[sdiy] transformers, power amps, and op amps.

rsdio at audiobanshee.com rsdio at audiobanshee.com
Wed Aug 19 11:56:45 CEST 2015


Tom is right, all you need is an op-amp. That Class B Audio Amplifier you're looking at is a *power* amplifier for driving speakers. You shouldn't use it unless you actually want to drive speakers. All you need is a *voltage* amplifier to go from line level to your ±12 V system. An op-amp with a ±12 V supply can easily boost line level inputs to the voltages you need. Just look for basic op-amp voltage gain circuits. Basically, add a couple of resistors and you're good.


On Aug 19, 2015, at 1:25 AM, Tom Wiltshire <tom at electricdruid.net> wrote:
> "Line level" varies a bit, but you can expect +/-0.5V to +/-2V signal levels. You can boost this to "modular synth" levels (often +/-5V, e.g. 10Vpp in a Eurorack modular with +/-12V supply, like your amp uses) using an op-amp. There's no need for transformers.
> On 19 Aug 2015, at 08:15, alfred.pear at gmail.com wrote:
>> my main reason for asking is that i'm interested in using line-level devices within a +/-12v system, so i know they need to be stepped-up via transformer at some point.. i'm essentially wondering if it's possible to use one transformer for multiple functions. 

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