[kn19h7]

  Hi James
 
Obviously the BHA-1’s “raison d'être” is that of a fully balanced headphone amp and an excellent one at that but I’m sure there must be other users who are also experiencing the opposite problem with the gain on the unbalanced input.
This sort of mirrors the headphone gain on my previous BP25P and B60R and was surprised that the maximum gain was not increased on the BHA-1 when using unbalanced sources.
The way I see it is that if the overall gain of the BHA-1 is increased to accommodate the unbalanced input the balanced chain may be too high, the gain switch and volume control have been configured as such to accommodate a number of different headphones and works as intended.
Maybe I’m asking too much, but I’m wondering if in fact it may have been better to have incorporated a more conventional linear volume control and that the gain switch equalized the volume level when switching between the balanced and unbalanced input as the ‘majority” of users appear to be using full-sized lower efficient phones.
 
Robert

I actually thinks the opposite, even the "low" 14db gain on BHA-1 is a bit too high for me..
 
Even using HD800 in single-ended mode with single-ended input to the amp, the gain is still a little too high for me that I'll have to use digital volume control in some cases. And even doing so my volume knob still never passed 9 o'clock. Not to say with the efficient TH600, where use of digital volume control is a must. Noise level isn't a problem though.
 
I would hope the next product to have true low-gain modes like 0db, 6db etc. (btw please continue the non-ventilation-holes housing design as it is a big plus in BHA-1 to me...)

 

[Rob80b]

 
I actually thinks the opposite, even the "low" 14db gain on BHA-1 is a bit too high for me..
 
Even using HD800 in single-ended mode with single-ended input to the amp, the gain is still a little too high for me that I'll have to use digital volume control in some cases. And even doing so my volume knob still never passed 9 o'clock. Not to say with the efficient TH600, where use of digital volume control is a must. Noise level isn't a problem though.
 
I would hope the next product to have true low-gain modes like 0db, 6db etc. (btw please continue the non-ventilation-holes housing design as it is a big plus in BHA-1 to me...)

It is interesting that there have been a lot of opposing views with regard to the volume, I'll see what have laying around in terms of sources to double check.

 

[R Giskard]

  When I turn off the preamp on my M-DAC it automatically sets the volume to 0db.  The problem that I have is that with the M-DAC set at 0db I only go to around 9:00 to 10:00 with my HE-500's before I find it too loud, as I am a quiet listener.  I tried with my Sony MDR-7520's last night and I could only turn the volume to around 7:00-8:00 before it was too loud and it was very tough to find my preferred volume.  This is with the BHA-1 set to low gain and I am not running balanced cables from my M-DAC to the BHA-1 yet...
 
The thing is that I have balanced cables on order and I read that that increases volume by another 6 db's, so the only option I can see is to not bypass the preamp in my M-DAC and turn down the volume on the M-DAC.  Do you think this will cause lesser sound quality if I turn it down around 10-15 db on the M-DAC?
 
Thanks.

Presuming you are talking about Audiolab M-DAC, it has a 32 bit architecture. If you are for instance listening to a 16 bit music file, you have 16 bits extra that are not used but can be used to decrease volume. Since 1 bit equals 6 dB of attentuation, it amounts to 16 x 6 = 96 dB of attenuation before you start losing quality. Absolutely no problems there! If you are, on the other hand, listening to a 24 but music file, that leaves you 8 bits extra for volume manipulation till you start losing quality. In other words, it amounds to 8 x 6 = 48 dB of attenuation.
 
That being said, the attentuation is a mathematical downsizing of the data and the lowest bits are taken away first so losing a few will not cause any obvious diminishing of sound quality.
 
Modern DACs have around 20 to 21 bit effective resolution because the average dynamic range is around 120 dB, versus 144 dB which is the theoretical limit of 24 bit converters.
 
So to conclude, there should not be any obvious loss of quality and this is absolutely true for 16 bit audio.
 
Cheers!
Antun

 

[Dave74]

  Presuming you are talking about Audiolab M-DAC, it has a 32 bit architecture. If you are for instance listening to a 16 bit music file, you have 16 bits extra that are not used but can be used to decrease volume. Since 1 bit equals 6 dB of attentuation, it amounts to 16 x 6 = 96 dB of attenuation before you start losing quality. Absolutely no problems there! If you are, on the other hand, listening to a 24 but music file, that leaves you 8 bits extra for volume manipulation till you start losing quality. In other words, it amounds to 8 x 6 = 48 dB of attenuation.
 
