[Hottuna_]

Well my balanced build is all wired up and making very awesome music.

I was expecting a large improvement but was still blown away by it. My HD650 is singing like it has never sang before.
I do not have any point of reference to compare it to other high end amps but all I can say is that it sounds absolutely incredible.

Things that struck me immediately:
Very impressive soundstage.
The HD650 has strong bass, boomy at times but with this amp the bass it very controlled, iron-fisted control and it goes deeper than ever before.
Increased impact/detail of the music. The HD650 by most accounts is a laid back/veiled phone but its certainly more lively now.
I can listen to it at lower levels and not lose detail which is excellent for longer listening sessions.
It does run rather hot, biased the B22 to 100mA to keep temps down but I reckon I will refrain from using it during the hotter days. (it is summer now in Australia and it can get pretty damn hot down here in Melbourne)

I would like to express my thanks to johnwmclean for his advice and many tips that helped me along the way for both this B22 build and my earlier Buffalo32s build.
AMB for having put in the time and effort designing and supporting the design.
Linuxworks for suggesting what turned out to be the silver bullet in debugging my one dodgy board.
And ofcourse the Head-fi community for causing much grief to my wallet!

 

[johnwmclean]

Thanks Hottuna_, welcome to the Beta22 club!

 

[nattonrice]

Even better welcome to the Aussie B22 club!
There seem to be a fair few of us that built one =)

 

[fishski13]

Hottuna,
congrats! yes, it's a wonderful amp.

i think there is 2 B22 owners here in Minnesota =).

 

[qusp]

hmmm i'm paused on the buy button for some PCBs, wont be ages till I collect all parts as I've recently blown some serious money on source and cans. i'm still undecided TBH even though I know the rep and have experienced the wonderful sound of the B22. reason i'm paused is I mostly listen to my JH13 even at home and my plan is to add discrete buffers to the transformer output of my new sabre (ackodac) and drive my cans directly as I have with my buff; but I really would like to build a B22


so come on aussies; talk another one into the fold

 

[Possede]

I've had this built for a while, but have been enjoying it too much to take it apart and take pictures. I started this build in July 2009, and finished it mid December. It has definitely been a great learning experience as this was my first time attempting something of this magnitude. I have to take my hat off to Ti, as without him none of this would have been possible. And many thanks to everyone else who has chipped in along the way when I have stumbled into bother. I apologise for the following pictures but I am less than competent with a camera:

In total I spent around £850. I can now appreciate it when people say that this is an expensive project! The only annoying thing that cropped up was that the data sheet for the Neutrik NCJ6FI-V detailed the required holes as 3.2mm, so from that I ordered the front panel to have M3 countersunk holes to support the Neutrik connector. It was only when putting everything together that I realised that M3 screws are too large, so now I'm using M2 screws in a M3 countersunk cavity.

Apart from that everything went smoothly! Time to go back to listening...

 

[adamus]

looks f'ing great.

Where are you based. I need me a listen of a b22

 

[Possede]

Quote:

Originally Posted by adamus /img/forum/go_quote.gif looks f'ing great. Where are you based. I need me a listen of a b22

Cheers. I'm from Scotland, United Kingdom.

 

[johnwmclean]

Possédé, beautiful build - congrats.

 

[nattonrice]

Very nicely done!

Only thing that may be of concern is the ventilation.
The s22 box is most likely fine but the b22 may be operating very (!) hot.

 

[johnwmclean]

Quote:

Originally Posted by nattonrice /img/forum/go_quote.gif Very nicely done! Only thing that may be of concern is the ventilation. The s22 box is most likely fine but the b22 may be operating very (!) hot.

hehehe it’s a scottish Beta22 - I reckon it’d be fine

 

[Possede]

Thanks for the kind comments.

nattonrice, I have biased the quiescent current at ~100mA to try and bring the temperature down. The case does get warm, hopefully it doesn't overheat. I was wondering, does increasing/decreasing the quiescent current affect the sound quality?

 

[amb]

MOSFETs like to be biased heavily to sound their best, but on the β22, cascoding linearizes the effective transfer curve so it is not required to go crazy with biasing. That said, the higher the quiescent current, the more deeply in class A the amp operates in, which means that it would remain in class A even when asked to deliver a large swinging signal into a low impedance load.

 

[linuxworks]

latest take on my reconvert-a-case(tm) for my b22:

I had some wooden end panels cut to slightly larger than the raw metal chassis dimensions. I'm going to see if I like this look or not. certainly better than *nothing* on the ends

some kind of hard wood at the lumberyard, then cut to size and beveled on the edges with a router. I took the boards home, gave them one coat of stain and attached them to the metal with wood screws thru holes in the edge of the metal frame.

I have some smoked plexiglass for the top panel but it does not have vent holes cut yet. not sure I'll use the plexiglass or something else (metal perf screening, maybe?)

also you'll have to forgive the rat shack knob

I have nothing that is of that size and all the smaller ones I have look worse on a box this box. need to get something 1.5" or even larger, and in black metal.

 

[fishski13]

Possede,
i'll second Adamus and say that looks f'ing great. i love the simple aesthetic. congrats!!! enjoy the tunes!!!