Wiring Amplifiers PSU

[AndrewT]

Hi,
It's not normal with +28dB power amp and 90dB/W/m speakers to hear any hiss or any hum at the speaker.

Are you listening to the noise generated by the Zin resistor?
Short the input RCA either with zero ohms, 0r0, or use a resistor that matches the source equipment output impedance ~ 200r, connected from RCA signal pole to return pole.

 

[Stinger]

Hi Andrew,
I shorted the input RCA with a small lead. The hiss is still there!

 

[Rainwulf]

Is it a noise, or a hiss?

Is your power supply a linear one? Or a switch mode one.

 

[Stinger]

Is it a noise, or a hiss?


Is your power supply a linear one? Or a switch mode one.

It's a hiss. The Linear PS is drawn at below the first diagram.
http://www.diyaudio.com/forums/attachment.php?s=&postid=1792720&stamp=1238766687

 

[Rainwulf]

Well there is no reason for that to hiss thats for sure.
What is your voltage?
With the amps connected, what is the voltage of the rails.

 

[Stinger]

+16.1V and -16.0V

 

[Rainwulf]

Well thats within specs.

Dont know!!

Unless something you have done, or the kits themselves arent using the data sheets intended circuitry, it should be fine.

 

[AndrewT]

Hi,
what gain is the tda set to?
What is the minimum gain specified by the manufacturer?

 

[Stinger]

The circuit is absolute the same as the datasheet suggests. Gain = 22K/680 ...

 

[AndrewT]

but post15 shows r1=r2=1k0

 

[Stinger]

but post15 shows r1=r2=1k0

I was lazy when I draw the schematic. so didn't change any label...

 

[AndrewT]

and then ask for help

 

[Stinger]

and then ask for help

My intention was to show Rainwulf how my Amps have two separate grounds. so there was no need to label each part exactly.

 

[Rainwulf]

So apart from the hiss, you are happy?

 

[Stinger]

So apart from the hiss, you are happy?

Yes! I could get rid of the hum...! and As I said the his is a tad!

Best Regards to you!