Turning a car amp into a pc amp

[JDAudio]

Hi, I'm new to this forum but have watched it off and on for awhile. I've loved home audio since a child, turned to car audio in my teens, and I'm coming back to home audio again. I like building speakers and would like to setup a small system for my PC. I've been looking for a physically small integrated amp that would deliver at least 20 wpc, but i'm not having much luck. I'm thinking about building a custom amp but don't want to spend alot of money at this point. I've got access to free materials to build a chassis. I happen to have a profile california 35 wpc car audio amp that has discrete outputs and nice sound. I also have an industrial 15A 12V power supply that is very well built. I thought about pulling the boards and installing them together in a custom chassis. The problem is that i would like volume, bass, and treble controls on the unit and i'm not sure how to set this up. Anyone have a decent preamp schematic that would work in this application? Any suggestions on how I should set this up? Any help would be greatly appreciated.

Thanks,

JDAudio

 

[cunningham]

Have you ever made active filters using op-amps? You can make bandpass filters of 20dB/dec, 40dB/dec, or 60dB/dec. This seperates the full bandwidth into smaller bands of frequencies, then run each output through a pot, as an adjustable voltage divider, and then an output buffer amp, unity gain. Take each output buffer and add them together by making a summing amplifier as the output. All this using op-amps makes things simple. Choose the crossover frequencies cuttoff by the R & C components.

 

[JDAudio]

Thanks for the reply,
No i really haven't much experience building electronic circuits. Most of my experience comes from troubleshooting industrial controls. I also have pretty decent soldering skills. I can look at schematics and identify most components and would like to learn more about building amplifier and preamplifier circuits. What you are describing sounds like it would work great for tone controls or an equalizer. Do you have any links to any examples? I'm looking for something pretty simple to get started. All I really want is a master volume control, bass level, and treble level controls that would boost or cut at standard frequencies. I read an article in audioexpress magazine were in a project the author used an IC designed for car stereos and tv's that controlled volume, bass, and treble. Would something like that work here? If I could get this amp going I would like to build a pair of speakers for my PC, then come back and experiement with somemore amplifier designs. I'd kinda like to build a tube amp and see what all the fuss is about. I would appreciate any help getting me going in the right direction.

Thanks,

JDAudio

 

[cunningham]

Come to think of it, there is an IC, I can't think of the part number right now but it allows you to change the bass & treble leves using a variable DC voltage. Actually there may be more than one but I haven't used them. The way I understand it, you have to calculate the resistors and capacitors to make the filters, but it controls both R & L channels. Has a balance control too if I am not mistaken. I have only got so far as to just think of using one.

It may be much simpler but I don't know of the output quality. If anyone else on this forum has experience with this type of chip, holler out!