Amp questions: power amp, power supply, how to convert AC to DC

[edo1123]

I' m sorry for adding this thread without a proper research on the forum (I actually did it, but with not so good results).
I took a look at the "amp discovery" discussion and I saw these tpa amplifier and someone who built a real head with a Sunn preamp. I bought one of these board, but I don't get anywhere near the amount of volume I'd like to have, so I started making my researches for something that can put out at least 30watt. End up on tpa2009 and then on a project based in the tpa7040 (I don't remember if it's the right ic, but it's the Tiny Giant). This project requires 5A at 12V and should give 20watt.
What I thought was: could I use more of these to drive 3/4 speakers with only one preamp and four tiny giant (ore something based on some tpa ic)? If so how do I supply 5A to each board?
For the supply I know I should use a transformer and a rectifier, but since I'm a total newbie in amp building I decided to ask help to someone how knows something more.
I play bass and guitar just for fun so I don't need to tube amp or something super fancy (for now) also I don't have a huge budget so I'd like to spend more for speakers.
Hope someone will help me in my research.

[rocket88]

i meant to this earlier, but forgot. i built the mini model t using one of the TPA based power amps. first thing to keep in mind is the output is determined by the speaker impedance. the TPA3118 power amp is rated at 60watt at 4ohm, and 30watt at 8ohm if i remember correctly. you also need to keep in mind the number and size of the speakers, larger and more speakers means more volume due to the increased air moving.

i used a TPA3116 based power amplifier rated at 100watt at 4ohm and running at 24V. when i run it through my 2x10 ampeg cabinet it has less output compared to when i run it through my mesa boogie 4x10.

now on to answer your questions:
1. i don't believe you can use multiple tiny giant amps to run different speakers unless each speaker has it's own input and you're running the tiny giant amps as individuals. if you want more wattage i think it would be better to find a different premade mono output class d power amp.

2.  to get 12V at 5A you can do it with a power supply that will supply the correct voltage and amperage or you can use a converter stepdown board like this.

3. speakers are more of a personal taste, so i can't tell you what i think you should get. typically guitar speakers don't do well with bass, and bass speakers will have less high end then guitar speakers. i play more doom metal and psych rock so using one of my bass cabinets with guitar works out great, but i plan on making a 4x12 cabinet for guitar wired at 4ohm, but haven't figured out what speakers and figure it's gonna run me around $350 for the speakers alone.

[edo1123]

Thanks for replying. So the best option would be to buy two boards and run them in parallel (one for guitar and one for bass) to two separate speakers but I still need at least 10A at 24V that's the reason why I needed a transformer (never found a power supply with these specifications). Moreover I don't know where to find, in Europe, some good 4ohm speakers since at 8ohm there's this volume drop everyone talks about.

[rocket88]

I'm confused at what you're thinking about doing. If you're planning on building an amp that can run both guitar and bass then i would build 2 different amps (1 guitar preamp, 1 bass preamp) which you can do in 1 chassis, with 2 different speaker cabinets (1 guitar speakers, 1 bass speakers). You don't need a transformer, the board i posted will put out enough amperage to run them, you'll just have to split the power coming out so it can power both boards if you're using 1 chassis or if you build 2 completely separate amps just get 2 power boards. The speaking impedance comes down to how you wire them togther. Take a look at this from Celestion.