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Hicksy
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Amp for old IMF Compact II speakers

Hey there,

I'm looking for a suitable amp for my dads old IMF Compact II speakers. Originally he had a Sansui A-80 Amp,either connected to a DVD player, turntable or cassette player but in recent years its died on us. I'm not looking for anything inparticular, just looking for something relatively in-expensive to get them working again.

jackfish
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Re: Amp for old IMF Compact II speakers

Those speakers don't require a lot of power. How about an NAD C315BEE for $350?

http://www.soundstage.com/revequip/nad_c315bee.htm

If you are going to hook up a turntable you could get the NAD PP-2 phono preamp for $125.

http://www.hometheaterreview.com/equipme...iewed002143.php

Jan Vigne
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Re: Amp for old IMF Compact II speakers

I don't know of an IMF design that didn't eat up watts for beakfast. This figures out to be about an 83dB @1 watt system; http://imf-electronics.com/CompactII/index.html

And though the impedance is relatively flat, there is a dip to approximately five ohms shown that would make the speakers a somewhat difficult load.


Quote:
Those speakers don't require a lot of power.

Do you have anything to support that statement? I would be a bit surprised if the small NAD was sufficient for the speakers in question.

Jan Vigne
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Re: Amp for old IMF Compact II speakers

What's "relatively inexpensive" mean to you?

jackfish
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Re: Amp for old IMF Compact II speakers

Driving Power Requirements
15 - 40 watts

Although the efficiency rating and impedance curve would suggest they could use more.

Jan Vigne
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Re: Amp for old IMF Compact II speakers

When I sold that model it made LS3/5a's sound like JBL's. That's a long time ago but I seem to remember recommending nothing less than about 75 watts of Tandberg or McIntosh to properly drive these speakers and the more and better the power the better the speakers would sound.

jackfish
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Re: Amp for old IMF Compact II speakers


Quote:
...the more and better the power the better the speakers...sound.

An axiom that applies to loudspeakers in general?

Jan Vigne
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Re: Amp for old IMF Compact II speakers

"Better", yes. "More", no.

jackfish
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Re: Amp for old IMF Compact II speakers

So dynamic headroom is a myth?

jackfish
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Re: Amp for old IMF Compact II speakers

So, this guy could look at an NAD C355BEE or a Cambridge Audio Azur 640A v2 to drive the IMF Compact IIs. We are looking for relatively inexpensive in the entry level category.

Jan Vigne
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Re: Amp for old IMF Compact II speakers


Quote:
So dynamic headroom is a myth?

Not seccenarily. Most amps can deliver a certain amount of peak power beyond their R.M.S. rating. I've been told that relying on the concept of "dynamic headroom" to get you through is relying on a loosely regulated power supply to swing substantial amounts of voltage that then might not be there in reserve should the next big thing come along. Voltage and current are not so easily managed under these dynamic conditions and current might be what you need. The power supply caps can only refresh themself at a given rate, if they are drained to hit one peak, then you might fall flat when the next peak comes along.

NAD tells the story differently.

Jan Vigne
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Re: Amp for old IMF Compact II speakers


Quote:
We are looking for relatively inexpensive in the entry level category.

I don't know, we seem to have lost our op. If his funds permit, I might opt for a Vincent integrated amp. If he can't stretch that far, I'd probably try one of the Cambridge units.

jackfish
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Re: Amp for old IMF Compact II speakers

Its funny you should mention Vincent. I just had the opportunity to listen to the Vincent SV-226 through some Triangle Antal EXs. Nice package. The Jolida JD 1501A should also be considered as a less costly yet effective solution.

Hicksy
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Re: Amp for old IMF Compact II speakers

I'm not lost, just busy. Thanks for the suggestions guys. I'm really don't know too much about speakers and amps, so yeh, any suggestions are good ones to me, i'll check them out

Jan Vigne
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Re: Amp for old IMF Compact II speakers

The issue with the Jolida would be its output impedance. As a transformer coupled, tube output amplifier it is very likely higher than any of the solid state amplifiers and therefore will have some interaction with the impedance load of the IMF's. This might cause frequency response errors that are unacceptable. A listen is in order if at all possible. Jolida makes a well respected product at a not very expensive price and offers a different take on sound quality compared to NAD, Cambridge or Rotel.

commsysman
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Re: Amp for old IMF Compact II speakers

What you need is the Outlaw Audio RR2150 Receiver. It costs $699 plus shipping and has lots of great features; it also has 100 watts per channel, which you NEED for those relatively inefficient speakers. Available online only from the manufacturer. This unit has been recently recommended by both The Absolute Sound and Stereophile.

It also includes a phono input with selectable sensitivity for either MC or MM phono cartridges; impossible to beat for the price! It even has a USB input for computer audio.

If you go to Equipment Reviews on this website, you will find a detailed review on this unit from the March 2006 issue.

www.outlawaudio.com

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