best output voltage to input voltage match.

P.C.

Well-Known Member
May 30, 2010
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Was interested to hear from any Wadia owners who have use the Wadia internal digital volume, what internal voltage output you used along with your amps input voltage.
For example I until recently had my Wadia 381 set to just 0.5 volts and my Nagra PSA SS 100watt amp to its max 2 volt input. This enabled me to keep the volume levels in the high 80s to 90s for all my cds.
But have just recently found out that by doing so my Amp was actually only putting out about 6 watts max ! due to this input /output discrepancy.
I have just changed the PSA's input voltage to the lower default 1 volt setting which should give me at least a few more watts! but not any where near the 100watts available My speakers are Harbeth M40.1s which I believe Harbeth recommends sould have around 50-100watts available to them.
This change has mean't the volume it now set lower to around the mid 70s to mid 80s which is still above the 74+ that Wadia recommends.
My final option would be to reset the Wadia to the higher 1 volt output to better match the Nagras 1v input but I expect this would mean the volume levels would be only in the 60s which will loose me a little resolution? But would at least enable more of the Nagras PSA 100watts to be on tap for sudden musical peaks.
I was therefore interested in what other forum members have found works best.
I know a separate line stage would solve these issues but I presently do not have the funds for a suitable one and am very much enjoying the performance I'm getting , just was interested in more feedback.
Thanks Philip.
 
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Champ04

Member
Sep 24, 2012
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2
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Illinois
Understanding exactly what those numbers mean will help you determine the best settings for your system.
First the amplifier. What you are referring to as the "input voltage" is better referred to as "input sensitivity". This is maximum voltage that can be fed to the amp without it clipping. It's also the point of maximum output.
The output voltage on the Wadia is referring to the maximum output when a signal is 0dB. This is the loudest it will ever get.
So, theoretically, if you were to set the output voltage of the Wadia to 1V and the input sensitivity of the Nagra to 1V then you could literally run the Wadia at ANY volume level, and with any musical content and be certain the the amplifier would never go into clipping.
The same would hold true setting the Wadia to 2V output and the Nagra to 2V input.
Unfortunately, in the real world, things are not so simple. You also have to take into account the sensitivity of your speakers. It is often safe to have an output voltage that exceeds the input sensitivity of an amp. If you have very sensitive speakers your amp could be run at a point where it is far from clipping and yet it still be far to loud to listen to.
BUT! On the other hand, if you have speakers with very low sensitivity, then it is entirely possible that your amp will go into clipping quite often, even at moderate listening levels.
But there is one more thing that will effect this far more than anything else. And that's the type of music being listened to.
Classical music has, by far, the largest dynamic range encoded on a CD. Rock, on the other hand, is probably the lowest dynamic range. This is a general rule, of course.
So for a given volume level, Rock will sound WAY louder than Classical because all of the instruments are recorded at their highest possible levels and there is typically little to no time intervals where the musical content itself is quite. Classical is just the opposite. Even though many pieces of music can get really loud, for the most part it's a quieter type of music.
This will profoundly effect how you listen and at what volume levels.

Let me give a concrete example to help describe this.
I have a DAC that does not have the variable output settings like the Wadia. But I was inspired by the Wadia design. So I redesigned the output circuit of my DAC to have a maximum output voltage that exactly matched the input sensitivity of my amp. In this case, it is 1.5V for both units. I also have speakers that are moderate in sensitivity levels.
What I have found is that when I listen to classical I run the DAC at full volume and this is a good listening level for me. On especially soft passages, or on music that was recorded well below 0dB, I sometimes wish I had just a little bit more to work with. But for the most part it works well. However, if I were to listen to Rock at that same level it would be too loud. My neighbors would complain. It's not loud enough to damage either my amp or my speakers, but it is still too loud to listen to.

