BK monolith subwoofer toroidal transformer spacer

warning - there's big caps in here, make sure everything is discharged and use common sense before taking this apart! If you struggle to remove the backplate (note only the exterior most 3mm allen bolts need to be removed), plug an XLR cable and pull hard, there is a small rubber seal/glue that you need to break (I never replaced it and I think it's really unnecessary). Alternatively you can grip the heatsink with some pliers, it's not directly attached to a PCB so whilst you'll mark it, it will work just fine. In order to free the PCB, there where two zip ties to cut connecting the speaker itself then disconnection is easy. I replaced them after to avoid the cables vibrating in the cabinet. 

The model itself is really stupid, I'm really posting it so that people might find this as a solution to remove buzzing from their BK monolith subwoofer (mine is > 10yr old but has been buzzing for a good few years, just got bad enough for me to really look into it recently!). I first replaced the main capacitors which BK sell but they are really annoying to unsolder without a proper pump, and in my case did not fix the issue (maybe a mild improvement, hard to tell). This change however made the sub completely silent. It's possible that simply tightening everything would do the same, but the bolt hardware was pretty badly placed in my case and had started deforming so I didn't feel this was a good solution and decided better isolation would be best.

I believe the original bolt is a 5/16", I replaced it with an M8 bolt (mine is 60mm but ideally you'd take an 80mm) as you then don't need to drill the steel plate. I then took the largest washers and a nylock nut. I printed this in TPU shore 95a, and placed it on the backplate. I then reassembled the stock metal holder with both original vibration absorbing covers. Note that it's also worth tightening all the bolts as some may have gotten loose over time.

If you tried similar, let me know if it worked, even if you didn't print my model, might help others find it. I suspect that this strategy could be used on the ‘plus’ model and probably any toroidal transformer.