Have questions about TDA2050 Amp Circuit.

[audioguru]

The TDA7377 has two bridged amplifiers that produce the same 14 Watts into 4 ohms each at clipping with a 13.2V supply as all the other amplifiers.
But it is rated with a new mumbo-jumbo way to exaggerate the power number (severe distortion so it has square-waves output) to 30 Whats and 35 Whats per channel.
Its low distortion is only rated with 10W into 4 ohms with a 14.4V supply.

 

[Trance183]

I see. Audioguru you seem to really know your stuff. Thanks alot to all of you guys. I will keep you updated on my progress.

 

[Trance183]

Quick question. I have a cheap 6ohm subwoofer. If I parallel this 6ohm sub with one of the 4ohm speakers. What ohm do I end up with? Since crutch said that two 4ohm speakers in parallel become 2ohm, what does 6ohm and 4ohm become?

 

[Nigel Goodwin]

Product over sum - 2.4 ohms.

 

[Trance183]

Good will Mr. Goodwin.

 

[audioguru]

A sub-woofer usually has a lowpass filter and its own power amplifier.

 

[Trance183]

Nah not this one. This Subwoofer is from a Sony Home Stereo. lol. But I got a good question. I use regular Carbon Film 1/4w 5% resistors and regular Monolithic Ceramic 50v and Electrolytic Capacitors 16v. Do you guys recommend using Metal Film 1/4w 1% resistors instead? And instead of Ceramic should I use Mylar or Tantalum Capacitors?

I also googled Bootstrap and I'm still not sure why I should use it or go without it. From what I understood its used to kinda help boost output voltages meaning a little more power?

Thank you for helping me.

 

[audioguru]

Audio coupling capacitors should use film capacitors. Supply bypassing and the RC at the output to ground should use ceramic capacitors.
Years ago tantalum capacitors failed frequently. I haven't used them since.
Use 25V or 35V electrolytic capacitors. In my 6V projects I use 16V electrolytic capacitors.

A couple of TDAxxx amplifier ICs use bootstrap to boost the drive voltage of the output stage so it goes as high a voltage swing possible with the supply voltage. 6W without bootstrap and 6.5W with bootstrap. You won't notice such a small change.

 

[Trance183]

Thank you buddy. When you say film you mean Polyester Film? Audio Coupling is the cap that you connect the input to right. After so many questions will u guys get annoyed?

 

[audioguru]

Film capacitors are made from many different metalized plastic films. Polyester or Mylar film is good.

 

[Trance183]

I did it!

So after a couple months of waiting for parts and juggling my schedule I was able to make a TDA7377 amp. It was a pain to build on a perf board. It sounds pretty good but Audioguru you were right. After about 14 watts it sounds it loses its clean crisp sound. Even when using an 18v power supply is still didn't push out what I was hoping for.

Now as for the TDA2005. The pins could not fit in my perf board. Do they make perf boards with bigger more spread out holes? If so where cause I've looked around and haven't seen any. Thanks for all your help fellas.

 

[audioguru]

With a 14.4V supply, the TDA7377 amp is rated at 35 Whats when its output is a horrible sounding square-wave with severe distortion. It is rated at 20 Whats with 10% of awful clipping distortion which is about 14 Watts at a low distortion just before the output clips.

The TDA2005 has about the same output power but needs boostrap capacitors to achieve it.

 

[Trance183]

Thanks.

Yes. Thank you so much buddy. It was fun but now I want more power. Do you happen to know if there is such thing as a perf board with bigger holes to fit bigger pins, and where to buy them for a good price?

 

[audioguru]

I use stripboard, not perf board. For ICs like amplifiers with the pins in two rows close together I make a pcb.