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Review and Measurements of Massdrop THX AAA 789 Amp
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Viper Necklampy
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My amp is clipping in gain 2 / II / Mid gain, With SMSL M500 mk1 as a dac via XLR Cables and Hifiman HE-R9 headphone on XLR or stock SE cable. At a certain volume of course, but for music i would like to pass that volume sometimes...
Is also a strange thing that it reaches the same volume on gain III before clipping?
What in the world..??
It happens even with RCA's by M500, in every gain!!
Is also a strange thing that it reaches the same volume on gain III before clipping?
What in the world..??
It happens even with RCA's by M500, in every gain!!
Last edited:
Jimster480
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Is your volume too high? I've never had this amp clip.
olds1959special
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The manual states I may experience clipping if I run too much voltage in from the DAC at the III gain position. Should I be using a lower gain setting or attenuating the DAC? I'm using a SMSL DO100 Pro at max volume with XLR cables.
Jimster480
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Depends on how much voltage is too much.... Is that specified?
unpluggged
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Input sensitivity when gain set to "III" is 2 V RMS regardless of used input (SE/balanced).
olds1959special
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I think I noticed the soft clipping when running the DAC at max voltage with the gain set to III. It sounds better reducing the DAC to 74 from 99. This sounds different from running the DAC at full volume and using the gain setting of II. Which is better?
unpluggged
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Better is to use the lowest amp gain that allows to achieve your desired volume level. I would also prefer to adjust volume at the DAC side to avoid pot artifacts.
So, to conclude for your case: set the amp gain to "II", turn the amps's volume knob to a position where it gives you a volume that is just too high for comfortable listening when the DAC is set to maximum output, and leave it there (assuming the volume setting is out of the pot's channel imbalance zone at its lowest positions). From there, adjust your listening level at the DAC. This way you will be safe if your DAC accidentally resets its volume (rarely, but it can happen).
olds1959special
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Revisiting this. I actually don't think I hear distortion going full volume from my DO100 Pro DAC (balanced) like I thought I did previously, when using the III gain setting. I am using a balanced headphone cable too. The III gain setting sounds best to me. The manual is confusing about whether or not I should be doing this. Can someone clarify?
The explanation given above was accurate, but if you are happy with what you're hearing then no need to overthink it. Listen and enjoy.
olds1959special
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From the manual of the amp:
From the manual of the dac:
I'm using the XLR to XLR. If the DAC is outputting 5.2Vrms this is under 7Vrms so then no need to attenuate, right? Then why the recommendation to use setting II instead of III? Wouldn't 2.1V be for single ended? Still confused, please help.
unpluggged
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This post is a good breakdown that I've referred to for my own 789. My E50 puts out 5V and I listen on his gain with no issues.
olds1959special
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I read this thread and couldn't make sense of it. What gain do you use with your E50? 1, 2, or 3?
3 sounds the best to me, but I'm not sure if I'm hearing soft clipping or not.
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I feel like you're way overthinking this. There are a number of possible voltage combos/gain structures to achieve a given output. Whatever you choose, if it sounds good then it is good and that's all that really matters.
To answer your question, I've used all of the gains over the years based on whatever I felt was needed to achieve the volume and sound I wanted. Aeon Closed RTs are a pair that I often choose and they're pretty demanding, but I get the volume I want on any gain; just a matter of how high I turn it up.
rcstevensonaz
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Same thing here. I have the Monoprice variation, but have essentially the same answer.
I will regularly switch between the gains based on the interplay of the volume of the music on the source, the dynamic range of the music, and whether the audio is coming in at lower voltage (via RCA) or higher voltage (via XLR) inputs, and which headphones I'm using at the time.
My approach is to have the gain set to the level where I am keeping the volume knob between the 9:00 and 3:00. And change the level whenever needed based on what is being played, from which source, and to which headphones.
olds1959special
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Gain 2 turned up does not sound the same as Gain 3 turned down to match the same level!
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How do you match the levels to come to such a conclusion?
olds1959special
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with the volume knob.
unpluggged
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You should use a voltmeter.
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