Inductors for line-level passive crossover?

Design and use of Chokes for PS, anode and filament use.
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Joined: Tue Jun 21, 2005 11:39 am

Inductors for line-level passive crossover?

Post by pRC »

Yo, Dave - Greetings from Raleigh, NC

I'm in the middle of updating my Azurahorn setup, currently using a 170Hz line-level high-pass between the preamp and 'il monstro' to power Fostex 206ES-r drivers in the horns and bi-amping with 70W single-ended MOSFET amps for the open-baffle 15 inch woofers for bass.


The current not-so-matic preamp uses 27 tubes with 150H parafeed chokes into Altec 15095 outputs (15k:600)

Il Monstro has Altec 15095 as stepup input trannies (600:15k) into an 845 driver and output, with tweaked parafeed caps to roll off bass at ~120Hz.

Today, line-level bump-in-the-cable has 2.2uF cap in series and 2400 ohm resistor in parallel with 600:15k input tranny. OK so far, but mebbe can be better -- still getting a lot of energy from the Azuras below 150Hz.

Thinking about a second-order bump-in-the-cable with a 1.1uF cap in series and a 750mH L in parallel with the 600:15k input tranny.

27 preamp will soon be replaced with a parafeed 46 version using remote-controlled slagle-formers from John Chapman that have been sitting on the shelf since last VSAC. Not sure what that will do to the output impedance and match up into il monstro, but hey, life is an adventure.

Comments? Tut-tuts? What would a pair of your wound nickel beasties run for such a task?

dave slagle
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Post by dave slagle »


My only thoughts are getting the remote units up and running and replacing the 15K:600 lineouts with them. Then anywhere below say 12dB of attenuation is gravy. The really cool thing is the +7dB of gain may also allow you to dispense with the 600R:15K's on the other end.

The chokes are $200 a pair and can be tapped to allow for different X-over frequencies or impedances.

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Post by pRC »

Awwwwwwesome. Got the 'new hotness' OB woofers assembled this weekend: ... ot_119.jpg ... ot_115.jpg

Working on the new preamp now, full soldering ahead!

Will think on this, build, test, and get back to you - Thanks for the reply!

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Post by reVintage »

Hey pRC,
Interesting with the side panels forward instead of usual flat or rearward. Looks great but are they sonically rewarding?
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