Anybody biamp Allison 4s?

I have 2 identical TAD 60 amps and a 2002 Allison 4.. In another thread I have been reassured that I can biamp these vertically, but my audio repair guy, who has never let me down and is a pro, told me I couldn't. Hence the question: has anybody ever tried it? I am afraid of shorting the two inputs if the crossover isn't designed for biamping and blowing up the amp (and possibly the speaker!) would appreciate information. Have just joined Allison yahoo group but will take a while to be accepted and post.
Hopefully you will get your answer from an Allison owner. If not I've seen your post in the other forum and I believe the rub is that some speakers may have extra binding posts but that the internal high/low x-overs are not actually independent.

I use to service Allison's and do not remember that being the case but I will not stake my life on it as it was a long time ago.

However it seems to me that there is a very easy way to tell if the posts will work for biamping if you have a SS amp available for a simple test.

1) remove the jumpers

2) hook up the hot and ground the to the "lows", you should only get the bass.

3) move the hot and ground up to the "highs", you should only get mids and highs.

4) hook up the ground of the "lows" and the hot of the "highs", you should get nothing.

5)hook up the "hot" of the "lows" with the ground of the "highs", again you should have nothing.

Of course be sure to turn off the amp when you swap connections around and to be safe remember that no matter how you criss cross the wires to the binding posts on the back of the speaker you always want one hot and one ground at any given time. Also do not use a tube amp for this test as tube amps do not like to be unloaded when amplifying a signal.

Hope this helps.
Great idea! I'll do it. Thanks!
Jjrenman, Very simplistically, isn't the fact that there are jumpers proof that low and high ends are separate? Would just testing for continuity between both sets of posts with a voltmeter not be simpler and equally informative? Is this so or is there a more complicated aspect that you are alluding to that I am not getting?
Springbok10, The only reason I suggested that he test the Allison's in such a manner is that in a different forum another poster had suggested that some speakers have multiple sets of binding posts but that the crossovers inside were not necessarily independent. I've never seen such a thing in all my years of speaker repair but then I have not worked on all the brands that are out there. Yes, if the speakers only worked with jumpers it would prove that they have indeed independent high/low x overs. Also, another blogger had said that the only info he could find on Allison 4's showed a single set of binding posts. So to be safe I thought of the above test. In step one I mention removing any jumpers but none of the original posts mention the speakers as having any, so this was just to cover my keester. As far as a voltmeter goes I do not entirely trust them to check speaker hook ups as they are using DC and music is AC. I agree that it should be as easy as checking continuity between the two grounds and the two hots but since the OP has his tech telling him not to vertically biamp I wanted to think of a simple, no test equipment needed, way for him to try out.
Thank you for all your trouble, JJrenman. My repair tech/guru (Larry at Approved Audio, Litchfield, CT - I mention his name as he is so impressive - both in terms of personal integrity and the quality of work he does). After initially telling me that he didnt think it would work, (I think based on the fact that the original Allison 4s had one set of binding posts) he apparently called all over the country on his own dime, off hours, to find out the nature of the crossover, and called me back to say he had found someone who had successfully bi-amped Allison 4s and told me to go ahead! This, obviously, on the newer 4s with 2 sets of posts. So, thank you all - this is a terrific forum with helpful people, exemplified by you, and I would like to give a plug to Approved Audio, too (He has repaired my ss amps, tube amps, 3 tuners and CD players flawlessly over the past many years)