new guy here

[jovial_cynic]

Hey folks -

I've been dabbling with some DIY audio schematics, and managed to cobble together the LM386 Little Gem amp, and I'm onto my next project.

I've got a KA4558 op-amp chip handy. All the schematics I've seen show similar op-amp chips used in pre-amp circuits, and not in actual amplifier circuits.

Can the KA4558 or similar op-amp chips be used to make a small practice amp, or are they only useful in the pre-amp circuits?

[Cal Weldon]

Hi and welcome to the forums. You might wish the post the question in another forums as not everyone looks in here.

[jovial_cynic]

Thanks! Will do -

[Lsharptec1]

jovial_cynic,

The KA4558 is a common replacement for any of the 4558 family of dual opamps.

Basically, it's two improved 741 opamps in an 8 pin package.

It will make a nice preamp and tone control section for a mono practice amp.

Larry

[jovial_cynic]

Originally posted by Lsharptec1
jovial_cynic,
It will make a nice preamp and tone control section for a mono practice amp.

Ah, interesting. I've never used a pre-amp before, so I'm not completely certain how it shapes the sound. Like I said - I've build the LM386-based Little Gem, and it did what I wanted it to do. You are suggesting that a KA4558-based pre-amp to go into the Little Gem amp would be an improvement?

Do you suppose a 9v could power both of them, or am I going to need to use a 9v for each of them?

[Lsharptec1]

jovial_cynic,

Here is a link for the spec sheet on the KA4558.

http://www.fairchildsemi.com/pf/KA/KA4558.html

The spec sheet does not show practical schematics for a preamp, but you can find those all over the web. Just do a search for
"dual opamp audio preamp".

You can get away with using a single 9V battery for both devices, but be advised that battery life will be shorter.

Good luck.

Larry