| T O P I C R E V I E W |
| jnewman |
Posted - Feb 23 2010 : 1:46:28 PM
Hi Guys, just need a bit of advice really. As part of a project, I need a simple, but effective amplifier for a speaker (nothing big, probably one of those cheapy cardboard coned ones). Out of our course textbook, there are two circuits suggested. I was wondering if anyone had any idea on which one is better in terms of power output, etc.
The first is a pair of MOSFETs in a feedback loop. After rummaging through our parts trays, we couldn't find any similar/matching N-type and P-type MOSFETS, so I am going to have to order some. Which MOSFETs shall I use? Preferably not that expensive, other parts of the system use TL061s, so sound quality isn't a huge issue. Also, what approx value would that resistor connected to ground be (and why)? I'm really sorry for the awful diagrams
The book recommends I use L272M op-amps, is this OK? Also, what rough value would those 2 resistors be?
Sorry about the length of this, but any help would be much appreciated =D |
| 1 L A T E S T R E P L I E S (Newest First) |
| audioguru |
Posted - Feb 23 2010 : 6:29:43 PM
Your Mosfets won't work because their gate voltage (input) needs to be up to 10V higher than their source voltage (output).
The very old opamps won't work because they are not audio power amplifiers. They have very poor high audio frequencies response and their output current is much too low. They also do not have a case that can be cooled with a heatsink. |
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