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Review and Measurements of Benchmark DAC3

BAMCIS

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OK, the DAC3 HGC that Benchmark was kind enough to send arrived today. So I put it on the bench and ran a few tests. I will be on the road tomorrow late morning so if you want to have anything else measured (hopefully not!), ask right away.

NOTE: all measurements are using balanced output unless noted, with -10 dB jumper applied as the original review.

Let's start with our Dashboard view:
View attachment 14207

Right away we see a 2 dB or so improvement in SINAD/reduction of distortion compared to the loaner unit I had from @dallasjustice.

Let's look at the contested Jitter measurements using Benchmark's own ASIO driver:
View attachment 14208

We see a substantial improvement in jitter sidebands. We went from -108 dB or so to -131 dB!

No, it had nothing to do with using ASIO4ALL:

View attachment 14210

As you see, it makes no difference which driver is used. Both generate the identical, much improved results.

For completeness, let's run through the rest of our tests:

View attachment 14211

We see a marked improvement in low frequency noise/distortion (in green/brown). Gone is also the varying channel response that I saw (in red) in the first unit I tested. This matches our dashboard view of better THD+N/SINAD.

Here is IMD vs level and comparison to some other devices I had tested later, specifically Oppo UDP-205:

View attachment 14213

The Benchmark DAC3 HGC (in red) has substantially lower noise than all the other DACs I have tested. It starts to saturate a bit at maximum level where it then runs into Oppo UDP-205. But otherwise beats it handily.

And here is the spectrum of 1 kHz distortion and noise (saved for future reference):
View attachment 14214

Distortion products are well under -120 dB, satisfying our even most conservative standard for audibility or better said, lack thereof.

Finally, linearity:
View attachment 14215

Using balanced output (which is used in all of the tests above), the DAC3 nails the performance here. There is something you don't see in these graphs which is how much my analyzer struggles to get stable set of measurements. With every DAC I have tested, it usually times out and picks the last value at lower amplitudes. Not so with Benchmark DAC3. The results instantly converge allowing the analyzer to run through all the values. There is exceptional engineering here to generate such stability and precision at such low amplitudes.

Alas, the small blemish on unbalanced output remains.

Summary
This second loaner unit of Benchmark DAC3 (HGC) finally lives up to the standard and reputation of Benchmark as a company. Measurements are exceptional with no faults found anywhere. OK, there is a setback in linearity for unbalanced output but otherwise, this is as good it gets guys.

It is a puzzler as to why the previous loaner did not generate as exceptional of results as this unit. I hope Benchmark works with the owner of the other unit and investigates.
Can an amplifier without adjustable gain use a 12 volt signal? Can a standard pre amp use that level? I was under the impression 4 volts was the level they are supposed to work with. It would be good to see the max volt output and a measurement at 4 volts.
 

DSJR

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My geriatric preamps can give 10V from their RCA outputs and when I turned the power amp gains right down and ran the preamp flat out, I got it to (admittedly soft) clip. If the Benchmark can more than double that, then 12V max wouldn't be an issue. I was informed that it's a good idea to put a goodly voltage down the interconnects to keep noise and so on down, but this may be a rats nest of preconceptions.
 

¥€$

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Now using -20 dB pads and I'm going to leave them be. I used the -10 dB pads for several months so I must've gotten used to that since everything sounds the same now, except maybe more "dynamic" even though that may well be placebo, volume pot is now set @ 12 'O clock. If disabling attenuation was as simple as flicking a switch at the back, I'd try the 0 dB setting one more time but now I'm finally done with this. The -20 dB setting has a lower output impedance than -10 anyway so that suits me also. And about the clicks mentioned earlier, they must be some sort of heat related phenomenon of the DAC cover plate, since relays would be extremely predictable in behaviour. Anyway, they are gone now.
 

strada

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Hi Amrin, what do you mean by the higher output level being useful for room EQ? What does higher output level even mean in this context?

