Pre Amp wiring.

**METAL Rulez 4ever** · 16-03-2017, 11:18 AM

Hello to all,

Hope all is well with you.

I have a pre amp wiring assembly with 4 pots (2xA20K and 2xB500K). There are no capacitors. I am installing this into a Yamaha YB style with P Bass style pick ups. Do i need capacitors or not please ?

**wokkaboy** · 16-03-2017, 11:21 AM

Hey Metalrulez, all good no need for capacitors. I just installed a 4 pot pre-amp into my jazz bass. The treble control will be similar to a tone control. Presume the 4 pots will be balance (split sound between 2 pups), master volume, treble and bass

**Simon Barden** · 16-03-2017, 11:14 PM

There should be a pre-amp circuit board or encapsulated board along with the pots that were supplied with the pre-amp kit. All the active tone controls are on the board (either open or encapsulated) so you won't need any external ones (which are for passive tone controls).

**METAL Rulez 4ever** · 24-03-2017, 01:46 PM

Thank you Gents...WokkaBoy and Simon. Much appreciated. I will endeavour to attempt this build in this next coming weeks.

**METAL Rulez 4ever** · 08-04-2017, 11:36 AM

Ok, i have the Pre Amp Wiring Kit with the J Style and P style Pickups. I have looked everywhere on the internet on how to solder this. But none are specific enough for my liking. I have attached a picture. Could anyone please offer some assistance on how to solder the pickups to which pots ? Two pots are A20K, one pot is B500K and the other is MN500K. The MN500K has 6 lugs (doubled row rather than 3 in a single row like the other 3 pots).

Click image for larger version.

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**Simon Barden** · 08-04-2017, 04:49 PM

The two 20k pots are the treble and bass tone controls. The B500k is the volume pot and the MN500k is the pickup blend pot.

Both pickups get wired to the blend pot.

Here's a SD diagram for a passive version, but the wiring for the blend pot should be the same. https://docs.google.com/gview?embedd...1V_1T_1Bld.pdf.

You can attach the ground wires to the back of the blend pot if you wish, as it often makes it easier (though looking at pictures, it might not have a metal back, in which case, solder the grounds to the back of the volume pot). The hot wire of the P bass goes to the centre tag of the row of 3 tags nearest the shaft, the J-bass hot wire goes to the centre tag of the row of 3 tags furthest away from the shaft (which hopefully means that you turn it forwards/clockwise for the P-Bass and backwards/anti-clockwise for the J-bass). If it ends up being the reverse, then you can either live with it or swap the two connections over.

I'd twist the two J-bass pup wires together, as it does reduce the amount of noise picked up by the leads, plus it looks neater.

**METAL Rulez 4ever** · 30-07-2017, 10:47 AM

Originally Posted by Simon Barden

The two 20k pots are the treble and bass tone controls. The B500k is the volume pot and the MN500k is the pickup blend pot.

Both pickups get wired to the blend pot.

Here's a SD diagram for a passive version, but the wiring for the blend pot should be the same. https://docs.google.com/gview?embedd...1V_1T_1Bld.pdf.

You can attach the ground wires to the back of the blend pot if you wish, as it often makes it easier (though looking at pictures, it might not have a metal back, in which case, solder the grounds to the back of the volume pot). The hot wire of the P bass goes to the centre tag of the row of 3 tags nearest the shaft, the J-bass hot wire goes to the centre tag of the row of 3 tags furthest away from the shaft (which hopefully means that you turn it forwards/clockwise for the P-Bass and backwards/anti-clockwise for the J-bass). If it ends up being the reverse, then you can either live with it or swap the two connections over.

I'd twist the two J-bass pup wires together, as it does reduce the amount of noise picked up by the leads, plus it looks neater.

Thank you for all your help guys, very much appreciated. Simon, your instructions and link worked perfectly. Converting the Wilkinson's from passive to actives with the Belcat pre-amp sounds great. Here are photos attached of the finish product on my Yamaha RBX Bass.