They're coming!!!!!

[xki]

+1 TO ABOVE POST #139

;D

[ultramic]

Sitting here looking at my pair of XPA-1's, I'd much prefer an understated, simplistic design for an amp (although this view may change when I get to see the XPR series in person).

Leave the "bling" and the flashing lights to the pre/pro.

My 2 cents.

[Nemesis.ie]

Mar 26, 2012 16:14:55 GMT -5 jamrock said:

You are always going to get great value with Emo products. And the Reference Line will also represent good value. However, when I talk about exclusivity, I'm talking about real performance over the other lines. Not just a different look or few more features. In other words: Can you HEAR the difference? Then and only then will folks feel that the additional prices are justified because the Reference Line of products are going to cost more. This is the reason I argue for the Reference Line to only involve products where REAL PERFORMANCE CAN BE OBJECTIVELY REALIZED and it is not left to a few exuberant members or audiophiles to "sell" subjective performance.

OK - so what you mean is "genuine high performance" rather than exclusivity I think. That I can go with.

[macromicroman]

Thanks all for the explanation about amp gain. Guess I have been lucky and have no hiss with my emotiva amps and Elite VSX-52. I have Klipsch speakers with high efficiency and still get no hiss.

[kellys]

Mar 26, 2012 18:04:38 GMT -5 jamrock said:

There is nothing wrong per se with a high gain amp. The above post #138 is generally true. But hearing a constant hiss means that there is/are components in the chain that has a high noise floor. So, a high gain amp will usually reveal that flaw. Remember, the hight gain does not cause the hiss. It simply reveal that it is already there. My UPA-7 is also high gain at 31. My speakers have a sensitivity of 88dB. Yet, I have never heard my And yeah, I will keep you in mind for the next time.system to hiss, and I play it at very high volume regularly.

One of the advantage of high gain that readily comes to mind is that you can play the system very loud without having to tax the amp. So, there is very little possibility that you are going to over drive the amp before your ears start bleeding. Personally (no scientific support) I believe that a high gain amp is also able to reveal subleties in a presentation at low volume that you would normally miss with other amps until you increase volume significantly. This is one of the reasons I believe that Emo amps are so highly praised for being "musical" It getting more 'drive' at low volume.

Sorry Jamrock, but I disagree with most of what you said.

High gain has no intrinsic benefit, and some drawbacks. In fact, most electronic components tend to perform worse when the gain is high. Distortion and other factors become more pronounced, due to a reduced amount of negative feedback applied.

What is important is the overall system gain factor. That is, components should be well matched, where they all are operating within their optimum levels. This usually means near full output (most electronic components are best within about -20db of the full output).

In my opinion, the XPR series should be matched to the ERC/XDA/UMC/XMC and reach their full output at the voltage those units put out. My XPA-5 reaches full power at 1V, but the UMC (to my knowledge) has 2V output. This means that some dynamic range is lost due to attenuation. A gain of about 28 dB would be a better match (25x versus 40x). They should also be different if the output power rating is different. I don’t believe that setting all the amps at the same gain has any benefit other than manufacturability (which is important for Emotiva).

Somewhat off topic, but I measured the XPA-5 input voltage required to drive my speakers at a comfortable nighttime listening level… 12 mV. You can see how the system signal to noise level would be improved by increasing the input voltage, i.e. reducing the amount of gain in the XPA-5.

Also, your analogy is wrong. Gain is more comparable with RPM or horsepower. Torque is analogous to output current capability.

[bootman]

Mar 27, 2012 12:37:15 GMT -5 kellys said:

Mar 26, 2012 18:04:38 GMT -5 jamrock said:

There is nothing wrong per se with a high gain amp. The above post #138 is generally true. But hearing a constant hiss means that there is/are components in the chain that has a high noise floor. So, a high gain amp will usually reveal that flaw. Remember, the hight gain does not cause the hiss. It simply reveal that it is already there. My UPA-7 is also high gain at 31. My speakers have a sensitivity of 88dB. Yet, I have never heard my And yeah, I will keep you in mind for the next time.system to hiss, and I play it at very high volume regularly.

One of the advantage of high gain that readily comes to mind is that you can play the system very loud without having to tax the amp. So, there is very little possibility that you are going to over drive the amp before your ears start bleeding. Personally (no scientific support) I believe that a high gain amp is also able to reveal subleties in a presentation at low volume that you would normally miss with other amps until you increase volume significantly. This is one of the reasons I believe that Emo amps are so highly praised for being "musical" It getting more 'drive' at low volume.

Sorry Jamrock, but I disagree with most of what you said.

High gain has no intrinsic benefit, and some drawbacks. In fact, most electronic components tend to perform worse when the gain is high. Distortion and other factors become more pronounced, due to a reduced amount of negative feedback applied.

What is important is the overall system gain factor. That is, components should be well matched, where they all are operating within their optimum levels. This usually means near full output (most electronic components are best within about -20db of the full output).