Thanks!
 

terfenol-D

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Hi Amrin, what do you mean by the higher output level being useful for room EQ? What does higher output level even mean in this context?

Thanks!

I'm a beginner with this so hopefully I get this correct. When setting target EQ's you set a target decibel level. If you set it too high you are only eq'ing the peaks. If you set it low you might be able to end up with a better eq but your overall volume will be too low. Using the higher output is a way to add the volume back.

This video (at the 11:00 minute mark) addresses setting the target levels and discusses associated reduction in volume.
 
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Sunnysideup

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No, there’s not really anything else connected that I can think of — the issue persists when I move it to another room. I think I’ll just go with switching off the power strip. Thanks everyone for the suggestions!
My unit exhibits this as well and came across your post from 2 years back when I searched for answers.

The faint high pitched noise appears only when it is on standby and goes away if I remove the power supply or when it is powered on.
 

amin

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Here is the unbalanced tests from Benchmark DAC3. It is not the full suite due to shortness of time but should give you a flavor of what is going on.

First, dashboard:
View attachment 13384

As with balanced the DAC3 has healthy level of drive even out of its RCA plugs at over 3.1 volts. So it should have no difficulty driving any unbalanced inputs on your pre-amp or amplifier.

Next, let's look at Jitter and Noise:
View attachment 13385

Here I am comparing the two outputs: balanced vs unbalanced. Same distortion spikes exist over USB. Noise floor is nicely lowered together with the lower output so dynamic range more or less remains the same. I wonder if they attenuate and convert the balanced output to unbalanced and hence the reduction in noise level.

THD+N likewise looks like this:

View attachment 13386

Here, we do see slightly degraded performance due to higher noise levels. So maybe the dynamic range is a bit lower. :)

Now here is where it gets interesting: linearity:

View attachment 13397
Unlike balanced output, the unbalanced response is considerably worse with one channel worse than the other.

As a way of reference, I put the Topping D50 through the same test and as before, it has textbook output to -120 dB.

Since these are new Linearity tests on my new Audio Precision APx555, I thought I do a sanity check and look at the waveforms at -120 dB with the analyzer filtering in place:

View attachment 13388

While you can't see the linearity error itself, you can easily see the varying levels in the output of Benchmark DAC3 on the right. Clearly one or the other channel output is in error and that is what the Linearity measurement showed. The Topping on the other hand, most of the time produces identical output (once in a while one channel would be a bit lower).

This is more remarkable than it seems since the output of the Topping D50 is lower (1.9 volts RMS vs 3.1 on DAC3). All else being equal, it is harder to get a clean lower voltage output than higher (with respect to noise).

This is a very surprising result. I will leave the door slightly ajar on instrumentation issues due to newness of the linearity test on the APx555 which I have developed. But the arrows certainly point to less than optimal implementation of unbalanced output from DAC3.

Summary
While the benchmark DAC3 generally measures well on its unbalanced output, reproduction of low level signals is not very accurate. There certainly is no excuse for a $250 DAC to beat it in such tests as linearity.

So sadly, I cannot recommend the Benchmark DAC3 for unbalanced output.

As always, comments, correction and criticism are welcome.
Dear Amir,
Thnx for detailed input,
Do you have any experience with T+A DAC8DSD to compare with Benchmark DAC3 or RME.
Technically point of view numbers of DAC chipsets and configuration is how effected on the output sound?

Best Regards,
Amin
Here is the unbalanced tests from Benchmark DAC3. It is not the full suite due to shortness of time but should give you a flavor of what is going on.

First, dashboard:
View attachment 13384

As with balanced the DAC3 has healthy level of drive even out of its RCA plugs at over 3.1 volts. So it should have no difficulty driving any unbalanced inputs on your pre-amp or amplifier.

