Bottlehead Forum

Other Gear => Speakers => Topic started by: RPMac on October 28, 2015, 05:14:54 AM

Title: 605b crossover
Post by: 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?

Title: Re: 605b crossover
Post by: marantzfan 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.

Title: Re: 605b crossover
Post by: Skip Pack 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

Title: Re: 605b crossover
Post by: Paul Birkeland 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.

Title: Re: 605b crossover
Post by: Paul Joppa 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.

Title: Re: 605b crossover
Post by: RPMac on October 30, 2015, 04:38:05 AM

Thanks, that's the info I needed