That being said, the attentuation is a mathematical downsizing of the data and the lowest bits are taken away first so losing a few will not cause any obvious diminishing of sound quality.
 
Modern DACs have around 20 to 21 bit effective resolution because the average dynamic range is around 120 dB, versus 144 dB which is the theoretical limit of 24 bit converters.
 
So to conclude, there should not be any obvious loss of quality and this is absolutely true for 16 bit audio.
 
Cheers!
Antun

Great!  Thanks. R Giskard.  That leaves me with a lot of room to play with, even with my 24 bit tracks.

 

[fradoca]

  Hi
 
Please email Stuart Taylor at Bryston - I spoke with him today about your questions and he has some questions in return
 
He also said we could do a custom unit for you if needed.
 
staylor@bryston,com
 
james

James,
i've written an email to Stuart Taylor as you suggested me.Thank you very much!!! I'll wait for his reply.

 

[R Giskard]

  Great!  Thanks. R Giskard.  That leaves me with a lot of room to play with, even with my 24 bit tracks.

Sure, no worries!
 
Cheers!

 

[philo50]

I have owned both the BHA-1 and BDA-1 for 3 or 4 months now and have enjoyed them mightily. As many do I had them stacked with the BHA-1 on top. Today I took delivery of a new rack and for the first time separated the 2 components. Everything else is the same(power cords, interconnects etc). I was astounded at the difference in the sound.....more pronounced bass for sure and increased clarity I think.
 
I have heard in the past that separating units was recommended but I ignored that. I was pleased before....am ecstatic now. If you have your components stacked try to separate them....sure worked for me!

 

[BournePerfect]

How do you like the M9 w/ the HD800 compared to the BHA-1? Have you tried both using the same source?
 
-Daniel

 

[philo50]

  How do you like the M9 w/ the HD800 compared to the BHA-1? Have you tried both using the same source?
 
-Daniel

jumped the gun on my sig....won't have the M9 until next week...will compare then

 

[punit]

  How do you like the M9 w/ the HD800 compared to the BHA-1? Have you tried both using the same source?
 
-Daniel

+1. am interested in this too. WTB a balanced amp & am torn between the M9 & BHA-1. I have the Master 1,  so do not need a pre-amp hence was considering the BHA-1 as it is primarily a HP amp so assumed it should be slightly better for HP's SQ wise & also due to slim form factor, but if they are the same SQ wise, would rather go with M9, as have a very good & positive experience with Kingwa's gear.

 

[Trance_Gott]

The BHA1 is an amazing combo with my LCD3 and LCD-XC. But with my 2 very efficient headphones T5p and Signature Pro it always has a low noticeable hum in the background whatever volume setting I have. Bryston modified my low gain setting significantly lower but this doesn't solve the problem. I think this is one of the handicap for an otherwise outstanding amp.

 

[kn19h7]

The BHA1 is an amazing combo with my LCD3 and LCD-XC. But with my 2 very efficient headphones T5p and Signature Pro it always has a low noticeable hum in the background whatever volume setting I have. Bryston modified my low gain setting significantly lower but this doesn't solve the problem. I think this is one of the handicap for an otherwise outstanding amp.

Wow, Bryston can actually offer lower gain for this amp? My only issue with this amp is the slightly high gain even on low gain mode.
Btw what is the value of your modified low gain?
 
I don't hear any noise with BHA-1 and TH600 which is also a very efficient headphone, I think maybe the problem is at something else instead of the amp.

 

[Trance_Gott]

Wow, Bryston can actually offer lower gain for this amp? My only issue with this amp is the slightly high gain even on low gain mode.
Btw what is the value of your modified low gain?

I don't hear any noise with BHA-1 and TH600 which is also a very efficient headphone, I think maybe the problem is at something else instead of the amp.

I contacted Mike Pickett from Bryston and the distributor for Germany makes the modification for me.
I have the TH900 and it is also dead silent with the BHA1.

 

[kn19h7]

I contacted Mike Pickett from Bryston and the distributor for Germany makes the modification for me.
I have the TH900 and it is also dead silent with the BHA1.

Hmm maybe I should try my luck contacting them for a custom unit sometime
 
Just tried with IE800, dead silent also.

 

[Chris J]

The BHA1 is an amazing combo with my LCD3 and LCD-XC. But with my 2 very efficient headphones T5p and Signature Pro it always has a low noticeable hum in the background whatever volume setting I have. Bryston modified my low gain setting significantly lower but this doesn't solve the problem. I think this is one of the handicap for an otherwise outstanding amp.

 
Try unplugging the source (the DAC) from the BHA-1, do you still get hum?