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For Sale: β22 "beta22" 2-channel Headphone Amplifier - Newly Built

post #1 of 7
Thread Starter 
This Classified is Closed

For Sale:
β22 "beta22" 2-channel Headphone Amplifier - Newly Built

Will Ship To: CONUS

UPDATE:  The new price is as low as I'll go on this.   BTW I'm finishing up another unit identical to this one except it will have a genuine NOS Alps RK40 "Black Beauty" pot instead of the RK27 "Blue Velvet" that this one has.  The to-be-finished unit w/RK40 pot will be listed $75 above this one.  Having listened to the "sound" of the pots I can't tell a difference, certainly not one that'd survive A/B/X testing.  But some like fancy pots. 


Offered is a new 2-channel stereo β22 headphone amplifier built by me. It uses a σ22 ("sigma 22") power supply, comes complete as shown, works perfectly, is fully tested and adjusted to recommended specifications.  


Thick, heavy, solid aluminum high-quality enclosures with good ventilation. Each case is approx. 8 3/8" W x 3" H (w/feet) x 10 1/2" D (w/jacks) - allow 12" min depth w/plugs connected. They're height stacked is approx. 5 3/4" and combined weight is about 13 lbs. Can be used sided by side as well.
This represents a robust single ended/passive ground β22 build in a most compact size.  Features:


* Two AMB β22 channel amplifier boards using standard BoM components mounted to over-sized external heat-sinks.  Unlike most β22s, this implementation barely gets warm in operation & most heat is external to case.  This serves to extend expected electrical component life.

* Custom front-panel integration board with Apls "Blue" RK27 volume pot, Zobel network, 1/4" jack and AMB ε12 ("epsilon 12") turn-on delay muting and DC offset protection. An important feature to guard against headphone damage due to malfunction or misbehaved input source.

* PS to Amp umbilical cord has secure threaded collar DIN plugs & connectors.  Gold RCA jacks for INPUT & LOOP OUT.  High-quality solid aluminum volume knob. Gain is 5X which is the "best" general gain setting.

* Amp's front panel LED lights at output (ε12 relay) latch. Newer AnTek transformer has an enhanced wrap & "static shield" connection to ground.

* Full 30-day Warranty from date of purchase for original purchaser covering defects in material or workmanship (purchaser responsible for ALL shipping & insurance costs).  Repairs available after warranty period on a time/material cost basis.


Available for local audition & pickup. CONUS only & price is firm with me covering Paypal fees and buyer all shipping & insurance costs. Will ship well-packaged within 3 business days of cleared payment.


I'm an experienced/established builder with a dozen or so DIY amp builds, four of which have been β22s.  See my feedback, examples:


"Chris sets a new, high standard for online sellers! He's the most meticulous, reliable seller you can imagine. His packaging and description of the unit were superb. A true gentleman and pleasure from start to finish. Great transaction. Love the B22!!!"


"I am the proud new owner of cfcubed's GORGEOUS beta22, and feeling like I just got the steal of a century. It's a unbelievable piece. Needless to say, the transaction was easy, and he's the chillest dude ever. One of my new favorite head-fiers!"


"Another great buying experience with cfcubed. The amp is built like a tank and sounds great. He patiently explained lots of things to help me understand the amp. Just to clarify, he built this amp for himself and not meant to sell, but I robbed him of it."

Edited by cfcubed - 10/26/13 at 9:10am
post #2 of 7

This is a gorgeous build.

It's so rare to see people do off-board heatsink with B22 because it's so much more difficult and adds so much more labor and part costs.

Since it runs cool, why not double the idle current to 300mA on it so that it can output as much Class-A current/power as balanced ones. I'm sure those heatsinks will be able to handle those extra heat just fine. As will the heatsinks in the PSU. Only question is does your transfo have enough juice.

post #3 of 7
Thread Starter 

You have a good point & the transformer can handle higher quiescent current than the recommended (120mA-160mA), its presently set to 150ma.

IIRC Ti related that at this setting the amp should stay in class A for most or all cans driven to human volumes (if I find the ref I'll post it).

But if the buyer would like the amp biased higher for some reason I'd have no problem doing that.

post #4 of 7

beautiful build, inside and out.  great price too.

post #5 of 7
Thread Starter 

Thanks Corey.  And I forgot to thank e1965- for his nice words as well:)

post #6 of 7
Can't believe this is still here. One of the best amp ever....
post #7 of 7
Thread Starter 

Thanks man.  Whether you're talking about the β22 in general OR my particular build here I agree:)


There's a lot of opinion around here, and I mostly steer clear of it, but here goes...  There's a line of expenditure in a dynamic can setup ($2k total or so?) that one should think twice about crossing, better to jump to electrostatic (at many time the price, hard to justify for me personally).  I've built & heard a lot of setups including balanced ones, my own & those at meets, and for me HE-500s + 2-channel β22 is my endgame (tho LCD-2s are another option).  And that's why I've built these amps.  To provide a robust, compact 2-channel β22, w/ε12 & warranty, at very reasonable cost.


N.B.  Have seen others' opinions on amb's M³ vs β22 and owning both here's mine:  A nicely built/outfitted, perhaps higher biased M³ may approach β22 level but will not reach it.  Though I do agree M³ is a lot of amp for the $$$ and perhaps preferred for cans that could use a bit of taming of their highs (T1s, HD800) OR for some that'd make use of M³'s bass boost option.

Edited by cfcubed - 10/27/13 at 5:16am
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