605b crossover

RPMac · 5686

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Offline RPMac

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on: October 28, 2015, 05:14:54 AM
I'm looking to build Markwart crossovers for my Altec 605B's.
The woofer circuit calls for a 4.6 mH inductor in series with the woofer and a 4.7 uF cap across.
I can find 4.5 mH and 4.7 mH inductors.
Can I use either of these?


Offline marantzfan

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Reply #1 on: October 28, 2015, 05:46:33 AM
Here is the a link to a thread on my altec 605b's which includes some pictures of the completed crossovers. 

http://www.audiohaven.org/forum/hi-efficiency/439-my-altec-duplex-journey

I went with 4.5mh in my build.

Also, here is a layout I drew up for the crossover.
« Last Edit: October 28, 2015, 06:13:15 AM by marantzfan »

BeePre, Paramounts 1.1, Eros, Thorens TD-124/AudioMods Tonearm/Ortofon 2M Black, IFI Micro Idsd, HQPlayer,  Altec 604-8G Duplex/620 Cabinets/Markwart Crossovers

S.E.X. 2.1, AKG K701

Offline Skip Pack

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Reply #2 on: October 28, 2015, 08:25:22 AM
The russian K75-10 caps are fairly available and cheap in 4.7 uf. I am using them on my 605 OB crossover and have been happy with the result. I have three (two sizes) in each crossover. A small, green tank farm.

Skip


Offline Paul Birkeland

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Reply #3 on: October 28, 2015, 10:34:06 AM
Quote from: RPMac on October 28, 2015, 05:14:54 AM
I'm looking to build Markwart crossovers for my Altec 605B's.
The woofer circuit calls for a 4.6 mH inductor in series with the woofer and a 4.7 uF cap across.
I can find 4.5 mH and 4.7 mH inductors.
Can I use either of these?
You can unwind the 4.7 to make a 4.6.  There are calculators online that can help with this, or you can buy a DATS or Woofer Tester to measure the coil as you unwind it.

You can buy a 4.5 and a 0.1, put them in series, and make a 4.6.


Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Paul Joppa

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Reply #4 on: October 28, 2015, 05:37:54 PM
It's +/-2%. You won't easily find a capacitor with better than 5% accuracy in these values, so the effect of a 0.1mH error is minor.

Paul Joppa

Offline RPMac

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Reply #5 on: October 30, 2015, 04:38:05 AM
Thanks, that's the info I needed


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