I use a 3/4 Plywood Bass to which I have a one of Bob's DBT (Double Big Twin).The bass is shop standard ie:- original in all departments.including the Bridge. Now as far as I'm concerned I get a GREAT! sound from the DBT through my GK400 RB. So about a month back in a weak moment I blew out and purchased a brand new (Full Size) Plywood.It was a Good deal with case/Bow/set of Thomastic's. I did OK! First thing I thought I do is get one of Bob's Adjustable Bridges as I wanted to experiment with lower action . At the same time I thought about a new transducer.... I was going to try the Gage "Realist" however, having got a GREAT sound from Bob's DBT I decided to stay safe and placed an order for both the adjustable bridge and a DBT. These parts arrived last Friday, and I have spent the best part of the last 12 hours adjusting and fitting the new bridge to the bass. This turned out GREAT ! and I am very pleased with the action. Last Night, I fitted the NEW DBT ....to the same configaration as my existing 3/4.ie:- about 1/8th down from each string. As with my original DBT, I contacted the pads in place as I found this gives a good seal with the face of the bridge. When I turned on the GK and began to lift the Volume (Via a PRE-AMP) I found the Volume to WAY down on the 3/4,and as I raised the volume to be heard, in came the Feedback Big-Time! I played with the unit for a good 3 hours trying different settings.... but really was NOT getting the sound that I can dial-up in an instant on the 3/4! with or without using a Pre-Amp. My question to ALL and Sundry are as follows:- 1. Bob's Maple Adjustable Bridge is a BIG SOLID BRIDGE compared with the standard bridge that I had on the Bass(SIZE WISE) ... I followed Bob's instructions to the letter in regard to fitting the bridge , I'm wondering whether the THICK density of the bridge has any bearing on the output of sound from the DBT? 2. Also ,does the Aluminum adjusters effect the sound from the DBT? 3.And why can I set the GK with Volume and Tone and then plug in the 3/4 and get a GREAT sound straight up with no feed-back and still have head room for more volume if required. Then pull the lead out and plug in the FullSize without changing any settings and have the full size take off in to full on Feed-Back! I have just received a reply from Bob.... he seems to think it must be the bridge! Would appreciate any comments from you....and remedies please!