Next, let's look at Jitter and Noise:
View attachment 13385

Here I am comparing the two outputs: balanced vs unbalanced. Same distortion spikes exist over USB. Noise floor is nicely lowered together with the lower output so dynamic range more or less remains the same. I wonder if they attenuate and convert the balanced output to unbalanced and hence the reduction in noise level.

THD+N likewise looks like this:

View attachment 13386

Here, we do see slightly degraded performance due to higher noise levels. So maybe the dynamic range is a bit lower. :)

Now here is where it gets interesting: linearity:

View attachment 13397
Unlike balanced output, the unbalanced response is considerably worse with one channel worse than the other.

As a way of reference, I put the Topping D50 through the same test and as before, it has textbook output to -120 dB.

Since these are new Linearity tests on my new Audio Precision APx555, I thought I do a sanity check and look at the waveforms at -120 dB with the analyzer filtering in place:

View attachment 13388

While you can't see the linearity error itself, you can easily see the varying levels in the output of Benchmark DAC3 on the right. Clearly one or the other channel output is in error and that is what the Linearity measurement showed. The Topping on the other hand, most of the time produces identical output (once in a while one channel would be a bit lower).

This is more remarkable than it seems since the output of the Topping D50 is lower (1.9 volts RMS vs 3.1 on DAC3). All else being equal, it is harder to get a clean lower voltage output than higher (with respect to noise).

This is a very surprising result. I will leave the door slightly ajar on instrumentation issues due to newness of the linearity test on the APx555 which I have developed. But the arrows certainly point to less than optimal implementation of unbalanced output from DAC3.

Summary
While the benchmark DAC3 generally measures well on its unbalanced output, reproduction of low level signals is not very accurate. There certainly is no excuse for a $250 DAC to beat it in such tests as linearity.

So sadly, I cannot recommend the Benchmark DAC3 for unbalanced output.

As always, comments, correction and criticism are welcome.

Dear Amir,
Thnx for detailed input,
Do you have any experience with T+A DAC8DSD to compare with Benchmark DAC3 or RME.
Technically point of view numbers of DAC chipsets and configuration is how effected on the output sound?

Best Regards,
Amin
 

9h9m

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Either connection will work but the direct connection from the DAC2 to the power amplifier will provide the best SNR and lowest THD.
Hi John,
I have the DAC3L and AHB2. Is there a way to bypass the preamp section of the DAC3L, to feed the Dac output to the AHB2 directly?
I really enjoy the combo so far, btw.
 

eyes-on-you

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I have a AHB2 and DAC2 combo.

Yesterday i tried different XLR pads in the dac.

Output impedence change depands on pads position as you know.
60 Ohms (Attenuator off)
425 Ohms (Attenuator = 10 dB)
135 Ohms (Attenuator = 20 dB)

My listening position is nearly 3 meters away from the speakers for this reason, setting 0db to xlr pads is too loud. Volume pot located 9 o’clock position in this settings.

I changed attenuator to -10db. Setting volume is much comfortable but i feel trable rolls of too much in this settings.

Is it possible?

After that, setting -20db, i feel bass quality improved much, soundstage goes deeper, i feel trable has much more energy but volume pot position in between 15/18 o’clock, sometimes maximum in this setting at my listening position. In additon, for some tracks volume is too low to listen.

Should i listen music with maximum volume ? Is this technically correct?

Benchmark DAC2 manual says, factory defult setting of pads is -10db.

But in the DAC3 manuel, benchmark says you should use 0db with AHB2.

I’m very confused.

Waiting your comments.
 

anmpr1

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I have a AHB2 and DAC2 combo. Yesterday i tried different XLR pads in the dac. After that, setting -20db, i feel bass quality improved much, soundstage goes deeper, i feel trable has much more energy but volume pot position in between 15/18 o’clock, sometimes maximum in this setting at my listening position. In additon, for some tracks volume is too low to listen.

