Super Dumb Newbie Question...

[OneLiterPeter]

I recently setup my ML Source mains. They are connected to a Yamaha RX-V663 receiver which is rated at 95 watts per channel at 8 ohms. My ML Source's are 5 ohm and are rated at 200 watt. I can set my receiver for either 8 ohm or 4 ohm for the mains.

So I'm wondering if it's OK to run my receiver at 8 ohm based on this scenario... Having my receiver set to 8 ohm would deliver 152 watts to my ML's (8/5 (or 1.6) * 95 watts = 152 watts). I'm still well within the operating limits of my speakers so I should be OK. Right? Providing my math is correct.

Any insight would be helpful.

Thanks, Pete

 

[zaphod]

I recently setup my ML Source mains. They are connected to a Yamaha RX-V663 receiver which is rated at 95 watts per channel at 8 ohms. My ML Source's are 5 ohm and are rated at 200 watt. I can set my receiver for either 8 ohm or 4 ohm for the mains.

So I'm wondering if it's OK to run my receiver at 8 ohm based on this scenario... Having my receiver set to 8 ohm would deliver 152 watts to my ML's (8/5 (or 1.6) * 95 watts = 152 watts). I'm still well within the operating limits of my speakers so I should be OK. Right? Providing my math is correct.

Any insight would be helpful.

Thanks, Pete

there is more to life than watts and ohms and RMS. there was a recent thread here on that very subject a week or two ago. basically, a well built power supply in a quality amp - even if rated very low - can out perform a high rated lesser amp.

i'm not making any statements about your amp just amps in general.

logans - particularily the 'stat flavours can be a real load on an amp and overwork it. that's bad for the amp, the speakers and your listening enjoyment.

i've heard some people say that they prefer the 4ohm taps over the 8ohm, and that's for your ears to decide.

i have a feeling that i didn't help at all with your math, just your math anxiety

 

[OneLiterPeter]

Zaphod...

Thanks for the reply. I understand (for the most part) what you mean. Quality has always taken precedence over quantity in my book. Although budget does dictate the level of quality I can afford.

I did wander across a thread where someone had a Sony receiver and wanted to drive a pair of Sources with it. Hopefully I'm spared some of the responses he got.

When I purchased the ML's I anticipated that I'd need some external amplification but decided to listen to them with what I had first. Needless to say they sound absolutely stunning with what I have and if driving them with my relatively low end receiver results in it's early demise... I can't say I'd be too upset. My main concern is with the speakers and from what you've said I don't think that my receiver pumps out enough power to do them any harm.

I do believe however that my Yamaha will still work pretty well as a preamp though. Most of my budget was spent on the Sources along with a Matinee center channel and Dynamo sub. With the few dollars I have left I'm looking at getting an Emotiva XPA-3 http://www.emotiva.com/xpa3.htmlamp to power my mains and center channel. Granted it's not super high end but it falls within my budget.

Anyone care to comment on Emotiva products?

 

[VanDaRo]

1) That receiver will run out of current before the speakers run out of ability to deliver. Whatever you decide, if you hear the amp start to clip, back off the volume immediately.

2) Martin Logan is kinda famous for downplaying the impedance and phase of the reactive load. I haven't seen the actual curves for the Source speaker, but if the rule of averages holds true, the panel drops to ~2 ohms or less at high frequencies. A high current amplifier(s) is recommended.

3) Almost without fail, people running their Logans with tube amps prefer the 4 ohm taps. If you have this option (uncommon on receivers), try it.

4) Strongly consider buying a good stereo amp for your Logans. Most receivers have the ability to operate just as a preamp by way of a bypass. You will enjoy much higher levels of control, extension, soundstage and ease.

My 2 cents.

~VDR

 

[amey01]

As far as I know, the four ohm tap on valve amps is different to a four ohm setting on some inexpensive amps. These are purely current limiting devices to protect the amp from the low impedance load. The eight ohm tap will usually sound better.

Just a note about calculating watts, etc - as others have indicated, the maths changes as the frequency and load changes, so it is not always valid.

The most important thing above all else is to practice common sense. Don't overdrive the amp or run it into clipping. There are some of use here using 3w SE valve amps with great results. Likewise, you can damage "200w" speakers with such an amp if you don't practice common sense.

So my advice - use whatever tap sounds the best and practice common sense - be VERY careful about overdriving the speakers.

Oh, and try and invest in a stable, high-current amp at some point in the near future - the results will be well worth it!

 

[VanDaRo]

Emotiva amps = good stuff. Go for it !!

