chris_b Posted December 12, 2012 Share Posted December 12, 2012 Chaps, I'm not after a description of the difference in sound/tone/volume, but what is the technical difference between a 9v system and an 18v electrical system on a bass and is it possible to just add another battery. Is there a technical reason, like you'll fry the 9v components if you add another battery? Cheers Quote Link to comment Share on other sites More sharing options...
LukeFRC Posted December 12, 2012 Share Posted December 12, 2012 about 8.5v I would guess in practice! Seriously thoguh I think it depends on the circuit - and yes one without high enough rated components could go pop. Quote Link to comment Share on other sites More sharing options...
obbm Posted December 12, 2012 Share Posted December 12, 2012 It's all down to headroom. A circuit designed to run on 18-volts has more headroom than one designed to run on 9. You can't just add another battery as the biasing of the components will be all wrong. Quote Link to comment Share on other sites More sharing options...
Happy Jack Posted December 12, 2012 Share Posted December 12, 2012 So how does it work when a pedal (e.g. the Catalinbread SFT) says that it will work with either 9V or 18V? I can see how using better / stronger components can handle the overall extra power, but wouldn't the biasing still be askew? Be gentle with me Dave, you know I'm inexperienced in this sort of activity ... Quote Link to comment Share on other sites More sharing options...
LukeFRC Posted December 12, 2012 Share Posted December 12, 2012 [quote name='Happy Jack' timestamp='1355329461' post='1897035'] So how does it work when a pedal (e.g. the Catalinbread SFT) says that it will work with either 9V or 18V? I can see how using better / stronger components can handle the overall extra power, but wouldn't the biasing still be askew? Be gentle with me Dave, you know I'm inexperienced in this sort of activity ... [/quote] cos it will be designed to work higher voltage but still work at lower voltages. Quote Link to comment Share on other sites More sharing options...
flyfisher Posted December 12, 2012 Share Posted December 12, 2012 It all depends on the circuit design. obbm is right about the headroom thing but it can be achieved in different ways. 18v could be 0-18v or could be -9v gnd +9v. split power rails are very convenient for op-amps, for example. As for pedals being able to cope with 9v or 18v, that might have nothing to do with the audio circuitry and everything to do with the input voltage regulator. Given the wide varietty of pedal PSUs and the inevitable mistakes that people will make with them, any decent pedal manufacturer would design the power input socket to be able to cope with a wide range of input voltage and also reverse polarity, but none of that need have any bearing on the actual audio circuitry. Quote Link to comment Share on other sites More sharing options...
mart Posted December 12, 2012 Share Posted December 12, 2012 [quote name='obbm' timestamp='1355328565' post='1897012'].... You can't just add another battery as the biasing of the components will be all wrong. [/quote] In some circuits you can, at least without frying anything. Some people say it improves things; others reckon they're just hearing an improvement that they expected to hear. I think it's safe to say: 1) it depends - adding a battery might be possible or might not, depending on the particular preamp you have. 2) it's complicated - 18v can be used in different ways, as flyfisher mentions. Which, I think, is why the sticky on this topic isn't very conclusive. Quote Link to comment Share on other sites More sharing options...
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