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Post by Nemesis.ie on Nov 23, 2009 12:21:54 GMT -5
Hmmm, if you don't have channels connected, then they would not be used 100% of the time. I think this would be the main concern - when not actually connecting anything for a permanent install. Such as might happen to me using an XPR-7 + XPA-5. Sorry bout that nemisis, not trying to give bad advice, I just assumed from the original post that he listens to music ~80% and might go more towards HT if he gets a BDP. Harming the amp might be a concern if nothing were ever connected to it, but it sounds like he might want to connect for 5.1 down the road. My point was only that even if you neglect the other channels, I got the impression from a conversation with an EMO tech that the shortened life span would be miniscule at worst. But someone correct me if I am off base here. I am definitely not the highest authority in amps I didn't mean to say you were giving bad advice or anything of the sort, just putting forward another PoV/concern. ;-)
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Post by glock3540 on Nov 23, 2009 13:38:09 GMT -5
nemesis, My center does sound better now but have not listened to it enough to give you a good description of how much better. Whenever I get delivery of my new HDMI cables, I will give you a more detailed evaluation. Blessings, Brian
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Post by Nemesis.ie on Nov 23, 2009 13:42:41 GMT -5
Thanks B!
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Post by escape on Nov 23, 2009 13:57:04 GMT -5
I just finished talking to the same tech at eMotiva. His name is Nick. (didn't give his last name)
He repeated that emotiva does not recommend running XPA-5 with only three channels connected. "system is not designed to do this, it will stress the system'. He is not able to provide any more technical explanation than this. For my need, he said, i should buy XPA-3.
I asked him if he is willing to reply to this thread with his answer but he said he does not participate in discussion forums.
This puts me in a dilemma. I don't have a 7 channel set up now because i only have a 5.1 processor. But i am waiting for BD player prices to drop and more movies come out so I can use 7 channel *connected* set up may be after 1 year. It is a waste for me to sell XPA-3 then and buy new amp again..
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Post by Nemesis.ie on Nov 23, 2009 14:05:49 GMT -5
Maybe Dann or Lonnie can comment so we hear it from all sides?
Also, if it is only an issue when some channels are totally disconnected, would it be worth putting e.g. an 8ohm shunt on the output?
With no input, the respective channel should still do very little leaving headroom for the others but with luck keeping the amp circuit happy?
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cgolf
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Post by cgolf on Nov 23, 2009 14:57:22 GMT -5
I'm using an XPA-5 for 2 channel music and TV right now until I can get the rest of my speakers bought and hooked up. I guess that's not good either. I also thought that we had heard in an earlier post that it was OK and not an issue.
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Post by bigred7078 on Nov 23, 2009 15:27:31 GMT -5
I just finished talking to the same tech at eMotiva. His name is Nick. (didn't give his last name) He repeated that emotiva does not recommend running XPA-5 with only three channels connected. "system is not designed to do this, it will stress the system'. He is not able to provide any more technical explanation than this. For my need, he said, i should buy XPA-3. I asked him if he is willing to reply to this thread with his answer but he said he does not participate in discussion forums. This puts me in a dilemma. I don't have a 7 channel set up now because i only have a 5.1 processor. But i am waiting for BD player prices to drop and more movies come out so I can use 7 channel *connected* set up may be after 1 year. It is a waste for me to sell XPA-3 then and buy new amp again.. Nick is a smart guy and he must have a reason for saying this, otherwise i'm sure he would ask Lonnie to double check. I would like to see a response from Lonnie on this subject as i just can't quite wrap my head around why this would be detrimental to the amp.
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Post by strindl on Nov 23, 2009 15:41:44 GMT -5
X's 2
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Post by strindl on Nov 23, 2009 15:54:53 GMT -5
has anyone sent a PM to either Dann or Lonnie with a link to this thread?
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Post by bourbonncigars on Nov 23, 2009 16:20:44 GMT -5
This discussion is putting an anal raping on my curiosity. If anything, I would have thought it was actually *better* for an amp if all channels weren't driven. I thought that was the whole deal behind the marketing of receiver's amps sections that don't specify "all channels driven" and give a higher power rating. I'm dying to know the answer here....
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Post by tchaik on Nov 23, 2009 17:24:05 GMT -5
just got done speaking with nick at emo. short term use of a few channels is no problem. long term use is not good for the wear on the modules especially if you are continually running them past their rated power.
just thought y'all needed to know.
after reading this i was concerned since i will be running my xpa-5 on 3 channels for a short time. xpa-2 will be on front l/r. making the phone call gave me peace of mind.
tchaik...........
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Post by glock3540 on Nov 23, 2009 17:34:54 GMT -5
Men, This is the first I have ever heard anyone from Emo stating that there was ANY issue with using ANY combination of channels on ANY of their amplifiers. I am going to be using only 4 of of my XPA-5 channels for the forseeable future. I run my amps pretty hard, so now do I need to be concerned my amp will not last as long using it this way? If so, this is somewhat disappointing news...... Brian
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Post by slbenz on Nov 23, 2009 18:18:29 GMT -5
just got done speaking with nick at emo. short term use of a few channels is no problem. long term use is not good for the wear on the modules especially if you are continually running them past their rated power. just thought y'all needed to know. after reading this i was concerned since i will be running my xpa-5 on 3 channels for a short time. xpa-2 will be on front l/r. making the phone call gave me peace of mind. tchaik........... If that is the case, then there are quite a few multi-channel amps with separate power supply modules for each channel in the same situation. Of course the power modules being used over the long-term will statistically be the ones failing vs. the power modules that never get used. But from Nick's comments, sounds like if you constantly overdrive the power supply modules, then will you at least statistically run the higher chance of power supply module failure. That would be true of any power supply module by any manufacturer.