In my opinion, the XPR series should be matched to the ERC/XDA/UMC/XMC and reach their full output at the voltage those units put out. My XPA-5 reaches full power at 1V, but the UMC (to my knowledge) has 2V output. This means that some dynamic range is lost due to attenuation. A gain of about 28 dB would be a better match (25x versus 40x). They should also be different if the output power rating is different. I don’t believe that setting all the amps at the same gain has any benefit other than manufacturability (which is important for Emotiva).

Somewhat off topic, but I measured the XPA-5 input voltage required to drive my speakers at a comfortable nighttime listening level… 12 mV. You can see how the system signal to noise level would be improved by increasing the input voltage, i.e. reducing the amount of gain in the XPA-5.

Also, your analogy is wrong. Gain is more comparable with RPM or horsepower. Torque is analogous to output current capability.

Actually the UMC can put out 7V.
But just like an amp, the output is not constant and varies with the source output levels.
I would rather have the 7V of max output, because I'm assured that whatever voltage is needed is at a low distortion.

Compression and distortion doesn't just happen at the amp stage.

[kellys]

Mar 27, 2012 13:48:04 GMT -5 bootman said:

Actually the UMC can put out 7V.
But just like an amp, the output is not constant and varies with the source output levels.
I would rather have the 7V of max output, because I'm assured that whatever voltage is needed is at a low distortion.

Compression and distortion doesn't just happen at the amp stage.

Actually, I think you missed my point entirely, and I am aware the UMC-1 is a 7 V peak output, but of what value is a 7 V peak output when your amp clips at 1.25 V input. A 7 V rms signal would need a 10,000 W amplifier with an amp gain of 32 dB.

There is also the problem of having discrete attenuation levels, with a 7 V input you may have such large jumps at the low end of the volume control that is don’t ever get above the first few steps. The absolute best volume control will do no harm to the signal but most will actually decrease sound quality and resolution as more attenuation is applied.

As far as I know, the amplifier input sensitivity (and therefore gain) was set based on lower output consumer products for UPA and XPA amplifiers. Even with the higher power of the XPR series, the 32dB gain is really necessary on the highest power amplifiers.

There is an excellent article on this topic at diyaudio.com

www.diyaudio.com/forums/diyaudio-com-articles/186018-what-gain-structure.html

[jamrock]

Despite everything that you have stated, one thing that is evident, is that you don't like high gain amplifiers. So you only see one side of the equasion. When an amplifier has examplary specifications in drive capability and noise, it is irrelevant what the gain is. The noise you are likely to hear is the weakness in the other components. The power amplifier does not affect the performance of the other components. It simply magnifies whatever is sent to it. Take a look at the specs for the UPA-7 and tell me what fault you find.

Specifications


Number of Channels: 7
Amplifier Gain: 32db
Signal to Noise Ratio: Full Power: >120db
Input Impedance: 23.5kohms
Transformer Size: 850VA
Secondary Capacitance: 90,000uF
Output Devices: 4 per channel Topology: Fully Discrete, Dual Differential, High Current, Short Signal Path Class A/B
Power output (all channels driven):
185 watts RMS @ 4-ohm (0.1% THD)
125 watts RMS @ 8-ohm (0.1% THD)
Power Band Response: 20 Hz to 20 kHz with less than .05db deviation at rated powerBroadband Frequency Response (]3db): 5Hz to 150kHz
Size: 17h W x 7.75h H x 19h D
Weight: 66 lbs (84 lbs boxed)

[jdskycaster]

^Obvious. Far too heavy. Weight to gain ratio is completely out of whack!

[kellys]

Mar 27, 2012 19:40:26 GMT -5 jamrock said:

Despite everything that you have stated, one thing that is evident, is that you don't like high gain amplifiers. So you only see one side of the equasion.

Sign...

This is not a new topic of discussion. Gain Structure has long been a factor in selecting components. I would encourage evyone who is following this gain discussion to read that diyaudio article. It is a good read and quite interesting. I didn't give it much thought myself before rwading ibut have proved it too myself since. It can explain things much better than myself apparently. For the record, I love my XPA-5, I just wish it had slightly lower gain (27 or 28 dB would suffice). Any further discussion is best saved for another thread.

Back on topic (sorry moderators), The XPR series will likely have similar gain. After reviewing the Emotiva sources, they do seem to be set at about 1 V rms nomial output, which is lower than I thought. Iit seems as though the Emo crew has a good handle on this.

[ausman]

so any date for release dan or lonnie?

[jamrock]

Mar 27, 2012 22:41:00 GMT -5 jdskycaster said:

^Obvious. Far too heavy. Weight to gain ratio is completely out of whack!

This is really hilarious! It gives proper weight to the 'serious nonesense' of this discussion

Ha, ha, ha!
Ha, ha, ha!
Ha, ha, ha!

You tell em JD ;D

[geebo]

Mar 27, 2012 22:41:00 GMT -5 jdskycaster said:

^Obvious. Far too heavy. Weight to gain ratio is completely out of whack!

