Anyone experimented with building active filters?

trcose

I'm a hopeless Luddite and can't bring myself to buy a MiniDSP because I listen to so much vinyl. This isn't a rational decision on my part; I'd just like to get the analog portion of my system as close to optimal as I can before I start adding digital correction. One thing I'd really like to try is an open baffle in the style of Martin J King:

http://www.quarter-wave.com/

The crossover components get very pricey with this kind of setup (low pass around 250hz) though and I typically use tube amplification, so power is a premium.  I've been toying with the idea of building an active line level filter and using multiple amps to handle high and low frequencies. Something along the lines of Linkwitz:

http://www.linkwitzlab.com/filters.htm

If just using a full-range driver crossed over around 200-300hz to a large woofer (probably h-frame), it looks to me like the filter wouldn't be too terribly complicated. Has anyone here experimented with this?  I would like to start with an opamp active device, but if it works well I might end up completely losing my mind and building a tube filter.

D1PP1N

I tried using a mini dsp for a 2 way and i was getting a weird clicking. I kind of got frustrated and just gave up after a few days of messing with it. 

greywarden

I know Charlie Laub used to sim and then build Active circuits for his speakers before he moved to whatever DSP he uses now. Marchand (I think Roman is about to build one for Alice) makes and sells tube active crossover kits.

R-Carpenter

greywarden said:

 (I think Roman is about to build one for Alice)

I actually went all passive. Didn't finish the design because me and Mrs moved to a new apartment and am busy with renovations.

Ron_E

I used to build active filters but it's passive or digital for me now. Bodzio's Ultimate Equalizer software will do things you just can't do with analog. Since I build my own PC's and have lots of amps lying around the cost of entry wasn't a barrier to go all active.

When I was building my own from scratch I found the "Active Filter Cookbook" by Don Lancaster to be a great reference. I've also used board kits from Marchand which I thought were quite nice. http://www.marchandelec.com/xm1.html There are also active filter calculators on line. http://http//www.analog.com/designtools/en/filterwizard/

Ron

trcose

Thanks for the reading everyone!  I'll keep researching and check out the links/references.

Got a new phono design and a power amp that I want to finish first (both hybrid ss+tube, what have I become?), but I think the speaker setup will become the bottleneck before too long.

ani_101

Hey, do you have any simple and basic Tube power amp? I checked your website and most of your recent builds are headphone amps. I am looking for straight forward easy to build tube amps. Craig's tube amp is definitely one i am considering.