View Full Version : BX63. Finally

02-21-2018, 04:58 PM
After copious research and searching, I finally scored a BX63 without giving up my right arm. I have been using a new manufacture Ashly 1001 crossover with decent results but as many of you know, it's not sloped per JBL specifications and lacks the 6db hump at 26hz. Wow, what a difference. I also moved my B380 from between and to the left of my mains to the left wall of my space slightly rear of center. That move was made with the Ashly crossover still in-line and there was an improvement felt. Adding the BX63 feels like a larger improvement. I also really like the bypass switch. I am running the B380 with a pair of L220's and sometimes it's nice to hear those boys full range. Following JBL's phasing instructions proved more difficult than it initially seemed. One is supposed to place the crossover in bypass, select some program material with a solid base line and slowly increase the BX63 level while putting the unit in and out of bypass until base levels are uniform with the unit in bypass and out of bypass. Then switch phasing and see if the bass gets louder or softer, louder being in correct phase. I have the ability to turn off my mains via a Bryston switch box (also a nice new addition) because I for some reason love A-Bing my speakers... and even with the mains off, I have a hard time hearing the difference when switching from normal and inverted phasing. How subtle is the difference? Everything sounds great but I thought the phasing change would be more obvious. Should I worry? Or just leave it be.

rusty jefferson
02-22-2018, 05:10 PM
Glad you found one and hope it's working properly, but based on my experience with several BX-63As, it may not be. The ones I own or friends own have all developed the same problem, failing power supply capacitors. The symptom is pretty easy to identify.

Turn on your preamplifier and set the volume to a moderate volume level. Turn on the BX-63(A) and turn the volume all the way down. Turn on your sub amplifier. Leave your full range amplifier off. Start the track with good steady bass. I use https://www.youtube.com/watch?v=X4HMFsh--bo which has a steady drum kick and electric bass line. Slowly but steadily increase the volume on the BX-63(A). It should be very linear just like turning up the volume on anything else. If you start to hear music, but then hit a dead spot in sub volume even though you're continuing to increase volume, then suddenly get a big jump in sub volume, you've got the problem. If the volume is even and constant from low to very high, yours is still working properly.

The description in the manual for set up, is for using the crossover as intended. That is, for controlling the passive high pass filter on your full range speakers as well as the active low pass for the sub(s). The idea is that you wouldn't necessarily hear any difference between your full range speakers (network out) and your full range speakers high passed (network in) with the sub doing the lowest frequencies with normal music/listening. But, when the source goes deeper than than your full range speakers can on their own (pipe organ, synthesizer, cannon, tympani, etc.) the sub will seamlessly fill in the bottom and take the load off the full range drivers, thereby reducing distortion. Not exaggerated bass, but deeper, and with less effort from the full range speakers.

To find the correct polarity more quickly (assuming the crossover is working properly), use a music track like the one mentioned above at a moderate/high level. Adjust the BX-63(A) so the bass is a little too loud/bloated. Turn off the amps without altering the volume, change the output on the crossover and try again. You should be able to notice the difference now between having less bass or about the same/more bass. The louder of the 2 is the correct polarity. Adjust the bass accordingly. Good luck.

04-05-2018, 05:16 PM
Thanks for the heads up. It seems to be working properly in that regard. The system sounds fantastic other than a slight amount of noise from the sub. It still sounds much better than the Ashly unit I was using prior. Something is up but I will troubleshoot it later. I actually just scored a second B380 and BX63A for stereo subs😜. Is the preferred hook up for two subs a Y cord from the correct low freq output to the sub amp(s)?

rusty jefferson
04-05-2018, 06:23 PM
...... Is the preferred hook up for two subs a Y cord from the correct low freq output to the sub amp(s)?
It can be. The Y splitter outputting to 1 or 2 subs will be a summed mono signal, and that's fine imo if you crossover low enough. If you want stereo subs, you'll need to use both crossovers, one for each channel. Battery test both subs before hook up to be sure they both move the same direction on the same positive charge. Doesn't matter which direction, just that they both move the same way.

Glad to hear your crossover(s) are working properly. That's unusual at this point in time. I've seen at least 8-10 of them displaying the issue I described.

09-21-2019, 12:15 PM
So I've been running the B380 for the last year or so with a JBL 6290. Fine amp and works well for powering two subs due to the dual mono option switch which takes the single summed mono output from the BX and splits it to two signals for each channel internally without the need to use a lame y-cord but the fan noise of the 6290 is getting a little old. I wouldn't mind a bit more power either...I'm looking at going with either two Crown PS400's bridged for each sub or maybe two JBL 6260's depending on what I can find. The Crown's give me more power but honestly the 300 watts from the 6290 is probably a bit underrated. That looks like it will put me back into a y-cord. It is possible to use both the standard and inverted low freq output on the BX to run each sub and amp with the y-cord? Will it sound stupid?

rusty jefferson
09-21-2019, 06:59 PM
.... It is possible to use both the standard and inverted low freq output on the BX to run each sub and amp with the y-cord?....
Nothing wrong with the y cable/splitter. Technically, you could probably do this but you'd have to reverse the speaker wiring connection on 1 of the channels so both subs are operating the same way. You'd have to determine whether normal or inverted is the proper connection with 1 sub, then reverse the other to match the operation of the first. Easier to use a splitter or y cable on the crossover output. I use something like this: https://www.crutchfield.com/S-31sMns7lCdQ/p_703M22FRHD/AudioQuest-Hard-RCA-Splitter.html?XVINQ=GLX&awkw=75647687065&awat=pla&awnw=g&awcr=47748539305&awdv=m&awug=9007872&gclid=EAIaIQobChMI3tGbrabj5AIV0-DICh3n6gxlEAQYBiABEgLHXvD_BwE

I'm personally not a huge fan of bridging amplifiers as it tends to add noise, but I appreciate the need for more power.