Its not a limitation but what SPL levels are you trying to acheive? What cans are you intending to use with that output level?
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Fostex T50RP-mk3 power needed, based on Tyll's measurements and calculated with Digizoid.
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Hifiman HE-560 power needed, based on Tyll's measurements and calculated with Digizoid.
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Beyerdynamic DT880 600 Ohms version - power needed, based on Tyll's measurements and calculated with Digizoid.
Peaks of around 115dB for few ms are sometimes welcome, when some of us want to listed louder for few minutes. Also, when listening to normal average levels of 80-85dB SPL, that still means peaks between 95-105dB SPL, depending on music's compression rate. A good to read article would be here: http://nwavguy.blogspot.com/2011/09/more-power.html, although is more related to the output power and to the actual gain, which might be better to be related to 1V RMS input source instead of 2V RMS sources (seems that HD600 needs 4.16V RMS to hit 115db SPL based on Digizoid and https://www.innerfidelity.com/images/SennheiserHD600.pdf).
You might want to make HPA1 compatible with 1V RMS input sources as well. I listen to lot of -3dB music (jazz, classic etc.) that really need a higher gain, especially when listening to HE-560, but also on Fostex T50-RP mk3 and DT880 600 Ohms cans.
A headamp should be more powerful that the headphones, so amp's distortions to not sum up with headphones distortions. There's a great article on that matter on Audioholics, where they explained very well why a power amp needs to be more powerful as the speakers. Also, I really think a headamp should be able to get all of my cans up to the insane 120dB SPL level, even if I'll never use such an amount of power. It's about that power reserve that most of us sleep better if we know it's there; it's like when you purchase a car able to speed up too 250 km/h, even if you never get over 160km/h on the highway.
If you have an easy way to increase the gain on the HPA1, then doing this might be a good thing, at least from a marketing perspective. After all, most customers will only read the specs and compare them with other headamp.
P.S.: I have a headamp around LME49720 + LME49600 that outputs a clean output 1KHz power of 7.02V RMS at max. gain. With HE-560, but especially with the DT880 600 Ohms, when I listen to old jazz music (around -3...-4dB SPL) I sometimes find myself that the volume knob got to the max., even if in my ears the power if not so high. It happens with classic, rhythm & blues and other genres too (usually with music recorded before the "loudness war").
Having been a qualified noise officer, dealing with people with hearing damage and trying to prevent it, I would with the greatest of respect suggest that you *really dont* want your cans to go up to 120dB or even 115dB as you suggest above. The exposure time before potential damage at those levels is surprisingly short. In many countries the HSE 8 hour exposure (LAeq,8h) limit is 85 db(A) . Every 3db increase above that you half the time.
So 115dB(A) will be 30 seconds !
I have tested the amp with a range of cans and it certainly goes loud !
Thank you, I'm aware of that, but probably most of us are getting peaks over 110dB when we listen at high volume (for few minutes or so). I say few ms peaks, not average.
My average listening loudness is somewhere around 80-85dB, which might create peaks up to 105dB.
How are you measuring the levels? I do have a B&K meter which calculates LAeq as you go along.
I think he meant the equipment. BK is known to have very high precision and can last for years without big shift after one calibration. Cheap mics can't last and cheap level calibrators are inaccurate themselves.I use REW's meter all the time...
Bela Fleck - Daybreak CD
LAeq displayed.
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Logger
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They are indeed super expensive.
If your computer does a reasonable job with digital volume control it should be fine. In some cases you can have the volume control in the DAC. So if your DAC has volume control you can send BP to the DAC and then the DAC will do stuff to control the volume. Most DACs are Delta-Sigma so it gets transformed anyway.Question. If there's no volume knob... can you use bitperfect audio? Say in Windows or Linux.
Not using BP audio would be a no go for me...
Question. If there's no volume knob... can you use bitperfect audio? Say in Windows or Linux.
Not using BP audio would be a no go for me...
I'm using jRiver with ASIO (not on MarchAudio DAC, but similar XMOS transport chip) and I am able to control the internal volume. I think ESS's datasheet worth reading: http://www.esstech.com/files/3014/4095/4308/digital-vs-analog-volume-control.pdf.
P.S.: I guess you could add a cheap passive preamp between your DAC and headamp, if really worried or...old school.
I guess this is exactly what HPA1 designer had in mind too: less devices in the signal path.Yes, or... you know, use an AMP with volume knob? I'm not looking forward to putting more devices on the signal path.
Of course you can, just give it a try on a Linux live distro.[...] I'm not sure if I can turn the digital volume down on Linux, too