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mid freq switch

Bartolini HR-4.6AP/918

The Bartolini HR-4.6AP/918 preamp harness makes a great upgrade to the output of your bass. This particular kit includes:

(1) Bartolini NTMB-918F Module
(1) 250k Volume Potentiometer with Push/Pull Active-Passive Operation
(1) Dual 250k Potentiometer For Dual Pickup Blend
(1) 50k Mid Potentiometer w/ Push/Pull Operation For Mid Frequency Selection
(1) Dual 50k Stacked Potentiometer For Treble/Bass Stack
(1) Stereo Output Jack
(1) Set Of Plastic Knobs For Stacked Treble/Bass Pot

The HR-4.6AP/918 comes pre-wired for 9 Volt Operation. For 18 Volt operation, simply install the additional 9 Volt battery clip (included). All pots and the output jack are pre-wired and tested at Bartolini. Pots and Output jack include mounting hardware. With the supplied instructions, installation is a breeze.

Technical Info:

Dimensions: NTMB-918F Module = 1.75"L x 1.5"W x 0.5"D
Dimensions: NTMB3F Module = 1.25"L x 1"W x 0.5"D
Bass Control: +/- 16dB Centered at 30Hz.
Mid Control: +/- 11dB Centered at 250 Hz or 800 Hz Treble Control: +/- 15dB Centered at 10kHz.
9 or 18 Volt Operation (batteries not included), Additional 6dB with 18V Supply
 
A Bart pre would be clearly identified in large letters on the side of the pre. How about a pic of what you have?
... this is what I have...the mid pot is the one with the brown wiring coming from it.... the short one...
 

Attachments

  • preamp.jpg
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Not all preamps can have a mid-frequency switch added. The preamp you have looks like everything is sealed, and there isn't any access to insert different components into the circuit to change the mid frequency.

The Bart preamp actually has wires coming out of it to be hooked up to the mid-frequency switch.