I've gotten the Powersupply working giving me a steady +-25V, but when I connected the amp to the powersupply, and switched on the thing with a 10ohms resistor on the outputs, it combusted rather spectacularly.
However my DMM only showed 0.1 or 0.2V of difference, right before it blew up. What could possibly be wrong with the circuit? Any connections I should double check?
Should I cut off all the unused pins right to the edge? I left 2mm sticking out.
Thanks in advance! The chip LM3875 looked fine tho, didn't get warm or anything.
However my DMM only showed 0.1 or 0.2V of difference, right before it blew up. What could possibly be wrong with the circuit? Any connections I should double check?
Should I cut off all the unused pins right to the edge? I left 2mm sticking out.
Thanks in advance! The chip LM3875 looked fine tho, didn't get warm or anything.
hey~!! You're from Singapore as well?? Well guess what...you could try a mail order company if you really wanted to..like RS and farnell
www.rscomp.com.sg
and
www.farnell.com (choose Singapore)
if you're really lazy and dun wanna spend 7 bux for the shipping...just use a junk speaker...I could lend one of mine to u...
www.rscomp.com.sg
and
www.farnell.com (choose Singapore)
if you're really lazy and dun wanna spend 7 bux for the shipping...just use a junk speaker...I could lend one of mine to u...
Haha yeah I am... I didn't know we had mail order in Singapore. 
Guess I'll start buying things again.
Using the innards from an altec lansing computer speaker set. ACS48. They've got an 80VA toroid inside and a nice little powersupply section that i just snapped off the PCB. Works fine.
I'll try the junk speakers later. Thanks for the help!
Guess I'll start buying things again.Using the innards from an altec lansing computer speaker set. ACS48. They've got an 80VA toroid inside and a nice little powersupply section that i just snapped off the PCB. Works fine.
I'll try the junk speakers later.
Thanks for the help!
Used the gainclone from here.
http://www.euronet.nl/~mgw/diy/amps/geenkloon_lm3875_schema.jpg
Used paralleled caps .1uf caps for the .22uf cap, cos I didn't have one lying around, a carbon resistor at 21.5k and 1k metal film for the feedback bits, and 47uF cap instead of the 22uF cap.
other than that, all per schematic. I didn't differentiate between signal ground and power supply ground tho. Just connected them all to one star point.
Inputs were +-25V as stated before, cos the other trans I had was +-40 and I wanted to test the amp first.
No input cap. I didn't connect the input to anything.
All ECs are the right way, nothing's touching, 1000uF caps are abt 1.5 cm away from the power pins.I'm going to wrap all the pins with electrical tape next to make sure nothing's touching AT All.
Are you interested in getting resistors and capacitors? I need to get a collection of them so I can build more of these amps, like 50 of the most commonly used values. They're rather easy to put together, and I'm working on a step by step way to solder all 9 components for a little surround sound amp. I can break the order up and mail the parts to you.
The speaker is 6ohms. And I'm not sure why I'm getting AC and DC at high voltages.
http://www.euronet.nl/~mgw/diy/amps/geenkloon_lm3875_schema.jpg
Used paralleled caps .1uf caps for the .22uf cap, cos I didn't have one lying around, a carbon resistor at 21.5k and 1k metal film for the feedback bits, and 47uF cap instead of the 22uF cap.
other than that, all per schematic. I didn't differentiate between signal ground and power supply ground tho. Just connected them all to one star point.
Inputs were +-25V as stated before, cos the other trans I had was +-40 and I wanted to test the amp first.
No input cap. I didn't connect the input to anything.
All ECs are the right way, nothing's touching, 1000uF caps are abt 1.5 cm away from the power pins.I'm going to wrap all the pins with electrical tape next to make sure nothing's touching AT All.
Are you interested in getting resistors and capacitors? I need to get a collection of them so I can build more of these amps, like 50 of the most commonly used values. They're rather easy to put together, and I'm working on a step by step way to solder all 9 components for a little surround sound amp. I can break the order up and mail the parts to you.
The speaker is 6ohms. And I'm not sure why I'm getting AC and DC at high voltages.
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