EEVblog Electronics Community Forum

EEVblog => The AmpHour Radio Show => Topic started by: AFSR on February 26, 2014, 04:03:29 pm

Title: bypass a IL4558 on a phono amplifier.
Post by: AFSR on February 26, 2014, 04:03:29 pm
i have an old sony stereo and has a phono input! but its to sensitive for connecting any device to it!. you barely give it any input and distorts. can i bypass the IL4558 that is just after the input jack's? how can i lower the gain of these input?
Title: Re: bypass a IL4558 on a phono amplifier.
Post by: dr_dan on February 26, 2014, 04:29:29 pm
A few years ago I used this circuit - it lowers the input level and compensates for the non-flat input characteristics of the phono input.

http://www.epanorama.net/circuits/phono.html (http://www.epanorama.net/circuits/phono.html)
Title: Re: bypass a IL4558 on a phono amplifier.
Post by: AFSR on February 26, 2014, 04:46:38 pm
that is great! but i will not use the phono input anymore ( have no turntable). can i just remove the il4558 and bypass the pins? >:D
Title: Re: bypass a IL4558 on a phono amplifier.
Post by: SeanB on February 26, 2014, 07:12:13 pm
Would recommend you just remove the feedback network and turn the 4668 into a plain buffer amplifier instead. Then add an attenuator on the input side as it will still need about 6db of attenuation to handle a standard line level input.