[Jazz and Baroque]

I am thinking about bi-amping a woofer.  I know that Bryston and Marchand make good active crossovers.  Are there any other sources ??

Thanks,
Mike

[mgalusha]

Lots of them but almost all built for pro audio.

http://www.fullcompass.com/category/Crossovers.html

If you are a diy type Rod Elliott (http://sound.westhost.com) has some nice designs.

mike

[doug s.]

i'd recommend marchand.  when i was looking several years back, several folks why tried both, recommended the s/s marchands over the bryston, even tho they are less expensive.  i found them wery transparent.  if you are wanting to spend the money on a bryston, get a marchand tubed unit.  also, if you can diy, you can save money w/marchand, as they offer kits...

doug s.

[Scott F.]

I use the vintage Pioneer SF-850 in my main reference system. This is just me but I don't particularly care for the sound of opamps. I prefer the sound of a traditional gain stage (transistors or tubes). This particular Pioneer is reasonably transparent. I rebuilt the power supply with some new diodes, Elna Cerifine caps and Jupiter beeswax as bypasses. The other active crossover I use is the Audio Research EC-3. It's fully tubed with 12 - 12AX7's. Bill at Response is playing with it right now. It is a nice crossover too but way overpriced in todays market.



The Pioneer is very flexible. As you can see from the pic, you have easily switchable XO frequencies and easily adjustable slopes. To my knowledge, no other XO (current or vintage) offers this kind of flexibility while providing a traditional gain stage (read=no opamps). IMHO, this is an absolute must, especially went you start crossing speaker over into the upper bass range and above. The AR EC-3 is a nice XO. You can easily adjust the XO frequencies but the slopes are fixed at 12db. That often works but at times isn't enough in other situations.

There is a Pioneer SF-850 on eBay right now. It should sell for less than $1k. The AR EC-3's, though far more limited, can sell for 50+% more than that. Fortunately, I bought mine years ago when they cost far less.
current eBay auction
The SF-500 and 750 don't sound near as good as the 850.

While I haven't fully explored the Marchand's it appears that they have a fixed slope, which might work in your situation. Also, it appears that you change the XO points by swapping out boards but with this solution, you need to buy extra boards.

The DEQX's out there seem to be enjoyed by some. With these you have almost infinite adjustability. Trouble is with these, they take your analog signal, convert it to the digital domain where you apply XO points-slopes-EQing-gain adjustments, then you convert that processed signal back to analog and pump it out to your amps. For some this is a good solution, for me, I'll stick with my all analog approach.

Though I haven't listened to every active XO out there, I've owned and listened to quite a few. For my needs, the SF-850 has been the best and most flexible solution for every set of actively crossed speakers I've set up. YMMV

[Dan_ed]

Hi Scott,

can you offer more input on the Audio Research EC-3? I bought an EC-4a on eBay last month for $500. I'm still gathering parts for a bi-amp system so I haven't hooked up the EC-4 yet.

[Scott F.]

The EC4, if I remember correctly was the EC3 with fixed XO points.

Here is a website with the schematics and some internal pics.
http://www.arcdb.ws/EC4/EC4.html

If you are familiar with any of the AR line, they all seem to have, sort of a 'house sound'. IMO, this is from their choice in coupling caps. As it is with most tube gear, swapping the coupling caps can make a dramatic difference in the sound. When it comes to the basic design, the EC4 is very similar to the 3. The 4 just isn't adjustable via switches and gain pots.

REALLY big version of the Audio Research EC4 Schematic

When you look at the design of the power supply, it is (IMO) the weakest link. AR designed a voltage ladder with Zener diodes. It works but its not my favorite of designs. One of these days, I'll build a separate and dedicated (proper) power supply for my AC3. Overall, the unit sounds very nice but it could definitely be tweaked to get some more resolution out of it.

Great buy by the way 

[Val]

I also like the Marchand, but there are a couple others: Hsu Research High-end crossover and NHT X2.

[Jazz and Baroque]

Thanks for all the information.

Mike

[woodsyi]

I am thinking about bi-amping a woofer.  I know that Bryston and Marchand make good active crossovers.  Are there any other sources ??

Thanks,
Mike

Mike, I have a spare Marchand XM9 2 way and a XM44 3 way you can borrow to check out biamping.  Give me a PM.

[Dan_ed]

I agree Scott. The power supply is the first thing to address if I decide to go forward using the EC-4. Also, it doesn't look like it will drive very hard so short, low capacitance cables out to the amps are probably desirable. But, for the price, it is a decent active line-level crossover to experiment with. I'm expecting it to have a somewhat warm, unexciting sound.

[KBK]

The Bryston 10b can do all these things. They can be ordered from the factory with the 11 steps I decided on, from 1.7khz to 4khz. You have an adjustable high level out, and 6-12-18db slopes. Balanced or single ended is possible.

[BillB]

Ever thought of building your own? One can use tubes or op-amps for active filtering.

If you want to look at design check out this book:
http://focus.ti.com/lit/an/slod006b/slod006b.pdf

I used a 15w +/-15v medical SMPS in a preamp I just built and it is dead quiet and very small...large pack of gum sized. It is the LAMBDA KMD151515.

I have not built an active filter yet but I have the parts to try an 80hz lowpass and see how it goes.

[Ericus Rex]

The Bryston 10b can do all these things. They can be ordered from the factory with the 11 steps I decided on, from 1.7khz to 4khz. You have an adjustable high level out, and 6-12-18db slopes. Balanced or single ended is possible.

How much is it?

[doug s.]

The Bryston 10b can do all these things. They can be ordered from the factory with the 11 steps I decided on, from 1.7khz to 4khz. You have an adjustable high level out, and 6-12-18db slopes. Balanced or single ended is possible.

the machand xm9 deluxe has 24db/octave slopes, one of the attractions for me, besides retailing for about 1/3 the price of the bryston.  it didn't hurt that three separate individuals had told me the marchand is more transparent.     i also liked its feature that allows adjustment of gain at the x-over frequency as well as for low-pass & high pass gain adjustment.  (on the two-way x-over.  three-way adds midrange adjustment, of course.)  you can buy indiwidual plug-in x-over points for ~$12/pair...  or solder them up yourself for less...

doug s.