Would you mind posting what they wrote to you?
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DAC straight to amp
- Thread starter svtcontour
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Here's a subjective observation (mine) and want to see if anyone else's radar confirms this. When the OP's question is relatively straight forward and "relatively" non-contentious, and is answered in the first dozen replies... the group gets bored and starts to feed on itself... lol. The OP's original inquiry pretty much satisfied... gives license for ancillary skirmishes to keep the knives sharp. Don't mind me... "I'm just sitting here watching the wheels go round and round... I really love to watch them roll... No longer riding on the merry-go-round." 
Darkscience
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I just called both times and spoke with them, I have nothing in writing.
Darkscience
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I do not know how to post links. Here is what John posted on these forums on August 7, 2019. This is him explaning how adding the preamp makes the sound better, (I hope that is what I am reading). Anyways good luck!
"The HPA4 or LA4 will improve the measured system SNR in an all-Benchmark system by 2 db at most volume settings. This is counter intuitive. How can adding an active component decrease the noise? Here is how:
The HPA4 or LA4 will allow the DAC2 or DAC3 to operate at full output which is +24 dBu at 0 dBFS. This means the D/A converter is always delivering its full rated SNR. Please note that at this calibration, the DAC2 and DAC3 converters still have an additional 3 dB of headroom available for the accurate reproduction of intersample peaks (but this is another topic).
The clip point of the AHB2 power amplifier is reached at an input level of +22 dBu. This was set 2 dB lower than the typical +24 dBu at 0 dBFS calibration used in most studios so that studio D/A converters could drive the AHB2 2 dB into mild clipping. The down side is that this calibration elevates the D/A converter noise by 2 dB. This 2 dB is fully recovered if the HPA4 or LA4 is inserted between the converter and the power amplifier.
If you were to measure the system SNR, you would find that it improves by 2 dB when the HPA4 or LA4 is inserted between a Benchmark D/A and Benchmark power amplifier. This is only possible because the AHB2 and HPA4/LA4 have a greater SNR than the D/A converter. If you use any other power amplifier, the power amp will limit the system SNR. Likewise if you use any other preamplifier, the preamplifier will limit the system SNR. With the combination of the Benchmark AHB2 and HPA4/LA4, the D/A converter will almost always be the limiting SNR factor in the system (the Benchmark power amplifier and preamplifier have higher SNR performance than most D/A converters. The key point is that the Benchmark preamplifier will allow the full use of the D/A converter's SNR.
Another advantage of the HPA4/LA4 is that it optimizes the interface between any D/A converter and any power amplifier. This optimization will produce the highest possible system SNR, given the limitations of the D/A and power amplifier.
The reason that this optimization is possible is that the preamp section of the HPA4/LA4 has a SNR that exceeds 140 dB.
If you are using an AHB2 with a non-Benchmark D/A converter, the HPA4/LA4 preamplifier may yield an improvement of much more than 2 dB. The reason for this is that other D/A converters are not necessarily matched to the gain structure of the amplifier. The insertion of the preamplifer optimizes the gain staging between the D/A and the AHB2.
The system-level SNR improvements can easily be measured."
"The HPA4 or LA4 will improve the measured system SNR in an all-Benchmark system by 2 db at most volume settings. This is counter intuitive. How can adding an active component decrease the noise? Here is how:
The HPA4 or LA4 will allow the DAC2 or DAC3 to operate at full output which is +24 dBu at 0 dBFS. This means the D/A converter is always delivering its full rated SNR. Please note that at this calibration, the DAC2 and DAC3 converters still have an additional 3 dB of headroom available for the accurate reproduction of intersample peaks (but this is another topic).
The clip point of the AHB2 power amplifier is reached at an input level of +22 dBu. This was set 2 dB lower than the typical +24 dBu at 0 dBFS calibration used in most studios so that studio D/A converters could drive the AHB2 2 dB into mild clipping. The down side is that this calibration elevates the D/A converter noise by 2 dB. This 2 dB is fully recovered if the HPA4 or LA4 is inserted between the converter and the power amplifier.
If you were to measure the system SNR, you would find that it improves by 2 dB when the HPA4 or LA4 is inserted between a Benchmark D/A and Benchmark power amplifier. This is only possible because the AHB2 and HPA4/LA4 have a greater SNR than the D/A converter. If you use any other power amplifier, the power amp will limit the system SNR. Likewise if you use any other preamplifier, the preamplifier will limit the system SNR. With the combination of the Benchmark AHB2 and HPA4/LA4, the D/A converter will almost always be the limiting SNR factor in the system (the Benchmark power amplifier and preamplifier have higher SNR performance than most D/A converters. The key point is that the Benchmark preamplifier will allow the full use of the D/A converter's SNR.
Another advantage of the HPA4/LA4 is that it optimizes the interface between any D/A converter and any power amplifier. This optimization will produce the highest possible system SNR, given the limitations of the D/A and power amplifier.
The reason that this optimization is possible is that the preamp section of the HPA4/LA4 has a SNR that exceeds 140 dB.
If you are using an AHB2 with a non-Benchmark D/A converter, the HPA4/LA4 preamplifier may yield an improvement of much more than 2 dB. The reason for this is that other D/A converters are not necessarily matched to the gain structure of the amplifier. The insertion of the preamplifer optimizes the gain staging between the D/A and the AHB2.
The system-level SNR improvements can easily be measured."
DAC3 has the same output.