Should i listen music with maximum volume ? Is this technically correct? Benchmark DAC2 manual says, factory defult setting of pads is -10db. But in the DAC3 manuel, benchmark says you should use 0db with AHB2. I’m very confused.

Proper settings between the DAC2 and AHB2 should be made in order to reduce S/N. For lowest signal to noise I believe Benchmark advises 0dB for the DAC2 preamp, and 22dBu on the amplifier.

Subjective impressions at different settings are likely due to: a) level variances and b) vagaries of memory; the former can be mistaken for 'quality' differences, differences that are simply not present when levels are matched, while the latter is simply a reliability issue that most everyone experiences when comparing components from memory.

One thing--> with different volume pot settings and as output gain changes, there could be some small channel imbalances. Whether those imbalances are audible as distinct sonic phenomenon is something I can't talk about. Also, as gain changes, intrinsic loudspeaker distortion characteristics will certainly manifest, and that could be mistaken for, and attributed to, amplifier/DAC properties.
 

eyes-on-you

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Proper settings between the DAC2 and AHB2 should be made in order to reduce S/N. For lowest signal to noise I believe Benchmark advises 0dB for the DAC2 preamp, and 22dBu on the amplifier.

Subjective impressions at different settings are likely due to: a) level variances and b) vagaries of memory; the former can be mistaken for 'quality' differences, differences that are simply not present when levels are matched, while the latter is simply a reliability issue that most everyone experiences when comparing components from memory.

One thing--> with different volume pot settings and as output gain changes, there could be some small channel imbalances. Whether those imbalances are audible as distinct sonic phenomenon is something I can't talk about. Also, as gain changes, intrinsic loudspeaker distortion characteristics will certainly manifest, and that could be mistaken for, and attributed to, amplifier/DAC properties.
Output impedence does not effect?
 

anmpr1

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Output impedence does not effect?
I would highly suggest that you go to the Benchmark site and download the DAC2 documentation, if you have not already done so, or if you do not own the manual already. Then, do a quick word search on the word 'impedance'. That will highlight all instances in the manual, and tell you all you need to know, anent your question. The purpose of the pads and how they affect device output in relation to the amplifier interface.

What you should be wanting to do with these settings is to minimize the maximum S/N of the devices in combination. If you can't get the volume 'right' at your listening position using the recommended settings in conjunction with the rotary volume control, then frankly I don't know what to tell you. That's a new one on me.

Edit: What you should be wanting to do... is to maximize the S/N of the devices in combination. In my defense, it is early in the AM here and my fingers take a little time to integrate with my brain. But I can assure you that, to (mis)paraphrase Alice, I do usually mean what I say, but I don't always say what I mean. :facepalm:

alice_mad_tea.jpg
 
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John_Siau

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I have a AHB2 and DAC2 combo.

Yesterday i tried different XLR pads in the dac.

Output impedence change depands on pads position as you know.
60 Ohms (Attenuator off)
425 Ohms (Attenuator = 10 dB)
135 Ohms (Attenuator = 20 dB)

My listening position is nearly 3 meters away from the speakers for this reason, setting 0db to xlr pads is too loud. Volume pot located 9 o’clock position in this settings.

I changed attenuator to -10db. Setting volume is much comfortable but i feel trable rolls of too much in this settings.

Is it possible?

After that, setting -20db, i feel bass quality improved much, soundstage goes deeper, i feel trable has much more energy but volume pot position in between 15/18 o’clock, sometimes maximum in this setting at my listening position. In additon, for some tracks volume is too low to listen.

Should i listen music with maximum volume ? Is this technically correct?

Benchmark DAC2 manual says, factory defult setting of pads is -10db.

But in the DAC3 manuel, benchmark says you should use 0db with AHB2.

I’m very confused.

