Unimpressive sound from Tannoy B475 subwoofer?

Oh, cool. I think I got it. I just solder the ground to the outside of the RCA connector?

When I touch a ground wire manually, the hum goes to almost nothing, so I assume that's the right approach.

Thanks for the insights!

The ground and negative wire should be attached to the grounding post of the RCA. The shield really doesn't matter as long as it doesn't touch the positive post.

Or, you could just use an XLR to RCA adapter. The best thing would be to get a balancing transformer from someone like Jensen.

08-07-11: Rwwear
Pro subs are designed for high output but not necessarily low bass. Your sub will go down to around 28hz but you may not get that in your room. The SMS-1 will come with a setup mic to tune the sub to your room. It will have video out to see the results and allow you to adjust for your room and give you the ability to have 5 different settings plus have remote control for the volume and different modes. Velodyne's DDS series has this built in

Above post was right on the money of what I was emplying with the sms-1 or any other eq. The nice thing about the sms-1 type is you get a nice grapch on your screen and some auto eq to get you started. You need to get that sub playing lower even if it costs you some max output at the 50hz and up freq responses. Home theater subs need to hit around 25hz to really get you excited about the .1 channel.

Thanks for the operational breakdown. Unfortunately, I can't tell any difference between that method and connecting an extra ground wire to the case of the pre-amp or to the RCA shield. Which matches your "really doesn't matter" point...

I was going to try a Jensen since they are "only" around $100. From their web page it seems the JT-11-BMCF would be the best bet or is that complete overkill?

http://www.jensen-transformers.com/faqs.html#faq5

The subs are great and seriously tactile at high volume with bass heavy music; I'm just hoping for something more precise at lower volumes. One improvement was from adding a sound isolating pad to separate them from the house foundation (which had various resonances that I'm sure displeased the neighbors).

But, I'm getting the feeling I perhaps should have spent the extra money to pick up some velo 18s that were for sale locally from porchecab or held out for some triad platinums...

The transformer looks like the right one.
An SMS-1 could be picked up used for around 400.00. It would help greatly.