JBL 4301 Rebuilding Network

[OldBlindJim]

Hi there,
Going to rebuilt the networks in my set of JBL 4301 8" 2 way monitors to use in my home studio.

Schematic out there?

OBJim

[Fangio]

4301 regular crossover schematic (network 3103):
http://www.jblproservice.com/pdf/Net...%20Network.pdf (http://www.jblproservice.com/pdf/Network%20Schematics/3103%20Network.pdf)

[OldBlindJim]

4301 regular crossover schematic (network 3103):
http://www.jblproservice.com/pdf/Net...%20Network.pdf (http://www.jblproservice.com/pdf/Network%20Schematics/3103%20Network.pdf)

Thanks
On with the madness:D

[OldBlindJim]

In Bypassed Caps (http://www.audioheritage.org/vbulletin/showthread.php?t=3555) Is there an equation to figure the bypassed cap value and in the 4301 network would be only be necessary to apply to C1 of the high pass section of the network.

OB Jim

[grumpy]

In terms of capacitor value, adding a .01uF across a 7uF cap won't produce anything
with an equation... cap tolerances are -much- worse than that.

Personally, I'd try just the HF section first, but experiment away... :) -grumpy

"These bypass capacitors were smaller, higher quality polypropylene and polystyrene capacitors which exhibited greater linearity, spaciousness, and dynamics." (a repeat from the referenced
thread).

[boputnam]

Is there an equation to figure the bypassed cap value...I don't believe so.

Most applications/mods discussed here involve(d) the 0.01 uF polypropylene caps - that is what I used in my 4301B's.


...and in the 4301 network would be only be necessary to apply to C1 of the high pass section of the network.No, you'd bypass each main capacitor, such as the "C1A", "C2A" etc bypass caps shown in Post #4 of the Bypassed and Biased Capacitors thread you quoted.

[OldBlindJim]

I don't believe so.

Most applications/mods discussed here involve(d) the 0.01 uF polypropylene caps - that is what I used in my 4301B's.

No, you'd bypass each main capacitor, such as the "C1A", "C2A" etc bypass caps shown in Post #4 of the Bypassed and Biased Capacitors thread you quoted.

Then this would be the result, a bypass at 7uF with a 0.01uF with 7uf being my C1 and 0.01uF as C1a
http://home.earthlink.net/%7Ejvanhornrlh/Altec/4301%20mod.jpg
Do I need to add another to the 16.5uF?

[grumpy]

Do I need to add another to the 16.5uF?

Your speakers, your call. You have two suggestions :applaud: -grumpy

[boputnam]

Personally, I'd try just the HF section first, but experiment away...

The benefit of the bypass cap may not be as noticable in the LF section; however, if you refer to post #3 of the Bypassed and Biased Capacitors (http://audioheritage.csdco.com/vbulletin/showthread.php?t=3555) thread, in the N110A JBL did bypassed the LF cap.


Your speakers, your call...That is always the case. :p You could use some alligator clips and 'speriment...

[OldBlindJim]

The benefit of the bypass cap may not be as noticable in the LF section; however, if you refer to post #3 of the Bypassed and Biased Capacitors (http://audioheritage.csdco.com/vbulletin/showthread.php?t=3555) thread, in the N110A JBL did bypassed the LF cap.

OK,
Thank You
Now back to the Madness!

[boputnam]

The benefit of the bypass cap may not be as noticable in the LF section; however, if you refer to post #3 of the Bypassed and Biased Capacitors (http://audioheritage.csdco.com/vbulletin/showthread.php?t=3555) thread, in the N110A JBL did bypassed the LF cap...Been thinking more on this.

In a two-way system, having a higher and single crossover point, the effects on the LF will be noticable because it is doing duty as MF, too.

I'd bypass both the "main" caps in the 3103 network (and I did! :p ).

[grumpy]

ha. no argument here. I just thought it would be interesting to hear the difference
in phases (which is what I would do). :) ... as in step 1, step 2, not electrical/audio phase ...

[OldBlindJim]

ha. no argument here. I just thought it would be interesting to hear the difference
in phases (which is what I would do). :) ... as in step 1, step 2, not electrical/audio phase ...

So 0.01uF at 7uF and at 16.5uF

OB Jim

[grumpy]

ja mon.