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Alpha-core advise?

I recently tried some Alpha-core MI 2 speaker cable and was quite impressed. When I made inquiries at Alpha-core, two different engineers gave me conflicting advise. Perhaps some one here can straighten me out. My curent system uses a Threshold S/500 series II driving Thiel 3.5's. The Threshold according to Jon Soderberg who used to work for Threshold is capable of doubling down. The Threshold is rated as 250 Watts per channel. The Thiels are rated as 4 Ohms nominal and 4 Ohms minimum. Independent tests show this to be rather accurate (an amazingly flat load) with one peak at about 33 Hz to about 8 Ohms. Ergo the amp may be pushing up to 500 Watts per channel. It was originally suggested by Alpha-core that I use a pair of MI 2's for my requested 8' run. They latter suggested that I run two pairs (not a traditional bi-wire situation). Unfortunately the speakers binding posts couldn't accept more than one set of the attached silver spades. When I called back, a different engineer suggested MI 3's. I'm a bit confused by the "characteristic impedance" issue. If one were to double up runs of these speaker cables, would the "characteristic impedance" half?, remain the same?, double? or something else? One advantage to this speaker cable line is that they can be made in such a way that they could have integral "spades" rather than added on ones. The advantage of the MI 3's over the MI 2's, due to greater width would be increased surface area if they were terminated in this fashion. The advantage of using double runs of MI 2's would be decreased cost and perhaps (and this depends on the answer to the previous question) better impedance matching. The Alpha-core web site suggests that this design needs little break in. Would these cables benefit from the use of a cable cooker? BTW, I am now considering using 3 meter to 10' runs. What's a boy to do?
unsound
loontoon
301 posts
 
I recall Nelson Pass commenting that the capacitance of the ribbon cables could cause some amplifiers to oscillate. I believe he was refering to his older T-hold models of which yours is one.

A quick note to Nelson or Wayne at Pass Labs should give you a quick answer. It's worth asking to prevent damage to the amp.

Better safe than sorry,

Loon
unsound OP
7,332 posts
 
Rabelais, thank you very much. You have confirmed what I suspected about "characterisic impedance". Knowing is so much better! With regard to "bulk discount" it actually appears to be inverted; as you go up the line you pay a HIGHER rate! Very odd. Since I've already accepted the Alpha-core's as being superior (at least to my ears, in my system, at this time) to other manufacturers offerings, its come down to deciding between alpha-core's products. The scale that Alpha-core offers on their web site re: application in systems seems to be a rather general guide line rather than a strict requirement. Sean's opinion (for which I have great respect) seems to at the very least bear this out. The fact that the difference in price more than doubles is worthy of consideration too. IMHO, the MI 2's appear to be quite a bargain in comparison to just about anything else I've heard. The MI 3's, well thats a different ball of wax. I can't help but wonder if the market segment being pursued here may be more responsible for the elevated price more than the cost of materials.
Loontoon, thank you for the heads up. I believe the use of the afore mentioned Zoebles resolves the amplifier oscillation issue.
pops
2,275 posts
 
Unsound, a little late to the thread, I use MI 2's on thiel 3.6's with Mcintosh mono's - 500 watts per side. I get great sound and don't see the need for a larger guage cable like the MI 3's. Very coherent top to bottom and the amps run cool. Just my nontechnical 2 cents...
rabelais
20 posts
 
Right on, Unsound. You're right about the price jump from MI2 to MI3, but strangely, MI2 < 2 * MI1; e.g.

8' MI1 = $99 + termination;
8' MI2 = $172 + termination;
8' MI3 = $424 + termination

Anyway. Re "Sean's opinion (for which I have great respect)... ." Ditto.

My guess is that MI2's will suit your situation fine, but they have a good team at Alpha-Core and offer a money-back guarantee if you order direct, so you may approach them with the proposition that you'd like to order a set of MI2s and one of MI3s--with every intention of returning one--and see if they'll go for that. Then you can make a decision where it matters most: in your listening room.

Best to you
clio09
3,360 posts
 
They went for that deal when I purchased from them. I tried the MI-2 and Python bi-wire and kept the MI-2. Very nice folks to deal with and prompt refund on the returned cables.
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