Waiting your comments.
The DAC2/DAC3 output impedance changes from 60 Ohms to 425 Ohms (when engaging the -10 dB pads), but this is not an issue when driving the AHB2. The input impedance of the AHB2 is about 1 megohm when fed with a balanced signal. The input capacitance of the AHB2 is also very low, and you will not experience any change in the high frequencies when changing the jumpers on the DAC3 (or DAC2). This is easy to verify on a AP test station when analyzing the combined performance of the DAC3 and AHB2. The frequency response of the combined system does not change when you move the jumpers from 0 dB to -10 dB or -20 dB.

Any perceived differences are probably due to slight level changes and the fact that you had no way to compare the two conditions in real time.

If you set the jumpers to -10 dB on the DAC2, the DAC2 will only be able to deliver 14 dBu at full volume. The AHB2 requires 22 dBu to reach full output. This means that you will only be able to drive the AHB2 to 8 dB below full output when you are using the -10 dB jumpers. This means that your maximum output would be 15.8 W per channel instead of 100 W per channel. If you find this reduced output level is sufficient, there is no harm in running the system this way, but it offers no advantage. The maximum signal level at the speaker terminals is reduced by 8 dB and the noise voltage at the speaker terminals is reduced by about 6 or 7 dB. At a 0 dB jumper setting, the output noise of the DAC2 is the limiting factor in the system output noise. With the -10 dB pads engaged, the output noise drops to that of the AHB2 amplifier itself. The SNR of the amplifier is 132 dB while the SNR of the DAC2 is 127 dB at full output and 125 dB at the 22 dBu output required to drive the AHB2. But ...

Do not get hung up on the change in output noise. In either case, the noise voltage at the speaker terminals is too small to create audible noise at point blank range from the speakers unless you are using very high efficiency horns. With any of the three jumper settings, you will find that your system makes no audible noise at point blank range from the speakers, even when the DAC2 volume is set to maximum.

If you have very high efficiency horns, you could consider using the -10 dB setting on the DAC2(3). Otherwise I would recommend leaving the jumpers at 0 dB.

Note that the -10 dB setting will be required for most non-Benchmark power amplifiers. When the DAC2 was introduced, the Benchmark AHB2 power amplifier did not exist. For this reason, the DAC2 converters were shipped with the jumpers set to -10 dB. Our professional studio customers would move the jumpers to 0 dB, but everyone else could leave them at -10 dB.

The AHB2 is a low-gain amplifier that is designed to be driven by full studio signal levels (+22 dBu at full output). This has many advantages.

Once we introduced the AHB2, we began shipping our DACs with the jumpers set to 0 dB.
 

walt99

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John, as a quick follow up to the above, I am currently running LA4-DAC3B with 2 AHB2's in bridged mode. With the extra 6db gain from the amps I was typically running the LA4 down in the -45db range. Would I be better off with the 10db pads engaged on the DAC to raise the volume position on the LA4? What is the ideal setup for this?
PS: I am extremely happy with my current system, it runs all day until we go to bed, it sounds phenomenal.
 

eyes-on-you

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The DAC2/DAC3 output impedance changes from 60 Ohms to 425 Ohms (when engaging the -10 dB pads), but this is not an issue when driving the AHB2. The input impedance of the AHB2 is about 1 megohm when fed with a balanced signal. The input capacitance of the AHB2 is also very low, and you will not experience any change in the high frequencies when changing the jumpers on the DAC3 (or DAC2). This is easy to verify on a AP test station when analyzing the combined performance of the DAC3 and AHB2. The frequency response of the combined system does not change when you move the jumpers from 0 dB to -10 dB or -20 dB.

Any perceived differences are probably due to slight level changes and the fact that you had no way to compare the two conditions in real time.

