Description: This is a stereo amplifier kit designed to make use of the STA540 power amplifier IC. Once this kit is completed you have a fully functional, two-channel audio amplifier, complete with a standby switch, volume control and indicator LEDs. The kit also includes a 6400BG heatsink for the STA540 to dissipate any damaging heat.
In this kit, the STA540 is configured as a dual bridge amplifier capable of delivering up to 2x 38W (4Ω at 18V). Power supplied to the kit directly powers the STA540 and should be within 8 to 22V.
This kit comes as a bag of parts, you’ll need to solder everything to the PCB. All components are through-hole, so it shouldn’t be too difficult; but this kit is a bit more complex than our other through-hole kits.
Based on 9 ratings:
1 of 1 found this helpful:
I bought this kit in 2014 for a part of a project I didn’t get around to. I’ve finally gotten around to finishing it and I’m impressed with its performance. I’ve noticed some background hiss (I haven’t tried using a ground isolator as another review suggested) but the output is otherwise clear, even when turned up louder than I care to listen. (Hm. I should try temporarily replacing the amp for my my living room speakers with this and see what I think of it.)
Assembling the kit was straightforward, even though this was the first time I’d soldered any nontrivial PCB. (Make sure you have flush cutters — there are lots of bent leads you want to clear out of the way to get at the next joint.)
Here are some minor problems/inconveniences I encountered, some of which I think could be helped by changes to the design of the kit with little added cost:
• The spacing between the amplifier chip and heat sink is not quite right, or the assembly procedure needs improvement. I ended up with the chip being at an angle to the heat sink, not lying flat against it, which doesn’t help heat transfer. (I’m glad I used a solid “thermal pad” which fills the gap with its thickness rather than heat sink compound.)
• It was very hard to read the capacitors confidently and tell them apart. I had to sort out all the capacitors and compare the number of each type I had to the labeling before I got them all straight.
• All of my audio sources have cables with plugs. While the screw terminals may be nice for using this as a component of a larger project, I think it would make more sense to include a 3.5 mm jack, or 2 RCA jacks, for input, and anyone wishing to direct wire inputs could simply leave the parts out and solder wires in place of the screw terminals.
• The included instructions say “connect 12V to the power terminals”. They don’t mention, as the product description does, the larger 8V to 22V allowable range.
• I think it would also be worth mentioning that the input “-” terminals are wired to ground, and that the output “-” terminals aren’t.
• The output screw terminals should be changed to ones that accept larger diameter wires or pins. There’s plenty of room on that end of the board, and standard speaker wires can be pretty thick.
2 of 2 found this helpful:
The simplicity, the clarity… omg the power in such a tiny little package. Add an option to bridge the input and outputs and you have a serious contender here. It’s raw this is true but I’ve played with and owned pro grade qsc and crown amps and I’m simply blown away. And it only takes about 20 min to build if your serious about getting it done.
2 of 2 found this helpful:
I had this kit together in no time at all. I do have to say I am experienced in electronics, but I still believe that anyone can do this. One thing that could really improve this product is a 3 mm stereo input jack. This would make a nice clean connection for a iPod or for a computer. Now with that said, something really fun you can do with this is pair it up with a Raspberry Pi with Shairport (AirPlay) and you can play music right off your iPhone. VERY COOL. I hooked this up to my Pi and some in ceiling speakers. The idea is you could have a Pi per room in your house and listen to different music in each room. Here is the link on how to setup the Pi with Shairport: http://www.raywenderlich.com/44918/raspberry-pi-airplay-tutorial
Seriously great amp, especially for the price. Good quality sound, and powerful.
After assembly, I tried it with a lab supply I use for such things. At whisper volume the amp was fine. Increasing the volume resulted in a loud thumping and the Peak light started flashing. Tech support recommended a higher current supply. I tried connecting it to my car battery. Same problem. I was given a refund. I think the problem is that the amp is not rated for 4 ohm speakers as stated in the spec. or maybe there is some kind of feedback causing the pulsing.
I just assembled this kit, it doesn’t work and has the following behaviors- can anyone think of an obvious mistake I may have made on assembly? - With 10VDC the power LED illuminates - With the switch on “Standby” the ON LED illuminates - With the switch on “ON” the ON LED turns off - With the switch on “ON,” no amplified audio output, but a periodic thump every .25 sec and flash of the Peak LED as if a Capacitor is charging and discharging.
I’ll assume user error here, based on the other reviews. Thinking I cooked a component or miswired. Any knowledgeable comments greatly appreciated.
Have you contacted our technical support department @ email@example.com ? They’re usually very good at helping figure out issues like this!
had it together in no time, works perfect with my mp3 trigger, make sure to use a ground loop isolator, highly recommended. Cody from tech support was very helpful in my decision in choosing this amp, thanks Cody for all your tips.
Some users have noticed that their amp will oscillate or ‘thump’ when power is applied rather than operate normally. There are usually two causes for this and both are pretty easy to fix.
The first is that you may not have a power supply that can supply enough current for the kit to work. You need at least a 12 volt power supply that can provide 2.5 amps or more current. Supplies up to 20 volts will work but you still need 2.5 amps or more current to play it safe.
The second issue that can cause trouble is if you have a lot of flux leftover on the back of the board from soldering. We recommend that you solder all components except for the potentiometers first, then thoroughly clean off any leftover flux from the board. Once the flux is cleaned off, solder the potentiometers and you should be fine.
Hearing a buzzing sound? There are a few reasons why you might be hearing a buzzing sound. We have heard of problems with the audio amplifier kit due to the power supply or needing some additional decoupling capacitors. If the power supply is not providing constant power and is noisy, there can be problems amplifying sound. Maybe the bench and laptop power supply units are not giving enough peak current to your STA540 Amp Kit. Also, try adding as a shunt capacitor to reduce the lower signals out of the amplifier as opposed to in series which would increase the lower frequencies. Try looking at this tutorial for more information on stabilizing the signal => https://learn.sparkfun.com/tutorials/capacitors/application-examples . This might help with any issues using the audio amplifier kit.