Serious Distortion Issues with TDA2030 Amplifier Kit

It's time you bought that transformer, then.

what the hell is the battery doing with a transformer? You don't need transformer, if you are using battery, get 12 V regulator.

You need a dual supply, plus and minus 12 volts with a common ground. Here is one you might look at:

http://www.transkommunikation.ch/dateien/schaltungen/diverse_schaltungen/power_supplys_circuits/Regulated%20Plus%20and%20Minus%2012%20Volt%20Power%20Supply.pdf

Or if you want to use batteries, get 2 12 volt batteries in series. Connect the ground to the point between the batteries.

You require a transformer with middle tap or however it's called, 24 V AC between the secondary end connections which means 12 V AC between each end connection and the center tap.

As there should be a rectifier on-board you should be able to supply +/- 12 V DC from two 12 V batteries but you need to check the diagram before doing that. Normally you'd connect two 12 V batteries in series and the middle connection would be the 0V, the negative pole of the 1st battery would be -12 V and the positive pole of the 2nd battery would be +12 V (in some other topic someone asked how a -10 V is produced :) ).

Though 2x 12 V AC does not exactly correspond to pure +/- 12 V DC around a common 0 VDC (GND).

A single DC voltage is NOT a direct substitute for a dual rail power supply (what this circuit converts the 12-0-12 transformer voltage to) unless you connect it in EXACTLY the right points (not before rectification that is) and make a little mod, to keep ground exactly half-way from rails, using matched bleeding resistors parallel to each rail capacitor. If you don't, any difference in capacitance or leak current between rails would move the (floating then) ground and inputs out of rated CMR area, and induce distortion. This mod will also give more margin before clipping distortion, so more useful power. Now all this applies if you have not already fried or semi-fried any ICs. S.M.

If you are using batteries, you need 2 batteries. Connect the two batteries in series. the center connection of these bateries is the 0V, the other one are the +12, and -12.

THe reason that it distort at low volume is because you dont have a firm 0 V ground, but floating ground. A dual supply amp will not work properly with single supply.

I tried your suggestion and now I just get a loud scratching sound when I turn the volume control and still as much distortion. I just bought a class D amplifier board instead. http://www.ebay.co.uk/itm/251593017347?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

What is the DC voltage of your output relative to the ground (i.e. , the connection between the 2 12 volt batteries)? It should average zero, (or be close to zero with no input to the amplifier). If it is much positive or negative, then likely one side of your amplifier is fried.

A loud scratchy sound when you change the volume control could be a noisy (dirty) pot, where the wiper is not making good contact. Also it could be that you have a poor solder connection somewhere (likely) and your amplifier is not getting proper feedback. It's really hard to guess without a schematic.

Assuming that components are installed correctly (diodes, electrolytic caps, ICs, transistors, etc), the most likely problem with assembled kits is bad solder connections. Cold solder joints are when the component lead and circuit board trace are not heated above the solder melting point so the solder does not flow between the two before solidifying (or there is insufficient solder). Too much solder applied can result in solder bridges between components which are not supposed to be connected. Examine the back of the circuit board with a lighted magnifier and resolder any connections that look suspect. If there is a solder bridge, the excessive solder can be removed with solder wick (copper braid that can be obtained at an electronics store).

Keep in mind that you need to apply enough heat that the solder flows between the component and circuit board trace but be careful not too apply heat any longer than necessary because excessive heat can damage semiconductors.

Good luck!

In addition to the points made about the supply voltage(s), I might add that, looking at the specs and pictures, you are going to need some substantial, electrically-insulated heat sinks on those output transistors. If you try to drive that amplifier with more than a Watt or two out, there is no way those small tabs on those devices will dissipate the heat. My guess is that, in addition to supplying "funky" supply voltage and having a noisy volume control, you have damaged one or more of the transistors by overheating them.

It works a bit better now. I just put a battery on each of the two main power capacitors. I can get it to go much louder without distortion but the sub channel is still quite bad. The scratching sound only happens if I connect one battery before the other. If I connect them in a different order or both at the same time, there is no problem.

As already pointed out, you simply need a 12-0-12 transformer, it tells you that in the ebay article:- Power Input: Dual AC 12V( 12V-0-12V)

Playing about with batteries is simply a waste of time.....if you needed it to be portable, you should not have bought that one.

By the way, how did you attach the TWO batteries? They probably need to be connected like this to work, assuming no onboard transformers of course and only single diodes, one for each polarity:-

I cannot be absolutely certain as I have not seen any schematic for the amp....

Hi

Don't PC power supplies have + and - 12v

if so get hold of a redundant PC and use that.