BRYSTON BHA-1 HEADPHONE AMPLIFIER

GrooveControl · « **Reply #1300 on:** 4 Jun 2022, 03:56 am »

Hi vlach, bha-1 works well as a preamp and sounds fantastic, but please read this thread about connecting the bha-1 to an unbalanced amp…

https://www.audiocircle.com/index.php?topic=170919.msg1809376#msg1809376

vlach · « **Reply #1301 on:** 4 Jun 2022, 06:11 pm »

What a sweetheart you are! Thank you so much for sharing this link and saving myself from potentially damaging my amp! I'm really glad i followed my instincts and asked before odering these cables!

That said, I find it rather strange that these cables/adaptors are safe on some devices and not on others, i had assumed there was an industry standard for this type of thing.

Another member, 'Jon L' (in the link you forwarded) mentioned he ordered adaptors from Moon Audio however he doesn't mention if pin 3 is floating...i will try to reach out to him or maybe contact Moon-Audio directly to confirm this.

Again, a BIG thank you!

Armaegis · « **Reply #1302 on:** 5 Jun 2022, 03:18 pm »

A very simple alternative is to get a 1/4" TRS to RCA adapter and use the non-balanced headphone jack on the front to feed your power amp.

vlach · « **Reply #1303 on:** 5 Jun 2022, 03:31 pm »

Wouldn't that be double amping though? I was always under the impression that the rear XLR outputs tap into the preamp section bypassing the amp portion, or do i have this part totally wrong?

Armaegis · « **Reply #1304 on:** 5 Jun 2022, 05:10 pm »

I believe the preamp output is tapped off the power outputs... but I could be wrong on that.

Also, a TRS to RCA cable is maybe $10 so very cheap to try and just something to have in the toolkit so to speak.

vlach · « **Reply #1305 on:** 5 Jun 2022, 08:45 pm »

I would think that if the rear XLR outputs are meant to be used as a line stage to drive a power amp, then surely these outputs are not identical to the front XLR outputs because usually preamps have higher output impedance than SS headphone amps, but i'm just commenting based on my very 'general' knowledge and i'm far from an expert. I even looked at the schematic and can't really tell.

jcn3 · « **Reply #1306 on:** 7 Jun 2022, 05:45 pm »

Quote from: vlach on 3 Jun 2022, 09:58 pm

Hello,

I'm a new member on this forum and a BHA-1 enthusiast!

Is anyone using the BHA-1 as a preamp driving a power amp through the balanced outputs? I would like to try this, however my amp only has SE inputs.

I should be able to use XLR to RCA cables to make it work right? Just wondering how this set up is working for anyone using it.

Thank you.

I did for a while. Got some xlr to rca adapters (from hosa) and used rca cables.

vlach · « **Reply #1307 on:** 7 Jun 2022, 07:08 pm »

Out of curiosity, did you have to cut off the connection between pins 1&3 on the adapters?

jcn3 · « **Reply #1308 on:** 7 Jun 2022, 07:32 pm »

Quote from: vlach on 7 Jun 2022, 07:08 pm

Out of curiosity, did you have to cut off the connection between pins 1&3 on the adapters?

i used the hosa adapters out of the box -- no mods. i think this is the one: https://www.amazon.com/Hosa-Technology-GXR134-Signal-Converter/dp/B000068O4F?th=1

vlach · « **Reply #1309 on:** 7 Jun 2022, 09:17 pm »

I'm surprised you didn't have any problems, the product description clearly states that pin 3 is grounded. A few posts back Mike from Bryston issued a warning to float pin 3 if using the rear XLR outputs for SE applications. Anyway, i'm glad nothing happened to your amp!

It turns out every XLR to RCA adapter i've looked up has pin 3 grounded. I'm not taking any chances, i will cut off the connection between pins 1&3 just to be safe.

On an unrelated note, I found different circuit topologies when doing a search, notice the four large capacitors in the attached photo? This is different than the photos a few posts back showing the amps on the test bench at the factory, I wonder when this change happened...

Highendfool · « **Reply #1310 on:** 8 Jun 2022, 01:50 am »

Quote from: vlach on 7 Jun 2022, 09:17 pm

I'm surprised you didn't have any problems, the product description clearly states that pin 3 is grounded. A few posts back Mike from Bryston issued a warning to float pin 3 if using the rear XLR outputs for SE applications. Anyway, i'm glad nothing happened to your amp!

It turns out every XLR to RCA adapter i've looked up has pin 3 grounded. I'm not taking any chances, i will cut off the connection between pins 1&3 just to be safe.

On an unrelated note, I found different circuit topologies when doing a search, notice the four large capacitors in the attached photo? This is different than the photos a few posts back showing the amps on the test bench at the factory, I wonder when this change happened...

Excellent question and, good catch!
Let’s see what the guys @Bryston have to say!

