[doveman]

question: is it safe to both plug in and unplug headphones while leaving the BHA-1 turned on? or running it with no headphones attached at all?

[James Tanner]

question: is it safe to both plug in and unplug headphones while leaving the BHA-1 turned on? or running it with no headphones attached at all?

No problem sir.

james

[MellowVelo]

Hi James,

Regarding the volume control on the BHA-1...I seem to recall reading that, up to a certain point on the volume control, the amp is actually operating at unity gain. Is this true? Of course, I can't find a post where this is written, so maybe I'm not remembering correctly. 

[Grit]

That'd actually help me... a unity gain would allow me to use my SP3 as the volume control.

[MellowVelo]

Hi James,

Regarding the volume control on the BHA-1...I seem to recall reading that, up to a certain point on the volume control, the amp is actually operating at unity gain. Is this true? Of course, I can't find a post where this is written, so maybe I'm not remembering correctly. 

Friendly bump. 

[James Tanner]

Friendly bump. 

Hi

Please email Mike on this.   mpickett@bryston.com

[James Tanner]

Hi James,

I thought I'd take the time to tell you I received my BHA-1 and am blown away. The build quality is truly excellent, switches and volume pot feel fantastic. Turns out the balanced question was semi irrelevant because this thing has made my HD800 scale up hugely, plugged in single ended. It's like I'm hearing my music for the first time all over again (which of course is sacred).

Please pass my compliments to the entire Bryston team, you folks are doing really fantastic work.

Ian

[Grit]

Friendly bump. 

Hey MelloVelo, would you share what you learn?

Thanks,

- Garrett

[95Dyna]

Hi James,

I thought I'd take the time to tell you I received my BHA-1 and am blown away. The build quality is truly excellent, switches and volume pot feel fantastic. Turns out the balanced question was semi irrelevant because this thing has made my HD800 scale up hugely, plugged in single ended. It's like I'm hearing my music for the first time all over again (which of course is sacred).

Please pass my compliments to the entire Bryston team, you folks are doing really fantastic work.

Ian

Hi James,

When Ian mentions "the balanced question" is he referring to a single ended input connection to the BHA-1 precluding a balanced output to the headphones?  Put another way if my input is unbalanced (e.g. tape loop out from the BP26) should I not use the balanced outputs?

[95Dyna]

Hey MelloVelo, would you share what you learn?

Thanks,

- Garrett

+1.  If true this this would provide more flexibility for those of us who want to use preamps or processors as the source for the BHA-1.  It's difficult to find a preamp that has a fixed level balanced output.  Ray Samuels and ARC are the only two I can think of.

[MellowVelo]

+1.  If true this this would provide more flexibility for those of us who want to use preamps or processors as the source for the BHA-1.  It's difficult to find a preamp that has a fixed level balanced output.  Ray Samuels and ARC are the only two I can think of.

Will do. I'll report back.

[MellowVelo]

Will do. I'll report back.

Ask, and ye shall receive. From Mike Pickett:

The output amplifiers in the BHA1 run at 14db and 20db of gain, in low and high gain modes, respectively.  The position of the volume control doesn’t change this, but does change the overall gain through the BHA1.
 
In terms of ‘clock face position’, the points at which the BHA1 is operating at overall unity gain occur around 3:00 in low-gain mode, and 10:30 in high-gain mode.

[R. Daneel]

Hi!

Regarding unity gain, does operation at unity gain benefit audio in some way?

From what I understand, operation at unity gain means the signal voltage at the output is the same as the voltage at the input so no additional current is drawn from the circuit. If my understanding is correct, then perhaps operation at unity gain means the amplifier is as linear as it can be. Would this be a logical conclusion?

If yes, then exceeding unity gain would draw more current and depeneding on the circuit quality, would result in a frequency response that is not as flat as it would be when the amplifier was operating at unity gain, right?

I have noticed that most manufacturers specify the amplifier power output in Watts and only at 1 kHz. No doubt, the amplifier is less capable when full 20 Hz - 20 kHz audio range is in question.

This is for (my) educational purposes, I have no hidden agendas so please comment if you know! 

Cheers!
Antun

[James Tanner]

Hi!

Regarding unity gain, does operation at unity gain benefit audio in some way?

From what I understand, operation at unity gain means the signal voltage at the output is the same as the voltage at the input so no additional current is drawn from the circuit. If my understanding is correct, then perhaps operation at unity gain means the amplifier is as linear as it can be. Would this be a logical conclusion?

