Very simple Yuan Jing build (noob questions)

[hollowboy]

Hello, some basic questions.

I'm using mini DSP and want to multi-amp on a budget.

Is getting and powering 2 * 50W amp as simple as:

1) buy 2 Yuan Jing boards
Yuan Jing Audio - ON SALE! - TPA3116 Class-D 2.0 Stereo Amplifier Board [50W+50W] - USD $16.99
2) Buy two appropriate (for Australian AC) laptop bricks (24V, 5A)
3) Cut the output plug off the laptop bricks & clamp the wires into the "VCC" and "GND" sockets of the Yuan Jing board

From looking at other projects, it seems as simple as this, I'm just after an idiot check

I'd run signal in similarly - halve an RCA cable, solder the bare wire ends to the Yuan Jing board inputs.

I have a multi metre, a temperature adjustable soldering iron, some experience ...but I need to overcome my trepidation with anything involving more power than a passive crossover.

Thanks in advance.

 

[OffGridKindaGuy]

Go For It! Sounds like fun to me but I don't have any A.C. power..

 

[kasey197]

sounds like you're all set - just get the plus and minus right for the power supply connection to the board (that multi meter will help make sure!)and then wire up the speakers and inputs and let the music flow!

 

[hollowboy]

Thanks guys.

Also, a similar basic / budget question (not sure which forum most appropriate) , why is
there no such thing as a cheap passive preamp (to just switch sources and adjust volume)?

Why can I buy lots of 10-50watt amps for around $100 but the only passive preamps are multiple times that cost?

As far as I can see, a good passive preamp = a stepped attenuator plus a few switches and sockets, so I'm shocked that no company like Yuan Jing is slapping them together for <$100.

 

[Buehgemeiste]

There are better class d modules than those you linked.
They were hyped in the forums, because they are easy to mod.
Almost every TPA3116 board sounds better.
Look for the whole TPA311x-family.
And you should consider the other chips, too.
TDA7492 is available with on a 6$ (blue) board which is absolutely worth its money.
Its bigger brother the TDA7498 is available for 12$ on a quite good sounding module.
I like my TDA8932 board.
It is very small, 6$ cheap, and comes as in mono-BTL.
It can be placed inside a speaker very close to the speaker.
A board with TI's TAS5611 is available for ~20$.
It is my favorite in this weight class atm (TDA7498 was before that).

(The only chips mentioned that work with 4 Ohm speakers are TPA... and TAS....)

....
Maybe you want to leave the plugs on the power bricks, buy some female connectors and put that stuff into a box.

 

[xrk971]

Yes, it is that simple. Here is my TPA3116D2 (Ybdz Wiener and a miniDSP) glued onto a piece of foam core. I later put it in a chocolates box with terminal posts.

Works great - been using this setup for all my builds now. Very versatile and flexible. Get two setups and you can make a 4-way active stereo setup for $300 including amps.

Here is the same setup in a proper low profile chocolate box with a LM317 power supply for the miniDSP when running without laptop:

My next miniDSP setup will use these $40 LM3886 boards with BB opamp. I have demonstrated that these amps can work with dual 19v SMPS laptop bricks in series for a split rail power supply without a big iron (read, expensive) toroidal trafo.