[DaveNote]

Dave,

Thanks, should be OK now.

-Greg

Sorry Greg, still showing your inbox is full. Unable to answer your personal message.

Dave

[OgOgilby]

Sorry Dave, I must have been way over the limit... There should be plenty of space now.

-Greg

[Todd R]

What phones Todd???

james

James,
Hifiman HE-500 (balanced, 4 pin)
Denon D5000 (soon to be re cabled and balanced)

Source is a PS Audio Perfect Wave II DAC using the balanced output to feed the Bryston.

I breifly tried my JH Audio 16 IEM's and did not detect any noise with these very sensitive phones.
TR

[James Tanner]

James,
Hifiman HE-500 (balanced, 4 pin)
Denon D5000 (soon to be re cabled and balanced)

Source is a PS Audio Perfect Wave II DAC using the balanced output to feed the Bryston.

I breifly tried my JH Audio 16 IEM's and did not detect any noise with these very sensitive phones.
TR

Hi Todd

Great - thanks. Really good cross section of phones. I hear good things about the Denon phones. I look forward to the feedback given the variety of loads.

The BHA is VERY quiet 

James

[OgOgilby]

James,
Hifiman HE-500 (balanced, 4 pin)
Denon D5000 (soon to be re cabled and balanced)

Source is a PS Audio Perfect Wave II DAC using the balanced output to feed the Bryston.

I breifly tried my JH Audio 16 IEM's and did not detect any noise with these very sensitive phones.
TR

Congrats on getting the BHA-1 Todd! What other headphone amps have you tried?

-Greg

[OgOgilby]

A lot of the frequency responses I see though are not flat with a roll off as frequency increases   A lot show serious dips and peaks at the higher freqencies

James

This may help someone (from innerfidelity.com):

Headphone acoustics are significantly different than room acoustics because you are using an acoustic coupler as opposed to propagating the sound through free-space - technically called the “free field” in audio terminology, and defined as three-dimensional space where there are no reflecting surfaces. When measuring speakers, you measure the sound out in the free field with a reference microphone and assume if the sound measures flat, you’ll hear it as flat if you put your head where the microphone was --- which is true. But with headphones, there is no free field in which to measure the sound. Due to reflections and modal oscillations within the enclosed volume between the headphones and your ear, the sound at any particular point within that space may be different than the sound at another point. As a result, the only legitimate place to measure the sound from headphones is at the eardrum.

That’s a problem because if the sound is flat out in the free field and you stick your head in it, the sound is no longer flat by the time it hits your eardrum. This difference between flat sound in the free field, and the EQ of the sound you hear at the eardrum when you stick your head in the sound in the free field, is called the Head Related Transfer Function.



The image above shows the independent of direction Head Related Transfer Function of the Head Acoustics HMSII.3 head acoustics simulator.

Multiple things come into play that effect the EQ of the sound reaching your eardrum:

Your chest and head volume provide some acoustic gain at mid-frequencies.
Between 2000Hz and 5000Hz the concha (the little cup in your outer ear around the entrance to your ear canal) acts as a focusing dish to get sound into your ear canals, and as a result provides some significant gain to the signal at these frequencies.
The length of the ear canal provides opportunity for modal artifacts; typically peaks at 3kHz, 9kHz, and 15kHz roughly, depending on the exact size and shape of the ear.

Flat sound in the free field is not flat by the time it gets to your eardrum.

This is the frequency response measurement sheet that came with my LCD-2 headphones showing the HRTF compensation:





-Greg

[Todd R]

Congrats on getting the BHA-1 Todd! What other headphone amps have you tried?

-Greg

Most recently, My Bottlehead SEX 2.1. (for sale if anyone is interested)
The 2 amps are close, but the Bryston pulls ahead with a bit more detail. The soundstage is also a little wider due to the ability to used a balanced signal all the way from the source to the headphones (yes I tried a single ended path too).

The Bottlehead might have a bit of an advantage in bass power when running the power hungry HiFiMan phones as it puts out 2 wpc. I'll need to run a comparison again once the Bryston gets some more hours on it.

[James Tanner]

^^^^^^^^^^^^^^^^^^^^

Very interesting this HRTF ?

james

[OgOgilby]

^^^^^^^^^^^^^^^^^^^^

Very interesting this HRTF ?

james

Quite interesting. For whatever reason, ordering the BHA-1 has motivated me to learn more about the technical aspects of headphone listening instead of only focusing on 2 channel speaker setups and room treatments. I never gave much thought as to how your ears can and do amplify specific frequencies and I had never heard of HRTF.

The information I posted is on the page:
http://www.innerfidelity.com/content/headphone-measurement-proceedures-frequency-response

The measurement videos at the bottom are worth viewing if you are interested in this stuff.

-Greg

[OgOgilby]

Most recently, My Bottlehead SEX 2.1. (for sale if anyone is interested)
The 2 amps are close, but the Bryston pulls ahead with a bit more detail. The soundstage is also a little wider due to the ability to used a balanced signal all the way from the source to the headphones (yes I tried a single ended path too).

