[FritzS]

The ALPS RK27, according to some person who posted on here, is an unworthy volume control. I say BS. So many high end amps use it.

Hardly anyone uses TDK Potentiometer https://www.hificollective.co.uk/potentiometers/tkd-potentiometer.html
Noble Potentiometer - DISCONTINUED https://www.hificollective.co.uk/potentiometers/noble-potentiometers.html
Penny & Giles Rotary Fader RF11, RF15 / Potentiometer? DISCONTINUED? https://www.head-fi.org/threads/goo...ce-about-penny-giles-rf11-rf15-series.110451/
(I didn't buy these at the time)

 

[FritzS]

Haven't kept abreast of all the newer technology but looks like SMT is the current de facto.
I remember when Bryston released their BHA1 head-amp and it was one of their first components with surface mounted components, wasn't convinced on the longevity but so far no issues after 10 years.
.......

BHA1
https://bryston.com/amplifiers/bha1/

But for what is the single blue electrolytic cap at each of the four power stages? Cap in series to output?

 

[FritzS]

The inside of the Score One from a different perspective

.....


NOMAX

PS.lol

Here are only two power stages - or am I mistaken - for fully balanced four needed
XLR - use balanced to single converter?
IC probably DC offset correcter
Relay at output for protection

 

[Rob80b]

BHA1
https://bryston.com/amplifiers/bha1/


But for what is the single blue electrolytic cap at each of the four power stages? Cap in series to output?

Good question….I'm not an electrical engineer but looks like it may be implemented after the bias... noise reduction?, fully block DC on power up?
Schematics.
https://bryston.com/wp-content/uploads/2020/06/300028BHA1.pdf

Could ask over at…
https://www.audiocircle.com/index.php?topic=104028.1240

 

[FritzS]

Good question….I'm not an electrical engineer but looks like it may be implemented after the bias... noise reduction?, fully block DC on power up?
Schematics.
https://bryston.com/wp-content/uploads/2020/06/300028BHA1.pdf

Could ask over at…
https://www.audiocircle.com/index.php?topic=104028.1240

The 4700µF electrolytic cap are in series to the output and protect headphones from DC.
It looks like these are bi-polar (non-polar, uni-polar) electrolytic capacitors, drawn in schema + --||-- +

 

[Rob80b]

The 4700µF electrolytic cap are in series to the output and protect headphones from DC.
It looks like these are bi-polar (non-polar, uni-polar) electrolytic capacitors, drawn in schema + --||-- +

Thanks, I saw that after looking a little closer. The caps in question are marked 6.3 volts.

 

[Rob80b]

But for what is the single blue electrolytic cap

Hi Fritz....I've sent an inquiring addressed to James Tanner over in the AudioCircle.......
https://www.audiocircle.com/index.php?topic=104028.msg1965954#msg1965954

Believe Stuart Taylor had a hand in the original design...
https://www.soundstageglobal.com/in...ntent&view=article&id=172&catid=71&Itemid=195

 

[Rob80b]

Hi Fritz....I've sent an inquiring addressed to James Tanner

This is why one loves a company, when the CEO gets back to you ASAP on a Sunday morning
"Hi Robert - email Mike on that - mpickett@bryston.com"
So I'll email Mike on Monday. : )

 

[FritzS]

@Rob80b
Thanks!
Years ago it was common practice for DC protection to install capacitors in series with the output. At that time, high audio grade bi-polar capacitors were still being produced - e.g. by Jelmax BlackGate or by Elna and other top manufacturers. Jelmax no longer exists, high audio grade bi-polar electrolytic capacitors are hardly produced anymore.
Today a servo circuit is used to keep the DC offset low. In addition, a protective circuit with a relay is often installed at the output of the amplifier, which disconnects the headphones (or loudspeakers) from the amplifier in the event of a fault.

 

[Rob80b]

Years ago it was common practice for DC protection to install capacitors in series with the output.

A lot of Bryston is tried and true old school, they also get a lot of their components made specifically to their specifications. So who knows. : )

 

[Rob80b]

Now back to the Composer.....
I was doing some early morning listen to the BBC3 live vocal works and went through the HD800S, HD660S2 and the AKG K872s.
With regards to imaging and definition, the S2 was the most diffused, the HD800S was not bad but the K872 had the sharper better outlined presentation, a more "you are there".
Curious if AA have retained some of this clarity in the Composer?

 

[FritzS]

A lot of Bryston is tried and true old school, they also get a lot of their components made specifically to their specifications. So who knows. : )

I read about Bryston's circuit ideas in AES Papers at a time when there was no Internet. I still have some AES Convention preprints lying around somewhere.
At that time, orders were ordered by post and paid for by international bank transfer.

 

[FritzS]

Now back to the Composer.....
I was doing some early morning listen to the BBC3 live vocal works and went through the HD800S, HD660S2 and the AKG K872s.
With regards to imaging and definition, the S2 was the most diffused, the HD800S was not bad but the K872 had the sharper better outlined presentation, a more "you are there".
Curious if AA have retained some of this clarity in the Composer?

K872 wasn't my thing, I like K812 with the mesh from K872 better.
Strange that my DT1990 can hold its own so bravely with analytic pads, sometimes overtaking the K812.
I listen alternately (depending on my mood) with Composer or DT1990.
With the analytic pads, the DT1990 has a slight “hump” in the mid-bass range, which makes it sound a touch warmer than Composer (“dead straight frequency response” in this range).
The ~8kHz Beyer peak is noticeable in around 20% of my music on the DT1990. Only a slight reduction helps, -5dB at 8kHz is enough.
Composer has no problem with these pieces of music!

 

[xxx1313]

Now back to the Composer.....
I was doing some early morning listen to the BBC3 live vocal works and went through the HD800S, HD660S2 and the AKG K872s.
With regards to imaging and definition, the S2 was the most diffused, the HD800S was not bad but the K872 had the sharper better outlined presentation, a more "you are there".
Curious if AA have retained some of this clarity in the Composer?

They did. Imho the general presentation of the Composer is closer to the K812 than to the K872 however, but without the sibilance of K812 and much improved in almost every respect.

 

[Rob80b]

K872 wasn't my thing, I like K812 with the mesh from K872 better.

There is the closed vs open to consider.

Strange that my DT1990 can hold its own so bravely with analytic pads, sometimes overtaking the K812.

DT1990 may be next on my list, have a tentative a buyer for my Neumann NDH30 so may be sooner than later.