMS, I get about \$36-37\:\text{V}_\text{RMS}\:\text{CT}\$. I would want windings capable of perhaps \$250\:\text{mA}_\text{RMS}\$, so a rating of about \$9-10\:\text{VA}\$.

^{simulate this circuit}

For the \$5\:\text{V}\$ supply, I get about a DC rating of \$2\:\text{A}\$. Looking at their output capacitor, I again get a voltage ripple of as much as \$5\:\text{V}\$. Plus perhaps another \$3\:\text{V}\$ of overhead for the simple circuit, rectifying diodes, and its current limit feature. Again, this has the half-winding (CT) voltage requiring a minimum of \$13\:\text{V}\$, which again is only half the winding. So I'd be looking for something around \$18\:\text{V}_\text{RMS}\$ and rated at about \$40\:\text{VA}\$.

^{simulate this circuit}

For the \$5\:\text{V}\$ supply, I get about a DC rating of \$2\:\text{A}\$. Looking at their output capacitor, I again get a voltage ripple of as much as \$5\:\text{V}\$. Plus perhaps another \$3\:\text{V}\$ of overhead for the simple circuit, rectifying diodes, and its current limit feature. Again, this has the half-winding (CT) voltage requiring a minimum of \$13\:\text{V}\$, which again is only half the winding. So I'd be looking for something around \$18\:\text{V}_\text{RMS}\:\text{CT}\$ and rated at about \$40\:\text{VA}\$.

I hate to suggest something specific, but if you are looking to get both in a single transformer, this might work: Bel Signal Transformer 36-2 at Mouser.com. See the datasheet at Bel Signal Transformer 36-2 Datasheet. If you went with two transformers, it would be cheaper to get. But at least this gives you an idea.