:rocker:

~VDR

 

[OneLiterPeter]

Emotiva amps = good stuff. Go for it !!

:rocker:

~VDR

Thanks VanDaRo :rocker:

I was hoping to get some feedback on the amp.

The 3 channel XPA-3 amp is priced within my budget and looks to be a good solution for driving my mains and center channel.

amey01... I'm not too worried about over driving the amp but thanks for the warning. You can never be too careful. Typical listening volume for me is on the level of loud un-amplified singing (no idea if there's some kind of measurement for that or not).

Thanks again for pointing me in the right direction.

Pete

 

[FISH_MAN]

you should get a $50 dollar sound meter from radio shack your speakers should play comfortable at 80-95db from a distance of 8' - 11' if they do not you need more power. be sure to set it to slow C. this meter is also good for speaker level setup

 

[Jeff H]

I was drving my SL3's, then Clarity's with a Denon 3805. They sounded fine at all levels. I then hooked the speakers up to a Atlantic Technologies 5 channel amp. Pretty much the same wattage as the Denon. The difference was night and day. The Martin Logan's came alive. I was amazed at the diference, even a low levels. Go out and buy a decent 2 channel amp. I promise you won't regret it. Good Luck!

 

[TomDac]

I was drving my SL3's, then Clarity's with a Denon 3805. They sounded fine at all levels. I then hooked the speakers up to a Atlantic Technologies 5 channel amp. Pretty much the same wattage as the Denon. The difference was night and day. The Martin Logan's came alive. I was amazed at the diference, even a low levels. Go out and buy a decent 2 channel amp. I promise you won't regret it. Good Luck!

I concur 100% with this statement... You won't know what you're missing until you do...

 

[OneLiterPeter]

Just wanted to give a little update on my progress.

I bought myself an Emotiva XPA-3, 3 channel (200w per channel) amp. I'm using it to drive my Source mains and Matinee center. You are all correct... the difference really is like night and day.

Thanks to all for the advice! :rocker:

 

[68sting]

I have a Sunfire Ultimate Receiver and wonder how it would compare to a couple XPA-3 amps. Can a more expensive receiver out perform the more cost effect seperates?

 

[OneLiterPeter]

I have a Sunfire Ultimate Receiver and wonder how it would compare to a couple XPA-3 amps. Can a more expensive receiver out perform the more cost effect seperates?

Or One XPA-2 for the mains and an XPA-3 for the center and surrounds. :music:

I think it really comes down to the design and build of the components and not so much the price. Emotiva's business model is direct to consumer versus the standard model of Manufacturer to distributer to retail. Every time some one has their hand in the pot the cost goes up. Case in point... I got my ML's from a friend that works for a major retailer and saved 30%. He told me that the typical retail mark up is around 40%. How much a distributer marks something up before it gets to a retailer I can only guess.

With that said... (and a little bit of internet research)

A Sunfire Theater Grand 3 which retails for $4999.95 can be gotten new on ebay for $1800.00.

The equivalent from Emotiva would be... MPS-2 Amp (7 x 200w) at $1700.00 and a UMC-1 processor at $700.00

With the Emotiva equipment totaling out to $2400.00... the Sunfire ends up being less money.

As for whether or not one sounds better than the other... That's something that I don't think I'm qualified to answer.

 

[Gordon Gray]

By the by Pete,

There is no thing as a dumb question. Only the arrogant would think so and this Club really tries to be the opposite.

GG

 

[68sting]

I have a Sunfire Ultimate Receiver and wonder how it would compare to a couple XPA-3 amps. Can a more expensive receiver out perform the more cost effect seperates?

Any one compared these?

 

[JonFo]

I have a Sunfire Ultimate Receiver and wonder how it would compare to a couple XPA-3 amps. Can a more expensive receiver out perform the more cost effect seperates?

In this case, the Sunfire wins IMHO. Mostly because the amps are one of the few to deliver very high current.

The Sunfire Receiver pretty much integrates the same amp as their separates. Since the design runs so cool, packing in five or seven channels plus a preamp is not too big a deal for them.

I’m not aware of any other receiver I’d make that statement for. So in general, separates are better, but in this instance, the Emotiva would not quite reach the level of the Sunfire amps in the Sunfire Ultimate Receiver.

 

[twich54]

Can a more expensive receiver out perform the more cost effect seperates?

The most costly receiver IS at a price point where good quality sperates begin. While flexibility and HT convienence are their with the receiver, for serious two channel listening seperates win easily. Keep in ming this is a 'general' statement but given what the high end in receivers cost I'm willing to bet most of us on this forum could easily put together a better seperatetwo channel rig.