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  1. #1
    ride a jet ski Tarheel_'s Avatar
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    Is .2% THD too high

    searching for a nice receiver to replace my 2002 HK avr.

    I've been looking at Pioneer stuff and found a great looking/feature rich model, but the THD looks odd and high. Can you hear the difference at this level?

    I'm running 6ohm Revels and Infinitys in a 7.1 setup.

    Pioneer VSX-1015TX

    here's the stats:
    Power Amplifier Design: Advanced Direct Energy MOSFET

    Surround Power: 840 Watts Total System Power - 120 watts x 7 (20 Hz - 20kHz .2 THD @ 8 Ohm)

    Stereo Power: 240 Watts Total Stereo Power - 120 watts x 2 (20 Hz - 20kHz .2 THD @ 8 Ohm)

  2. #2
    Suspended markw's Avatar
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    You won't be able to hear it.

    If you're into measurements, then others will look better on paper but, in the real world, you won't hear this.

    Now, if you drive your receiver into clipping, then this tiny figure will be dwarfed by what it will be putting out in distortion levels, assuming it doesn't shut down first.

    I'd be more concerned by what those wattage and distortion figures translate to when looked at in the terms of true RMS over a 20 - 20khz range with all channels driven simultaneously.

    Additionally, what's the distortion figures at a lower level, say one or two watts? Remember, you don't listen to all 120 watts except briefly on peaks. Most listening is done at the level of a few watts (> 10) at most.
    Last edited by markw; 10-06-2006 at 05:27 AM.

  3. #3
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    I worked for CBS' tape facility in Terre Haute IN. Part of my responsibilities involved EQ of our QC listening rooms and A/B rooms for Mastering and Product. I had one QC person who heard 1% distortion on a new 1K level tape we used for level setting. My ears couldn't tell, but hers could. We replaced it of course.
    It's not unusual to see THD readings of .5 - .8 on lower priced receivers. Panasonic is one that comes to mind. It's also not unusual to see higher distortions on tube amps. I believe my McIntosh 40 had a THD of .5. I don't think you can tell a big difference, but when comparing amps or receivers and noticing SS amps have THDs of .0015 it's difficult to justify adding over 100 times more distortion to your system, no matter how cost effective the unit is.

  4. #4
    Mutant from table 9
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    FYI here's a link to a review by an unfortunately named reviewer (Steve Guttenburg).http://reviews.cnet.com/Pioneer_VSX_...1426274-2.html

    Mark's right. You won't hear it. Ambient noise can provide a good comparison. I've got some cooling fans that I can't hear over my system, but open the glass door on my cabinent and you can hear them whirling away. Also, I've got lots of wall rattles from my sub that I only really notice while using test tones. While I don't care to argue with people who would claim to be able to hear the difference between .2% THD and .02%, I would just leave it that I find it unlikely. Generally if you stay below 1% THD and above like 85db signal to noise, you'll be fine.

    HOWEVER, and this a big however, I'm running a separate amp for my mains that is 170 watts at .003% THD and intermodulation distortion (IMD) at 127db signal-to-noise with the first 15 watts in class A operation, and you could not pay me to swap it out for a Pioneer Receiver. So whats my point? Well I got 2 points.

    First, when a manufacturer publishes "170(class A/B)/15 (class A) watts @ .003 THD w/ 127db s/n both channels driven 20-20khz" you can be sure they are not fudging. When the write "120 watts x 7 (20 Hz - 20kHz .2 THD @ 8 Ohm)" I get suspicious. Especially if they could have written it as a more honest "70 x 7 at .02 THD." The phrase "Total System Power" should always raise questions.

    Second, start acquiring separate amps. That way, when you upgrade recievers, your only concerned about its processer performance and preamp performance. Your amplifier section will remain constant. Look on Audiogon or Ebay for Parasound, Nad, Adcom, ect. You can get those amps for literally $1/watt, which is a bargain.

  5. #5
    Silence of the spam Site Moderator Geoffcin's Avatar
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    Those ratings can be misleading

    Quote Originally Posted by Tarheel_
    searching for a nice receiver to replace my 2002 HK avr.

    I've been looking at Pioneer stuff and found a great looking/feature rich model, but the THD looks odd and high. Can you hear the difference at this level?

