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could an Audio Research Classic 150 amp 'fry' La Scalas?


m8o

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Hello everyone... Post #1 for me. I hope to be a proud Klipsch owner soon. I bought a 3 sets of in-walls for a friend's whole house system I'm doing for him, and I was re-introduced to the Heritage line while researching the in-walls. I have some old Martin Logans supplemented with 4 foot ribbon tweeters, tube amps, etc. for the 2-channel system, and using Miller & Kreisel [M&K] S-150 THX speakers for the media room ...so with that said, I'm currently bidding on a pair of La Scala's and Heresy II's, with plans of either replacing or running along side the M&K system in the multimedia room. If I miss winning that I see there are other La Scala auctions ending a few days later as luck would have it.

So, question to any in the know... I have a pair of Audio Research Classic 150 monoblocks. They are 140 or 150 watts each, hybrid amps with solid state input stage and lushious tube output drive stage. They are currently driving the electrostats only in my Martin Logans (I ripped out the passive x-over and using a TaCT digital x-over / room correction system now), but I'm thinking of using the amps with the La Scalas (with fingers crossed).

...But do I run the risk of damaging the speakers with that amp?

Other ideas I have to drive them is :

a) buying a pair of Flying Mole 100watt monoblocks

B) Use my NAD 7140 (or is it 7240?) receiver.

I guess what would have some bearing on what I'll do is the impedance curve of the La Scala (early 90's run). If the La Scala impedance goes too low at some frequencies the Flying Mole would be out as that can't handle 4ohms well let alone lower, as configured by the engineers (I read an engineer reply to one test that they can be stable to 1/2 ohm if so configured. But as they're designed, the ones you can buy don't handle -- i.e. perform or sound well -- at a 4ohm or lower load I read).

Additionally, I find whether I use the 4ohm or 8ohm or 16ohm output transformer taps of the Classic 150 tube amps have a very noticable effect on soundstage across the frequency spectrum .... you really want to use the tap that matches the speaker's impedance, with speakers that don't have too radical of an impedance curve.

So, is the impedance of the La Scala 'all over the place' across the frequency spectrum, or is it somewhat 'docile'? I don't have experience with the impedance curve of horn loaded drivers, so I can't venture a guess @ the moment. Does anyone happen to have an impedance curve graph they could post? I have one of these at home:

http://www.terrasonde.com/products/color.php

(yes, drool ;) ) and will measure the speakers once I get them. Just being impatient as well as planning ahead for how to drive them.

Thanx much.

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Congrats and welcome to the madness.

Just don't drive them into clipping and you'll be fine. That K33 woofer will take 100 watts all day long if you can stand it that loud. I know one guy here who hooks up like 400 watts per channel into LS on a daily basis and hasn't blown up anything yet (although his sanity might be in question)

Michael

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I run a Sherbourn 7/2100A 7-Channel True Mono Block Amplifier rated at 7 X 200W @ 8ohms or X 300W @ 4ohms for my all Klipsch Heritage Home Theater.

They never see that much power due to the efficiency, but I have cranked it to in excess of 120db+ without any hint of breakup or distortion so they should handle the 150W fine.

Common sense and good judgement prevail here.

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Thanx all for the quick replies ... I see I'm not the only one who has trouble keeping his mind on work at times! <grin>

What you all say makes perfect sense regarding 'more used less is better then less pushed 'til there's no more' (I just made that one up! [;)] ). Just remember too that the amp has a multi-position input attenuator at 3db steps, so I was thinking I could use that for safety's sake.

Regarding the later question, so has anyone ever see an impedance curve of the La Scala or have a pic to post?

Thanx again.

P.S. Oh, and I also just remembered ... I already am a Klipsch owner ; the KSS line of speakers, if you consider that 'Klipsch' compared to this heritage stuff tho... [:P]

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