Voltage and Power Output of BP25 headphone output

rob80b · « **on:** 14 Jun 2006, 04:19 pm »

As noted in another post I've been wrestling with the headphone output of my BP25P.
http://www.audiocircle.com/index.php?topic=28320

What I'm curiuos about is the actual specs for the headphone output voltage and power.

Hopefully James can enlighten me.

James Tanner · « **Reply #1 on:** 16 Jun 2006, 01:27 pm »

Hi James;

The headphone output is in fact the same feed as the output to the amplifier, and is nominally around 1-2V. This is to prevent ear damage from excessive loudness levels. It is designed to require the volume control to be advanced quite a bit to give loud levels. This also eliminates an amplifier stage, which reduces noise and distortion on the headphone feed.

I hope this is helpful information. Thanks for thinking of Bryston.

Chris Russell
Bryston Ltd.

rob80b · « **Reply #2 on:** 16 Jun 2006, 04:25 pm »

Thanks for the reply.

The Bryston preamps are obviously capable of supplying enough voltage to all the phones to drive them to fairly loud volume levels.
My Sennheiser HD580’s which are rated at 300 ohms are driven quite efficiently by the BP25P and have never sounded better.
On the other hand my Grado SR325i’s at 98dbs impedance 32 ohms and the AKG k501’s 94 dB impedance 120 ohms sounded better with the Creek OBH-11se Rev B having more body (fullness and bass extension) and clarity in the highs even at lower volume levels.
Ironically the HD580’s sounded ok on the OBH-11SE but much more enjoyable with the BP25.
I guess it comes down to the design of the amp in terms of current draw and impedance matching.
Volume is evidently not everything, an ipod is capable of driving Grado’s at higher than needed levels but comes no where close in terms of getting them to produce the level of sound quality they are cable of, (the Grado’s not the ipod).
Casual headphone listeners would be very content with the BP25/26, it is very good, but those of us who do a lot of headphone listening get obsessed with getting the very best out of all our phones and notice the difference.

So as much as I really like the BP25p it may still need to be augmented with a dedicated headphone amp in order to fully appreciate a collection of different phones

Or.. is there anything that can be done with the headphone output to make it a better match for all phones (Grado's) .

rob80b · « **Reply #3 on:** 19 Jun 2006, 02:11 pm »

Ok I sometimes hate this hobby; one has a tendency to get a bit neurotic.
Anyway, after spending some more time with my Grado SR325i’s and the BP25P/MPS-1, Bryston have done it once again.
All that I said previously,

“On the other hand my Grado SR325i’s at 98dbs impedance 32 ohms and the AKG k501’s 94 dB impedance 120 ohms sounded better with the Creek OBH-11se Rev B having more body (fullness and bass extension) and clarity in the highs even at lower volume levels.”

I take back, sort of.

With a better signal to noise ratio and power supply the BP25P is cleaner so that stage depth on good recordings is superior over the Creek, the same goes for the bass and highs, not obviously better but better.

The “sort of” comes in if you want a bit more life or fullness with the Grado’s then the Creek or similar headphone amp would be a better choice. For it’s price the Creek OBH-11SE Rev B is still an excellent amp and served me well for a few years.
With the Bryson you just have to be patient and take the time to realize how their equipment just gets out of the way any.

niels · « **Reply #4 on:** 14 May 2007, 02:24 pm »

Interesting.
I have a Bryston B100-DA and sold my Stax Signature, 006t & 4040 !!
Have a cheap Koss HP-1 and Sony headphones now meant for the computer, and using those with the Bryston I have the volume at around 12.00.
The sound is extremely clean and neutral, but my plasma tv drives the headphones with more "ooomph".
Anyway, I have new headphones in my sight, Audio Technica w1000, a closed model with a 40 Ohm impedance, so according to your experience these would maybe be difficult for the Bryston ?
I have Graham Slee Solo headphone amp lined up on my short list if the Bryston isnt up to it....

Edit : might just go for HD 580 Precision on second thoughts....

rob80b · « **Reply #5 on:** 16 May 2007, 09:14 pm »

You make want tp check this other post
http://www.audiocircle.com/index.php?topic=28320.0
I eventually bought another headphone amp just to be on the safe side so that not to have the phones removed without turning down the volume. With my AKG K501's the volume could be turned up fully clockwise, and Senns HD580 are around 11 to 1 o'clock depending on the music.

niels · « **Reply #6 on:** 16 May 2007, 11:05 pm »

Yes, I read that thread. I pulled the plugg on the phones one time already with the volume at 12.00, my wife almost killed me !
I have my eyes set on this one : http://www.gspaudio.co.uk/preamps/headphone.htm
Just bought a used Sennheiser HD580 Precision. I will test with the Bryston first then, maybe I will get used to turning the volume down first....

rob80b · « **Reply #7 on:** 17 May 2007, 10:04 pm »

If you are into headphones you make want this check site
http://www.head-fi.org/
if you have not already.

The Solo is highly regarded headamp, good choice
http://www.head-fi.org/forums/search.php?searchid=4433636

niels · « **Reply #8 on:** 22 May 2007, 10:04 pm »

Ok, got my HD580 Precision today and used them a bit on the Bryston. Not bad, but coming from a bright and wildly detailed Stax srm 006t & 4040 system it takes some getting used to.....
I have a little problem though I dont quite understand.
Since I am still waiting for the dac module to arrive here from Bryston I use the Squeezebox 3 in analog mode, and the volume is very low compared to my Philips dvd 963SA player.
The SB3 is having "a full 6.0 volt output", and the Philips standard 2.0 volts.
The setting on the Bryston with the SB3 at 15.00 on the volume equals that of app. 11.00 from the Philips.....
Why is this ? Very irritating with not enough gain.....please explain the volt from the SB3 to me.....
http://www.slimdevices.com/pi_squeezebox.html

Sorry, I dont know what happened here, now, an hour later I listened again, and the volume is just about the same on both, weird, but I rest my case and retract the above...
Now I save money for the Solo I think...

rob80b · « **Reply #9 on:** 24 May 2007, 02:54 pm »

Basically the headphone out of the Bryston is the same as the line-outs.
If you do decide to go the route of a dedicated headphone amp you will have a lot more gain and control. My Grado’s run about 9 o’clock on my Meier Corda Headamp and about 12 o’clock on the Bryston, like wise for my HD580’s, 11-12 o’clock on the Corda and 1-2 o’clock on the Bryston.
Also through extended listening I find the Corda has a bit more air and dimensionality and prefer it overall to the output of the Bryston.
But as I mentioned in another post, those who are not into headphones in a big way would be more than happy with the Bryston headphone output.