My new 4430 system

[Zilch]

Several members, including myself, have done 4430 active biamp according to JBL specs using the JBL card in 5235, and gone back to full passive.

Here's the N3134 passive-only charge-coupled (biased) crossover I built, so you can get an idea of what it is as implemented by the Zilchster:



It's been tweaked a bit to run the different HF system shown.

It's still biampable, but that requires two batteries, ideally, one each for HP and LP....

[spkrman57]

You said:

"It's still biampable, but that requires two batteries, ideally, one each for HP and LP...."

You should not need 2 batteries for bi-amping as the resistors between the battery and crossover will keep any interaction from happening.

If you see reasons to the contrary, please comment as I am interested in your opinion on this!

Regards, Ron

[hjames]

Maybe 2 batteries, but - one for each speaker (left and right), not one for each driver!

You said:

"It's still biampable, but that requires two batteries, ideally, one each for HP and LP...."

You should not need 2 batteries for bi-amping as the resistors between the battery and crossover will keep any interaction from happening.

If you see reasons to the contrary, please comment as I am interested in your opinion on this!

Regards, Ron

[Zilch]

Maybe 2 batteries, but - one for each speaker (left and right), not one for each driver!

Nope, one for each driver/filter. Look again at 4313B's schematics to apppreciate the need for two batteries. There are two in the biamp implementation.

Why is that? Because, with a single battery, it's (-) connection must be common to both filters and amplifiers.

If you are biamping using one amp per channel, (I forget if that's "horizontal" or "vertical,") that may not be an issue, if it's permissible to common the output "grounds," but, using separate amps for HF and LF, particularly different types, it's asking for trouble....

[spkrman57]

That was a situation that I did not anticipate.

Regards, Ron

[3dbdown]

Zilch, are you saying that if I Bi-amp though my QSC's, that I should do the Low and Hi-freq out of amp "A", for left channel, and the Low and Hi-freq out of amp "B" for my right channel, as opposed to Low-freq left and right ought of amp "A", and Hi-freq out of amp "B" for both channels ??.....
And, if so, why?

Also, thanks for the pix of the biased 3134's.....Are those Solens, or Clarity SA's in the photo??

Waiting with baited breath,

Rick

[Zilch]

They are Solens. Big caps are 24, 16, 12. 16 + 12 = 28.

I do not typically use one amp on each channel, rather, a smaller amp for the HF of both channels.

[3dbdown]

Zilch.......

Yeah, that's what I thought.......must have been too much Sun around here today!! Comfortijng to know I won't have to re-wire my system!!

I am getting ready to order the Solens for my first step in tweaking the 4430's, but the CC version will be Phase 2. I need to start out with a reference point, so am just going to change the 30 year old caps for now, and give it a listen. It's just that my number 1 rule has always been: Does this sound good to me? This process can be so very subjective, and I've never found a better approach.

I spent all day Saturday going through the threads on CC. After 4313B posted the schematics, I reasoned that I really, after all, should do my homework, instead of asking for a lot of info that's already been posted. It was very nice of him to do that for me though. The research really helped me to catch up on technology, and to learn why you guys do these things, and what you do and do not like about certain mods. A real treasure of quality info! Not to mention quite a trip through the looking glass, Alice!!

I suspect that if I do not like the straight cap change, I will not bother to add the bypass caps. I will, rather, proceed with building the CC's. Didn't seem to be much support for the bypassed version, and I am thinking perhaps the Solens will not need it or benefit from it.

I think I will try to configure the CC version external to the cabinets, rather than inside. Seems easier to peak and tweak, and keeps me from opening the cabinets too often if I decide to try different things.

I was curious as to your inductors, as far as which ones you are using. Are they a PartsExpress line, or what? Also, your L-pad plate looks like the PartsExpress one, but I was unable to locate the 30 ohm rheostat. Any thoughts?

Rick

[3dbdown]

Also, I think I will stay with passive, but I did have a question for 4313B.

You mentioned that the other pole of the 2-pole filter was in the 5235, which I do not have. How does that square with my dbx 223 crossover, if I do decide to try the bi-amp version?
Thanks,
Rick

[Zilch]

I was curious as to your inductors, as far as which ones you are using. Are they a PartsExpress line, or what? Also, your L-pad plate looks like the PartsExpress one, but I was unable to locate the 30 ohm rheostat. Any thoughts?

It's all Parts Express. I use terminals 3 and 2 of an L-pad, i.e., 0 - 8 Ohms, for the rheostat, as I found from experience that the HF always adjusts to the very lowest portion of the 30 Ohms. You can simply put a fixed resistor in series to move the adjustable range.

Alternatively, you can use terminals 1 and 2 to cover the stock range, but the control operates backwards, providing max attenuation fully clockwise....

[berga12]

Hi,
if I'm using 2420 16ohm instead of 8ohm version, should I double "L" and divide by 2 "C" value in the HF session right? for a first trial...?

[Earl K]

Hi,
if I'm using 2420 16ohm instead of 8ohm version, should I double "L" and divide by 2 "C" value in the HF session right? for a first trial...?

The 2420 was only available in one impedance & that was ( officially called ) 16 ohms .



Here's an actual impedance measurement of the le85 ( which is the consumer version of the 2420 >> this was measured by Zilch, I believe ) ;



You can see that AC impedance is a frequency dependent, moving target ( since it's actually a curve > specifically in the area where LC components to their work ).

Putting an 8-ohm Lpad right before the driver ( & dialing in a few db of attenuation ) will knock the working impedance of the HF circuit down to an almost ( flat-line ) 8 ohm load .

[berga12]

So,looking at the curve means I can use at 1000hz the standard 4430 crossover with the 8ohm Lpad....

[grumpy]

Ultimately, I would think you would want an 8-ohm diaphragm (D8R2421 or perhaps a dusted Ti version),
as I believe the system was already limited in the level matching between drivers given the HF EQ required
(http://www.audioheritage.org/html/pr...bl/4430-35.htm)

[berga12]

Understood

maybe a slight adjustment on the Crossover is needed, even if i'm also thinking on a "passive" bi-amp, let see, it's just for fun!

I've 2420....so I need to use them, is a Beryllium diaph existing?