Whats this problem ?

Diy_Ambitious · 24th November 2004, 07:58 AM

Im building my first amp with a TDA7265 chip. Data Sheet link here
TDA7265

I followed the "Test and Application Circuit (Stereo Config)" page 7 schematic with the values they showed on page 8.

My electronics store ran out of 0.1uf caps, so I only have two 0.1uf caps for C8,C9. Will it be ok if i didn't have the other two supply voltage caps ?

It powered on fine, but when I play songs through my speakers I hear about 90% of every song extremely distorted or is it oscillation ? ( NOTE I did put a volume control before the input signal )

And for C7,C6 how is that connected. -Vs to the caps then ground ? or are the two caps on ground ? ( I couldn't explain it any better, Im no good at explanations, forgive me

) Is -Vs the same as ground ?

Netlist · 24th November 2004, 08:11 AM

+Vs would be 25V, -Vs would be -25V.
So -Vs is NOT ground.

/Hugo

Frank Berry · 24th November 2004, 08:25 AM

"My electronics store ran out of 0.1uf caps, so I only have two 0.1uf caps for C8,C9. Will it be ok if i didn't have the other two supply voltage caps?"

The other .1uf caps are important to the stability of the amplifier.
If you can't find any .1uf caps, use .15uf or .22uf caps. They should work fine. Without the caps, the chip will probably go into oscillation.

Diy_Ambitious · 24th November 2004, 08:47 AM

So -Vs does not Connect to the input signal AND Speaker Ground ?

so i need a power supply like +25V_0_-25V

peranders · 24th November 2004, 08:55 AM

If you check the datasheet you have also a schematic for single supply operation, page 2, fig. 2

Diy_Ambitious · 25th November 2004, 06:35 AM

Ok, thanks all. I'll try the single supply schematic.

Diy_Ambitious · 25th November 2004, 06:35 AM

YEEAAAHH It's workin'

I also changed to output caps to 2200uf and bass is sick LOW my two ears can't handle it

hehe

. Chip doesn't get hot at all and my transformer (120VA) has got more juice than it needs, I got a TDA7294 (50W X 1) may be i should stick it in also and have a 2.1 AMP ?

24th November 2004, 07:58 AM	#1
Diy_Ambitious diyAudio Member Join Date: Sep 2004 Location: NZ	Whats this problem ? Im building my first amp with a TDA7265 chip. Data Sheet link here TDA7265 I followed the "Test and Application Circuit (Stereo Config)" page 7 schematic with the values they showed on page 8. My electronics store ran out of 0.1uf caps, so I only have two 0.1uf caps for C8,C9. Will it be ok if i didn't have the other two supply voltage caps ? It powered on fine, but when I play songs through my speakers I hear about 90% of every song extremely distorted or is it oscillation ? ( NOTE I did put a volume control before the input signal ) And for C7,C6 how is that connected. -Vs to the caps then ground ? or are the two caps on ground ? ( I couldn't explain it any better, Im no good at explanations, forgive me ) Is -Vs the same as ground ?

24th November 2004, 08:25 AM	#3
Frank Berry diyAudio Member Join Date: Sep 2003 Location: Midland, Michigan	"My electronics store ran out of 0.1uf caps, so I only have two 0.1uf caps for C8,C9. Will it be ok if i didn't have the other two supply voltage caps?" The other .1uf caps are important to the stability of the amplifier. If you can't find any .1uf caps, use .15uf or .22uf caps. They should work fine. Without the caps, the chip will probably go into oscillation. __________________ Frank

24th November 2004, 08:55 AM	#5
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	If you check the datasheet you have also a schematic for single supply operation, page 2, fig. 2 __________________ /Per-Anders (my first name) or P-A as my friends call me

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24th November 2004, 08:11 AM	#2
Netlist diyAudio Moderator Join Date: Jan 2003	+Vs would be 25V, -Vs would be -25V. So -Vs is NOT ground. /Hugo

24th November 2004, 08:47 AM	#4
Diy_Ambitious diyAudio Member Join Date: Sep 2004 Location: NZ	So -Vs does not Connect to the input signal AND Speaker Ground ? so i need a power supply like +25V_0_-25V

25th November 2004, 06:35 AM	#6
Diy_Ambitious diyAudio Member Join Date: Sep 2004 Location: NZ	Ok, thanks all. I'll try the single supply schematic.

25th November 2004, 06:35 AM	#7
Diy_Ambitious diyAudio Member Join Date: Sep 2004 Location: NZ	YEEAAAHH It's workin' I also changed to output caps to 2200uf and bass is sick LOW my two ears can't handle it hehe . Chip doesn't get hot at all and my transformer (120VA) has got more juice than it needs, I got a TDA7294 (50W X 1) may be i should stick it in also and have a 2.1 AMP ?

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