The Bottlehead might have a bit of an advantage in bass power when running the power hungry HiFiMan phones as it puts out 2 wpc. I'll need to run a comparison again once the Bryston gets some more hours on it.

Thanks Todd. So the main improvement in using balanced over single ended was a wider soundstage?

-Greg

[Todd R]

Thanks Todd. So the main improvement in using balanced over single ended was a wider soundstage?

-Greg

That's what I'm noticing so far.

[Vipers]

Thanks Todd. So the main improvement in using balanced over single ended was a wider soundstage?

-Greg

Is it easy to convert over to balanced? I've got a pair of Grado PS1000's, if it offers a further improvemnt with balanced it is definately something I will have to look into.

Even though I've had my BHA-1 on order for what seems like an age I'm going to get my first listen on Monday over at PMC here in the UK so I'll take my Grado's along, see how it compares to the headphone out from my SP3.

[terrycym]

Didn't I hear that Bryston were offering a headphone balanced cable replacement service?
Will the UK distributors being doing this over here on their behalf?

[Todd R]

Is it easy to convert over to balanced? I've got a pair of Grado PS1000's, if it offers a further improvemnt with balanced it is definately something I will have to look into.

It depends on the headphones. If all 4 wires are carried to the plug, then it's easy to cut off the 1/4" plug and install a 4 pin or 2 - 3 pin XLR plugs.
Unfortunately, the last Grado's that I looked at had the grounds connected where the cable splits which only leaves you 3 wires at the plug. In that case, the headphones would need a complete re-wire.

[OgOgilby]

Is it easy to convert over to balanced? I've got a pair of Grado PS1000's, if it offers a further improvemnt with balanced it is definately something I will have to look into.

Even though I've had my BHA-1 on order for what seems like an age I'm going to get my first listen on Monday over at PMC here in the UK so I'll take my Grado's along, see how it compares to the headphone out from my SP3.

Apparently they can be recabled:

http://www.head-fi.org/t/512849/sale-pending-f-s-balanced-grado-ps-1000-with-4-pin-xlr-and-stock-cable

-Greg

[Vipers]

Didn't I hear that Bryston were offering a headphone balanced cable replacement service?
Will the UK distributors being doing this over here on their behalf?

Hi Terry, this is definately something that I will look into, as it looks like it is definately the way to go especially when pairing the Grado's with the BHA-1.

[terrycym]

There are quite a few 3rd party replacement headphone cables available (Cardas is just one), just google it.
A number of companies offer this service but they're all in the US.
PMC could do it over in the UK or maybe some new fledgling Bryston dealer perhaps?

[Vipers]

PMC could do it over in the UK or maybe some new fledgling Bryston dealer perhaps?

Now that's a good idea Terry, got anyone in mind

Well at long last at a Bryston day at PMC on Monday I actually got to hear the BHA-1, I couldn't resist taking a picture -



To say I was impressed was an understatement, I'm so used to my Grado PS1000's using the SP3 headphone out, which sounds fantastic, but I really wasn't prepared for how much better they were going to sound using the BHA-1, basically the Grado's just came alive, it does make you wonder how many people own good headphones and never unlock their true potential.

Using the BHA-1 just gave more drive at the bottom end, but kept the control so the bass was tight, powerful and detailed, but for me it was the mid/treble that just went on to another level, I know the Grado's are good and I'd heard them described before as the only Dynamic headphone to take the battle to Stax but on previous comparisons I still felt that the Stax headphones had the edge with overall detail and clarity, I'd love to do that comparison again now using the BHA-1 to drive the PS's as I was amazed how much cleaner the presentation was and the overall insight into the recording, I feel that the BHA-1 was really driving the Grado's to their max, obviously I'd have loved to have spent longer with the BHA-1 to get a 100% conclusion but early impressions are looking extremely favorable .

I had to wait a long time to get to hear the BHA-1 and it certainly did not disappoint, another high class product from Bryston, the only problem I can see is that I'm still waiting for mine, come on James get another shipment over to the UK asap

[Marius]

Hi James,

Im lining up for the BHA1, but still need some advice. Since I'd want to position the BHA near my favorite chair (that is not very close to my main setup)  I'd want to opt for the balanced connection. My Bp26 balanced out is in use... How do I proceed? Ive got the tape out you mentioned before, or could use the second RCA out, but the latter is contrary to your advice I believe. the former already in use...

Is there some modification I could opt for, or would I have to wait for the Bp27 that would have a second balanced out? or a balanced tape loop of sorts?

I feel a bit in limbo here, so please help me out.

Marius

Ps wouldn't dare to ask for headphone advice. (but still do of course, the lcd2 or 3, sennheiser 800, hifiman and beyer dynamics t1 on my shortlist. Stax I would really want to consider, but then I would have to forgo on the BHA1, so not an option....)

[terrycym]

Hey Marius, you could get one of these.
http://www.goldpt.com/sw2x.html