Crossover for bi-amping

[giaisa]

Hi,

I was able to put together a VOTT system using the following drivers:

HF Driver 291-16k
Horn Type 311-90
LF Driver 416-8b
Bass cab A7

I am planning to bi-amp using two identical 2a3 tube amps.Its very difficult to locate an original altec crossover to mate with my drivers in this part of the world.So i have decided to have a tube electronic crossover made to put these all together, while im waiting for that elusive Altec crossover network. I would like to ask for help on what would be the ideal specification for the crossover considering the drivers i have: 12db or 18 db slope? how about crossver point, 800, 1.4K or 2K?

Would really appreciate your help.

Thanks,
giaisa

[cclark65]

I have seen the Altec crossovers with 500 and 800hz modules on ebay, one of them within the past month. They have the horn eq module for CD horns, but I believe that can be removed. They also have delay on them for time alignment.

[taudo]

I was thinking of trying the Rane AC 22 for the bi-amp system I'm planning. Easily available, not expensive, has all the bells and whistles. Steep slope, though, 24 dB/octave. 'Be interested to see if anyone has had experience - good or bad - with this crossover.

taudo

[dennis gilliam]

The Altec passive models (9025-1 or -2) are great if, as you say, you can find a pair.

I have been vaey happy with the Furman electronic CO's. They are for the pro-audio market, with balanced I-O, rackmount, and other features. Of course, they are rife with silicon, and there are situations where that is not welcome.

Henceforth, if you have the resources for DIY, here is a link with all sorts of schematics for tube-based designs:

http://www.enjoythemusic.com/tubecros.htm

DG

[joyspring]

Giaisa & Taudo,

The Rane AC22 is (IMHO) the best for the price... Linkwitz-Riley filters, 4th order, LF all-pass continuously-variable delay and - best of all - solid engineering and build quality, excellent objective specifications and (of course) subjectively neutral sound...

You could build your own of course -- generic PCBs exist online for 2nd and 4th order op-amp-based filters. The `Active Filter Cookbook' (Lancaster, SAMS Publishing) is an excellent, relatively math-free resource though you should supplement that with info online if you're interested in L-R filters.

You can then choose the filter type (Bessel, Butterworth, Chebychev, Linkwitz-Riley); quiet, inexpensive opamps (NE553x, OPA2134, OP275, TL07x); and perfectly match gain and crossover frequency between channels. All this for under US$125, including a regulated, bipolar power supply!

(Now for my rant that we ought to demand better math, science and music curricula in US public education, and perhaps a lot more consumer skepticism as well...)

Finally, mount all this in a 3-U rack chassis, outfit it with Bakelite knobs and open-frame telco switches, add 10 lbs. worth of ballast weight and tell your friends that it's full of ECC83/12AX7 tubes, Jensen or Sowter transformers, exotic silver wire, mineral oil or copper-film caps, specialty resistors, Sorbothane(tm) thing-a-ma-jigs, etc. and have them regale you with the "It's so warm, sweet unlike those grainly, veiled solid-state crossovers." that they read about in Stereophile.

Only you would know the difference ;-)

BobR

[taudo]

BobR opined:

>The Rane AC22 is (IMHO) the best for the price...

====
Thanks for this feedback - I'm definitely going to give this unit a try! (I grew up with tubes, and frankly don't see the allure [except the nice glow at night]. Silicon seems fine - if it's quality silicon, of course.)

Speaking of which - have any opinions about Adcom amps?

taudo

[Fitts]

Hi,

My system:
HF Driver 291-16a
Horn Type 311-60
LF Driver EV Force 15
Bass cab A7 (75 sq. inch port)

I have a 12 db per octave crossover fixed at 560 hz. I like the slope that 12 db gives and the fact that the horn can sit on top of the A7 with the voice coils lined up. If you go for 18 db you should make a delay circut which would probably be hard to do using tubes. The alternative is to go for 24 db per octave but that would require quite a few stages and more tubes.

Don't rule out ICs for your construction, they really do a fine job.

Regards,

[giaisa]

Hi guys,

Thank you very much for your replies. Guess i have to start experimenting with the options:

1. Rane AC22 (will try to borrow one)
2. Tube crossover diy: probably at 12db slope and crossed between 500-600 (It seems Dave we have very similar set-up so i will give this a shot
3. Active Filter cookbook design

I will get back to all of you as to the result of this quest for a matching crossover. I really appreciate your ideas.

Thanks,
Giaisa

[HiFiPlayer]

So coincidently,
D-Day has one up on auction now,

I think a lot of people will goto place a bid.

Don't let it goes.

[cclark65]

A friend of mine has used Adcom amps for year, and he will never use any solidstate amp besides them if he has his choice.
They are pretty touchy amps though, make sure you turn it off if you are going to move the speaker. It seems that even if the wire going to the amp gets wiggled, it will blow the internal fuse - at least on the first generation GFA series.