Audible differences between 2-channel s/s amps and AVRs, when operated below clipping? - Page 5 - AVS Forum
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post #121 of 127 Old 07-22-2013, 04:51 AM
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Quote:
Originally Posted by carp View Post

Some of you may have seen this gtg but for those who haven't here goes.

I feel lucky, I have quite a few local avs guys that are as into this stuff as I am so one day we decided to figure out for ourselves if amps really make a difference.

We are all pretty open minded guys. Personally I have always leaned towards the side that says amps will sound the same if they aren't clipping but I was for sure open to the idea that amps make a significant difference. In fact, I was hoping we would prove to ourselves that amps did make a difference because I like buying gear and trying new things out so that would be another fun toy to research and buy to power my speakers.

Well, that night we thought that we discovered that amps have a very obvious and different sound. We took out as many variables as possible, level matching the amps withing .2 to .3 decibels at the most and often even closer than that.

We weren't going to discuss what we thought during the comparisons but right off the bat we realized that the sound differences were so obvious that we couldn't help but discuss.

In the end we realized a fatal error had thrown all of our findings out the window. The receiver used to direct the signal to the amps turned on Audyssey when it was accidentally turned off and then back on. So everything we were hearing was the Audyssey settings for the different pre-outs of the reciever (LRC, side surrounds, rear surounds, etc.) and accounted for why the different amps sounded so different.

Ha, it was quite the whirlwind. In a few hours I went from thinking amps didn't matter too much to thinking they made a ton of difference and back again.

The next day some of us did it again making sure evil Audyssey did not turn itself on again. This time... no difference. Well, with one exception. We had a cheap HTIB receiver in the mix just to test all kinds of amps. It did sound different, the soundstage was all off and the other amps all sounded better - and identical, even at pretty high volumes. We even had a 20 watt T amp that was indistinguishable from an expensive 2 channel Emotiva amp. Other than one person (not me) none of us knew which amp was which during this testing.

Being able to immediately switch makes all the difference. Even though our original findings got all screwed up it was still a blast and worth it to finally have the answer for myself if amps really do make a noticeable difference below clipping.

Check out the video avs member Chirpie made of the GTG. Very cool video, looks professional.



BTW the distortion during the 8 sub demo is the microphone, the bass was completely clear (and crazy) in person.




Thanks for a such a thoughtful investigation.
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post #122 of 127 Old 07-22-2013, 07:51 AM
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Quote:
Originally Posted by carp View Post

Being able to immediately switch makes all the difference. Even though our original findings got all screwed up it was still a blast and worth it to finally have the answer for myself if amps really do make a noticeable difference below clipping.

You are about half way to ABX. I' agree that you eliminated some but far from all of the confusing influences that completely trash most audiophile A/B comparisons.

You provided quick switching of level-matched alternatives (can't really tell how close the levels were matched) at the listener's discretion which is all good and which almost nobody does. Hearty and sincere congratulations!

Sighted bias was still part of the evaluation. If someone wants to argue that you were unknowingly biased towards the "no differences" conclusion, its hard to argue against that.

My next shot at ABX will be based on some fairly simple software and this device:

http://www.amazon.com/SainSmart-Eight-Channel-Relay-Automation/dp/B0093Y89DE



Basically your little program outputs one character via a USB port that controls the open/close status of all 8 relays. No sweating someone inadvertently paralleling any of the amps! $35 out of pocket - arguably cheaper than your 8 light switches.
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post #123 of 127 Old 07-22-2013, 10:56 AM
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Originally Posted by arnyk View Post

You are about half way to ABX. I' agree that you eliminated some but far from all of the confusing influences that completely trash most audiophile A/B comparisons.

You provided quick switching of level-matched alternatives (can't really tell how close the levels were matched) at the listener's discretion which is all good and which almost nobody does. Hearty and sincere congratulations!

Sighted bias was still part of the evaluation. If someone wants to argue that you were unknowingly biased towards the "no differences" conclusion, its hard to argue against that.

My next shot at ABX will be based on some fairly simple software and this device:

http://www.amazon.com/SainSmart-Eight-Channel-Relay-Automation/dp/B0093Y89DE



Basically your little program outputs one character via a USB port that controls the open/close status of all 8 relays. No sweating someone inadvertently paralleling any of the amps! $35 out of pocket - arguably cheaper than your 8 light switches.



Thanks Arny. Yeah, I have to say it was a bit stressful switching back and forth. I never made a mistake but a friend of mine did and he smoked one of the 2 little T amps we had in no time flat. Still, I'm very impressed with avs member Archaea with whipping that switcher up in basically no time flat and it worked great.

For me personally I had enough that second day for my curiosity to be satisfied. I know it wasn't a completely perfect non-biased type of setup, but the fact that we didn't know which amp was which, all amps level matched within .2 decibels etc. was enough for me. Honestly for me it was pretty obvious from the get go that second day that we weren't going to be able to tell a difference between any of the amps. (except for one which ended up being the HTIB receiver).

Even if there are small differences which I was unable to hear, they would be minuscule compared to the differences in speakers and rooms so that's what my focus will be. In my experience the biggest variable is the speakers. This is in MY room. In other rooms maybe the room is the biggest factor, but for me it's the speakers. I have 4 tri trap bass traps and 4 large acoustic panels and while they do make a difference and I love having them they do not compare to a change in speakers (once again, in MY room).

Still, I like the treatements enough to plan on more. I plan on buying 3 more 242 GIK panels for a cloud on the ceiling and then I think I'll be done with treatments.

Like I said before, I am a bit bummed that I couldn't tell a difference in amps, I was planning on getting one for the speakers. I probably still will eventually but it's hard to justify spending the money right now since their sensitivity is 101 and I am 9 feet away from the mains and center. If my math is right I need 1 watt to get roughly 92 watts at my LP, so I get 104 db's (basically reference peaks, 1 db short) with 16 watts.

Ok, got off topic a bit with this post... I tend to do that. smile.gif
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post #124 of 127 Old 07-22-2013, 10:59 AM
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Originally Posted by bladerunner6 View Post

Thanks for a such a thoughtful investigation.

Thanks! It was a lot of fun. Very disappointing when we realized the issue with Audyseey but still worth it in the end to have an answer for myself after wondering for years and reading threads like this. smile.gif
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post #125 of 127 Old 07-28-2013, 12:41 PM
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Is this argument including preamps or just amplifiers that dont sound different?
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post #126 of 127 Old 07-28-2013, 02:06 PM
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Is this argument including preamps or just amplifiers that dont sound different?
Well, keep in mind that preamps are generally designed to sound different, at the listener's discretion. They have volume and tone controls, and maybe DSP and room correction and bass management and who knows what else. The basic circuitry of preamps should generally sound the same, if you could isolate those bits--say with a bypass line-out.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #127 of 127 Old 08-31-2013, 08:28 AM
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Thanks Carp and Arnyk. You guys have saved readers thousands
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