Transistor Amplifier Build





Introduction: Transistor Amplifier Build

I've made a couple of these. I found the original schematic online then modified it because I did not have one of the parts the original plan calls for. My design allows the use of much more common parts. Although it uses more parts and is a bit more complicated.

Step 1: The Schematic

Looking at a schematic is always how I decide of I want to build a circuit or not so I will present it first. I found the one I based my design off of here:

Although mine isn't exactly like that one it is essentially the same topography. It sure looks simple enough doesn't it? That is why I choose to build it myself. I made my schematic because I did not have a TLE2141C Op-Amp. If you do then you can build the original and it should be easier than building mine.

IC1 and IC2 on my schematic are 15 volt regulators I used 12 volt ones. SL4 from the power supply section should power the lower voltage dual op-amp of course.

Step 2: Board

I've made so many of these I'm not really so sure which is what anymore. I know I cleaned the schematic up a little before I uploaded a screen capture of it for the previous step. I'll be honest, often when I am doing an electronics project I just want something to work so I don't spend as much time as I should making my schematics as neat as I could before I move on to the next step.

Just so long as everything is hooked up you know? Sometimes I find while I am routing a board that some things aren't connected to each other too! Then I have to go back and fix that.

Anyhow the one I am including here looks pretty good to me. If anyone finds any problems then let me know and I'll see what I can't do to fix it.

Step 3: Power Supply

First I'll cover the input stage of the power supply for this project. It is a center tapped, rectified, then filtered configuration. Exactly like what is described here. Now I'll get some mileage out of that Instructable. No one ever bothered with it as of now.

You can see in my picture that I have 40 volts between my VCC and VEE, which gives me +-20V. Close enough for the 22V the circuit calls for.

Step 4: Choose Your Poison

I've made this amp on perfboard, and etched boards for it too. Either way works. I'll offer some build pictures in this step.

Step 5: Closing Thoughts

This is a pretty loud and sweet sounding amp to me. With my circuit one of the op amp sections of the dual op-amp is used as sort of a preamp stage and the trimmer next to it is a gain control. I like mine loud. The other trimmer by the transistors is the bias setting, jack it up until amp misbehaves, then back it off some. You're good to go!

I've had a Fender tube amp, I have a Marshall Lead 12, and I've a couple of these amps I've built. I like my amps the best out of the bunch. You could easily find someone willing to soak you $100 or even more for an amplifier like this. So why not build one out of some junk and rock instead?

Oh for the output transistors any matched audio transistors seem to work to me. If the pin outs of your transistors are different either bend the legs around or change them in the schematic and reroute. If the whole project blows up, well that is even more rocking! One of mine already has.

This ain't no cheese whiz LM386 amplifier. This puppy pumps.



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    "Anyhow the one I am including here looks pretty good to me. If anyone
    finds any problems then let me know and I'll see what I can't do to fix

    Took a quick look at your board and must conclude that you dislike board layout as much as digital electronics ;)

    Normally I'd say "back to square one" to a layout like this - 8 unconnected traces, more than 10 acid traps, awkward component orientation and just as awkward "pads" and traces not commanded by the schematic, topped of with this very strange build-up of rectangles (was it meant to be a pseudo copper fill?). Not sure where you connect ground from the power supply either. Just went down with a fever and a blinding headache, so I might have missed other stuff.

    If you need help fixing it, just say so - I could make the schematic more readable as well.

    An even quicker look at the overdrive pedal that you link to, seems to have very similar layout "qualities". I didn't look at what other layouts you may have posted, but if it's a trend, you might wanna practice some simple layouts before diving in the deep end :)

    I am grateful for any help you can offer. Just link to your fixed files in the comment section here. Thanks for the comment.

    Thats what those NE4558CP chips are for... I looked them up and they had to do with amplifying the reverb or something. I took apart a Peavey that was broken and found those IC's in there

    if you want i can design a smaller and more efficient pcb for you. so that we don't need to buy expensive large pcbs and a lot of etchant. nice tible

    Post it. I'll check it out. I have to say taking all things into account my board design suits how I build. A board this big costs me about 50 cents to buy. That makes the cost a small factor all things considered.

    yeah sure, but in some countries those pcbs may cost about 10-15 dollars to manufacture, since this ible is made facilitate lijes of people or hobbyists.
    still glad that i got a reply

    It sounds to me like people in some countries are getting ripped off. I'd be rioting in the streets over board prices that high!

    what can i do. there is only one board supplier in Mauritius, so they take advantage of it. and eBuying is not recommended here for the time being. :P

    Excessive exploitation seems to be a recurring theme in your country. First the Dodo, now electronics supplies. I think it is up to you to buck the trend. Take a lesson from your extinct feathered friends, it usually doesn't pay to be too passive about abuse. Gandhi got famous because it worked for him, normally it doesn't.

    Get some of your geeky buddies together and toss a shipping container into the harbor or something! If you can manage to round up that many geeky friends then just start a company with them. Shipping containers are heavy, and the best you could hope for pulling off a stunt like that is getting all wet from the splash.

    If there is any meaning to life it is making your dreams real. In order to do that it involves a lot of effort in your waking hours though.