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3 quick and simple crossover questions regarding the Altec 902...


chops

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You're welcome Charles.

"...can we at least agree on the parts on his network and what their purposes are."

I didn't realize there was any disagreement. My focus was on trying to help him understand how the autoformer works so he could implement the changes to accomodate his new drivers and/or any future changes -- while you were addressing the low pass. I did say early on, either in this thread or another -- that he wasn't running the Type B3. What he was running was Type B filters, with crossover points shifted down to 4500Hz -- but using the low pass section of the Type B3.

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Now .... I haveta admit ...

the passive JBL 4430 X-over, sounds bettern' electronic

but, for what we are talkin' here , things are easily changed by goin' to, say , a DriveRack ...

Duke,

I see you mention the dbx DriveRack. I went to their site to check "it" out only to find there's like 8 or so of them to choose from! Which one are you referring to?

Also, what's so good about these DriveRacks over other parametric EQs? Any quotes on prices?

Thanks,

Charles

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So this is what I think I'm gonna build for my speakers. It will be a 1st order, 775Hz 2-way design. Very simple and staight forward. Items shown below are for 1 network only.

Also, since one of the Altec 902s measures 6.1 ohms and the other one measures 6.7 ohms, I averaged it out to 6.4 ohms x 8 (T2A autoformer tap #2) which would make the final impedance 51.2 ohms.

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1) Alpha Core Goertz 1.2mH 12 AWG Copper Foil Inductor

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1) 3636 Audio Autotransformer

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1) Hovland Musicap 4uF 100V

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And once I get some kind of approval on this autoformer bypass cap trick... This time, sized for the straight 6.4 ohm impedance of the 902 driver (hence bypassing the autoformer) at 22.5kHz.

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1) Hovland Musicap 1uF 100V and 0.1uF 600V

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Any thoughts and/or suggestions?

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Good choice on xover point/rolloff combination.

Looks well organized. Very minor questions.

Does L1 value of 1.23 mh factor in the inductance of the k-33?

Did you see my note on your other thread and the diagram provided concerning the use of resistors in a similar scenario (r2, r3, r4)? Not advocating R4, but r2 and r3 bear striking resemblance to the function of a swamping resistor mentioned often on this forum.

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That's an I get it don't get it kind of thing for me. Interesting.

Now see, it's comments like this that upset me and eventually get me pissed. If you're going to write something like that, then why not give an explination for the comment instead of leaving me hanging?

You're right in a way though. It is a "I get it don't get it kind of thing" because of the simple fact that EVERY time I make mention of the bypass cap and ask for clarification, the question gets ignored or avoided and I get a drawn out answer for something I didn't even ask about or given an option that I have made clear that I DON'T want.

I guess I'll have to bother Al K about this matter, since I can never get any straight answers elsewhere. At least Al finds the time to site down and give a thorough answer and doesn't try to talk me out of something.

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Good choice on xover point/rolloff combination.

Looks well organized. Very minor questions.

Does L1 value of 1.23 mh factor in the inductance of the k-33?

Did you see my note on your other thread and the diagram provided concerning the use of resistors in a similar scenario (r2, r3, r4)? Not advocating R4, but r2 and r3 bear striking resemblance to the function of a swamping resistor mentioned often on this forum.

Thanks Fritz.

No, that value does not factor in the 1mH from the K33.

And yes, I saw your other post, but I don't think I'm gonna worry about the swamping resistor for now. Since I'm running SS amplification, I doubt it will really be worth the hassle. It would be nice, but until I get some clarification on that as well, I'm going to hold off with it in my design.

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