[Iniamyen]

Well, I've continually felt like it's not *quite* ready for an official unveiling, but now it looks nice so I figured I'd post some pics of my Beta 22.

Single enclosure, SumR encapsulated transformer+s22+e22/B22, housed in a par-metal 16"x16"x4" alodine aluminum case, painted in Rustoleum "hammered black" =).

The only things I am still missing are a knob for the volume pot (RK27 at the moment) and some nice, big, rubbery feet =)

Initial impressions with Sennheiser HD600's (even though I've been listening to it for about 2 months now waiting to get it cased up): I'm amazed at the overall detail, to the point where it's incredibly obvious that I need to get a new source, even though the Alien DAC that I've been using up to this point has held its own. I'm even more amazed at the low-end detail that's been missing from everything else... from Joni Mitchell's "Carey" to Ayreons "The Shooting Company of Captain Frans B. Cocq"... The other thing I really notice is the attack of instruments such as piano, cymbal, guitar, even bass drum, which I would attribute to the slew rate of the B22 without knowing anything better to say about it

I am noticing some mid-freq hum at higher volumes, however, this is only with the Alien DAC attached as a source, so this may be due to my computer or the DAC itself. With no source attached, it's absolutely silent aside from some hiss at very high (read: unlistenable) volumes, which I am convinced is due to my choice of cost-conscious volume control.

The main thing I'm still planning on doing is adding an e12 unit in front of the e22 board (once I get one working), but until then this baby's working fine.

Many kudos to Ti Kan and the community! I may be the last guy to make one but as far as I'm concerned it's the best sounding one constructed yet

 

[krmathis]

Welcome to "Team β22"!

 

[compuryan]

Hey, do you hear any noise/hum with the transformer enclosed like that? I am debating putting all my β22 boards, sigma22 board, and transformer in a single chassis. But only if the transformer doesn't create interference.

EDIT: sorry I just read at the bottom of your post that the hiss/hum is minimal.

 

[digger945]

Well looky thair.
I bet that sounds sumpn perty dont it.

Totally dig the Mouser/Digikey shipping tags layin' on the carpet LOL, you a brotha fer sure.

You WILL let us know whatcha think, wont you?

 

[MoodySteve]

Very clean build.

Welcome to the ß22 family.

With some clear lacquer and elbow grease you could polish the front panel to a beautiful shine.

 

[Killercrush]

Nice build but what are those RCA outputs doing on the front panel ?!

 

[MoodySteve]

Preamp out, if I had to guess.

 

[GUINNE55]

So I thought I might be ready to start a project like this a year from now. How long did it take for you to put together and how much did it cost? If you don't mind me asking, I'm terribly jealous.

 

[amphead]

Very nice work! I especially like your layout, which is very clean.

 

[Mellow Mushroom]

merry christmas

 

[amb]

Quote:

Originally Posted by compuryan /img/forum/go_quote.gif Hey, do you hear any noise/hum with the transformer enclosed like that? I am debating putting all my β22 boards, sigma22 board, and transformer in a single chassis. But only if the transformer doesn't create interference.

That SumR transformer used in thus build is internally shielded, which helps to reduce magnetic fields. If you use an unshielded transformer, it would be very difficult to shield "after-the-fact". Even the internally-shielded transformer is not totally free of stray fields, so depending on how efficient your headphones are, you may or may not hear hum and buzz, but no doubt a noise floor spectrum analysis will show some spikes at the AC fundamental frequency and its harmonics.

If you could live with a 2-chassis solution, then that is the best way to prevent hum. There is nothing like sheer distance between the transformer and the amp boards.

 

[Iniamyen]

Yes, the RCA outputs on the front panel are for use as a preamp-out. I plan to hook them to the disconnectable solder tabs on the neutrik jack, so that when a headphone is in use, the pre-out is disabled (and vice-versa.) When I eventually get a Beta 24 built, I want to be able to use this as a preamp for it.

guinne55, looking back at all my past orders, it looks like I started the project around the end of July. So about 5 months is a good estimate. I'd rather not calculate exactly how much it all cost

but a good ballpark is probably $500.

amb is correct that a 2-chassis solution is ideal. However, I'm a true novice when it comes to casework so I wanted to keep that to a minimum. I was willing to pay for the fully shielded & encapsulated transformer to avoid this headache. The transformer was only around $100 with shipping and everything. Well worth it IMO. I don't believe the small amount of hum is the transformer anyway, because like I said it's present only with the DAC attached as source. I've yet to try it on other sources, however.

 

[wolf18t]

Welcome to the B22 club. I also used a shielded and potted transfo from SumR and no hum even with my 32ohm RS-1.

 

[Iniamyen]

Quote:

Originally Posted by wolf18t /img/forum/go_quote.gif Welcome to the B22 club. I also used a shielded and potted transfo from SumR and no hum even with my 32ohm RS-1.

Good to know, thanks. My results seem to agree with this. I tried some other "sources" (if you can even call them that) and it seems like stuff that's grounded to a wall socket gives some small amount of humming. The fact that it's not the same wall socket that the amp is on may be a clue, but I haven't tried switching that yet. Strangely enough, my 10-year-old portable CDP results in the blackest noise floor. I had it plugged into the same outlet, but it's not even grounded, so go figure.

I'll need to bring my older Senn's (HD497's) back from work and see if their lower impedance results in any more noise. I'm not too worried though.

 

[wolf18t]

Did you install a ground loop breaker? Ths could resolve this issue. It is very well documented on AMB website.