I recently acquired a PS Audio stack that included a BHK Preamp and BHK 300 Monos. In the past I ran my volume controlled DAC directly to my speakers and used speaker level connection from the amp to my subwoofer, a Rhythmik F12 SE. With the speaker level connections it was more than I needed and the gain was always turned at about 70%. Now I connected with two RCA interconnects from the BHK outputs to the Line In on the sub. Even if I crank volume/gain to max, I”m not getting the same impact as before with speaker level connections. I remember people mentioning using a splitter or y adapter with the RCA cables to gain an extra 6db. Is that what I lost and if so, what do I need to buy to get that back. My sub now feels underpowered for my room. Alternatively, any issue with running speaker level inputs out the back of the PSA BHK Signature 300 mono blocks to the subs like I did with my old amp? I remember seeing you did not want to do with all amps and think it has to do with possibly differential balanced amps. Thanks for the help.
There are lots of discussions about mono blocks and subs with high level connections. Most seem not to want to touch a “here is exactly what you need to do”, possibly because there is the possibility of amp damage because: unlike stereo amps, neither of the speaker outs of mono blocks are at ground potential and while even Paul describes the + and - as electrically different, for this discussion the important point is that they signs mainly indicate relative phase and both are “hot” relative to chassis ground. There is then the possibility that connecting a minus of a mono block to the minus of a sub (where the minus is actually at ground potential) will create the a short of the amp output. I only have worked with a REL sub so I looked up yours and from the companies advice, I would switch to using low level connection:
This general issue regarding balanced mono blocks and a single sub connected using high level input has been discussed. But as far as I remember it has usually involved M700s or M1200 and a REL sub. Folks reported success using the method Paul advocated year ago (high level sub cable using a floating ground and connecting one lead to positive left mono and other lead to positive right mono). I have used this method for 5 years with success - but with M700s and later M1200 and a REL sub. Other folks have cautioned against this method with only one sub stating that REL recommends two subs when working with balanced monos.
Hopefully, someone who has your specific equipment and scenario can chime in.
