To Amp or Not to Amp... - AVS Forum
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post #1 of 13 Old 08-05-2014, 02:15 PM - Thread Starter
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To Amp or Not to Amp...

I'm just looking for some opinions on whether *you* would feel compelled to ad an amp to this setup, and if so, why?

AVR: Marantz SR7008 (auditioning in prep for SR7009)
Front R/L: Martin Logan Motion 40
C: Martin Logan Motion 30
Surround R/L: Martin Logan Motion 4
SW: Martin Logan Dynamo 700w

I picked up the 7008 (just set up yesterday) as a means to audition Marantz and Audyssey, and I plan to exchange it for the 7009, once it's released. The 7009 is spec'd for 4-16 Ohm impedance, so that concern with the MLs being 4 Ohm is eliminated, and I want the integrated WiFi & bluetooth, and MultEQ XT32.

I'm in a relatively small, odd shaped space. Essentially half of a 20' x 12' room (so 10' x 12') with 9' ceilings, open to a 2-level foyer at the rear. 9' viewing/listening distance.

Nothing is fully broken in yet (speaks have only been in for a couple weeks), but after running Audyssey yesterday... I'm impressed. But I'm really wondering how much I'm going to be leaving on the sidelines by driving everything with just the AVR? Not necessarily in volume but in quality. I like it loud, but I live in a townhouse, I did enough hearing damage when I was younger, and it sounded plenty loud in my limited listening yesterday. But I get the feeling the MLs are hungrier for considerably more than the 7008(9) can offer, and that I will be rewarded with even better SQ.

Usage is probably 70% HT to 30% 2/2.1 music.

I'm looking at Emo XPA-3/5 and Outlaw 7125, 7200 or 7500. I also have a feeler out to Classic Audio on some ATIs, and am open to recommendations in the affordable range. i.e., <2k.

TIA
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post #2 of 13 Old 08-05-2014, 03:07 PM
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I don't see you needing an amp but whatever...

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
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post #3 of 13 Old 08-05-2014, 03:35 PM
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Ohm's law guarantees that zero more power will be provided at sny given volume level. Speakers cannot smell the unused potential power and for any voltage gain, current will be defined precisely and invariably by the complex inpedance of the speakers in light of the frequency content of the source material. I cannot walk through walls or jump off a 20 story building without serious damage because of the physical laws of our universe. And an amp csnnot supply more power than (simplified) voltage and resistance allow. Its not a law like the speed limit its a law like gravity. If your current amp has inaudible distortion at your listening levels a more powerful amp will perhaps make distortion more inaudible if that means anything but it cannot ever supply more power at any given spl.

Iow at any given spl a more powerful amp is just as likely to float off into space as to provide more power to the speakers
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post #4 of 13 Old 08-05-2014, 04:20 PM
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Quote:
Originally Posted by briden View Post
I'm just looking for some opinions on whether *you* would feel compelled to ad an amp to this setup, and if so, why?

AVR: Marantz SR7008 (auditioning in prep for SR7009)
Front R/L: Martin Logan Motion 40
C: Martin Logan Motion 30
Surround R/L: Martin Logan Motion 4
SW: Martin Logan Dynamo 700w

I picked up the 7008 (just set up yesterday) as a means to audition Marantz and Audyssey, and I plan to exchange it for the 7009, once it's released. The 7009 is spec'd for 4-16 Ohm impedance, so that concern with the MLs being 4 Ohm is eliminated, and I want the integrated WiFi & bluetooth, and MultEQ XT32.

I'm in a relatively small, odd shaped space. Essentially half of a 20' x 12' room (so 10' x 12') with 9' ceilings, open to a 2-level foyer at the rear. 9' viewing/listening distance.

Nothing is fully broken in yet (speaks have only been in for a couple weeks), but after running Audyssey yesterday... I'm impressed. But I'm really wondering how much I'm going to be leaving on the sidelines by driving everything with just the AVR? Not necessarily in volume but in quality. I like it loud, but I live in a townhouse, I did enough hearing damage when I was younger, and it sounded plenty loud in my limited listening yesterday. But I get the feeling the MLs are hungrier for considerably more than the 7008(9) can offer, and that I will be rewarded with even better SQ.

Usage is probably 70% HT to 30% 2/2.1 music.

I'm looking at Emo XPA-3/5 and Outlaw 7125, 7200 or 7500. I also have a feeler out to Classic Audio on some ATIs, and am open to recommendations in the affordable range. i.e., <2k.