    I'm running 6ohm Revels and Infinitys in a 7.1 setup.

    Pioneer VSX-1015TX

    here's the stats:
    Power Amplifier Design: Advanced Direct Energy MOSFET

    Surround Power: 840 Watts Total System Power - 120 watts x 7 (20 Hz - 20kHz .2 THD @ 8 Ohm)

    Stereo Power: 240 Watts Total Stereo Power - 120 watts x 2 (20 Hz - 20kHz .2 THD @ 8 Ohm)
    First they are taken into a 8 ohm resistor, with the load at FULL rated power. Most likely your going to be using your receiver at somewhat less power than that, and be driving something other than a resistor. All electro-dynamic speakers present a variable and reactive load to an amp. How well the amp responds to this load is MUCH more important to how it's going to sound than the raw THD numbers.

    The Pioneer VSX1015-TX, although now replaced, has developed a stellar reputation among mid-priced receivers. The amp section in particular is very strong, and should be able to drive you system with no problem.
    Audio;
    Ming Da MC34-AB 75wpc
    PS Audio Classic 250. 500wpc into 4 ohms.
    PS Audio 4.5 preamp,
    Marantz 6170 TT Shure M97e cart.
    Arcam Alpha 9 CD.- 24 bit dCS Ring DAC.
    Magnepan 3.6r speakers Oak/black,

  6. #6
    ride a jet ski Tarheel_'s Avatar
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    great responses guys...i realize a separate amp would be a huge benefit, but my HK has short-term memory loss and so i have to reset all settings everytime i use it. So, i'm gonna move it into another room and use it less frequently or just stereo.

    So, that means my budget is tight and i either replace it with another AVR or buy a separate amp and continue to go through menu after menu. My warranty is out and i can't bare to live without an AVR for a few weeks (to repair). so i guess i gotta replace. The Pioneer model above has been replaced with a model with HDMI, but it took a few hits from an ugly stick in the process.

    Later,
    Greg

  7. #7
    Silence of the spam Site Moderator Geoffcin's Avatar
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    Yes, I agree.

    Quote Originally Posted by Tarheel_
    great responses guys...i realize a separate amp would be a huge benefit, but my HK has short-term memory loss and so i have to reset all settings everytime i use it. So, i'm gonna move it into another room and use it less frequently or just stereo.

    So, that means my budget is tight and i either replace it with another AVR or buy a separate amp and continue to go through menu after menu. My warranty is out and i can't bare to live without an AVR for a few weeks (to repair). so i guess i gotta replace. The Pioneer model above has been replaced with a model with HDMI, but it took a few hits from an ugly stick in the process.

    Later,
    Greg
    The 1015 is a much nicer looking AVR than the doorless 1016. The 1015 also has basically the same guts (minus some bells and whistles) as the $1K Pioneer Elite 52tx. Good luck with your new receiver!
    Audio;
    Ming Da MC34-AB 75wpc
    PS Audio Classic 250. 500wpc into 4 ohms.
    PS Audio 4.5 preamp,
    Marantz 6170 TT Shure M97e cart.
    Arcam Alpha 9 CD.- 24 bit dCS Ring DAC.
    Magnepan 3.6r speakers Oak/black,

  8. #8
    Loving This kexodusc's Avatar
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    The 0.2 % distortion at 120 watts is actually a pretty great spec. If you were to plot distortion against wattage, the curve would look like kind of like a parabola - basically half of a big "U" as power increases. An incremental wattage increase would show a big increase in distortion - I'm guessing Pioneer just decided to pick the highest watt number with a reasonably low distortion number of 0.2% as a good marketing spec to report. I'd be shocked if at 1-20 watts the distortion wasn't a fraction of that.

    Not that it matters, as markw, Geoffcin and others have already said - if you can hear 0.2% THD as offensive, then I doubt any piece of electronic music reproduction apparatus will be to your liking.

  9. #9
    ride a jet ski Tarheel_'s Avatar
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    thanks everyone...no fear then on the Pioneer...now to pull the trigger and not go into the doghouse explaining how a $1200 receiver is being moved in a spare room... this hobby is a disease!!

    only thing that bothers me is the weight difference. The HK weights 42 or 44lbs and the Pioneer is like 10lbs lighter.

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