Four Kneez · « **Reply #1311 on:** 9 Jun 2022, 07:15 pm »

Just purchased a BHA-1 a few weeks ago after hearing it at a friend's place earlier this year. It's really an extraordinary amp. Absolutely the most dynamic solid state headphone amplifier I've ever heard, but it also images and stages well and is very resolving. At this point, I feel very content "retiring" from solid state amps with the BHA. My only complaint is that it isn't quite powerful enough for my AKG K1000. I'm pretty sure I was getting the amp to distort with that pair of headphones, but I guess that's what a Dynahi or CFA3 is for.

jcn3 · « **Reply #1312 on:** 9 Jun 2022, 08:56 pm »

Quote from: vlach on 7 Jun 2022, 09:17 pm

I'm surprised you didn't have any problems, the product description clearly states that pin 3 is grounded. A few posts back Mike from Bryston issued a warning to float pin 3 if using the rear XLR outputs for SE applications. Anyway, i'm glad nothing happened to your amp!

It turns out every XLR to RCA adapter i've looked up has pin 3 grounded. I'm not taking any chances, i will cut off the connection between pins 1&3 just to be safe.

On an unrelated note, I found different circuit topologies when doing a search, notice the four large capacitors in the attached photo? This is different than the photos a few posts back showing the amps on the test bench at the factory, I wonder when this change happened...

can you find mike's post and put in the link? i did several searches and couldn't find it.

vlach · « **Reply #1313 on:** 9 Jun 2022, 08:59 pm »

https://www.audiocircle.com/index.php?topic=170919.msg1809376#msg1809376

Pin 3 on the XLR outputs is an active high current amplifier output, and should not be grounded. Many adaptors will short pins 1 and 3 together to maintain compatibility with transformer balanced sources, and in most cases, as with our preamps, this won’t cause an issues. However, with the BHA1 it is important to float pin 3 instead. Assuming the XLR can be unscrewed, it should be simple to do this on an already assembled adaptor.

jcn3 · « **Reply #1314 on:** 14 Jun 2022, 03:54 pm »

Quote from: vlach on 9 Jun 2022, 08:59 pm

https://www.audiocircle.com/index.php?topic=170919.msg1809376#msg1809376

Pin 3 on the XLR outputs is an active high current amplifier output, and should not be grounded. Many adaptors will short pins 1 and 3 together to maintain compatibility with transformer balanced sources, and in most cases, as with our preamps, this won’t cause an issues. However, with the BHA1 it is important to float pin 3 instead. Assuming the XLR can be unscrewed, it should be simple to do this on an already assembled adaptor.

thanks! good to know!

rob80b · « **Reply #1315 on:** 16 Jun 2022, 06:37 pm »

Quote from: vlach on 7 Jun 2022, 09:17 pm

.............
On an unrelated note, I found different circuit topologies when doing a search, notice the four large capacitors in the attached photo? This is different than the photos a few posts back showing the amps on the test bench at the factory, I wonder when this change happened...

Early prototype....also notice the array of male XLR's for the headphone outputs....dah

vlach · « **Reply #1316 on:** 16 Jun 2022, 07:08 pm »

Interesting, i didn't notice the male XLRs...the photo was taken by Ken Rockwell at the 2012 CES show.

R. Daneel · « **Reply #1317 on:** 17 Jun 2022, 09:41 am »

Hi!

The male XLR connectors are optional, it doesn't mean the specimen shown was a prototype. I don't know if this option is still available though. At one point you could also have locking XLR connectors.

As for the balanced preamp outputs and converting them to single-ended, I must say fellas, this is one of the more interesting things I've recently read on AC!

Cheers!
Antun

vlach · « **Reply #1318 on:** 17 Jun 2022, 06:28 pm »

It is interesting indeed. I just completed this little project using this XLR to RCA adapter which was easy to open and cut off the connection between pins 1&3.

I figure why not use the free line stage that comes included with the amp. Now the preamp section is driving the power amp section of my vintage Yamaha CR-2020 receiver which is driving my HD800 (balanced) via the speaker taps and i must say, it is a significant step up; full bodied, rich, smooth, effortless. Gravity is lower. Mass is higher.

I kick myself for not doing this years ago!!!

Total cost: $15

R. Daneel · « **Reply #1319 on:** 18 Jun 2022, 10:04 am »

Quote from: vlach on 17 Jun 2022, 06:28 pm

It is interesting indeed. I just completed this little project using this XLR to RCA adapter which was easy to open and cut off the connection between pins 1&3.

I figure why not use the free line stage that comes included with the amp. Now the preamp section is driving the power amp section of my vintage Yamaha CR-2020 receiver which is driving my HD800 (balanced) via the speaker taps and i must say, it is a significant step up; full bodied, rich, smooth, effortless. Gravity is lower. Mass is higher.

I kick myself for not doing this years ago!!!

Total cost: $15

Interesting how you connected that!

Also interesting how you described it - Gravity is lower, Mass is higher!

Cheers,
Antun