IC 4440 Problems

TieBravo · Sep 6, 2021

Hello, i have a problem while making this circuit. When the volume is above 50% the bass and the entire sound is getting distorted too much. And after 2-3 days right channel got lower audio output than the left channel. I used new components and checked the polarity and connections more than 5 times.
Can any of you please provide a better circuit schematic for the ic 4440?
I'm using two 8 ohm box, inside each boxes there are two 8ohm speakers (tweeter and woofer) connected in a parallel crossover with low pass and High pass coils.

Nigel Goodwin · Sep 6, 2021

TieBravo said:
Hello, i have a problem while making this circuit. When the volume is above 50% the bass and the entire sound is getting distorted too much. And after 2-3 days right channel got lower audio output than the left channel. I used new components and checked the polarity and connections more than 5 times.
Can any of you please provide a better circuit schematic for the ic 4440?
I'm using two 8 ohm box, inside each boxes there are two 8ohm speakers (tweeter and woofer) connected in a parallel crossover with low pass and High pass coils.

It would probably have been better if you had continued in your original thread - but, if you remember, you changed a resistor value (for some bizarre reason - 820 ohm to 82 ohm) - and I suggested that had simply increased the gain. The result is that when you turn it up it goes distorted, as you're over driving it.

If you want LOUD you need more power, which requires a better amplifier, and much higher supply voltages.

audioguru · Sep 6, 2021

With a 12VDC supply and 8 ohm speakers, the maximum output power of an LA4440 is a puny 1.8W at low distortion per channel.

Nigel Goodwin · Sep 6, 2021

audioguru said:
With a 12VDC supply and 8 ohm speakers, the maximum output power of an LA4440 is a puny 1.8W at low distortion per channel.

I don't think there's any real need to get that detailed - or even mention the chip.

With a 12V supply and a single ended amp you get 4W in 4 ohms, 2W in 8 ohms, or 1W in 16 ohms. For a bridged amplifier these figures quadruple, 16W, 8W and 4W.

That's pretty well all you need to know about 12V amplifier powers

TieBravo · Sep 6, 2021

Nigel Goodwin said:
It would probably have been better if you had continued in your original thread - but, if you remember, you changed a resistor value (for some bizarre reason - 820 ohm to 82 ohm) - and I suggested that had simply increased the gain. The result is that when you turn it up it goes distorted, as you're over driving it.

If you want LOUD you need more power, which requires a better amplifier, and much higher supply voltages.

No, i was confused but i never replaced anything. And i wrote that thread about the CD6283.

audioguru · Sep 6, 2021

Yes Nigel, 2W or 3W sounds almost as loud as 4W.

The LA4440 was produced by Sanyo of Japan. Sanyo's datasheet does not show curves with a 12V supply.
The CD6283 is a Chinese copy. Here is the power vs distortion of the CD6283:

Nigel Goodwin · Sep 7, 2021

TieBravo said:
No, i was confused but i never replaced anything. And i wrote that thread about the CD6283.

Still the same - you're almost certainly turning it up too loud and clipping it.

TieBravo · Sep 7, 2021

Nigel Goodwin said:
Still the same - you're almost certainly turning it up too loud and clipping it.

Okay, but why the right speaker sounds power than the left one all of a sudden? It was working pretty good. I am using 9v battery

Nigel Goodwin · Sep 7, 2021

TieBravo said:
Okay, but why the right speaker sounds power than the left one all of a sudden? It was working pretty good. I am using 9v battery

Using a 9V battery is even less power - and overloading it has probably killed something. Have you tried swapping the speakers over, to make sure the speaker hasn't been damaged?.

rjenkinsgb · Sep 7, 2021

TieBravo said:
I am using 9v battery

A "9V" battery is only around 9V when new and at full charge. They gradually drop down in voltage and are at around 6V when near flat.
Also if it's a small battery (PP3) the current they can supply is not high and the voltage will "droop" every time the amp needs high current.

