I've been searching for a really simple amplifier circuit that requires only transistors, resistors, and capacitors. I want this simplicity because I already have an assortment of those parts and want to build something without having to buy more parts. All I want to do is drive maybe 15 to 30W speakers from my PC's audio out. I've seen simple Class-A audio circuits that are simple, but none had part specifications or resistor values. I have 6V and 12V transformers I could use. Is it possible to build such an amplifier?
Yes it is possible (most things are given time and money) The "Class A " website run by Geoff Moss for the Linsley Hood amp' is exhaustive for the home builder, try Google. I f the tranformers are for the the power supply you won't get the power you mentioned......then again you probably really don't need that much anyway. This amp' (The John Linsley Hood design) has it's own very large thread on this site. Put "JLH 10 watt class A" in the search funtion and you'll get well over a thousand posts. I imagine there are other designs around too. The chip amp' people also are worth a look if you want to spend a small ammount for an IC and relatively simple design. Good luck and welcome to the site. Jonathan
CalcProgrammer1 said:
Do you want class A, can you manage the heat? 10 watt class A is a very big heatsink and maybe not what you are looking for on a PC. Considered Class AB? there are many designs around that will work with the transformers that you have.
Do you want such a circuit and how complex do you need?
Regards
Nico
I'm looking for simple. Basically, I have some bookshelf speakers rated at 15W to 30W. My old PC (an HP) has an amplified out port, and I can plug the speakers directly into the port and run them fairly loud. I highly doubt it's actually approaching anywhere near 30W (maybe 5 at most) but it sounds good. My new PC has only a line-out. I'm looking for something really simple, I found one that used only a few resistors and a transistor or two, but it didn't have a part list or even the resistor values.
At this point I'm not caring too much about power efficiency or even sound quality, I just want to try something out for fun. I'd like to eventually get it to power an old car speaker as a cheap subwoofer (the speaker in question: NOM. 18W, MAX 35W, 6 OHM) which sounded really good when I plugged it into my parents' stereo amplifier.
At this point I'm not caring too much about power efficiency or even sound quality, I just want to try something out for fun. I'd like to eventually get it to power an old car speaker as a cheap subwoofer (the speaker in question: NOM. 18W, MAX 35W, 6 OHM) which sounded really good when I plugged it into my parents' stereo amplifier.
CalcProgrammer1 said:
Hi,
What are the parts you have? You'll need some fairly specific transistors to build an amp. You'll need a couple small signal types, a couple medium power types and a pair for output. Chances are you'll need to buy at least a few parts.
You might be better off with the chip amp solution (not nearly as fun though)
Transformers, you say 6V and 12V. Do you have one of each or more? Amps like split supplies.
Re: Re: REALLY simple amplifier?
Those are the right questions to ask, John. Lets see what he has and then what we can do to help him.
Regards
Nico
MJL21193 said:
Those are the right questions to ask, John. Lets see what he has and then what we can do to help him.
Regards
Nico
Another question CalcProgrammer1, are you capable of making or having a PCB made or need this be purely proto-type board. Give a little information of your capabilities so that we do not select either something to silly or to complex.
Death of Zen by Rod Elliott.
I built it a few years ago. It is simple, sounds very good and gets HOT. What else do you want?
http://sound.westhost.com/project36.htm
I built it a few years ago. It is simple, sounds very good and gets HOT. What else do you want?
http://sound.westhost.com/project36.htm
Re: NO output cap?
Ah, yes. Sorry you need a series output cap between amp and speaker. 8 Ohms would need about 2200uF.
Does this answer your question?
JORGETronic said:
Ah, yes. Sorry you need a series output cap between amp and speaker. 8 Ohms would need about 2200uF.
Does this answer your question?
Sorry as usual my English doesn't work properly.....
which is the voltage at the out point of the amplifier, IMO your circuit can have enough VCC during switch on that can affect the speaker
which is the voltage at the out point of the amplifier, IMO your circuit can have enough VCC during switch on that can affect the speaker
Re: Re: REALLY simple amplifier?
I agree with you. This circuit is unity gain thus provided he has sufficient voltage swing at the sound card output.
PMA said:
I agree with you. This circuit is unity gain thus provided he has sufficient voltage swing at the sound card output.
Okay it droops a little at 20kHz, but figures still acceptable for what he wants to do. Q1 & Q2 is of course the TIP 141. Did not have it in my library so I made it up quickly.
Kind regards
Nico
Kind regards
Nico
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