The Active Studio Speakers Project

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hello

recently i have discovered the wonders of DIY Audio, and im assembling parts to build some monitor speakers, since i been to a friends house and experienced some good Studio monitors (Roland MA15), my home cinema solution doenst have what it takes any more....

What i have so far besides good will and no money... lol


  • 2x Clarion SRF 1381 (2 Way @ 4ohm - it says 90W Music peak)

  • 2 bookshelf speakers EDIFIER USB

  • Creative Inspire 5100 set without transformer or Volume control (so i cant power on the Board
- 20W SW and crappy 8W*5 Speakers @ 8 ohm
- opened the sub and the board has a TDA7273a and a TDA8510J
  • Hercules XPS 2.1 (burn out power supply)
- 15W SW and 8W*2 @ 6ohm i think

  • A chinese Home Cinema 5.1 set, with DVD with a amplifier to a sub and the 5 sattelites (25W @3ohm sub and 5*15W@4ohm)


WHAT I WANT
Like i said, 2 good Active speakers, pref with volume and bass control, that i can take off the 5.1 creative board, and i am thinking of using the chips from the creative board (the TDA7273a and/or TDA8510J) to amplify the speakers

QUESTIONS

- Power Source
I have a 500W computer based PS, can it power 2 DIY for the speakers??

- anyone can kindly get some schemes to these chips, searched but couldnt find any



best regards and tks
Haelius
 
another question i have....


since the Edifier USB speakers are digital, i was wondering if there is any way to put the clarion drivers on it, with a more powerfull amp before the drivers, cause i think they are like 1.5W, but yet they deliver a good clean sound, and if i use the lineout from the PC to the DVD line in, its analog (isnt there loss of sound?)

PS... im a newbie at this forgive me for any mistakes lol


best regards
Haelius
 
the 8510j chip is your friend i guess.
chematics are in the PDF you have just linkt.
page 11 shows you how to do it.
The chip has total of 4 amplifiers in it.
the chematic shows how to do bridged mode, and single ended mode.
You need to make both amp pairs to be bridged.
The computer psu can be modded to power this thing.
It may or just may NOT work, depends on the quality of the psu.
switch on voltage spike can kill this chip.
Dummy load and a delayd relay may solve this part of the problem.

Simple Tone Control

this is maybe something you can manage to do.


but honestly, if i was you, i would "just" save up some money and order a kit tda2050 stereo amp, a decent toroid, and a kit lm1036 tone controll board.
should give the clean sound you want, tone controlls, and in the end at least its something that is fun, and usefull/worth to have.
 
i know that is the best option ofc, but like i said, cant spend money on this now.... so these chips will have to do for experiments....


currently its kinda ok, i made some enclosures for the Clarion speakers and hooked them to the DVD, and at least they sound better than the original speakers that came with the DVD... although i think it has like 20W and the speakers are like 90W... so hasnt got the juice to power the drivers decently but at least it sounds better than the original ones...


Anyone knows how to "mod" a power supply from the PC to be able to power these wonderfull chips? its a good stable 500W so i think thats a good option...
 
Even if it's 500W total, much of that will be for the +3.3V and +5V rails, useless an 8 ohm audio amplifier.

There should be a +12V output with considerable current capacity, and *IF* there's a -12V output, it will probably be limited to less than 1 amp.

So you're stuck with a 12V single supply amplifier. Might be okay for quiet listening...

I would just hold out for something better. Ultimately, trying to use the wrong parts for the application ends up costing more money.
 
one can fool the sense circuits so the psu provdes more than +12 volts.
I blew a few psu with this trick in my life.
Thing is, even if you tweek it by fooling the voltage sense, you can not get over 15 volts . Even that is not safe. The elco caps are rated to 16 volts, so you just end up blowing those up.

You can power the tda 8510J chip with the psu, whitout modding it.
on an 8 ohm load you might get something close to 8 watts or so.
There is no way it will be any better.
And still you risk the switch on surge killing the poor ic.
 
correct me if im wrong...


