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Hi everybody, I would like my EMG 81 in the bridge to run on 18 volts and my EMG 85 in the neck on 9 volts. I am attaching photo of a default connection and a second photo of the mod I am wondering will it work? Opinions please, will this work? And even if both work individually, when switch in middle position will they both maintain their own voltages?
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Without knowing anything about the internal workings of the EMG pickups, I'd assume that the signal wire going to the three way switch is isolated from the power supply wire. The signals are simply signals regardless of the voltage running the amps, and since there's no coupling caps elsewhere in the circuit they must be upstream of the signal leaving the pickup (that's the basis of my assumption). If that's correct, no problem with the voltage boost for the bridge pickup.
Disclaimer: I am not responsible for any 'magic smoke' leaving the pickups
If it still won't get loud enough, it's probably broken. - Steve Conner
If the thing works, stop fixing it. - Enzo
We need more chaos in music, in art... I'm here to make it. - Justin Thomas
MANY things in human experience can be easily differentiated, yet *impossible* to express as a measurement. - Juan Fahey
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eschertron Here is EMG schematic, does it still look OK :-)Last edited by Emetal; 08-20-2020, 06:13 PM.Comment
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It appears to me that it should work ok as there are caps blocking any DC.
But my question would be, why not run everything on 18V? Can the 85 not handle it?Originally posted by Enzo
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EMG 85 looses highs, it sounds dull, to my ears at least, when run on 18V. I simply do not like it. It sounds good on 9V.Originally posted by g1 View PostComment
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That's interesting. I suspected that you were looking for a little less gain out of the neck pickup, never thought that it would affect the tone. But yes, go for it!If it still won't get loud enough, it's probably broken. - Steve Conner
If the thing works, stop fixing it. - Enzo
We need more chaos in music, in art... I'm here to make it. - Justin Thomas
MANY things in human experience can be easily differentiated, yet *impossible* to express as a measurement. - Juan Fahey
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The opamp is different to a regular device in that it is programmable using a single resistor - presumably R8 in the schematic. According to the spec sheet "A single external master bias current setting resistor programs the input bias current, input offset current, quiescent power consumption, slew rate, input noise, and the gain-bandwidth product". The resistor is selected based on the positive supply voltage, which for this opamp is +/-1v to +/-18V. So no issues with the supply voltage being 9v or 18v, but there would be changes to the operating parameters which could only be established from the spec sheet.
Other than that the proposed circuit looks fine to me.Comment
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