TIA

I had no problem driving MartinLogan Motion 40’s ( 2 ), one Motion 8 center speaker, Motion FX surrounds ( 4 ),and Motion LX16 wides ( 2 ), with a Denon 4520 . It's rated 150 watts / channel to the 7008's 125 watts / channel. But you are only driving 5 speakers! I was driving all 9. I only added an external amp when I got 2 Motion 4 height speakers, since the 4520 only powers 9 channels itself, and I wanted 11 channels.
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post #5 of 13 Old 08-06-2014, 12:09 AM
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These forums are against dedicated power, to most a yamaha 361 will drive any speaker. Borrow a quality power amplifier and see for yourself.

Krell Evolution 900e x 7

Bose Jewel speakers.

 

Jealous of my speakers?

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post #6 of 13 Old 08-06-2014, 12:16 AM
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You could always just do what I did and get a separate two channel amp to power your fronts - taking stress off your AVR, while using the receiver to power the rest of the channels. I have an Denon X4000 and at the time was running 7.2 (now running 9.2). Full disclosure, it made absolutely zero difference to the sound quality - it was good before, and remained good - but there was absolutely no difference in the sound. It would probably take a bit of stress of your Marantz that being said, not having to drive all the channels, but more likely then not you'd be fine anyways.
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post #7 of 13 Old 08-06-2014, 09:06 AM
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Most of us are against spending money on things that will not cause audible improvement. This is based upon technical knowledge and years (decades in many cases) of experience. And most of us with decades in this game have been through the upgrade games, from cables to amplifiers to shorting dust caps for our RCA connectors. You can discount our opinions and knowledge base, of course, and ultimately all that matters is if it sounds good to you. But, many of us have spent a lot of money on things that sounded good to us at the time, only to learn later we had fooled ourselves.

And there are a few times I have spent money on things that did make audible improvements, including more powerful amplifiers. I just don't see it in this case.

It really sucked when I was in college and learned my parents actually knew what they were talking about...

YMMV, FWIWFM, IMO, IME, etc. - Don
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"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
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post #8 of 13 Old 08-06-2014, 09:22 AM
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Quote:
Originally Posted by Sean Spamilton View Post
You could always just do what I did and get a separate two channel amp to power your fronts - taking stress off your AVR, while using the receiver to power the rest of the channels. I have an Denon X4000 and at the time was running 7.2 (now running 9.2). Full disclosure, it made absolutely zero difference to the sound quality - it was good before, and remained good - but there was absolutely no difference in the sound. It would probably take a bit of stress of your Marantz that being said, not having to drive all the channels, but more likely then not you'd be fine anyways.
That's what I'm doing too, to run 11 channels. It does sound different but only because I have 11 speakers running now vs 9 before. I never ran out of " head room " or had any distortion at sound levels up to the point where everyone told me " it's too loud - turn it down " without the external amp though! A lot will have to do with the size of your room of course. Your room is smaller than mine, which is 23' x 17'6" x 11' tall ( peaked ceiling ).


On the other hand, Emotiva has amps on sale often - doesn't cost too much to get a 150 watt / channel 2 channel amp like I did.

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post #9 of 13 Old 08-06-2014, 09:39 AM - Thread Starter
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Thanks for the responses.

I came upon this article and associated thread today, and found them both to be enlightening.
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post #10 of 13 Old 08-06-2014, 10:25 AM
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Be careful in that forum, or you will be lusting for exotic power and speaker cables next!
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post #11 of 13 Old 08-06-2014, 12:05 PM
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Sometimes external amps sound worse, like when the external amp has hum you can't get rid of

"But this one goes up to 11"
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post #12 of 13 Old 08-06-2014, 12:46 PM
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There's no difference between a 4 ohm receiver and an 8 ohm receiver. All receivers can play both. They can't play the 4 ohm speaker as loud before clipping.
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post #13 of 13 Old 08-06-2014, 12:56 PM
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Quote:
Originally Posted by KidHorn View Post
There's no difference between a 4 ohm receiver and an 8 ohm receiver. All receivers can play both. They can't play the 4 ohm speaker as loud before clipping.
There could be differences.

A receiver designed for 4 ohm operation could have better heat dissipation. Seems like a good idea, anyway. A receiver designed for 4 ohms could be optimized for lower impedance, especially the power supply. Look at Harmon Kardon in the past, somewhat low 8 ohm spec, but supposedly high current output.

I also wonder why you clip faster into a 4 ohm load? That could be generally true, but if the speakers in question have the same sensitivity, you put out 1/2 the voltage and twice the current into the 4 ohm speaker. You shouldn't clip due to hitting the voltage limit, unless drawing more current causes the power supply to collapse. I could be wrong on this.

"But this one goes up to 11"
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