Differences between two channels may be differences in component tolerances, or just a fauilty component - in the amp, or the speaker as Nigel says.

audioguru · Sep 7, 2021

The amplifier is about 50% efficient. Then when the battery is brand new and you turn up the volume to 0.5W per channel into 8 ohms where clipping begins with a 9V supply, the stereo output is 1W but the battery must produce 2W (1W of total sound plus another 1W of heating) . Then the battery current is 2W/9V= 222mA.
That is a lot of current from a 9V alkaline battery so its voltage drops to 7.5V in a few minutes. A cheap "Super Heavy Duty" 9V battery is much weaker.

TieBravo · Sep 7, 2021

audioguru said:
The amplifier is about 50% efficient. Then when the battery is brand new and you turn up the volume to 0.5W per channel into 8 ohms where clipping begins with a 9V supply, the stereo output is 1W but the battery must produce 2W (1W of total sound plus another 1W of heating) . Then the battery current is 2W/9V= 222mA.
That is a lot of current from a 9V alkaline battery so its voltage drops to 7.5V in a few minutes. A cheap "Super Heavy Duty" 9V battery is much weaker.

Why i used a battery because connecting the amp using 12v transformer (which is attached with diode bridge using 4 diodes) produces a constant humming noise even when everything is earthed, and the humming increases when i connect smartphone on the input. Volume up and down wasn't effecting the humm.

TieBravo · Sep 7, 2021

Nigel Goodwin said:
Using a 9V battery is even less power - and overloading it has probably killed something. Have you tried swapping the speakers over, to make sure the speaker hasn't been damaged?.

No, tried that but the speakers aren't damaged. The ic got surge voltage protection, and pin to pin short protection and i am certain i did a neat job and checked 5 times for any connection or polarity errors. It it possible that the ic may be damaged? I never over powered it. And with 9v battery it was working pretty fine, and the left channel is still ok but not the right one.

Nigel Goodwin · Sep 7, 2021

TieBravo said:
Why i used a battery because connecting the amp using 12v transformer (which is attached with diode bridge using 4 diodes) produces a constant humming noise even when everything is earthed, and the humming increases when i connect smartphone on the input. Volume up and down wasn't effecting the humm.

What about the reservoir capacitor?, how large is that?.

TieBravo · Sep 7, 2021

Nigel Goodwin said:
What about the reservoir capacitor?, how large is that?.

Capacitor connected with the transformer parallelly is 2200uf 16v.

audioguru · Sep 7, 2021

You never connect an electrolytic capacitor parallel with a transformer. The capacitor will explode.
The capacitor from pin 5 to ground on the LA4440 amplifier filters out power supply hum. What value is yours?

A bridge rectifier with 4 diodes doubles your mains frequency, Then your hum will be 100Hz or 120Hz and the capacitor at pin 5 will remove it.
If the hum is the same as your mains frequency then either the input cable is not a shielded audio cable or the bridge diode rectifiers are not connected properly or are defective.

TieBravo · Sep 7, 2021

audioguru said:
You never connect an electrolytic capacitor parallel with a transformer. The capacitor will explode.
The capacitor from pin 5 to ground on the LA4440 amplifier filters out power supply hum. What value is yours?

A bridge rectifier with 4 diodes doubles your mains frequency, Then your hum will be 100Hz or 120Hz and the capacitor at pin 5 will remove it.
If the hum is the same as your mains frequency then either the input cable is not a shielded audio cable or the bridge diode rectifiers are not connected properly or are defective.

Its 100uf
I think i said it wrong, this is how it's connected (not 4700uf its 2200uf)

audioguru · Sep 7, 2021

The Sanyo datasheet for their old LA4440 amplifier says that the filter capacitor at pin 5 to ground should be 220uF.
But many people in You Tube videos from the other side of the world wrongly use 100uF.

Nigel Goodwin · Sep 7, 2021

audioguru said:
The Sanyo datasheet for their old LA4440 amplifier says that the filter capacitor at pin 5 to ground should be 220uF.
But many people in You Tube videos from the other side of the world wrongly use 100uF.

Such a minor difference (in electrolytic terms) is going to make sod all difference.

audioguru · Sep 7, 2021

ALL the electronics You tube videos are made by people on the other side of the world who carry the solder on the dirty tip of their soldering iron. The amplifier videos all show small speakers with no enclosures playing no low frequencies. A few of the videos show a little 9V battery.

Did you notice that the LA4440 and CD6283 look the same but their pin numbers are different?

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