Great response John - and thanks for your candour regarding this issue, that's the mark of an excellent company IMO.
Benchmark HPA4 Headphone / Line Amplifier Impressions
- Thread starter negura
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Thanks @jsiau for your through explanation and plans for rectification. I am very happy with your response and glad that my HPA4 will be looked after.
etc6849
100+ Head-Fier
I got an email about this issue, even though it only impacts some folks using only the RCA inputs and is greatly dependent on the upstream source. I honestly would have never known about this issue as I use the balanced inputs, as I assume most do. Most companies would have just took care of the few people who called in and not have emailed all US and Canadian purchasers.
This level of dedication to absolute technical perfection (and honesty) is very refreshing.
This level of dedication to absolute technical perfection (and honesty) is very refreshing.
Tonybo
New Head-Fier
Well, it will be good to know you will have the ground loop immunity in the future if you do ever find that wonder component that only has an rca output.
On another tack, now we have the HPA4 I wonder if the Benchmark guys are thinking of a simplified DAC in the 4 series that does away with the volume control and analogue, aimed at use with the HPA 4? I’m hanging on with my DAC 2 HGC until that arrives!
On another tack, now we have the HPA4 I wonder if the Benchmark guys are thinking of a simplified DAC in the 4 series that does away with the volume control and analogue, aimed at use with the HPA 4? I’m hanging on with my DAC 2 HGC until that arrives!
The DAC3 L has the headamp removed. You still have volume control, but you could set to "HT Mode".
What I want is a DAC-4 with a stripped down HPA-4 in it. 
Tonybo
New Head-Fier
Yep. Very difficult to find a simple but serious DAC with high level balanced output, though. The current Benchmarks are going through all sorts of complex automated mechanical settings to get to HT mode each time they power up.
jsiau
Member of the Trade: Benchmark Media Systems
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good observation
jsiau
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I can't say, but you saw it here first.
Tonybo
New Head-Fier
Nice one John. The biggest surprise I have ever had on a forum! I think I agree with YooperAudio!
Am I allowed to mention this at the Bonn hifi show tomorrow morning?
Am I allowed to mention this at the Bonn hifi show tomorrow morning?
jsiau
Member of the Trade: Benchmark Media Systems
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Head-Fi readers are the only ones that know right now, but feel free to share it. I can't say any more right now. When I can, you will see it here first.
etc6849
100+ Head-Fier
This is similar to what I want or need as well: an all in one box with the HPA4 headphone amp, USB input, and maybe one set of balanced analog outputs. Better yet, if multiple analog outputs are included, add some powerful DSP features like FIR filtering and time alignment so we can use these other outputs to bi or tri-amp our speakers. Further, I don't see why the volume control can't be 100% digital to simplify the design even more after eliminating the analog inputs.
RME's TotalMix (aka hammer fall DSP mixer) is an example of what I consider a really good digital based volume control; the RME hammerfall DSP driver that is included with TotalMix relies on an FPGA giving 40 bit floating point resolution. It isn't a 100% software based solution like JRiver which is also very good, but I suspect the 40 bit floating point resolution provides a SNR that can easily compete with the volume control in the HPA4. In fact, some tests at the link above show incredible noise floors that allow the hammerfall DSP to display signals below -144dB!?!
In fact, I use RME's Totalmix on my main system (output is via a PCI-E 16 channel in/out digital AES card) and I can turn the volume down below -64dB and easily understand every word. Even at -45 to -50dB strings and instruments have a clarity I haven't heard on other systems at that volume level (regardless of cost). Much like what I'm hearing with the bookshelf speakers + DAC3 + HPA4 and AHB2 in my office, but even clearer. However, I have my other system actively tri-amped using 10 AHB2 amps (5 3-way speakers) and crossed to multiple subs, so this isn't a fair comparison.
I understand the target market with the fabulous HPA4 though, and respect the engineering rigor it must have taken to design an all analog preamp that can do what it can. I suspect as time goes on, there will be fewer and fewer people using analog sources, so hopefully this brings us an all in one unit (in lieu of a DAC3+HPA4 [EDIT] or after scrolling down a DAC4+HPA4).
For now, the updated HPA4 manual shows some flat out impressive measurements that I have never seen another headphone amp do
RME's TotalMix (aka hammer fall DSP mixer) is an example of what I consider a really good digital based volume control; the RME hammerfall DSP driver that is included with TotalMix relies on an FPGA giving 40 bit floating point resolution. It isn't a 100% software based solution like JRiver which is also very good, but I suspect the 40 bit floating point resolution provides a SNR that can easily compete with the volume control in the HPA4. In fact, some tests at the link above show incredible noise floors that allow the hammerfall DSP to display signals below -144dB!?!
In fact, I use RME's Totalmix on my main system (output is via a PCI-E 16 channel in/out digital AES card) and I can turn the volume down below -64dB and easily understand every word. Even at -45 to -50dB strings and instruments have a clarity I haven't heard on other systems at that volume level (regardless of cost). Much like what I'm hearing with the bookshelf speakers + DAC3 + HPA4 and AHB2 in my office, but even clearer. However, I have my other system actively tri-amped using 10 AHB2 amps (5 3-way speakers) and crossed to multiple subs, so this isn't a fair comparison.
I understand the target market with the fabulous HPA4 though, and respect the engineering rigor it must have taken to design an all analog preamp that can do what it can. I suspect as time goes on, there will be fewer and fewer people using analog sources, so hopefully this brings us an all in one unit (in lieu of a DAC3+HPA4 [EDIT] or after scrolling down a DAC4+HPA4).
For now, the updated HPA4 manual shows some flat out impressive measurements that I have never seen another headphone amp do
What I want is a DAC-4 with a stripped down HPA-4 in it.
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