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Makes sense. Now I just have to find out if there is a way to get rid of the need for batteries. Would I be able to use a 18V center-tap transformer and just create two voltage regulators?
I don't have the book. I borrowed it from a friend of mine and just copied the pages relevant to my project. He is now in Kentucky though and I am in Ohio. Would it still work efficiently with the AC adaptor? I feel like since there is a time lag between the positive and negative half cycles it wouldn't be as effective? Could be wrong, just curious.
Single transformer Bipolar linear supplies are usually made with a center tapped transformer on the secondary side and a bridge rectifier.
Capacitors smooth out the AC. If there were no load on the supply, the DC voltage would be very close to the peak AC voltage. There are losses at no load and are likely at least 1.2 V per each one of the individual supplies that make up the bipolar supply because of the diode drops in the recifier.
When you draw current , the capacitor gets to supply some of it and the waveform looks something like a sawtooth at 2x the line frequency.
This seems promising. It'll be sorta cumbersome because I'll have this in a project enclosure attached to my pedal but not as cumbersome as having to unscrew 4 screws to replace batteries every time. Thanks! I'll let you know how it turns out once it is finished. I really appreciate the help!
You could build it in a box with feet, use a standard power inlet connector and power cord and switch. Use a DIN connector or CPC connector for power. Add some feet.
The kit has terminals, yes. Look at this P25A13D-R1B: MEAN WELL: Power Supplies & Wall Adapters It's a multi-output PS, but not one that will work for you. But this is the kind of style I'm suggesting that you make. At your device you would have a socket. DIN sockets will work and they are used on these kind of adapters.
The other connectors (Circular Polarized Connectors) also work, but are large. They connect and disconnect easily though. There is a smaller connecter that I have used which is easy to disconnect/reconnect.
When you think in terms of building an adapter, you have to consider other things.
1. How can I adjust the adapter. Do I need to purchase a voltmeter? Harbor Freight <$4.00 for cheap.
2.Case: plastic or metal - how do I drill/cut it?
3. Feet. Screw or rubber. You don't want to scratch the floor)
4. Ventilaton?
5. Grommets/strain reliefs to protect exiting wire or should I use connectors?
6. SHould I use a detachable line cord. I say yes. Should I solder or use fast on terminals?
7. Line fuse. Internal or External? Do I own a "D" punch? Do I need one?
8. Grounded or ungrounded case/line cord. Probably ungrounded. Grounded requires fastening the ground to the case if metal
9. Standoffs. The PS must be mounted off the case?
10. Do I use the feet to allow me to not countersink the screws for the standoffs. Will the thicknessof the case support the use of countersunk screws?
11. Internal size of the case required to support power switch,indicator and fuse?
12. Power on indicator? Low or line voltage? Built into switch?
OK, so I crunched the numbers and the power supply project would total around 50 bucks. If a pack of two nine volts costs 5 bucks, that means I would have saved my money by the time I changed the batteries 10 times. Its a steep price but I'm thinking its worth it in the long run.
Good. I'm sure that building it will be rewarding experience, but you'll probably forget something if you havn't done it before. You could post a list of parts, and or links and I'll look it over.
I think this is what I'm going to use. I'm using their parts list with the 7809 and 7909 voltage regulators as a replacement for the 12v regulators. I know I probably won't need all the 3300uF caps but I'm going to order them anyway just in case. Aside from that, I'm getting this wall wart:
Jameco and Mouser don't have both the 7909 and 7809 voltage regulators I need so I may need to go ebay for those or something but they have everything else that I would need. Mouser ended up being cheaper for everything else so thats most likely where I'm going to buy everything but the regulators.
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