Wow, a 2 dB SNR improvement (on a system that is already extremely low noise) for only $2600, sign me up!
Michael
Roland68
Major Contributor
If the only concern is not to degrade the DAC's SNR, wouldn't you achieve the same thing with a volume control with resistors (whether resistors in a potentiometer or switched with relays)?
I compared all my power amps with pre-amp in chain vs straight from a Soncoz SGD-1
With all but one power amp I preferred the sound with the pre-amp in the chain
Possibilities:
1) all in my head (comparison was sighted, no level matching)
2) I prefer the degraded sound
3) Something technical is happening that I don't understand.
Since I'm also paranoid about the DAC going to full output and blowing my speakers (although I know that's highly unlikely) I'm happier with the pre-amp in the chain.
With all but one power amp I preferred the sound with the pre-amp in the chain
Possibilities:
1) all in my head (comparison was sighted, no level matching)
2) I prefer the degraded sound
3) Something technical is happening that I don't understand.
Since I'm also paranoid about the DAC going to full output and blowing my speakers (although I know that's highly unlikely) I'm happier with the pre-amp in the chain.
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With due respect to @Mart68,please take this as friendly criticism.......................no level matching means a completely useless comparison. LEVEL MATCHING IS
JOB #1 in any listening comparison.
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mate - I know but I live alone so setting up even a rudimentary blind comparison isn't practical.
I already own various pre-amps so it's not like I am having to make a purchasing decision. If I was then I would certainly do controlled test before spending.
Darkscience
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It brings me extreme pleasure to operate, look at and listen to this fine. American made and engineered piece of audio instrument. IF you can afford it as Amir puts it:Wow, a 2 dB SNR improvement (on a system that is already extremely low noise) for only $2600, sign me up!
Michael
"It goes without saying that the Benchmark HPA4 garners my strongest recommendation for a headphone amplifier and preamplifier. It doesn't get better than this folks."
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Does not have to be blind. To make any useful conclusions you must match levels or there is no chance.
I'm aware of that hence why I included possibility 1) all in my head (comparison was sighted, no level matching)
That doesn't preclude either of the other two possibilities from being true however.
It would not be rational of me to use the configuration I prefer less regardless of the reason for that preference.
It’s a conceptual miss understanding here . Nowhere is it stated that it sounds better , the text stated that the SNR is always 2dB better in most situations so yes the systems performance is increasing and improved . That’s not in doubt .
Where do we make the jump to the conclusion that this is audible in the general case , for home listening ?
Better performance does not always translate to an audible difference .
How about trying this test. Have someone switch between preamp, no preamp and system off with nothing playing (with you blind to what is being used of course).
Can you tell from your listening position if your system is on due to audible noise? If you hear audible noise can you correctly identify when the preamp is being used due to lower noise level?
Michael
Can you tell from your listening position if your system is on due to audible noise? If you hear audible noise can you correctly identify when the preamp is being used due to lower noise level?
Michael
Darkscience
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I agree with you, I am pretty sure they told me it would sound better though, (I do not blame them for using salesmanship), I am just referencing something I heard over the phone almost 1.5 years ago because someone asked me about it.
To answer the OP's question, it looks like the answer is NO, getting a preamp will not make your sound better, (In a measured point of view). Like I said in my initial response, if you need more connections try it out and see if the sound is still ok. Get the cheapest well measuring preamp you can find if you do not care about anything else except the end product, the sound, and you will be good to go.
Darkscience
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I am not sure if you are talking to me here or not, but I think the misunderstanding is it looks like everyone read what I was saying as promoting the preamp and suggesting it will sound better, this is not the case. I am with you and everyone else who believes it does not, in the case of the Benchmark it looks like it helps a measly 2db, and it would be ridiculous for anyone to buy it just for that, (unless that is something they want I guess). When I bought mine I did not buy it for that reason, I did no audio testing because it did not matter to me, I plugged it in, sounded great and I went on to just enjoy more music.
I understand if anyone wants better sound, it is probably room treatment and speakers what one should look at. I surfed these forums day in and out before buying my gear and am fortunate to have found it so I did not go down the audiophool rabbit hole I was about to embark on.
It is encouraging anyway that benchmark actually has a preamp that does not impede the performance ?
This probably the usual result, that performance gets slightly worse ? Or at least was , maybe preamps got better .
there can be fine reasons to get a preamp.
Benchmark would be on the top of my list if I ever wanted an analog preamp .
This probably the usual result, that performance gets slightly worse ? Or at least was , maybe preamps got better .
there can be fine reasons to get a preamp.
Benchmark would be on the top of my list if I ever wanted an analog preamp .
Apesbrain
Addicted to Fun and Learning
Exactly the reason I avoid running a volume-controlled DAC directly into a power amp. Put a simple Goldpoint analog attenuator between them. Set your digital front end to 100% volume and use the attenuator to adjust to the loudest you'd ever listen. Now you're protected against "runaway". Your speakers will thank you.
I was more referring to @Mart68's claims that he preferred the sound with a preamp.
To be fair I am actually a bit surprised that Benchmark is only claiming a 2 dB SNR improvement. Doing some quick modeling based on their specs I would have thought that at lower volume positions the LA4 would have given you closer to an 8 dB improvement when used with the DAC3 / AHB2. Still given the starting point of a DAC3 / AHB2 has such low noise (~25 uV at speaker terminals) I don't see how you would notice the improvement even with very sensitive speakers.
Michael
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