Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 19th April 2008, 02:41 AM   #1
diyAudio Member
 
Join Date: Mar 2008
Default Where to start

Hey folks -

From what I've noticed, a lot of the amp builds around here are simply done from existing schematics or kits, and while I can follow directions easily, I'm having a little bit of difficulty figuring out exactly why things work the way they do. I've yet to see a writeup that explains, step-by-step, what the circuit is doing, and how one goes from building a very simple amp to a more complex amp. I don't know enough of the theory to know how to go from one to the other.

I'd prefer to have an understanding of what's going on. I've got a truck-load of components at my disposal, and rather than buy a kit or more parts, I'd just as soon dig through my box of power-transistors power-supplies, and passive components and throw something together... but I don't know exactly how to start.

I've just taken apart a JVC stereo tuner. By itself, I know that it's an audio amplifier -- a dual-channel 220watt amp that puts out a decent amount of sound. I'm in the process of scavenging parts off of it, because the panel (all the buttons) is defective, and rather than fix it, I'd rather learn on it.

The JVC uses two sets of power-transistors: a pair of 2SB1429 and a pair of 2SD2155. Using those transistors and the power supply that's in the JVC, how would I go about building the a simple audio amplifier? Or a moderately complex amplifier?

Thanks in advance. I ask a lot of questions, so please be patient with me.
  Reply With Quote
Old 19th April 2008, 03:00 AM   #2
CBS240 is offline CBS240  United States
diyAudio Member
 
CBS240's Avatar
 
Join Date: Aug 2005
Location: K-town
Hi

You must first start with a general topology that will achieve your set of specifications. And those specifications are............
__________________
All the trouble I've ever been in started out as fun......
  Reply With Quote
Old 19th April 2008, 03:11 AM   #3
diyAudio Member
 
Join Date: Dec 2007
Location: Vermont
Wow, going straight to a jog without taking baby steps or walking. You are brave. I would suggest a google search for some tutorials on electronics theory, they are out there, this will help you understand how things work, thus how you can use the parts you have to design an amp. I would suggest using one of the designs already available for your first project, with the necessary mods to accommodate the components you have.

Peace,

Dave
  Reply With Quote
Old 19th April 2008, 03:17 AM   #4
diyAudio Member
 
Join Date: Mar 2008
Quote:
Originally posted by CBS240
Hi

You must first start with a general topology that will achieve your set of specifications. And those specifications are............

That's a fascinating question. I think my objective is really less about meeting a particular specification, and more about understanding transistor-based audio amplifiers.

I liken it to this: Let's say you want to know how to build an outdoor playhouse. You could start with questions like "how many square feet do you want it to be?" "How tall do you want it to be?" etc., etc., but in reality, those questions are unnecessary to know *how* to build a playhouse. Building a playhouse is, in the most basic sense, a matter of a floor, walls, ports, and a roof. The specifications are only useful for finishing the work; they're not necessary to gain a basic understanding of the construction.

The understanding of the construction of transistor-based audio amplifiers is really what I'm shooting for. I've read up on what a transistor does, what an op-amp does, what resistors and capacitors do, etc., etc., but I don't have a good visual concept for what's going on with an audio signal as it goes from input to output.

I've built a couple of LM386-based mini-amps, and like I said -- I can follow instructions. And I could follow instructions for a transistor-based amp as well, but it doesn't help me gain any ground in understanding what's going on, and it doesn't allow me to expand on the circuit, or improvise. But that's exactly what I want to learn to do.
  Reply With Quote
Old 19th April 2008, 03:18 AM   #5
diyAudio Member
 
Join Date: Mar 2008
Quote:
Originally posted by dave_gerecke
Wow, going straight to a jog without taking baby steps or walking. You are brave. I would suggest a google search for some tutorials on electronics theory, they are out there, this will help you understand how things work, thus how you can use the parts you have to design an amp. I would suggest using one of the designs already available for your first project, with the necessary mods to accommodate the components you have.

Peace,

Dave

I've got the electronic theory about as well as I think I'm going to get. I could quote you a dictionary definition of what every component is supposed to do, and all that... but somehow, it's not bridging the gap between the components and the final product.

