Hi there DIY subbies!

Wanna ask guys. Have any of you ever brought in a plate amplifier and hadn't been asked to get a SIRIM certification? Thinking of making a 2.1 setup.

Hi Sifu,

I would like to build a powerful all in one integrated amplfiier, using several boards, may I know is there anything about license I need to worry about? I'm planing to sell several units as small business, is that legal? I'm not looking for big money though, just that I got passion to do anything related to HiFi audio.

More info please...macam best jer...

If small business online i dont think got problem...lot ppl also doing self DIY stuff and sell online....

I will buy boards include ODAC, O2, try to make these 2 into DAC + preamp first, then will hook to another power amp board from CLASS D Audio power amp max up to 300watts, I think this will be the best transparent and powerful setup without breaking the bank, cost in USD will be something like:

ODAC PCB - $99
O2 PCB - $99
CLASS D AUDIO POWER AMP PCB include SMPS - $285 to $500 (based on power watt range from 60 to 300)

Casing a bit headache, coz need very customize, most likely will need some time to work out the design

sounds interesting

Haha. You need a BRAND. Start think of a good name for the stuff that u want to sell.

ya, that's another headache stuff to think of

Hi bro, maybe this post is not suitable here.
But I need help, my Yulong DAH-1 DAC is down, no sound output to my speaker and headphone. Does anyone know where can I go for repair?

Hook up a PAM8403 5V amp (powered by USB) to a 4 inch 2-ways bookshelf. It works like charm! Enough for a room use. Not to mention, the sound is almost flawless without cracking and noise! Impressive!

Why all the costing so high one?

No.bzzzzzz...sound at 70% > without anyload (music).Most quite feel like a damage chip coz it really quite..
Bass feedback S1 & S2 on/off mode nice for 2.1 pc sub amp.. 6.5" - 10".


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Hi sifus here, this is a duplicate of my thread in the main forum, but there has been no response, so I decided to ask here.

I have a Corsair SP2500 gaming speaker, but its PSU board is blown already, so I am left with an unusable speaker, but its subwoofer and bookshelves speakers(tweeter and midrange) should still be working fine.



So instead of replacing the PSU board components or to get entirely new PSU system, I decided to wire the sub and speakers to LP-168HA amplifier, which I am currently waiting for it to be delivered. I needed suggestions and help on how to connect the wiring of the sub+speakers to the amplifier.

I have yet to check the impedance of my subwoofer, but I will look at it when I got the time. The subwoofer is rated at 120W RMS, and the speakers are 56W each(40W for midrange, 16W for tweeter).

Based on the output of the LP-168HA amplifier, it provides 68W for sub, and 40W for each speaker. I believe that the power output and impedance matching should be alright between this speaker and my amp. But the problem here is how do I connect my speaker(tweeter+midrange) to the amplifier connections.



As seen at the back, I have + and - for left and right speakers, and the bottom 4 ports are for the sub wiring, in parallel. But my speaker has 4 wires coming out from it, the + and - for the tweeter and midrange. How do I connect these 4 to my amplifier, which has only 2 ports?




Do I combine the top + and bottom + and connect them to the red port of my amp? Or do I need to get a crossover to separate them?

Base on the speaker connector, I believe you will need a crossover.

thanks for the info. What are the impact if I connect both of them together to the same port? Or what if i just connect the midrange?

tweeter must have crossover else u might damage the tweeter... midrange should be fine

Hi Audio DIYers..

I am interested to make another audio amplifier since after 19yrs ago my first amplifier was built with the help from my friend. I have no knowledge in electronics stuff due to I am a fully mechanical guy. I'm doing the casing n assembling work while my friend was doing the soldering n fine tune the amp. for me.

Recently when I was clearing my old junk drawer, I found an unused toroidal transformer, therefore I would like to start another DIY to make use this transformer.

The specs for the transformer,
Made: Nuvotem
Primary - 0 - 230v
Sec. : 2x 0-25v (2.4A)
Power rating - 120VA

Is there any DIY project amp. suitable to use this transformer?


Thank you.

This post has been edited by qboy123: Sep 6 2016, 11:51 AM

You can build some IC/chip based amp but won't able to drive lower ohms well,even though the IC/chip able to,as the transformer current is not large enough for the given output voltage....

Well, dont deceived by max current figures If we talk about peak current in speaker driving, then yes 2.4A is tiny. But in actuality the average current is more interested in. More accurately, the RMS current. However, looking at current alone still incomplete because we also need to consider the voltage and resistances as well. Therefore, the proper figure to see is RMS power.

To estimate power capacity of 25V-0V-25V, 2.4A transformer, just do P = V x sqrt(2) x I, assuming the 2.4A figure is max continuous current. sqrt(2) is there because the 25V is actually peak voltage, to convert to RMS need the sqrt(2). This can be observed when the transformer output is rectified and filtered. Using the equation we get 84.9W. But remember thats only half of the coil (the 0V means its center-tapped) so total power capacity is doubled to about 170W. Minus the efficiencies in amplifiers, etc, we probably can squeeze about 75W+75W of power, assuming stereo channel is intended. Quite sizeable amount of power

P/S: I am no electronics expert just know bits and pieces correct me if any sifus spot anything wrong

Finished this amp a while back but didn't notice this thread is here. Here's some pics



This post has been edited by penmarker: Feb 22 2017, 02:14 PM

Try the trusty lm3886. A lot of reference out there and seems about right for this voltage range.