TL071 opamp circuit needed

space2000 · 21st May 2008, 06:51 AM

hi,

i need to bost my input gain for my amp. i have seen that i can use opamp to bost the signal from cd player.

it gose like this....CD player-->--OPamp---> amp

i have TL071 ic for opamp. i need the circuit design for simple way to build opamp.

thank you.

Mooly · 21st May 2008, 07:10 AM

How much gain do you need ? what supplies have you got ?
You need 2 opamps or 1 dual TL072. See image.
The second one is phase inverting but this configuration can sound better to me. You can add a small ( around 4.7 PF ) cap across the 47 K ( This is where you need your 'scope

)

space2000 · 21st May 2008, 09:04 AM

hi mooly,

thank you for your circuit. i want to use it for a gain boster for amp. now i can calculate the gain for the amp.

for Precs-I, what us the highest gain should be? do you know?

thank you for help.

AndrewT · 21st May 2008, 09:21 AM

Hi,
the highest signal from a CD player is about 2Vac.
If you have a 100W into 8r0 amplifier then the highest signal to the speaker is 28.28Vac.
The gain you need is 14.1Times (+23dB).
most amplifiers are set up with a gain of between +20dB and +36dB.
You don't need any more gain in the preamp to achieve maximum power into your speakers.
You need attenuation.

sreten · 21st May 2008, 10:38 AM

Hi,

Something is very wrong if you need to boost a CD players output.

/sreten.

Mooly · 21st May 2008, 10:52 AM

Quote:

Originally posted by AndrewT
Hi,
the highest signal from a CD player is about 2Vac.
If you have a 100W into 8r0 amplifier then the highest signal to the speaker is 28.28Vac.
The gain you need is 14.1Times (+23dB).
most amplifiers are set up with a gain of between +20dB and +36dB.
You don't need any more gain in the preamp to achieve maximum power into your speakers.
You need attenuation.

Maybe they are quiet CD,s

space2000 · 21st May 2008, 12:43 PM

hi,

if my amp operate with my mobile phone. the sound is very strong and loud as it should be by the wats but when i attach the cd player it's gets flat and low sound like 50% less then mobile phone was used. so i was thinking may be it cause by the gain is too low for the amp.

thank you.

ssmith · 21st May 2008, 12:50 PM

what CD player are you using?

PMA · 21st May 2008, 12:58 PM

I just used one for a DC servo.

space2000 · 21st May 2008, 01:07 PM

hi,

i likie to thanks all of you. For the gain control circuit calculation

RF=47k
Rin=22k

Gain= RF/Rin

Gain=47/22 = 2.136db?

thank you.

21st May 2008, 06:51 AM	#1
space2000 diyAudio Member Join Date: Mar 2008	TL071 opamp circuit needed hi, i need to bost my input gain for my amp. i have seen that i can use opamp to bost the signal from cd player. it gose like this....CD player-->--OPamp---> amp i have TL071 ic for opamp. i need the circuit design for simple way to build opamp. thank you.

21st May 2008, 09:21 AM	#4
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, the highest signal from a CD player is about 2Vac. If you have a 100W into 8r0 amplifier then the highest signal to the speaker is 28.28Vac. The gain you need is 14.1Times (+23dB). most amplifiers are set up with a gain of between +20dB and +36dB. You don't need any more gain in the preamp to achieve maximum power into your speakers. You need attenuation. __________________ regards Andrew T.

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21st May 2008, 09:04 AM	#3
space2000 diyAudio Member Join Date: Mar 2008	hi mooly, thank you for your circuit. i want to use it for a gain boster for amp. now i can calculate the gain for the amp. for Precs-I, what us the highest gain should be? do you know? thank you for help.

21st May 2008, 10:38 AM	#5
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Hi, Something is very wrong if you need to boost a CD players output. /sreten.

21st May 2008, 12:43 PM	#7
space2000 diyAudio Member Join Date: Mar 2008	hi, if my amp operate with my mobile phone. the sound is very strong and loud as it should be by the wats but when i attach the cd player it's gets flat and low sound like 50% less then mobile phone was used. so i was thinking may be it cause by the gain is too low for the amp. thank you.

21st May 2008, 12:50 PM	#8
ssmith diyAudio Member Join Date: Aug 2005 Location: Paris	what CD player are you using?

21st May 2008, 12:58 PM	#9
PMA diyAudio Member Join Date: Apr 2002 Location: Prague, Kitakyushu, Fukuoka	I just used one for a DC servo.

21st May 2008, 01:07 PM	#10
space2000 diyAudio Member Join Date: Mar 2008	hi, i likie to thanks all of you. For the gain control circuit calculation RF=47k Rin=22k Gain= RF/Rin Gain=47/22 = 2.136db? thank you.

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