So it basically comes down to what you listen to. If the music you listen to most has a wide dynamic range, then you could set your Wadia and Nagra to have very close numbers. If you are listening to music with a very compressed dynamic range, then you will probably want a significantly lower setting on the Wadia.
Since both pieces of equipment are adjustable, you can play with the setting to get something pretty well fine tuned. Keep in mind that, for reasons beyond the scope of this thread, the Nagra will probably sound better on the higher voltage setting. So if it were me, I'd set the Nagra to 2V and then adjust the Wadia to something between 1V and 2V. I'd probably try to get it as close to 1.5V as possible. Then I could comfortably listen to the widest variety of musical content.
I keep the output of my DAC at exactly the input sensitivity of my amp because I want my classical recordings to sound their best, which would be at the top range of the volume control. Rock music isn't typically recorded as well, so I don't mind having the volume setting quite a bit lower when I'm listening to it. I'm not really listening critically with that content anyway.
 
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treitz3

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Outstanding first post, Champ! Welcome to the What's Best Forum.

Tom
 

AudioExplorations

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Apr 5, 2012
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Welcome Champ! That was a very interesting and informative post!

I have just looked up the details of my own personal situation - I run a Weiss Medea Plus DAC (adjustable voltage and digital volume) into a Burmester 911mk3 power amp (fixed input sensitivity).

I have the Medea set at the minimum setting of 490mV output voltage @ 0dB digital attenuation.
The Burmester input sensitivity is fixed at 770mV.

In terms of listening levels this seems to be a good setting given the relatively high gain on my amp and moderately sensitive speakers. Like you describe I use much more volume attenuation on modern music and much less on classical. Avro Part - Alina is the only LP in my collection where I find I cannot get enough volume at 0dB, I am able to use the volume control within PureMusic playback software to add anywhere up to +10dB.

The only thing I am wondering now is what the consequence is of running 0.49V into an 0.77V amp is, I guess this means I am loosing a significant amount of wattage from the power amp? Perhaps I should increase the voltage up to 0.77V on the Medea and, using more digital attenuation, see how this impacts the sound. On the other hand I listen mostly to 'modern' music so it may not be the best move after all. The system as it is setup now has absolute death grip control over the speakers so I do not think I am under powering the system due to the potentially reduced watts.

Any advice would be appreciated.
 

MarinJim

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Feb 2, 2011
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I want to name my first son Champ.:cool:
 

Champ04

Member
Sep 24, 2012
72
2
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Illinois
Hello Everyone, Thank you for the kind greetings!

AudioExplorations touched on a similar point that the original post did that I think needs to be addressed. And that has to do with exactly what the amp is doing in a system and how we use those "watts".
In short, there is only one situation where you are "losing watts".
A power amplifier is nothing more than a voltage multiplier. It takes whatever input voltage it's given and multiplies it by a specific amount. Because we're dealing with a logarithmic scale, the exact numbers can get tricky. So I'll use a simple example.
An amplifier's gain is typically specified in decibels (dB). By far, the most common gains in our industry are 26dB and 32dB. But, as I said, the math on that is tricky. So I'll describe an amplifier with only 20dB gain. It turns out that 20dB gain is exactly 10X the original voltage input.
So on this theoretical amplifier, if an input signal is 1.0V then the output will be 10.0 volts. Now, keep in mind that this is different from "power" (watts). Thats another matter entirely and throws current into the equation. Not important for this discussion.
Music is a constantly changing voltage, from zero (which is dead silence) to the highest peak in any given piece of music.
The only time we run into trouble is when we try to multiply the signal beyond what the amplifier can handle. So lets say this amplifier has an input sensitivity of 2.0V. This means that it's maximum voltage output is going to be 20 volts. If we feed it a signal that goes beyond 2.0V it won't be able to multiply at the same 10X. Even though the musical signal is still rising, the amp stops at 20V and stays there until the musical signal comes back below 2.0V. This is voltage clipping! Not good.

So what does this mean as far as maximizing our amplifiers capabilities? Not a whole lot, actually. It's not a bad thing to have an amplifier spend most of it's time operating at the lower end of it's capabilities. Actually, most amplifiers are more linear at that end of their output. This is where we get the idea that "The first watt is the most important." It's because that's where it spends the majority of it's time. But that isn't really relevant here.

