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Are pre-amps necessary
- Thread starter thejck
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GrimSurfer
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thanks for your response.
i guess. my lack of electronic knowledge is showing up. I hate to admit that some of his measurements are like greek to me. I wish he had a "reference" that stated what each graph is and how tis important and what to look for.
Stick with it. It will come.
Fine. I do not want to use my tablet or my phone because they are used for other things and are rarely exactly where I want a volume control. Besides, I also prefer the tactile/haptic properties of a physical knob.
Yes, I sometimes feel the same way. But I think we can gain a lot by reading the very valuable discussions that come up from time to time of these matters on ASR - on the difference between distortion and noise, why frequency response means, the (still confusing, for me) potential implications of ultrasonIcs, and so forth. I also find Google helpful, sometimes.thanks for your response.
i guess. my lack of electronic knowledge is showing up. I hate to admit that some of his measurements are like greek to me. I wish he had a "reference" that stated what each graph is and how tis important and what to look for.
When it comes to the better- rated DACs here, however, I doubt that you can go wrong.
What would be a good way to do systemwide digital volume control in Windows if one was doing a sub crossover in software, such as EKIO, and outputting to a multichannel DAC, (say for example a USB pro audio interface using ASIO drivers? One of those big knobs would be great, I'm just not sure what it should be controlling.
watchnerd
Grand Contributor
I saw "preamp" and thought this thread was about microphones or cartridges.
For which a "yes, they're mandatory" is the usual answer.
Silly me.
For which a "yes, they're mandatory" is the usual answer.
Silly me.
I cannot guarantee it will work for your particular application but I bought it on the chance it would work with mine. It controls Windows system audio and JRiver's internal audio using LAN or USB as output. (Yes, it includes contributing crossover, DSP, etc. in software.)
A noob question, Kal: The OP was concerned about reducing SNR by using a digital attenuator to reduce volume. A subsequent poster pointed out that this is unlikely to be a problem in most real-world situations using a good DAC. Nevertheless, does the device you use avoid this problem because, as you say, it is out of the signal path?
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I think it's worth emphasizing that dollar for dollar, the negative sonic impact on the fidelity of the signal chain is going to be much greater from an analogue preamp than a digital volume control.
Now, if for some reason the voltage output of your DAC or digital source is too low or too high for your power amp, then of course you will have a problem: if the digital output is too low, you won't be able to get enough volume out of your system; and if it's too high, you will have to attenuate the volume on your DAC/digital source so much that you could potentially start to compromise the bit depth/noise floor of the source (or you might just get annoyed that you can only make use of a very small part of the digital volume control's range).
In that case, you will need a preamp. Similarly, if the output impedance of your DAC/digital source is not a good match for your power amp, you will need a preamp - although I have generally not found this to be a problem. (Ironically, I've only ever found this to be a problem with standalone passive preamps.)
So if you have only digital sources, and your DAC-power amp combo gives you a volume level and range you are happy with, I'd say ditch the preamp. That's what I did, and I have never regretted it.
Now, if for some reason the voltage output of your DAC or digital source is too low or too high for your power amp, then of course you will have a problem: if the digital output is too low, you won't be able to get enough volume out of your system; and if it's too high, you will have to attenuate the volume on your DAC/digital source so much that you could potentially start to compromise the bit depth/noise floor of the source (or you might just get annoyed that you can only make use of a very small part of the digital volume control's range).
In that case, you will need a preamp. Similarly, if the output impedance of your DAC/digital source is not a good match for your power amp, you will need a preamp - although I have generally not found this to be a problem. (Ironically, I've only ever found this to be a problem with standalone passive preamps.)
So if you have only digital sources, and your DAC-power amp combo gives you a volume level and range you are happy with, I'd say ditch the preamp. That's what I did, and I have never regretted it.
watchnerd
Grand Contributor
We should be careful about using the term preamp too loosely as in the analog world there is a difference between passive vs active line stages.
Stepped resistor
It certainly does. It give me the option of using no preamp at all or of using my legacy Audio Research MP-1 if I keep it set to a high enough gain that its internal noise is inaudible. The MP1 has volume up/down buttons on both the front panel and remote control. No knob.
Zog
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My two cents.
I think you are on the right track to consider upgrading your DAC. I have upgraded mine a few times over the years and there has been a small improvement each time. (I am currently using the Matrix Audio Sabre X). I second the suggestion of checking out Amir's list.
Preamps: I only have one experience of using the DAC's volume control. It was a Wyred4Sound DAC and my preference was to use the preamp.
I am not really sure what I am talking about here but maybe there is some issue with impedances. Ie between the DAC & Power Amp on one hand and the Pre-Amp & Power Amp on the other hand. Hopefully some sage will chip in here.
I have not heard the P3 but being from Parasound I assume it is a goody. I have a pet theory about upgrading; I say just upgrade one item at a time. Money is important and you don't want to spread your resources too thin.
About the digital level:
Whatever the volume level technology, that makes little difference.
It's more important that the DAC output level is around the max level you'll be listening to, and not above.
Which will depend on your amp gain, speaker sensitivity, and so on.
As an example, here are some SINAD trends, with RME ADI-2 Pro fs, with variable Output range (the RME has several analog output ranges)
As one can see, if your listening level is around, say, -30dBFS (-17dBu, in that case, or around 0.11Vrms), there is as much as 8db difference in SINAD, depending on your output range selection.
That's more than what you're likely to find as an actual raw SINAD difference between good performance DACs...
(RME ADI-2 Pro fs in loopback, input range at +13dBu, Measured with Virtins Multi Instrument 3.8 @48kHz 24bits, 1kHz, 32768 FFT window size, Kaiser 6, 5 average)
Whatever the volume level technology, that makes little difference.
It's more important that the DAC output level is around the max level you'll be listening to, and not above.
Which will depend on your amp gain, speaker sensitivity, and so on.
As an example, here are some SINAD trends, with RME ADI-2 Pro fs, with variable Output range (the RME has several analog output ranges)
As one can see, if your listening level is around, say, -30dBFS (-17dBu, in that case, or around 0.11Vrms), there is as much as 8db difference in SINAD, depending on your output range selection.
That's more than what you're likely to find as an actual raw SINAD difference between good performance DACs...
(RME ADI-2 Pro fs in loopback, input range at +13dBu, Measured with Virtins Multi Instrument 3.8 @48kHz 24bits, 1kHz, 32768 FFT window size, Kaiser 6, 5 average)
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The RME ADI-2 has many virtues (such as tone and balance control, optional and adjustable dynamic loudness and some parametric filtering), but one of them is also that it has an optional auto reference level setting, for the best match between S/N and output level. And it has a very accurate digital volume control that is much better than any analogue one (and no, with modern DACs you do not lose resolution with digital volume control).
The RME ADI-2 DAC has balance control.
I don't know what you mean by "lose resolution".
The lower the volume setting, the lower the SNR.
My experience is that there are very few analog attenuators that have better performance.
But that may still be the case, if a device is specifically designed for that (as is the Benchmark HPA4, and as is the analog output stage of the RME ADI-2).
Using a (good and well implemented) transformer may also be a way to lower the level with better SNR.
I checked that since I plan to test my mic preamps, and, for that, I need a test signal around 1mV @150ohm.
I measured a better SNR with a Radial JDI direct box attenuating the level than with any other way (so far).
But that's a very specific requirement, for sure.
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The conclusion of which being what I said above.
"As long as the analog volume control has a noise floor better than the DAC noise floor, the analog one will win"
However, in practice, the digital control will win in usability, reliability... and cost.
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