If yes, then exceeding unity gain would draw more current and depeneding on the circuit quality, would result in a frequency response that is not as flat as it would be when the amplifier was operating at unity gain, right?

I have noticed that most manufacturers specify the amplifier power output in Watts and only at 1 kHz. No doubt, the amplifier is less capable when full 20 Hz - 20 kHz audio range is in question.

This is for (my) educational purposes, I have no hidden agendas so please comment if you know! 

Cheers!
Antun

Hi Antun

Bryston rates its' amplifiers fro 20Hz to 20,000Hz.

james

[R. Daneel]

Hi Antun

Bryston rates its' amplifiers fro 20Hz to 20,000Hz.

james

Hi James!

I suspected this might be true for Bryston but many other manufacturers aren't doing it. In my experience, Bryston BHA-1 is essentially as linear in it's power delivery as is possible. No matter the volume, with Sennheiser HD800 it always sounds exactly the same and never loses composure or control. It is my reference headphone amplifier and my favoirite audio component. It just seems to scale as high as the other components and never becomes a "bottleneck".

However, I'd still like to know whether my assumptions from my last post are correct.

Cheers!
Antun

[rob80b]

Speaking only as a layman…the output of most solid state amps should be linear at all volume levels…the biggest detractor would be the requirements for the drivers in headphones or speakers…. the later being more problematic as there is a large variance in headphones from 32 to 600ohms and that is not an indicator of their efficiency with regards to current/voltage draw and therefore almost makes it impossible for a manufacturer to predict how their amp will respond with all headsets.
So while most headphones can reach adequate volume levels with most devices..a full linear audio spectrum is not achieved, take AKG’s K700 series for example.. with an input impedance of just 63 ohms and a sensitivity of 105 db it is still highly accepted in the community that without adequate amplification bass can be sadly inadequate while the rest of the audio spectrum from the midrange to the highest treble is fine. Grados are another example, while being easily powered from any amplifier, those that can supply more current always allow the Grados to sound their best even though the volume output is the same.
So without an accepted industry standard as we have with speakers, where the majority sit between a “nominal” 4 and 8 ohms and manufactures have designed their amps to adequately supply a fairly linear power output to accommodate and maintain a flat frequency response in relation to the input signal..headphone users are not that lucky..but thankfully to their relatively low power requirements usually not an issue. Nor do we need concern ourselves with power output as much… as the space between our ears and the driver is more or less uniform unlike dealing with room sizes where a larger room would be require a more powerful amp to maintain higher volumes and dynamic peaks without distortion.
Also the most problematic dilemma when designing headphones is that of the interaction of the driver output with the ear canal is never linear/flat ..so even if the output of the amp in question is perfectly flat from 20 Hz - 20 kHz at all volume levels..the signal reaching the ear drum is not unless the headphone designer takes this into consideration and to complicate things we all have differently shaped ears and ear canals playing havoc on the signal which equates into a large disparity regarding a headphone’s performance, much more so than speakers.
Having said all that Bryston amps are extremely linear at all volume levels and this includes the BHA-1, is it the “perfect” match for all headphones, maybe not but it is as close as I’ve encountered.
Some of what I said may be in contradiction to itself but these are in fact the difficulties presented to product designers and necessitates some compromises in getting a final product to market.

With regards to unity gain one would need to design the amp to power a specific headphone at a set volume as in relation to the output of the source and while a nice idea totally impractical.

[R. Daneel]

Speaking only as a layman…the output of most solid state amps should be linear at all volume levels…the biggest detractor would be the requirements for the drivers in headphones or speakers…. the later being more problematic as there is a large variance in headphones from 32 to 600ohms and that is not an indicator of their efficiency with regards to current/voltage draw and therefore almost makes it impossible for a manufacturer to predict how their amp will respond with all headsets.
So while most headphones can reach adequate volume levels with most devices..a full linear audio spectrum is not achieved, take AKG’s K700 series for example.. with an input impedance of just 63 ohms and a sensitivity of 105 db it is still highly accepted in the community that without adequate amplification bass can be sadly inadequate while the rest of the audio spectrum from the midrange to the highest treble is fine. Grados are another example, while being easily powered from any amplifier, those that can supply more current always allow the Grados to sound their best even though the volume output is the same.
So without an accepted industry standard as we have with speakers, where the majority sit between a “nominal” 4 and 8 ohms and manufactures have designed their amps to adequately supply a fairly linear power output to accommodate and maintain a flat frequency response in relation to the input signal..headphone users are not that lucky..but thankfully to their relatively low power requirements usually not an issue. Nor do we need concern ourselves with power output as much… as the space between our ears and the driver is more or less uniform unlike dealing with room sizes where a larger room would be require a more powerful amp to maintain higher volumes and dynamic peaks without distortion.
Also the most problematic dilemma when designing headphones is that of the interaction of the driver output with the ear canal is never linear/flat ..so even if the output of the amp in question is perfectly flat from 20 Hz - 20 kHz at all volume levels..the signal reaching the ear drum is not unless the headphone designer takes this into consideration and to complicate things we all have differently shaped ears and ear canals playing havoc on the signal which equates into a large disparity regarding a headphone’s performance, much more so than speakers.
Having said all that Bryston amps are extremely linear at all volume levels and this includes the BHA-1, is it the “perfect” match for all headphones, maybe not but it is as close as I’ve encountered.
Some of what I said may be in contradiction to itself but these are in fact the difficulties presented to product designers and necessitates some compromises in getting a final product to market.

