Violectric HPA V281 - Vorsprung durch Balanced
Feb 22, 2017 at 6:48 PM Post #2,659 of 5,173

FumblingFoo

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Found the balanced version of the measurements @ http://reference-audio-analyzer.pro/en/report/amp/violectric-hpa-v281-balance.php
 
I was kinda crestfallen to see the THD and noise plots so laden with peaks and graph noise compared to the unbalanced measurements
frown.gif
. Are these real distortions or something like measurement error like the first huge peak found on all THD graphs?
 
Feb 22, 2017 at 8:32 PM Post #2,660 of 5,173

ArthurPower

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I can't say for sure but it looks like some weird anomaly with the oscilloscope. I can tell you Fried Reim is all about measurements when he designs gear. I have never seen a manufacturer so obsessed with measurements, especially very small amounts of measurable distortion which is never audible to most humans. So although I always find measurements of audio gear and headphones interesting it's often very hard to interpret unless you're an electronics engineer.

If you've ever seen the measurements of a tube amplifier, your first reaction would probably be there's no way I could listen to this and not hear distortion. Measurable distortion like this is often very difficult to discern, and it's not always something negative it's just part of audio reproduction.

The most important thing to keep in mind with any high quality amplifier, is not necessarily the total harmonic distortion, but the ratio of the individual harmonics that make up that total. Every amplifier regardless of design, produces 2nd, 3rd, 4th, and 5th harmonics. The key is the ratio of these harmonics that are produced together.

The odd harmonics (3rd and 5th) are the most fatiguing to the human ear. So keeping those two as low as possible is very important. However, the ratio between all these distortion figures is the art of using a quality transistor and designing circuitry around it that strikes a nice balance of these combined harmonics. So it's not just low distortion as a total combined figure, since there will always be some distortion in every amplifier, but ensuring that the distortion that is present is pleasing to your ears or at least less offensive. :)
 
Feb 22, 2017 at 9:22 PM Post #2,661 of 5,173

FumblingFoo

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That's great to hear; I'm very welcoming of Fried's obsession :). And when it comes to interpreting measurements I'm indeed a simpleton (with many other things too audio-related, lol), but its nice to know that at least part of what I was seeing was anomalous. Very informative btw!  The v281 sounds wonderful to me balanced or unbalanced , so props to Fried
L3000.gif
.
 
Feb 23, 2017 at 7:33 AM Post #2,662 of 5,173

AppleheadMay

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I'd like to ask two questions about this amp.
 
- Is the satandard volume control a potentiometer or stepped attenator?
- what are the differences in sound between the V200, V220, V280, V281? I read there is a difference in warmth?
 
 
 
EDIT: A third question actually. Did anyone have a chance to compare this to the Sony TA-ZH1ES?
 
Feb 23, 2017 at 9:12 AM Post #2,663 of 5,173

zhgutov

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  Found the balanced version of the measurements @ http://reference-audio-analyzer.pro/en/report/amp/violectric-hpa-v281-balance.php
 
I was kinda crestfallen to see the THD and noise plots so laden with peaks and graph noise compared to the unbalanced measurements
frown.gif
. Are these real distortions or something like measurement error like the first huge peak found on all THD graphs?


This is not the real distortion. This is hum (distortion+noise). If you make an experiment with the headphones, you can hear the white noise. Actually the distortion in balanced mode is much lower than in SE. Look at the graphs with more power - there are no visible harmonics at any reasonable level at all.
 
Feb 23, 2017 at 11:39 AM Post #2,664 of 5,173

FumblingFoo

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That's great to know, but when I play the headphones in unbalanced mode with the music off and crank up the volume all the way @ 0db pre-gain, the noise is about twice as quiet as in balanced mode (but still pretty faint), but that's to be expected because the balanced out has about 10db more power, right?
 
Feb 23, 2017 at 12:04 PM Post #2,666 of 5,173

zhgutov

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  That's great to know, but when I play the headphones in unbalanced mode with the music off and crank up the volume all the way @ 0db pre-gain, the noise is about twice as quiet as in balanced mode (but still pretty faint), but that's to be expected because the balanced out has about 10db more power, right?


Yes, 6 dB higher (twice) for balanced mode.
 
Feb 23, 2017 at 12:57 PM Post #2,667 of 5,173

AppleheadMay

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Stepped attenuator. The other questions IDK.

 
 
Hmm, weird. I asked because someone in a for sale post said the same as you, saying it's the 42 steps attenuator.
Strangly their webite claims the stock volume control is an Alps RK27 potentiometer.
Have they switched to pots now?
 
Feb 23, 2017 at 1:46 PM Post #2,668 of 5,173

FumblingFoo

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Strange, I thought that the v281 only changed volume via the stepped attenuator, either the 42 step or 128 step relay version. What you mentioned comes with the remote control upgrade, no stock, which is the 42 stepped attenuator. Maybe the motorized control is just that, and it just adjusts the stepped attenuator mechanically. I heard somewhere that the motorized control works via friction, so the volume can be adjusted via remote and manually at the same time (for the curious masochistic).
 
Feb 24, 2017 at 2:42 AM Post #2,669 of 5,173

davidespinosa

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The standard volume control uses an ALPS RK27 pot with 41 detents (I think it's 41).  The detents are little bumps that you feel when turning the pot.  It's NOT a stepped attenuator.  In fact, Violectric doesn't offer a stepped attenuator option.
 
The basic motorized volume control also uses an RK27 pot, but without the detents.  The pot turns smoothly, to make it easier for the motor.  You can also adjust the pot by hand.
 
The relay volume control also uses an undetented RK27 pot, but in this case, an A2D converter reads the pot position and adjusts the relays accordingly (in 128 steps).  The audio only goes through the relays -- never through the pot.  So the control path is:
 
  Remote -> Motor -> Pot -> A2D -> Relays
 
If manual adjustment wasn't necessary, the remote could directly control the relays.  But the indirect approach allows both manual and remote adjustment.
 
Feb 24, 2017 at 3:20 AM Post #2,670 of 5,173

AppleheadMay

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  The standard volume control uses an ALPS RK27 pot with 41 detents (I think it's 41).  The detents are little bumps that you feel when turning the pot.  It's NOT a stepped attenuator.  In fact, Violectric doesn't offer a stepped attenuator option.
 
The basic motorized volume control also uses an RK27 pot, but without the detents.  The pot turns smoothly, to make it easier for the motor.  You can also adjust the pot by hand.
 
The relay volume control also uses an undetented RK27 pot, but in this case, an A2D converter reads the pot position and adjusts the relays accordingly (in 128 steps).  The audio only goes through the relays -- never through the pot.  So the control path is:
 
  Remote -> Motor -> Pot -> A2D -> Relays
 
If manual adjustment wasn't necessary, the remote could directly control the relays.  But the indirect approach allows both manual and remote adjustment.

 
Thank you for the detailed info, it finally makes sense now!
I'd actually be fine with standard as I don't need one more remote and I prefer a pot to an attenuator.
 
Still looking into the offered options: V200, V220, V280 and V281. Balanced isn't something I'm after, I'm fine with SE and I don't need the balance control and ouput/preout options as well so on paper the V200 would be fine for my intended use. I just wonder how they differ sonically.
 

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