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  #61  
Old 03-03-2017, 10:13 AM
Marek Marek is offline
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After reading this thread (little late) I tried changing input impedance of my DIY preamp built for BGM Elevation pickup (similar to K&K PWM) installed in my custom dread.
I changed it from widely known "optimal" 1M to 390k and I must say - for me it works better - sound is much more transparent and "open".
The other big change in amplified tone was achieved by adding phase switch to the preamp - depending on the PA in the venue I played, switching phase change tone noticeably.
So my advice is to try (if you are able) different impedances of the preamp, because depending of the instrument and what is less obvious, type and size of the room you perform, 1M impedance is not always optimal.

Take care,
Marek
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  #62  
Old 03-03-2017, 10:29 AM
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Doug Young Doug Young is offline
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At 390K, you're mostly likely rolling off some bass, which can sound less muddy and more "open" depending on what tone you are looking for.

The phase thing is tricky, and there are at least 2 scenarios. If you're playing below some level, the tonal change you hear will be due to the interference between the amplified sound and direct acoustic sound reaching your ears. But the change in this case may not be something an audience will hear. You can convince yourself of this by recording your preamp's output, and switching phase. On playback, when you hear only the amplified sound, you should hear no difference. (You can also check this by wearing reasonably isolating headphones)

on the other hand, if you are playing loud enough that the amplified sound is interacting with the top - a sort of "pre-feedback", then the phase could alter the sound the audience hears, as well as affect the potential for feedback, which is when the phase switch comes in handy.
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