If AudioExplorations were to increase the output of his Weiss to 0.77V will his amplifier be doing more or less work? Will he be increasing the watts that his amplifier is putting out?
Actually, from the perspective of the amplifier, absolutely nothing changes!
A speaker will require a certain amount of voltage for a given listening level. That voltage comes from the amplifier. And that amplifier only knows to multiply whatever signal it's given by exactly the same amount up to the point where it craps out. The only thing thats going to make it crap out is a very low sensitivity speaker being driven to very loud levels. (Again, when considering voltage, this is true. Current is another matter.)
So, assuming we don't change the actual listening level that we prefer,(Ie. we don't start listening louder) changing the maximum output of the DAC has absolutely no effect on the amplifier. The amplifier is still seeing the exact same input level. The only change is in the DAC, where a lot more attenuation is taking place.

Now, here is where we DO have to pay attention. Because every DAC is different in how it handles it's digital attenuation. Some are transparent. Others start throwing away bits rather rapidly. But I think it's safe to say that all DACs (or CD players) will be better off operating at the upper end of their volume spectrum. But suffice to say, when we change the maximum output setting of a DAC, any changes in quality will come as a result of the quality of that DACs volume control. Again, because as long as we don't change the actual final listening level that comes out of the speakers, the amp is still multiplying by the same amount it was designed to which means the DAC is still putting out the same absolute level of voltage as before.

The best way I can conceive of dealing with the settings is to identify the quietest piece of music in one's collection. And then set the DACs output so that this piece of music can be played back at a volume that is enjoyable while the DAC's volume control is maxed out. (100%) Everything beyond that will necessarily use a lower setting on the volume scale of the DAC, but that's what we must deal with when we have a collection of music with such a wide range of dynamics.

Hope this helps!
 
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MarinJim

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Feb 2, 2011
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What a champ (literally)!;)
 

egidius

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Feb 13, 2011
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technique, music

Understanding exactly what those numbers mean will help you determine the best settings for your system.
First the amplifier. What you are referring to as the "input voltage" is better referred to as "input sensitivity". This is maximum voltage that can be fed to the amp without it clipping. It's also the point of maximum output.
The output voltage on the Wadia is referring to the maximum output when a signal is 0dB. This is the loudest it will ever get.
So, theoretically, if you were to set the output voltage of the Wadia to 1V and the input sensitivity of the Nagra to 1V then you could literally run the Wadia at ANY volume level, and with any musical content and be certain the the amplifier would never go into clipping.
The same would hold true setting the Wadia to 2V output and the Nagra to 2V input.
Unfortunately, in the real world, things are not so simple. You also have to take into account the sensitivity of your speakers. It is often safe to have an output voltage that exceeds the input sensitivity of an amp. If you have very sensitive speakers your amp could be run at a point where it is far from clipping and yet it still be far to loud to listen to.
BUT! On the other hand, if you have speakers with very low sensitivity, then it is entirely possible that your amp will go into clipping quite often, even at moderate listening levels.
But there is one more thing that will effect this far more than anything else. And that's the type of music being listened to.
Classical music has, by far, the largest dynamic range encoded on a CD. Rock, on the other hand, is probably the lowest dynamic range. This is a general rule, of course.
So for a given volume level, Rock will sound WAY louder than Classical because all of the instruments are recorded at their highest possible levels and there is typically little to no time intervals where the musical content itself is quite. Classical is just the opposite. Even though many pieces of music can get really loud, for the most part it's a quieter type of music.
This will profoundly effect how you listen and at what volume levels.

