I got potted and I liked it.

[Marky Screen]

So I recently noticed that my Yamaha BB 424x had got really microphonic and transferred loads of acoustic noise to the amp when tapping the pickups, body, control plate, anywhere on the bass really with the strings muted. 

gave it to my local tech, the awesome amazing Job Dickinson of Dickinson Amps in Crystal Palace and he did indeed diagnose the pickups as being very microphonic.

So we went for it and wax potted the pickups. From a bit of research I know it's a bit of a mixed bag at whether it'll sort the problem so didn't know what to expect. 

Got it back and had a jam yesterday and it been cured!! microphonic noise reduced to about a 10th of what it was before

So the trade off, and Jon did tell me about this pre-potting, was that the pickups would lose a bit of air and top end to  the sound.

They have indeed lost a fair bit of treble content which was instantly noticeable. Its almost lost too much by a hair, but the strings on it aren't the newest, I also dipped the tone a smidge before anyway and I've got plenty of pre-amp and drive control on my board to add this back in if needed.

however losing that air, and I'm guessing shifting the resonant frequency of the pups down a bit and getting rid of the acoustic transfer to amp has also given the bottom and low mids incredible thump and focus!! and doesn't sound scooped at all so no Quarter Pounder syndrome. 

If you thought the BBs sound was massive before it's even bigger now!

So all in all great to get it done and experience the results 1st hand and thou I had to trade a little top end now the bass sounds like a vintage voiced rock monster

[Dan Dare]

I found the same on my old J bass. The pickups had become microphonic, so I had them wax potted. Improved things no end. I didn't notice any loss of highs when I got them back. I wonder if the lost airy quality you refer to was in fact caused by the pickups being microphonic.

[Marky Screen]

On 12/04/2019 at 21:31, Dan Dare said:

I found the same on my old J bass. The pickups had become microphonic, so I had them wax potted. Improved things no end. I didn't notice any loss of highs when I got them back. I wonder if the lost airy quality you refer to was in fact caused by the pickups being microphonic.

yeah spot on! thought about it and res freq of pickups ain't changed, pole pieces wire and winds all the same after all, Doh!  so yeah the airy stuff loss and less smeary focus in the lows will be from the lack of acoustic transfer to amp. good call