BX63A

[Zilch]

Notes to Ti Dome regarding and subsequent to the repair of his BX63A:

1) The use of an 18 VAC transformer overloaded the simple Zener shunt regulation power supply circuit, smoking 100-Ohm R10 and killing the +V. That likely took out the TL084C op amp, which also got pretty warm.

2) The Zeners had obviously been working really hard to compensate for the overvoltage before it died. I replaced them, as well.

3) The power requirements of BX63/A are very modest. A tiny 12VAC, 150 ma. transformer, the smallest typically made, would likely be plenty. It draws about 20 ma, only. I don't have the factory transformer myself, either. Perhaps someone who has one can tell us the actual rating.

4) The rear panel openings don't line up well with the RCA input jacks. This is an artifact of the way the board is mounted inside. On mine, the previous owner enlarged the holes. To do this properly, the unit must be disassembled, though that's not a terribly big task. The connectors don't seat completely, is all. It works fine with the ones I used.

5) A/B final testing of Ti Dome's was the first time I actually hooked my BX63A up to B380's. I was surprised to discover that there's no sub output in "Bypass" mode. I guess that kinda makes sense, but when Zilch rules the world, there'll be other options.

6) The manual provides a method for determining the proper phase connection. Basically, it's get the system operating and then switch between the normal and inverted outputs to see which gives the most enhanced bass. That's the one to use.

7) Using B380 with 4430's, I think the lowest frequency setting (63 Hz) is optimum. No directionality, and just a bit of extra VLF boost for the 2235's already running.

8) RTA says I play the subs WAY too loud.

If they're just doing augmentation at the proper levels, I can hardly perceive them playing. They just kick in when the program material calls for it.

9) Enjoy your BX63A. It comes with Zilch's standard "30-30" repair warranty:

"30 feet or 30 seconds, whichever first occurs."

[Titanium Dome]

A big thank you to Zilch for his work on this. Next time I'm in the Bay Area, a few beers are in order and maybe an Afghani dinner or some sashimi.

I'm eagerly awaiting the BX63A's arrival. Then it's lock and load!

Is that "30 feet or 30 seconds" from the time and place I pick it up?

[Zilch]

Is that "30 feet or 30 seconds" from the time and place I pick it up?

Only if you gotta good lawyer....

[leif]

[QUOTE=Zilch]Notes to Ti Dome regarding and subsequent to the repair of his BX63A:


8) RTA says I play the subs WAY too loud.


LOL, he have not seen that there are a knob to ajust the volume for the sub?
What level have you set your sub for on the volume?

I have a B460 with the Bx63a, and have mine turned up to about "11 O`clock"
I also prefer to use it at 63Hz, but when I want to have a good time playing real loud, I ajust it up, to take some preassure away from the main speakers and their amp. It rocks!

[Zilch]

Gain control on BX63(A) establishes the balance between the mains and subs. The relative loudness also depends on what amps are being used for each, and their gain settings.

I'm running the stereo mains on 6230 at 1:00, B380 subs on 6260 in dual mono at 12:00, and BX63A at 3:00. My preamp on this setup (liberally interpreted to include this Sony car amp/CD) controls the master volume....

[Zilch]

I also prefer to use it at 63Hz, but when I want to have a good time playing real loud, I ajust it up, to take some preassure away from the main speakers and their amp. It rocks!

God has given you fair warning.

Better supress that urge for right now.

[And get an SPL meter.... ]

[mrbluster]

I also prefer to use it at 63Hz, but when I want to have a good time playing real loud, I ajust it up, to take some preassure away from the main speakers and their amp. It rocks![/QUOTE]

Correct me if I am wrong......
I believe the adjustable crossover only effects the Sub output. The impedance matching switch determines the crossover point for the Mains.

[Zilch]

http://www.jblproservice.com/pdf/Vin...BX63A%20ts.pdf

It's clear the frequency adjustment control has nothing to do with the HF output.

Regarding the impedance matching switch, manual says:

"The switch effectively adjusts the rolloff of the main loudspeakers. It is properly set when the sound at the corssover point is neither too 'thin' nor too 'full' -- in other words, when the subwoofer and the main loudspeakers are blending in the optimum way."

Also:

"The BX63A has a rear-panel 'Impedance Matching' switch. This should be set to correspond to the input impedance of the amplifier for your full range systems."

Choices are:

Low = 9-18 kOhm
Mid = 18-36 kOhm
High = 36 kOhm to infinity

My 6260 input impedance is 40 kOhms balanced, 20 kOhms unbalanced.

This is an unbalanced connection, so I should use "Mid."

Mrbluster is correct again....

[leif]

I will try to explain what I mean:
If the sub take more of the total job, the mains take less, right?
The main amp is 150 watt, while the sub amp is over 1.000 watt bridged.
So the main amp meet its limit while the sub amp is still "relaxing".
So to put a higher crossover point, the sub amp and sub get more to do, while the main speakers and amp get less to do. And therefore you can turn up the volume a little more. Understand what I mean?

[Zilch]

So to put a higher crossover point, the sub amp and sub get more to do, while the main speakers and amp get less to do.

Apparently not. The crossover frequency control does not change the output to the mains. It's in the sub signal path only. See the schematic, above....

[leif]

As I understand from your posting, is that the sub only adds on in the bottom, and that both the mains and the sub is playing in the area below the crossover.
That can not be right. It is very easy to test that out. I put on some music, and feel the woofers on the mains with my finger. I push the "network in" button on the BX, and the woofers do a lot less excursion.

[Zilch]

Nope. Not saying that. A rudimentary passive filter comprising a 0.15 uF capacitor and the selected input resistance does kick in for the mains when the filter is engaged.

We're saying the frequency control does not alter that, is all. The impedance switch does change it.

On another subject of interest, please look at your power transformer and tell us what the output rating is.

[John]

I have 2 BX63A units and both power supplies are 12V 830mA

[Titanium Dome]

I have 2 BX63A units and both power supplies are 12V 830mA

Do you have those hooked to bridged stereo amps? Is so, can you share your configuration and wiring scheme? Thanks.

[Zilch]

I have 2 BX63A units and both power supplies are 12V 830mA

Closest I could find for Ti Dome here locally was 13.5 VAC, 800 mA. Sounds like he'll be fine with that, then....