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power amplifier circuits with jrc 4558 as pre amp neded.

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timothy

New Member
please can someone help me with power aplifier with the ic ''jrc 4558'' as the pre- amp input or transistors A558/C547 as the pre-am input..?? please i'll really be very grateful as i have been on this for several years. 300watts to 600watts. THANKS....!! you can please send it to: bestguy4u@coolchannel.com
 

Chippie

Member
please can someone help me with power aplifier with the ic ''jrc 4558'' as the pre- amp input or transistors A558/C547 as the pre-am input..??


Could you be a little more specific with the kind of help you are looking for?
 

timothy

New Member
I HAVE TRIED SEVERAL TIMES TO BUILD A POWER AMPLIFIER. BUT AFTER BUILDING IT, THE POWER OUTPUT SIDE WORKS. BUT THE PRE-AMP SIDE DOES NOT WORK WELL. I USE THE IC; JRC4558. PLEASE CAN SOMEONE HELP ME WITH A GOOD CIRCUIT...???
 

Chippie

Member
The preamp side should be fairly easy to do........

What are the specs for the power amp ?

Input sensitivity for full power for a start would help....

Is there any special equalization needed for the preamp or does it neeed a flat response from say 20hz to 20khz....

What signal source are you feeding into the preamp, this along with the power amp sensitivity will set the over all gain of the preamp section......
 

timothy

New Member
SPECIFICATIONS FOR THE AMPLIFIER.

PLEASE I WOULD LIKE AN AMPLIFIER WITH BASE AND TREBLE. RIGHT NOW, I'M NOT REALLY TECHNICALY GOOD IN THE RANGE SPECIFICATIONS. BUT MOST IMPORTANT THING IT SHOULD HAVE GOOD RESPOUNSE AND NOT FLAT IN TONE. BUT PLEASE MOST IMPORTANT, IT SHOULD HAVE A POT VOLUME FOR A VERY HIGH GAIN OF ANY RANGE. THANKS FOR YOUR CONCERN....!!!! :D :D
 

Chippie

Member
You are still not specific with the details............

A tone control circuit is fairly easy to assemble using an op amp, but again I stress the need for more info.........no one can help if you dont help us!
 

efren sabio

New Member
Hi Tim,

I was looking for 'datasheet 4558' when Yahoo steered me to here, and
now I'm a member 1 minute old!

I'm currently fixing a channel of a mic/line mixer which uses the
opamp 4558. This is a dual opamp IC, an improved 741 type opamp.
This IC has been used in guitar and bass amps.

Your power amp, PA, does it use the 4558 as an integral part of the
PA circuit, or does it comes before the PA itself? You see, some designs
do use an IC opamp as 1st stage of the PA. If your 4558 has a capacitor
connecting to the PA then it's not the 1st stage of your PA and this is
much easier to debug.

Efren

. channel
 

efren sabio

New Member
Thanks for the datasheet.
I just done fixing 5 channels of a mic mixer which uses the 4558 and
they all had the same bug: the 2nd opamp is used as comparator in
the overdrive/clip circuit and the opamp just couldn't take it. What's
more the 4558 is more expensive here than the 5532. So I tried the
5532 as replacement. It worked! Not only I fixed the bug but the
sound is better!
 

laserdog3

New Member
heres some info on your parts

hello im new to the the site i was looking for parts my self

the parts you are looking for are the 2sa and 2sb prefix
2sa558 and the other is 2sb***
and the replacment for the ic is

ne5535 or mc1458

the 2sa558 is pnp

the 2sb*** is npn

the parts were used in power amps in the 1970s
and i have them if you cant find them
hope this helps thanks
laserdog3@juno.com
 

audioguru

Well-Known Member
Most Helpful Member
The MC1458 is very old and had poor performance. It can be replaced by a newer IC that has the same pins but has much better performance. I would use a TL072.

You answered somebody who disappeared more than 5 years ago.
 
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