With regards to unity gain one would need to design the amp to power a specific headphone at a set volume as in relation to the output of the source and while a nice idea totally impractical.

Thanks Robert!

This is intriguing! In your opinion, what is wiser, high-impedance or low-impedance haedphones?

I don't understand what they mean when they say low-impedance headphones are easier to drive. Surely, they can achieve a higher output at lower volume settings but that doesn't mean they are easier to drive. I have noticed that they are less consistent at different volume levels and one has to be careful with the amplifier because there is possibility of some hiss from the circuitry. I just think high-impedance should be reserved for high-end headphones.

You are right about the Grados too. They certainly benefit from capable amplification. Despite Grado's specifications, I don't find them particularly efficient and to play well at low volumes, they require a solid transistor amplifier.

Cheers!
Antun

[rob80b]

Thanks Robert!

This is intriguing! In your opinion, what is wiser, high-impedance or low-impedance haedphones?

...........................

Cheers!
Antun

Although technology is changing ..... a generally accepted rule of thumb ….higher impedance phones require more voltage due to their more robust but less efficient motor mechanisms,  and low impedance ..current and a few like the AKG K700 series like/require both.
Prior to the proliferation of portable monitoring devises most phones were high impendence and then with the advent of the Walkman in order to reach adequate volume levels low impedance  became much more popular.
The impedance of the headphone has no real bearing on sound quality when properly amped but mismatching can occur, for example I find my Sennheiser HD598s (50 ohms/ 112dBs sensitivity) sound pretty good off the computer or portable device, while my higher up HD700s (150 ohms/105dB sensitivity) sound rather mediocre, but driven off the BHA-1 both actually sound very good but the HD598s will start to distort way before the HD700s at the same volume output.
So for personal preferences comes down to the intended use, but if possible I normally gravitate to higher impedance phones.

Robert

[R. Daneel]

Although technology is changing ..... a generally accepted rule of thumb ….higher impedance phones require more voltage due to their more robust but less efficient motor mechanisms,  and low impedance ..current and a few like the AKG K700 series like/require both.
Prior to the proliferation of portable monitoring devises most phones were high impendence and then with the advent of the Walkman in order to reach adequate volume levels low impedance  became much more popular.
The impedance of the headphone has no real bearing on sound quality when properly amped but mismatching can occur, for example I find my Sennheiser HD598s (50 ohms/ 112dBs sensitivity) sound pretty good off the computer or portable device, while my higher up HD700s (150 ohms/105dB sensitivity) sound rather mediocre, but driven off the BHA-1 both actually sound very good but the HD598s will start to distort way before the HD700s at the same volume output.
So for personal preferences comes down to the intended use, but if possible I normally gravitate to higher impedance phones.

Robert

Hi Robert!

I prefer higher impedance headphones too.

Speaking of walkman, I have the Sony WM-DC2 (amorphous head, dolby C) that sounds fantastic with AKG K240 Monitor (600 ohm / 88 dB sensitivity) but not so good with the Grado SR225i.

But would you say the high-impedance headphones are generally more resilient to mishaps and their drivers last longer?

Antun

[James Tanner]

MEMO: To All Bryston Customers
SUBJECT: Bryston BHA-1 Headphone Amp Review

June 2015



The New Bryston BHA-1 Headphone Amp / Pre Amp: A Class of Its Own

Please see link below for full review.

http://notanotherhifiblog.blogspot.ca/2015/06/bryston-bha-1-headphone-amp-pre-amp.html