If you set the jumpers to -10 dB on the DAC2, the DAC2 will only be able to deliver 14 dBu at full volume. The AHB2 requires 22 dBu to reach full output. This means that you will only be able to drive the AHB2 to 8 dB below full output when you are using the -10 dB jumpers. This means that your maximum output would be 15.8 W per channel instead of 100 W per channel. If you find this reduced output level is sufficient, there is no harm in running the system this way, but it offers no advantage. The maximum signal level at the speaker terminals is reduced by 8 dB and the noise voltage at the speaker terminals is reduced by about 6 or 7 dB. At a 0 dB jumper setting, the output noise of the DAC2 is the limiting factor in the system output noise. With the -10 dB pads engaged, the output noise drops to that of the AHB2 amplifier itself. The SNR of the amplifier is 132 dB while the SNR of the DAC2 is 127 dB at full output and 125 dB at the 22 dBu output required to drive the AHB2. But ...

Do not get hung up on the change in output noise. In either case, the noise voltage at the speaker terminals is too small to create audible noise at point blank range from the speakers unless you are using very high efficiency horns. With any of the three jumper settings, you will find that your system makes no audible noise at point blank range from the speakers, even when the DAC2 volume is set to maximum.

If you have very high efficiency horns, you could consider using the -10 dB setting on the DAC2(3). Otherwise I would recommend leaving the jumpers at 0 dB.

Note that the -10 dB setting will be required for most non-Benchmark power amplifiers. When the DAC2 was introduced, the Benchmark AHB2 power amplifier did not exist. For this reason, the DAC2 converters were shipped with the jumpers set to -10 dB. Our professional studio customers would move the jumpers to 0 dB, but everyone else could leave them at -10 dB.

The AHB2 is a low-gain amplifier that is designed to be driven by full studio signal levels (+22 dBu at full output). This has many advantages.

Once we introduced the AHB2, we began shipping our DACs with the jumpers set to 0 dB.

Hello John,

First, it's nice to know that you're always here to help.

In my experiments, when I set the -10db pads, I felt that I could perceive the echoes more effortlessly and more clearly. The SNR values you are talking about are far beyond what a human ear can distinguish. It wasn't a complete blind test, so I don't know why. Probably I'm wrong.

My speakers are not high efficiency horns. I'm using the Revel F228BE and the sound I've heard since the day I paired it with your amp was the pursuit of tens of thousands of dollars spent in my audiophile adventure. I am grateful to both Revel and you for providing these opportunities.

If you say it's okay to listen to these speakers at approximately 16 watts, I'd like to continue with -10db pads.

I don't know if it counts as close range, but I'm listening in equilateral triangle position, 258cm from ear to treble unit. My speakers are 90db according to official data.

Finally; if I buy the DAC3, will the DAC2's limiting factor for the amp's SNR disappear?

Glad you're here to help, thanks in advance for your answers.
 

John_Siau

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John, as a quick follow up to the above, I am currently running LA4-DAC3B with 2 AHB2's in bridged mode. With the extra 6db gain from the amps I was typically running the LA4 down in the -45db range. Would I be better off with the 10db pads engaged on the DAC to raise the volume position on the LA4? What is the ideal setup for this?
PS: I am extremely happy with my current system, it runs all day until we go to bed, it sounds phenomenal.
The relay-controlled attenuators in the LA4 will always optimize the gain between the DAC and the amplifier. Do not engage the 10 dB pads on the DAC. You will get better noise performance with the DAC set to 0 dB. In either case, the system noise will be well below audibility. You should not be able to hear any noise coming from your speakers even when you put your ear next to the driver.

The relay-controlled attenuators will provide transparent attenuation at your current setting. The LA4 relay-relay controlled attenuators have a 127 dB range in precise 0.5 dB steps. You are in the upper half of this range.
 

John_Siau

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Hello John,

First, it's nice to know that you're always here to help.

In my experiments, when I set the -10db pads, I felt that I could perceive the echoes more effortlessly and more clearly. The SNR values you are talking about are far beyond what a human ear can distinguish. It wasn't a complete blind test, so I don't know why. Probably I'm wrong.

