I think I misread what the document was I originally saw - when it said 12v out of a 7805 I took it as a step-up regulator as opposed to what it normally is, a step-down regulator. All this circuit is therefore, is a way to reduce the voltage to a circuit by a little not increase it, via a 7805.
I don't think you can use a 7805 as a Step-Up, I have no Idea why People are so obsessed with them, they are EXTREMELY inefficient, cut down battery life, Add more heat to the case, and therefore take up more room. you may be better off getting a TI card. Use one of these http://focus.ti.com/lit/ds/symlink/tps61085.pdf
Then a 12V regulator and you get 12V without the heat of a 7805
Yeah, you can't use a 7805 as a step-up, I got confused from an article I read that was poorly written. I don't think the idea of using a 78xx with resistors is a good idea when using batteries, as the voltage changes depending on what you rig up. A 7.4v Li-ion cell for example is about 8.25v on full charge and drops until about 6.5v or your system stops working and you recharge (eg under 7v on a PSone screen when the screen goes off); thus, with voltage dropping, it will also on the 78xx and resistor circuit too. It is therefore better just using 7805 for 5v, 7808 for 8v and 7812 for 12v; your voltage in (batteries) needs to be at least 1.5v over the output stated.
As DNT states, better to use a TI card for 5v instead of a 7805, although 7805's are dirt cheap whereas TI cards aren't.
I have found a couple of circuits for 12v output using LM chips, will get around to experimenting during the week, assuming I have the other components in stock.
Tomorrow, I intend to rig up the Dina to the voltages stated, using a pack of 8 AA cells (12v), a 7805 for 5v (at this stage anyway), and 7905 for -5v. I have already done the composite mod (hope it works ok) and a few more things to do, will upload a guide later, assuming all works ok. Then can also look at 12v step-up regulator options, including one or two options on ebay.
Hailrazer - indeed, that's the item, I did a search on ebay recently and saw that/similar one.
DNT - indeed, however TI don't seem to send samples to the UK - I tried it a year or two back, got "order" confirmation, shipping intention; then they sent an email to say they blocked the order and not sending item out, but I could buy, etc etc. I managed through a couple of contacts on the forums to aquire a few. I have about 8 at the moment, however will use them over time.
If someone got a few of these TI cards, I am sure they could sell them easily for £3 each profit (plus postage), make a little profit for themselves and help out other UK members looking to make an N64 portable, or similar...