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Post by glock3540 on Nov 23, 2009 19:51:30 GMT -5
Hey Guys, If there were any detrimental effects of using the XPA-5 in 1,2,3 or 4 channel mode, why would Emotiva put this info on their "Online Store"?;
"Experience the power of the XPA-5...200 watts per channel @ 8 ohms, 350 per channel @ 4 ohms. A serious amp with serious headroom.
Full Specs:
Number of channels: 5 Amplifier Class: Short signal path A/B Output design: Triple Darlington with Toshiba output stages Differential Drive: Dual Differential input Types of inputs: Both Balanced (XLR) and Un-balanced (RCA) Type of outputs: Audiophile quality 5 way binding post Display type: Digital status indicators 200 watts RMS/channel into 8 ohms, all channels driven 5 channels - 8 ohm = 210 watts per channel 4 channels - 8 ohm = 230 watts per channel 3 channels - 8 ohm = 252 watts per channel 2 channels - 8 ohm = 275 watts per channel 1 channel - 8 ohm = 300 watts per channel 4 ohm rating: 5 channels - 4 ohm = 350 watts per channel 4 channels - 4 ohm = 375 watts per channel 3 channels - 4 ohm = 400 watts per channel 2 channels - 4 ohm = 450 watts per channel 1 channel - 4 ohms = 500 watts per channel THD+N at rated power output: 0.007% S/N ratio: >100db Frequency response: 10 to 120Khz (-3db) and 20 to 20 (with less than .15db deviation) Gain structure: 32db Transformer size: 1600VA Toroid Secondary capacitance: 60,000uF Weight: Approximately 70 pounds 17” W x 7.75” H x 19” D Additional notes: Glass epoxy pc boards, 1% resisters, metal film capacitors, soft start circuitry (does not have a current spike on start up).
Modular channel design for greater channel separation, auto rail detection relays for automatic voltage selection. The unit also has switches for turning the metering and/or the status LED's on or off.
This is a no compromise design. Every aspect of the amp was designed for superior performance and reliability."
If this last statement is true, and I believe it is, "A NO COMPROMISE DESIGN" and EVERY ASPECT OF THE AMP WAS DESIGNED FOR SUPERIOR PERFORMANCE AND RELIABLITY", Why would it be any kind of a compromise in amp longevity if Emotiva ADVERTISES the power output per channel using less than 5 channels? Something here is amiss. Either it IS a compromise design and does not work as well with less than 5 channels used, or it is a non issue and you can use any combination of channels and Still have the same amp life. In fact, I tend to agree with bourbonncigars and think the amp life could possibly be LONGER due to less stress on the amp. Brian
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Post by Deleted on Nov 23, 2009 20:36:38 GMT -5
PM sent to Dann, requesting that someone from Emotiva post a clarification on this matter. ;D
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Post by bourbonncigars on Nov 23, 2009 21:05:51 GMT -5
Aside from the few months I had my XPA-5s, I've been running an Outlaw amp with only 5 of its 7 channels in use for years.
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Post by nickwin on Nov 23, 2009 21:48:58 GMT -5
Yeah, I'm going to be pretty disappointed if it turns out that this is harmful to the amp and there is no mention of it at all in the manual. I have been using only 2 channels an LPA-1 for the past year. I bought it because the price was good (used) and I plan on going 5.1 as soon as the UMC-1 comes out. I've got to think that if this was a real problem EMOTIVA would have mentioned it in the description or manual.
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lonnie
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Post by lonnie on Nov 23, 2009 22:30:27 GMT -5
The short answer to the question is yes, you can use the amp with fewer channels running than what it was designed to do. As long as you stay within the power specs we state and give the amp plenty of air to cool, this won’t be an issue.
However………..
This is a question where the answer is both easy and complicated at the same time. You see when you use less than all five channels. All the energy of the power supply (well in excess of 1K watt) is directed at however many channels that are being used (which are designed to dissipate 300 watts RMS). This means the rail voltage on a specific channel goes up significantly which causes that channel to produce more heat (because it is dissipating more energy). Thus it is going to need adequate cooling to keep from stressing the channel(s). With the increased rail voltages you get more power and as long as you stay within the rated spec, no problem. But how do you know if you are within the rated spec? Honestly there isn’t any way for the average Joe to know without a lot of sophisticated gear to measure the output. So if you plan on driving the amp hard, you could over drive the module which isn’t good. But if you listen at a reasonable level, say something short of your ears bleeding then no problem. Honestly there are a lot of other things that should be considered, like the impedance curves of the speakers (how low do they dip), what other equipment is in the system (are they using an EQ with a lot of boost), etc. but we won’t go down those roads (not enough time). So there are a lot of factors involved in what we recommend and since we never seem to have all the information, I always tell everyone to err on the side safety. Stick with what the equipment was designed to do and everyone wins. I have told a lot of people that we don’t recommend using the multi-channel amps for strictly stereo or mono-block use. If you want a high power stereo or mono-block amp, then that is what you should buy. Using anything in a manner other than what it was designed for is never a good idea. ;D
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Post by glock3540 on Nov 23, 2009 22:36:21 GMT -5
Thanks Lonnie, Great Explanation.
Blessings,Brian
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Post by monkumonku on Nov 23, 2009 23:05:29 GMT -5
Thanks Lonnie, Great Explanation. Agreed, +1. That really clarified things. And like I said in an earlier post in this thread, that just provided excellent scientific post-justification for my recent XPA-2 purchase! ;D Lonnie says so!!
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