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Bryston BHA1 Headphone Amp


The Monkey

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The input selector is a toggle switch to the extreme left of the amp. The small knob is a balance control.

I'm not sure they are even discussing it there yet. I'll be waiting for the usual "Yeah, Spritzer, we know if it isn't Gilmore, its shit" response when you finally do get a crack in rofl.gif

So fucking true... Still it's a Bryston so it's certainly better than most of the crap out there.

Edited by spritzer
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  • 6 months later...

Here it is.

Begin analysis! Here are links to my Dropbox in PDF and PNG formats.

https://www.dropbox....jxhfoq/bha1.pdf

https://www.dropbox....u9vovq/bha1.png

Enjoy!

Thanks for looking, spritzer, and anyone else who's interested...would be interested in some feedback.

Edited by cutestory
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Is it just me or what's the point of this amp? Why on earth would anybody build something like this? So a fully balanced amp except it isn't since the input section is single ended and with only a two gang volume control which then feeds to two amp sections per channel. It's get better though as they capacitor couple the output so one gets to enjoy the sound of a quad of 4700uf/35V electrolytic caps. I truly don't understand this amp or the logic behind it.

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Is it just me or what's the point of this amp? Why on earth would anybody build something like this? So a fully balanced amp except it isn't since the input section is single ended and with only a two gang volume control which then feeds to two amp sections per channel. It's get better though as they capacitor couple the output so one gets to enjoy the sound of a quad of 4700uf/35V electrolytic caps. I truly don't understand this amp or the logic behind it.

Would you mind explaining to a layman why this is bad?

I'm not a circuit guy, but I understand the bit about the input section being single ended (which does seem silly). It's the "two gang volume control" and "they capacitor couple the output" parts that I'm not groking.

Thanks in advance...

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But then they would not have gotten the noise cancellation right? Or does it just happen at the transducer?

Noise cancellation of COMMON MODE noise happens wherever the phases of the signal are compared. If the phases are compared at the inputs, noise cancellation happens there. If the phases are compared across the drivers that is where the noise cancellation happens.

The cool thing with amps like this is you get noise cancellation regardless of whether you use the SE or balanced outputs. With 4-boards in one box amps (icky) you only get noise cancelation when running balanced. 4boards-1box amps also amplify the noise through the whole amp, gobbling up overhead - if you get rid of the noise early (in either SE or 2ch balanced amps) you can improve performance greatly.

A 2-channel balanced buffer would be infinitely better than 4-boards in one box. Separate is not equal.

Edited by nikongod
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Would you mind explaining to a layman why this is bad?

I'm not a circuit guy, but I understand the bit about the input section being single ended (which does seem silly). It's the "two gang volume control" and "they capacitor couple the output" parts that I'm not groking.

Thanks in advance...

Two gang volume control means it's only stereo. Why they took what is essentially a balanced input stage and then fed it through a stereo volume control and then onto a quad output stage is just odd. Why not go all the way and go balanced through out?

As for the capacitor output, this is used to block the natural DC offset of the output stage. This is a common feature in Bryston designs so I'm not surprised but it only takes a few parts to make a servo which is completely transparent (certainly more so than a PSU capacitor) and means the output can be DC coupled. Amps like the GS-X do it like this so more transparent.

I do agree with Ari that RCA inputs are often badly catered for but I've all but given up on them anyway. Why bother with them when one can go fully balanced...

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The cool thing with amps like this is you get noise cancellation regardless of whether you use the SE or balanced outputs. With 4-boards in one box amps (icky) you only get noise cancelation when running balanced. 4boards-1box amps also amplify the noise through the whole amp, gobbling up overhead - if you get rid of the noise early (in either SE or 2ch balanced amps) you can improve performance greatly.

A 2-channel balanced buffer would be infinitely better than 4-boards in one box. Separate is not equal.

Does this mean only the balanced output is worth listening to on this piece? Or that the whole thing is junk (relatively speaking, of course)?

It also sounds like spritzer says I should be ordering an amp from Justin, which I should think about doing anyway. :)

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Does this mean only the balanced output is worth listening to on this piece? Or that the whole thing is junk (relatively speaking, of course)?

No, it means that there should hardly be any difference at all. Which is very cool.

Ooh, unless the output impedance is different running SE and BAL.

People put WAY too much importance on Balanced amps, especially in high feedback circuits.

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