Bryston BHA1 Headphone Amp

[spritzer]

Balanced is most definitely overrated in the general sense but I still fail to see why the bloody amp wasn't just made balanced through out. Team overkill would never have done something like this...

The output impedance will be a factor in terms of SPL but only a bit. Easiest would be to just measure the output but it's a bit of a pain.

The GS-X is a hell of an amp but it was just the only fully DC coupled discrete amp I could think of. The Luxman amps appear to have AC coupled outputs as there are some suspicious looking caps near the output.

[luvdunhill]

Ari explained why above.

[cutestory]

Thanks for the explanations, all. It is much appreciated.

My balanced cable came in and is now connected to my LCD-2s, and I'm enjoying it quite a lot, design issues notwithstanding.

Semi-ignorance is bliss?

[spritzer]

It's indeed not always better to know. It was pure hell for me to buy a new source a year ago as there was nothing that was good enough and had the specs I wanted.

[cutestory]

Something odd.

Just got a balanced cable for my JH13s, and plugged them in. Now I know IEMs are pretty sensitive, etc. but I hear a little buzz and hiss at 0 volume that goes away around 10 o'clock. I'd think such a thing would just get louder and louder as I turned up the volume. This is on all three inputs, and whether set to low or high gain it goes away at the same point on the dial. So now I'm dialing down the volume on my PWD so I can listen at 10 o'clock and higher to avoid it.

Can anyone explain why this is happening? I mean, apart from me not getting a GS-X? I know that's one possible explanation.

[wink]

Could be an earthing issue.

You may need to elevate the signal earth above the chassis earth by around 10 or more ohms as a earth loop breaker.

[cutestory]

I'm sorry to be such a rube, but I have no idea what to do with this information...

[wink]

Seeing it's a commercial product, not much. Unless you want to do some of your own mods.

IEM's are notorious for picking up problems in headphone amps.

You could try lifting the signal earth as some amps do with a switch.

You would have to make a metal box with the input rca's shield isolated from the box, or have a resistor of around 10 to 100 ohms from input RCA earth to case. This acts as an earth loop breaker.

The Output rca is connected to the box to shield the area inside, so only the signal goes through from input rca to output rca.

You could also have a switch that when ON connects the earths, and in the OFF position breaks the connection.

You would need one for each channel.

Having one box for both channels could cause earthing problems in the system as you would then have 2 connections for the signal earths of each channel which is a rife recipe for earth loop problems.

If you're really keen, a 2 way switch with a centre position can give you a no connection in the centre position, connection on one side, and a earth loop breaking resistor on the other side.

Edited November 6, 2012 by wink

[cutestory]

Hmmm. Ok, thanks for the information.

Shit, I'm almost sorry how much I like the sound of my JH13s when dialed-in to a non-noisy position.

Looks like we could be looking at a re-investment in other equipment as "modification."

Fuck. Fuck!

[HeadphoneAddict]

Something odd.

Just got a balanced cable for my JH13s, and plugged them in. Now I know IEMs are pretty sensitive, etc. but I hear a little buzz and hiss at 0 volume that goes away around 10 o'clock. I'd think such a thing would just get louder and louder as I turned up the volume. This is on all three inputs, and whether set to low or high gain it goes away at the same point on the dial. So now I'm dialing down the volume on my PWD so I can listen at 10 o'clock and higher to avoid it.

Can anyone explain why this is happening? I mean, apart from me not getting a GS-X? I know that's one possible explanation.

Hmm, my JH13Pro are dead silent with my PWD at 100% and using my desktop ZDT amp. However, in past I had a hum that was fixed by grounding the ZDT to my WES which was also hooked up to the PWD at the same time. Now that the WES has been replaced by a KGBH the hum is gone.

[wink]

"Hmm, my JH13Pro are dead silent with my PWD at 100% "

The problem is that cutestory has hum in the first 30% of the volume control travel. Above that to 100% all is OK.

At zero on the volume control the signal input is at the same level as the signal ground.

[wink]

"Just got a balanced cable for my JH13s,"

Just a thought, could you have a connection between the earths of both channels in the cable?

They should be separate. A quick check with a multimeter would tell.

Check the cable removed from the IEM.

[cutestory]

"Hmm, my JH13Pro are dead silent with my PWD at 100% "

The problem is that cutestory has hum in the first 30% of the volume control travel. Above that to 100% all is OK.

At zero on the volume control the signal input is at the same level as the signal ground.

It's not entirely quiet above 30%, it's just that the buzzing sound goes away. I definitely hear some hiss above the 30% mark. This is not good, no?

"Hmm, my JH13Pro are dead silent with my PWD at 100% "

The problem is that cutestory has hum in the first 30% of the volume control travel. Above that to 100% all is OK.

At zero on the volume control the signal input is at the same level as the signal ground.

"Just got a balanced cable for my JH13s,"

Just a thought, could you have a connection between the earths of both channels in the cable?

They should be separate. A quick check with a multimeter would tell.

