In Reply to: RE: 2.6s vs. 2.5s ... posted by Davy on July 26, 2010 at 03:28:07:
Hi Colin,
As I currently have one of my "Frankenpans" down for fixing (so I can only listen in mono), I have time to spend answering your Qs! :-)) (Otherwise, I'd be too busy getting an eargasm! :-)) )
OK #1: Yes, getting those Tymps would cost you getting on for 800? pounds in shipping (given what I paid to have a pair of 2.5s shipped from Roma, a year or so ago)! :-(( And the top end of T1s is not that great, as I understand it! :-((
#2: Active biamping a pair of III/IIIa/3.Xs is straightforward. And using a passive XO between mid & ribbon is still good ... it's arguable, IMO, whether active tri-amping is a worthwhile spend!! :-))
#3: No, actively bi-amping a pair of 2.5s or 2.6s is not a problem. :-)) Not many amps can drive a 2.5 ribbon directly ... so all you need to do is add a series 1.5 ohm Duelund resistor to bring the ribbon up to 3 ohms - any good amp should be able to deliver 50 or so watts into 3 ohms. And your 2-way active XO will allow you to "level" one band relative to the other.
#4: There are advantages to active tri-amping but, having done that with my IIIas and then gone back to active bi-amping temporarily, I must admit that in terms of basic SQ, tri-amping may not deliver that much extra bang for the extra buck! :-)) And, for the ribbons (2.5/2.6 or 3.3), you need to have an amp which has no "power-on/off thump" - or you might blow a ribbon.
I use a 25w (into 8 ohms - 50w into 4 ohms ... and about 60w into 3 ohms) AKSA Lifeforce amp on my ribbons. See here for reference:
http://www.aksaonline.com/products/products.html
The 25w Lifeforce is simply a 55w LF with a reduced DC voltage rail - which enables it to better cope with a low driver resistance (and makes it sound better! :-)) ). Hugh can supply one made up, if you're not into DIY.
Best choice for an active XO on a limited budget would have to be (of the ones you mentioned) the Behringer DCX2496. And I understand you can have it "tweaked" to sound better?
But there may be another alternative which is basically equivalent (some would say better! :-)) ) ... and should be cheaper. And if you listen to (analogue) vinyl, maybe this is the way to go?
This is a Passive Line Level XO (or PLLXO) - this is a collection of resistors and caps which sit in front of the 2 power amps and divide the frequency. The reasons it is not widely used are:
* the component values in the XO depend on the input impedance of the power amps used.
* whilst 12dB slopes can be accommodated, I believe the 18dB slope of the 3.3 bass lowpass might be a problem.
* it's harder to match the level of the 2 bands (than an active XO).
Davey is the man to talk to about designing one of these for you.
But don't buy a bloody stock XO!
Good luck,
Andy
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Follow Ups
- OK, 3 Series Maggies ... - andyr 04:49:54 07/26/10 (1)
- Thanks Andy! - Davy 05:14:10 07/26/10 (0)