:: shrug ::
  Reply With Quote
Old 19th April 2008, 03:41 AM   #6
diyAudio Member
 
Join Date: Dec 2007
Location: Vermont
Hello J_C, I am trying to figure out a way to explain how the pieces go together, but I must confess that I've never tried this before, so it isn't easy. It is much easier to explain something like how an amp works when you have a schematic to look at and reference. It is another thing when you have to imagine general concepts and then translate those concepts to language that newbies will understand. I will think about this and try to get back to you. If no one else of greater knowledge than I comes along and helps you out, please drop another comment to remind me.

Peace,

Dave
  Reply With Quote
Old 19th April 2008, 03:48 AM   #7
diyAudio Member
 
Join Date: Mar 2008
well, I suppose you could pick a super simple transistor based audio amplifier schematic and we could go from there.

:: shrug ::
  Reply With Quote
Old 19th April 2008, 04:19 AM   #8
diyAudio Member
 
Join Date: Feb 2001
Location: Columbia, SC
Several more or less random points:
--Find a copy of Horowitz & Hill's The Art of Electronics
It's not enough to know the dictionary definition of the parts. You have to figure out how they act and interact. Unfortunately, things are a little more complex than applying a hammer to a nail to bind one piece of wood to another.
--If it's simple amps and rationale you want then hie thyself hence to www.passdiy.com and start reading the sundry construction articles. The circuits range from one notch above trivial to moderately complex, with multiple stopping points in between. And a lot of explanations along the way. Think Suzuki method: Learn to play, then go back and add theory.
--Some of this is just gut feeling. It's one thing to be able to say that you know Ohm's Law. It's another entirely to look at a a schematic and say, "Wait a minute...something's not right, here..." Experience takes time.
--If it were easy, everybody would be doing it. The fact that they're not--and that even a lot of the ones who claim they're doing it aren't doing it well (think of a kid running across the front yard holding a board as a wing..."Lookit me! I'm flyin'!"...in their minds, they're flying, in reality they have yet to leave the ground) is just part of the process.
--Don't let anything dissuade you if you are truly serious. Just don't expect miracles. The trick is not to get so serious that you burn out in six months. Play with it so that it's fun and you'll last a whole lot longer. Try a couple of simple to moderate projects first so that you have background music while you're designing your Magnum Opus.
--Sooner or later, someone will suggest that you simulate rather than build your circuit. I'll put it this way...there are inflatable sex dolls and there are real women. Once may get you through the night. The other might become a lifelong companion. Ask yourself which you would prefer.
--I myself tend towards vertical learning curves. About every two to five years, I attack something new. Right now I'm learning to make sausage. I've yet to make a bad one, but the ones I'm making now are a damn sight better than the first ones I made. I'm honest enough to admit that I'm not ready to win awards, but I'm also far enough along that we no longer have to buy sausage at the store. If you approach audio with reasonable expectations, relative to your own abilities, you'll have something to occupy many a midnight hour from here on 'till you go deaf in your old age.

Grey
  Reply With Quote
Old 19th April 2008, 05:37 AM   #9
dfdye is offline dfdye  United States
diyAudio Member
 
dfdye's Avatar
 
Join Date: Dec 2005
Location: USA
For good background information on what generic audio circuits are supposed to do, I typically try Doug Self's book first since it is written pretty simply, and I am a pretty simple guy!

He has a web site too, that may be of interest, but I haven't played around there enough to know.
  Reply With Quote
Old 19th April 2008, 08:00 AM   #10
Nordic is offline Nordic  South Africa
diyAudio Member
 
Nordic's Avatar
 
Join Date: Sep 2005
http://www.diyaudio.com/forums/showt...70#post1279670 start here
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Where to start? mattmcl Chip Amps 3 18th May 2009 07:49 AM
Will start my new Gainclone from Start, Need Help samsagaz Chip Amps 4 27th May 2008 09:39 AM
Where do I start? damonpip Pass Labs 23 18th April 2006 08:58 PM
ESL - Where does one start??? darcangelo Planars & Exotics 15 13th January 2005 11:34 AM
where to start?! samsagaz Solid State 1 30th August 2004 05:30 AM


New To Site? Need Help?

All times are GMT. The time now is 06:42 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2