Check the cable removed from the IEM.

If I can get my hands on a multimeter, I'll ask for further instructions. Or I could ask the person who made the cable for me...

[RudeWolf]

Simple impedance testing can be done without an actual multimeter. Get a 9V battery connect wires to both poles and one wire to one of the ground wires. You can try using a led and a resistor for indication but a tongue (or some other soft skinned body part) is perfectly sufficient. If there is any connection between the ground wires you will feel current with you tongue. Basically any "tastable" voltage will do if you don't have any 9 volts.

[Torpedo]

... Basically any "tastable" voltage will do if you don't have any 9 volts.

Yeah, why going sissy if you can join team overkill

[cutestory]

What the shit?

I connected an XLR to 1/4" adapter to my JH13s and connected it to the SE output on the amp, and voila, the noise is much much less. At first I thought it was gone totally but I turned up the gain to high and heard it again, then turned it down to low and I can just *barely* hear it. Since when is a single-ended connection less noisy than a balanced one?

I'm even more confused now.

And I'm pretty sure it's not the cable—I tried another one with a 1/8" to 1/4" adapter, same thing.

Edit: Wait, I'm an idiot—the balanced out has twice the gain and so the noise is amplified, duh.

Edited November 7, 2012 by cutestory

[wink]

" Wait, I'm an idiot " Whether we want to admit it, or not - we all have these moments of lucidity concerning our mortality.

[HeadphoneAddict]

What the shit?

I connected an XLR to 1/4" adapter to my JH13s and connected it to the SE output on the amp, and voila, the noise is much much less. At first I thought it was gone totally but I turned up the gain to high and heard it again, then turned it down to low and I can just *barely* hear it. Since when is a single-ended connection less noisy than a balanced one?

I'm even more confused now.

And I'm pretty sure it's not the cable—I tried another one with a 1/8" to 1/4" adapter, same thing.

Edit: Wait, I'm an idiot—the balanced out has twice the gain and so the noise is amplified, duh.

So, I forget, does the noise go away when you disconnect your source? Or is the noise coming from the amp itself?

[cutestory]

Noise is omnipresent whether source is connected or not.

With no source connected, the loudness of the noise goes from bal (loudest) to mini to rca (quietest) when I select the different inputs.

Looks like it's coming from the amp.

[spritzer]

It could be an attenuator issue. The Noble just could be a bit noisy or the balance control is acting up.

[cutestory]

Looks like Birgir was right—apparently 12 o'clock (well, "12 -1 o'clock," according to Bryston's rep over at the other place) is unity gain, so it looks like the attenuator is doing something nasty to the signal below that threshold.

I'm waiting to hear back (indirectly) from Bryston engineering; I fear their response may be to "use less sensitive or efficient headphones."

I know one person not having the problem, even using IEMs. He's also using a balanced connection with his IEMs: UERMs (112dB@1mW, 21 ohms @ 1kHz). Are my 13 Pros (116dB@1mW, 28 Ohms@1kHz) different enough spec-wise that this problem would manifest itself only on my side?

Anyway, I'll finally get to plug in my DSHA-1b today, so I've got that goin' for me. Which is nice.

[nikongod]

I connected an XLR to 1/4" adapter to my JH13s and connected it to the SE output on the amp, and voila, the noise is much much less. At first I thought it was gone totally but I turned up the gain to high and heard it again, then turned it down to low and I can just *barely* hear it. Since when is a single-ended connection less noisy than a balanced one?

*Random* noise is almost always 6db (twice as much) worse on an active balanced output as compared to an active SE output. This is one of the objectivist camp's big bitching points against balanced speaker/headphone drive.

The few exceptions to the noise rule use transformer coupled outputs, which so rarely measure well enough to even bother consideration for measurement by the objectivists that they don't acknowledge their existence.

With very very very sensitive headphones the difference in noise can be significant.

[Dusty Chalk]

I'm waiting to hear back (indirectly) from Bryston engineering; I fear their response may be to "use less sensitive or efficient headphones."

That should never be a response, but yeah, that said, a lot of vendors do say exactly that sort of shit.

There are attenuators that you could put inline, or you could have someone mod it with a better attenuator. Or you could have someone bypass the attenuator and put a preamp in front of it.

[cutestory]

...or I guess I could set it to unity and use my DAC as a preamp.

[Dusty Chalk]

...or I guess you could just leave the knob up and use whatever source you're using as a preamp. Although then you get into the question of whether or not the digital attenuation degrades the sound. (Short answer -- it depends on what algorithm they're using -- if it's one of the better companies, then it's probably fine.)

If you're doing it from within a computer, you could try just setting it to 50% or 25%, and using the knob on the Bryston in the upper half of its travel to adjust volume. That way you're only using 1 or 2 bits of information.

EDIT: That said, all of my suggestions were compromises. Especially the preamp -- not sure adding an extra component to your system is going to degrade your sound any more or less than using digital attenuation, even Windows digital attenuation.