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Thread: n7000/3105 schem/BOM

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    n7000/3105 schem/BOM

    After reading Zilch's reply about building a charge coupled 3105, I would like to build one. Although I am an electrical powerplant senior designer (35 years) I only do cad design in the office...no field/hands-on work since high school. I can read a schematic but need all the nuts & bolts to try and build a crossover. I have my dad's soldering gun from the 50's and will give it a go. This is for a 3110(stock recapped by a JBL service center in Chicago last month)/2441(16ohm)-HL89/075(16ohm)/LE10(16ohm)-PR10 self-made center channel. Can anyone help me with a detailed schematic and bill-of-material? Thanks in advance, Kurt

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    Biased 3105

    *Note: L1, L2 = 0.3 mH for 8 kHz

    Parts Express B/M:

    L1 = 255-234 Jantzen = $5.98
    L2 = 255-040 Jantzen = $4.19
    C1 - C4 = 027-542 Solen x 4 = $12.16
    LP1 = 260-262 (3/8" shaft) or -265 (1" shaft) = 9.25
    V1 = 140-205 UltraLife Lithium = $7.99
    Battery Holder = 140-982 Metal = $2.45
    Terminals = 091-1247 or Equiv = $6.91
    R1, R2 = Radio Shack 1/4 W Metal Film x 2 = $1.05

    Total = $49.98 Each

    Deduct $2.42 for 8 kHz version....
    Attached Images Attached Images  

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    Biased 3105

    Zilch,
    Thanks a bunch for the info. A couple more questions:
    a. #16AWG CU stranded wire OK for wire size?
    b. Does your schem work for a 16ohm UHF as well
    as a 8ohm?

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    RIP 2011 Zilch's Avatar
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    a. 18 Ga. is fine, actually, and 20 Ga. on the UHF, even.

    b. Ignore what impedance it says on them; they're all the same. Your UHF drivers are 8 Ohms, nominal. More like 10 Ohms actual, as I recall. Look in the Ring Radiator Comparisons thread where we measured a bunch of them....

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    Biased 3105

    Thanks Zilch for the BOM. I ordered the parts and will give it try. I'll report how it comes out. Kurt

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    Biased 3105

    Zilch,

    I take it that if I want 9kHz I would use 0.15 mH for L1 & L2 and for 10kHz
    I would use 0.075 mH. I see that on the '43 series monitors the 2405 is crossed-over above 9kHz and I'll buy for 7, 8, 9 & 10khz and listen for the best for me.

    Thanks & Best Regards,

    S20VERT

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    Senior Member cooky1257's Avatar
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    Hi Zilch,
    I'm assuming I must've asked a dumb question in my recent westy clone xover thread
    So from the link above, could you tell me if is it possible to drop in a 2441 /2397 for the MF section of those circuits with the Lpad just on the 2405a la 3105/6?
    I'm sorry if this a dumb one too but electronics is not my strong point and any xover software I've tried gives me completely different values(for 2nd order @10khz I get 0.36mh and 0.7uF) to the JBL ones here.

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    RIP 2011 Zilch's Avatar
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    S20R said 43xx monitors. I'm showing what was used in 4333.

    The others are likely posted or linked elsewhere in these forumus.

    JBL crossovers are engineered for specific drivers, typically. It's doubtful you will find many textbook designs among them.

    Driver swaps are thus a crap shoot. Find a JBL standard design that does what you want to do.

    Does 2440/1 play to 10 kHz? Is HF compensation needed for it to get there? On what horn? Using what diaphragm? Is 3110 optimum? With what woofer? In what box? Tuned how?

    There's at least one thread here on how to run JBL 2405 UHF at 10 kHz....

  10. #10
    Senior Member cooky1257's Avatar
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    Zilch, Thanks for the reply.
    I was using the 2440's on a 2397 horn with the 3106 xover and the 2405, which was an improvement over the (lower xover freq) 3105 I started with.
    I've since reconed with new 2441's that are indeed good past 10khz on this horn(without any hf eq help) and, to almost unanimous opinions, the 2405 sounds better crossed past 10khz too-hence my quest for the right way to do it.
    It's not for want of trying that I've not found the right thread-I'd rather not count the number of dead links from old threads I've clicked on this weekend
    I can't be the first to do this-I'll keep searching.
    Cheers
    Cooky

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  12. #12
    Senior Member cooky1257's Avatar
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    Thanks for your patience Zilch,
    I did read these (all 196) last night but just got very confused as in those circuits the hf cuts in at 1.2khz. I don't know what to remove to leave the (2441)HF 'open' for the above 800hz feed from the electronic xover.
    I need to study more.
    Cheers
    Cooky

  13. #13
    RIP 2011 Zilch's Avatar
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    First, here's the link to what you're doing:

    http://audioheritage.org/vbulletin/s...ad.php?t=20486

    You want to modify 3105 for use at 10 kHz.

    Mr. Widget suggests using the 4345 circuit for that and links to it.

    I link to the equivalent circuit, as provided by 4313B at post #170.

    Compare to the 3105 circuit. You'll use 4313B's UHF filter as drawn, plus an L-Pad in the location indicated.

    Now, what appears in the HF filter that is analogous to what's in 3105?

    Everything from 0.27mH rightward, no?

    That's the lowpass, possibly suitable to use with 2441 as mentioned there.

    Try it.

  14. #14
    Senior Member cooky1257's Avatar
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    Eureka!

    Ah, I get it. I had no idea it was that straightforward.
    I'll order the parts.
    Thank you.

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