A new spec: WGR

For the XPA-5 it would be .475 per channel
An UPA-1? .8125 per channel
An XPA2? 1.17 per channel
An XPA-1? a whopping 2.34 per channel
An Adcom GFA-555se: .66 per channel

[jamrock]

Long ago, I learned that as an audio layman, stay away from arguments with audiophiles who want or like to argue like an engineer without having the E.E. degree. Simply focus on the qualities that the component must have, and quite likely it is has good engneering behind it. For a power amp, once it has sufficient power to drive your speakers without clipping, it should also have a flat FR 20Hz-20KHz, good noise floor at rated power, at least -65dB channel separation, very low % ThD at rated output, low output impedance, stable 4ohm operation and limited stability into 2 ohm territory. Once those parameters are achieved, the only other consideration is price. The quibble about topology, class, etc. is of little value.

[geebo]

Mar 29, 2012 16:40:02 GMT -5 jamrock said:

Long ago, I learned that as an audio layman, stay away from arguments with audiophiles who want or like to argue like an engineer without having the E.E. degree. Simply focus on the qualities that the component must have, and quite likely it is has good engneering behind it. For a power amp, once it has sufficient power to drive your speakers without clipping, it should also have a flat FR 20Hz-20KHz, good noise floor at rated power, at least -65dB channel separation, very low % ThD at rated output, low output impedance, stable 4ohm operation and limited stability into 2 ohm territory. Once those parameters are achieved, the only other consideration is price. The quibble about topology, class, etc. is of little value.

But you forgot that it needs a good WGR too.

[jamrock]

I need to get an E.E degree. How else could I forget such an important spec as the WGR. Geeesh! My humble apology to all. JD, I love you man ;D

[autocrat]

Mar 27, 2012 19:40:26 GMT -5 jamrock said:

... Take a look at the specs for the UPA-7 and tell me what fault you find.

Specifications


Number of Channels: 7
Amplifier Gain: 32db
Signal to Noise Ratio: Full Power: >120db
Input Impedance: 23.5kohms
Transformer Size: 850VA
Secondary Capacitance: 90,000uF
Output Devices: 4 per channel Topology: Fully Discrete, Dual Differential, High Current, Short Signal Path Class A/B
Power output (all channels driven):
185 watts RMS @ 4-ohm (0.1% THD)
125 watts RMS @ 8-ohm (0.1% THD)
Power Band Response: 20 Hz to 20 kHz with less than .05db deviation at rated powerBroadband Frequency Response (]3db): 5Hz to 150kHz
Size: 17h W x 7.75h H x 19h D
Weight: 66 lbs (84 lbs boxed)

IMO the THD for the measured output is high for a standalone amp. My amp measures 0.005% THD+n at maximum output (185W into 8, 7 channels driven), but then it cost a hell of a lot more than the UPA-7.

[jamrock]

"IMO the THD for the measured output is high for a standalone amp. My amp measures 0.005% THD+n at maximum output (185W into 8, 7 channels driven), but then it cost a hell of a lot more than the UPA-7"

That seems like an impossible ThD spec. I have never seen that before. What amp are you using?

[autocrat]

Elektra Theatron, you've probably never heard of it. The new version (Elektra Theatre HD) measures 0.0003% all channels driven. Remember though that these will set you back around US $5K including delivery, so we're talking an order of magnitude, for which you'd expect an improvement in the noise floor.

If you wanted a step up in both price and distortion, there is a Halco monoblock that comes in at 500 parts per billion THD+n.

[jamrock]

Mar 29, 2012 18:04:01 GMT -5 autocrat said:

Elektra Theatron, you've probably never heard of it. The new version (Elektra Theatre HD) measures 0.0003% all channels driven. Remember though that these will set you back around US $5K including delivery, so we're talking an order of magnitude, for which you'd expect an improvement in the noise floor.

If you wanted a step up in both price and distortion, there is a Halco monoblock that comes in at 500 parts per billion THD+n.

Do you believe that Krell makes excellent amplifiers. Here is a small reading on the optimal Krell. And look at the ThD figure at rated output ;D

FEATURES

Power Supply
The Evolution 900e is equipped with two 3,000 VA transformers and 108,000 µF. This power source is the backbone for the output of the Evolution 900e. With this foundation, the Evolution 900e delivers 900 watts into 8 Ohms, 1,800 watts into 4 Ohms, and 3,600 watts into 2 Ohms. The FTC mandates that power ratings are quoted using a 1,000 Hz sine wave into a fixed 8 Ohm resistor with final power specification stated at 1% distortion. Krell engineering considers this specification too lenient and not indicative of what an amplifier is required to provide. Krell designs to a much stricter standard. Our power tests use a 20-20,000Hz signal into 8, 4, and 2 Ohm loads with our final specifications stated for .1% distortion.

Not bad for the discontinued Emo, eh? ;D

I thought so too! ;D ;D ;D