  • AMP (8510J) according to ohms law

P = E 2 / R

so if i have 12V at 4ohms (like the clarion drivers) i will have 36W


  • on the power supply it has 4.5 amps on 12V so again on ohms law

P = I 2 x R 4.5amps x 4ohms = 81 W


so i think the power supply will give enough power


even so the amp gives only 2 x 13W on 2 channels

"TDA8510J - 26 W BTL and 2 x 13 W SE power amplifiers"

right??
 
You are right and wrong.
Yess, the formula is correct for power output.
But if he is supplying an amplifier with 12 V rails, you will not get a 12V output.
Prehaps I would say it will yield something closer to 10 volts.
Drivers are not pure Ohmic resistors. They have reactance/impedance not resistance.
Even if we say it is an ohmic load, the values change a bit since the output swing is less then the amplifier supply voltage.

P= U^2/R
P= 10^2 / 4
so.. output would be less than 25 watts into 4 ohms.
Maybe if you mesure with a square wave you get that 26 watts with a distorsion so horrid I can not describe.
With 8 ohm load..
something around 12 watts or so.
With acceptible distorsion figures the 8 or so watts I wrote can be a good estimated value.

Even so, 8 watts can be LOUD.
Depends on:
Speaker efficiency, and listening room size, listening distance, listener's personal taste.

The thing is, an ATX psu can with ease power an amp like that, and that amp is a good start. You can find hudreds of horrid commerical amplifiers with far worse specs.
(like chepoo HT amps. And some say there is NO devil. )

Question is the turn on surge of the given PC psu. If it does not kill the chip, then its all just fine.

Those chips exsist for a good reason. They are not highest grade, nor the worse You can get.
 
Note that you'll only be able to get 10V across the driver with a bridged amplifier.

Otherwise, you'll have +5V / -5V swing with a single ended configuation.

And then that 5V RMS would only be for a square wave.

If we want to amplify a sine wave, then 5V peak sets the sine wave amplitude to 5V / sqrt (2) = 3.54V RMS.

3.54V RMS into an 8 ohm resistor is 625 mW, or 1250 mW for a 4 ohm resistor.
 
ok im gonna reverse a bit... and gonna use the creative board without getting the chips off.... it has the 7372 and 8510j tied, so my only problem is gonna power it cause the transformer is 12V AC 3.9A (lost it), but theoretically, its just needed to chant after the rectifier bridge right, after the big capacitator 4700uF 25v?


i am gonna post the back of the PCB so u guys please help if u can

i need to power it using the PC power supply, and THE MOST IMPORTANT, i need to bypass the power volume, cause it powers on the board, and i dont have it..... can anyone help a bit?
 

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"ok im gonna reverse a bit" -> do not.
and take a good look arund, i bet if you do you find a more suitable psu than the pc psu.

Wallplug adapters, old radio / other junk you or someone who you know does not need, and so on. You can salvage the parts needed, if You are realy upto do some low cost DIY.

Who knows, You might even find good quality stuff.
(like.. I managed to salvage nice TL74 IC thisway.. And other usefull things such as 6300 uf caps, and many handfull of ceramic caps, safety fuse, switch, acceptible pots, a few 78xx regulators complete with circuitry and so on..)

At any case, doing it DIY is the fun way.
And in Your position i would say it will be a lot more easy than to "whack" your way to power that amplifier.
 
Hello everybody!

I'd like to use the TDA8510J to power a 20W 4ohm driver. What would be different in this schematic?

http://1.bp.blogspot.com/-X5lqY0AE9...WkVVLb6uKE/s1600/TDA8510J+circuit+diagram.png

I'm new to DIY electronics and any help would be much appreciated :)

To be more precise:

  1. I would use a mono input signal from the subwoofer output of my amplifier. Would that be split to pins 15 and 17?
  2. Will I then leave pins 1, 3, 6, 8 and 9 untouched? Any others?
The simpler the better.
 
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