Let me give a concrete example to help describe this.
I have a DAC that does not have the variable output settings like the Wadia. But I was inspired by the Wadia design. So I redesigned the output circuit of my DAC to have a maximum output voltage that exactly matched the input sensitivity of my amp. In this case, it is 1.5V for both units. I also have speakers that are moderate in sensitivity levels.
What I have found is that when I listen to classical I run the DAC at full volume and this is a good listening level for me. On especially soft passages, or on music that was recorded well below 0dB, I sometimes wish I had just a little bit more to work with. But for the most part it works well. However, if I were to listen to Rock at that same level it would be too loud. My neighbors would complain. It's not loud enough to damage either my amp or my speakers, but it is still too loud to listen to.

So it basically comes down to what you listen to. If the music you listen to most has a wide dynamic range, then you could set your Wadia and Nagra to have very close numbers. If you are listening to music with a very compressed dynamic range, then you will probably want a significantly lower setting on the Wadia.
Since both pieces of equipment are adjustable, you can play with the setting to get something pretty well fine tuned. Keep in mind that, for reasons beyond the scope of this thread, the Nagra will probably sound better on the higher voltage setting. So if it were me, I'd set the Nagra to 2V and then adjust the Wadia to something between 1V and 2V. I'd probably try to get it as close to 1.5V as possible. Then I could comfortably listen to the widest variety of musical content.
I keep the output of my DAC at exactly the input sensitivity of my amp because I want my classical recordings to sound their best, which would be at the top range of the volume control. Rock music isn't typically recorded as well, so I don't mind having the volume setting quite a bit lower when I'm listening to it. I'm not really listening critically with that content anyway.

Really enlightening post, thank you.
As a side remark: I use the Wadia S7i together with a Berning ZH230 or Audio Consulting MIPA, with an interesting addendum: The Wadia is near me, running a long ic to the passive Audio Consulting Silver Rock TVA running with a very short cable to the amp. The TVA is only ever used, so I can adjust the basic volume of the Wadia in the 90ties, so it acts kind of like a buffer - but I am no technician ;-)
In any case, this is a fantastic setup which probably could be bettered by the cable...

Egidius
 

microstrip

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May 30, 2010
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Excellent posts, Champ!

They are very helpful, but however they show the fragility of most full digital attenuators and why most people still rely on old school analog attenuators. And there is an additional aspect that we can not forget - some equipment with several discrete output settings does not sound the same in all the positions.

I am currently hosting a Nagra CD player. It has a 1 and 3.5V output settings and the preferred setting depends more on the sound characteristics of the system than on the sensitivity of the receiving equipment.

As you wisely say, we must address this situation using music preferences and statistics.
 

MarinJim

New Member
Feb 2, 2011
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Really enlightening post, thank you.
As a side remark: I use the Wadia S7i together with a Berning ZH230 or Audio Consulting MIPA, with an interesting addendum: The Wadia is near me, running a long ic to the passive Audio Consulting Silver Rock TVA running with a very short cable to the amp. The TVA is only ever used, so I can adjust the basic volume of the Wadia in the 90ties, so it acts kind of like a buffer - but I am no technician ;-)
In any case, this is a fantastic setup which probably could be bettered by the cable...

Egidius

I tried my S7i directly to my Burmester 911 MK3 and even though it sounded excellent, adding my Concert Fidelity preamp to to another higher level, IMHO. I did keep the Wadia volume set to 99 though.
 

P.C.

Well-Known Member
May 30, 2010
34
0
1,561
Vancouver, WA, USA
Gosh after nearly two and a half months from starting this thread I'd sort of given up. Only to check back in today to find such great responses! Thanks for the initial reply Champ04.
I listen pretty much to classical only which helps as its often recorded at lower level which means a higher volume level with the digital attenuator, which is a good think.
I have Harbeth m40.1 which are about 84db/1w/1m. I tried the 1 volt output to 1 volt input but found I had to lower the volume into the high 50s - mid 60s which is bit low re: digital loss.
So I now have the Wadia at 1v and the nagra at 2 volts ( as per your suggestion) which allows my max vol to be in mid 70s up to the lowish 80s which is ok.
I suppose I could set the Wadia to the 0.5 volt mark to get closer to the max volume levels but am still unsure if I should.

Thanks again Philip.
 
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