My speakers are not high efficiency horns. I'm using the Revel F228BE and the sound I've heard since the day I paired it with your amp was the pursuit of tens of thousands of dollars spent in my audiophile adventure. I am grateful to both Revel and you for providing these opportunities.

If you say it's okay to listen to these speakers at approximately 16 watts, I'd like to continue with -10db pads.

I don't know if it counts as close range, but I'm listening in equilateral triangle position, 258cm from ear to treble unit. My speakers are 90db according to official data.

Finally; if I buy the DAC3, will the DAC2's limiting factor for the amp's SNR disappear?

Glad you're here to help, thanks in advance for your answers.
The output noise of the amplifier due to the amplifier itself is 132 dB below 100W. Since 1 W is 20 dB lower than 100W, the amplifier output noise is 112 dB below 1 W. You speakers have a sensitivity of 90 dBSPL at 1 W so if you do the math, (90 dBSPL - 112 dB = -22 dBSPL). This means that the noise of the amplifier when played through your speakers would produce a sound that is 22 dB below the threshold of audibility (0 dB SPL is the threshold of normal hearing). The DAC2 will raise this noise level by 7 dB because the DAC has a lower SNR than the amplifier, but the resulting noise will still be well below the threshold of hearing. Here is the math: -22 dBSPL + 7 dB = -15 dBSPL. This means that at a distance of 1 meter, the noise coming out of your speakers (with the DAC volume at maximum) will be 15 dB below the threshold of hearing. This also means that you will hear absolutely no noise even when placing your ear next to the speaker. Your system is already perfectly quiet. If you were to do an upgrade, I would recommend an LA4 relay-controlled preamplifier between the DAC2 and the AHB2. This would improve the measured performance of your system, dropping the output noise to -22dBSPL at most volume settings.
 

eyes-on-you

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The output noise of the amplifier due to the amplifier itself is 132 dB below 100W. Since 1 W is 20 dB lower than 100W, the amplifier output noise is 112 dB below 1 W. You speakers have a sensitivity of 90 dBSPL at 1 W so if you do the math, (90 dBSPL - 112 dB = -22 dBSPL). This means that the noise of the amplifier when played through your speakers would produce a sound that is 22 dB below the threshold of audibility (0 dB SPL is the threshold of normal hearing). The DAC2 will raise this noise level by 7 dB because the DAC has a lower SNR than the amplifier, but the resulting noise will still be well below the threshold of hearing. Here is the math: -22 dBSPL + 7 dB = -15 dBSPL. This means that at a distance of 1 meter, the noise coming out of your speakers (with the DAC volume at maximum) will be 15 dB below the threshold of hearing. This also means that you will hear absolutely no noise even when placing your ear next to the speaker. Your system is already perfectly quiet. If you were to do an upgrade, I would recommend an LA4 relay-controlled preamplifier between the DAC2 and the AHB2. This would improve the measured performance of your system, dropping the output noise to -22dBSPL at most volume settings.
Hi John,

Thanks for detailed explanation.

Last question is;
If there is no harm in using DAC2 with AHB2 at -10 db, I would like to continue with this. According to your explanations, this combination gives the best SNR value, right?

At this setting, I don't feel the turning up the volume beyond 12 o'clock. Are there any trouble driving the speakers?

Ps: LA4 is my next target with one more AHB2 to run with mono.
 
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John_Siau

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Hi John,

Thanks for detailed explanation.

Last question is;
If there is no harm in using DAC2 with AHB2 at -10 db, I would like to continue with this. According to your explanations, this combination gives the best SNR value, right?

At this setting, I don't feel the turning up the volume beyond 12 o'clock. Are there any trouble driving the speakers?
Not exactly. This configuration gives the lowest output noise, but the signal level is reduced more than the noise, so the SNR is actually reduced. In the -10 dB setting, you will not be able to drive the AHB2 to full output. If you do not need the full output, you could run at the -10 dB setting. The output noise will be inaudible either way.
 
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