The 'krmathis' β22 and σ22 Group Build Edition
Nov 25, 2008 at 5:11 PM Thread Starter Post #1 of 122

krmathis

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Dear fellow Head-Fi'ers,
Today is the day that I can announce the arrival of the β22 and σ22, which the community so gracefully have funded, built, and donated to me.
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For those who are not familiar with the history it began back in July when I mentioned in one of the β22 threads that I was really interested in a β22, and were looking for someone to build me one. As I am not into DIY myself.
I found no builder, until a few days later our fellow 'amphead' (Ron) started the http://www.head-fi.org/forums/f6/let...beta22-343869/ thread. Where he volunteered to build one full amplifier, labour only, and asked if someone else would contribute. Mr. β22 himself, Ti, joined the build team, and with the help of a lot of kind Head-Fi'ers it all became real. Fast forward four months (read more) and here we are.
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I am really grateful to all of you who have made this possible. By donating money, parts, build time, moral support, ... to the project.
Its hard to put my exact feelings into words, so for now I will keep it short.

04BluMach, aaron313, Afrikane, Akabeth, amb, amphead, Beefy, Blutarsky, cAsE sEnSiTiVe, Cool_Torpedo, dBel84, digger945, DoubleEs, error401, fatcat28037, fordgtlover, gates_2, GeWa, gz76, HeadphoneAddict, Headroom, JamesL, Jrossel, Jude, Lynxkcg, malldian, mark_h, MASantos, MisterX, MrMajestic2, mwofsi, n_maher, naamanf, NJ Head-Fi Meet, NoPants, nor_spoon, omegaman, pabbi1, penger, Ricey20, rockcod, ruZZ.il, samgotit, scompton, synaesthetic, tomb, torjeh, Uncle Erik, VeipaCray, Voltron, wavoman, wnmnkh, and I am sure others (have me excused)...
With a special note to 'amphead' (Ron) and 'amb' (Ti)!

[size=x-large]Thank you all ! ! ![/size]


Cheers!
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krmathis_black-white.jpg
 
Nov 25, 2008 at 5:12 PM Post #3 of 122

krmathis

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[size=medium]Unboxing, hooking up, fire up and first listen:[/size]

The amplifier was carefully unwrapped, inspected, and hooked up. Plugged in the power cable, flipped the main power switch in the back, then moved over to the front. Double checked everything, sitting there nervously. Then I pushed the front power button and was welcomed by several blue lights. It fired right up!

Let it run for a couple of minutes to stabilize, then turned off. Hooked up the Isabellina as source and the K1000, and turned it back On. Time to play some music... One "Play" button and volume adjustment later I was enjoying some music. It sounds effortless, dynamic, ..., but I won't go into details just now.

I have promised to post a lot of pictures, and of course write impressions.
Some pictures will follow shortly, while impressions will have to wait until I have spent some days with the amplifier.


[size=medium]Facts and technical information:[/size]

Some facts and technical information about this β22 and σ22:
  1. Four board β22 (fully balanced amplifier)
  2. Two board σ22 (power supply)
  3. Dual Par-Metal 20 series cases (12x12x3 inch) of clear anodize aluminum
  4. Front and rear panels of 6mm aluminum, prepared by Front Panel Express
  5. Balanced (XLR) and unbalanced (RCA) inputs
  6. 1x 4-pin XLR (balanced), 2x 3-pin XLR (balanced), 2x 6.5mm TRS (unbalanced), and speaker outputs
  7. 24 step stepped attenuator
  8. Blue LED's to light up the volume control, power button, and the cases

Its a well designed, crafted and put together amplifier. A pleasure for the eyes and ears.
smile.gif



[size=medium]Impressions:[/size]

I have now spend three days with the β22, and feel its time to share some impressions.
The β22 have been hooked up to the following gear:
  1. Transport -> Apple MacBook Pro and AirPort Express (Apple Lossless)
  2. DAC -> Red Wine Audio Isabellina
  3. Transformer -> Stax SRD-7 Pro (for the Stax'en)
  4. Headphones -> AKG K1000 and Stax SR-007BL

β22 -> K1000:
The first album to be played were Nils Lofgren "Acoustic Live". An album which usually make the K1000 shine, with their large and detailed sound stage, and ability to recreate details. The β22 make them shine, not unlike my RWA Signature 30.2. Its detailed, spacious, accurate, natural sounding, and it seems to have quite some power reserves. Holding the K1000 under strict control.
During the days I have listened to all kind of music. Øystein Sevåg, Katie Melua, Massive Attack, Pink Floyd, Ole Edvard Antonsen, .. to name a few. Where it has done a stunning job delivering warm, magic music that in some way draw you in.

Yesterday I did a quick β22 <-> Signature 30.2 comparison, and have to say they are both top-notch performers. The β22 have more power resources and can hence hold the K1000 under stricter control, while the Signature 30.2 have a little bit more details. Small nuances, nothing major I would say.

The β22 are simply a great match for the K1000.
k1000smile.gif



β22 -> SRD-7 Pro -> SR-007BL:
This morning I disconnected the K1000, and hooked up the SRD-7 Pro for some Stax love. My bellowed SR-007BL to be exact.
As I have felt in earlier attempts, the speaker amplifier -> transformer (SRD-7 Pro) route is not the ideal way to drive these 'phones. Compared to direct driven amplifiers that is (like the SRM-007t). The same story today, sadly. Probably because the transformers in the SRD-7 Pro come short handling the power.

Ok, they sound quite nice and all. But lack some of the micro-details I know the SRM-007t are able to deliver, which to your information the Signature 30.2 can't deliver either. The β22 show that is has some power reserves, and are able to bring out quite a bass punch and control of the SR-007BL. But without the micro-details, sound stage, .. its not all that enjoyable.
A quick switch to the SR-404 pretty much verify the same.



Summary:
The β22 are indeed a stunning amplifier. Great match for the K1000, with its details, sound stage and power reserves.
It come a bit short with the Stax'en. But then again, its an amplifier for dynamic headphones/speakers, and not electrostatic headphones. So I wont use that against it.


Thanks again to everyone involved!
...and please drop by for a listen if you're around my area.
tongue_smile.gif
 
Nov 25, 2008 at 5:26 PM Post #4 of 122

subtle

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Congratulations krmathis! That support from the community really is something special.

Take your time and enjoy those first few days with the amp. I'm looking forward to the pictures and impressions.
 
Nov 25, 2008 at 5:51 PM Post #6 of 122

vcoheda

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wow!

amazing generosity from head-fiers. congrats!
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Nov 25, 2008 at 6:00 PM Post #7 of 122

mikeymad

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Very cool story.. and enjoy.....

..... and post lots of pretty pictures....

Cheers,
 
Nov 25, 2008 at 6:05 PM Post #8 of 122

2deadeyes

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Kai, congratulations! That is one slick looking stack! I'm not too surprised as HF is well known for this kind generosity.
 
Nov 25, 2008 at 6:06 PM Post #9 of 122

pabbi1

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We should have made him keep it under the tree for another month...
very_evil_smiley.gif


But, a great ending to a great story - enjoy.
 
Nov 25, 2008 at 6:10 PM Post #12 of 122

moogoob

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This story made me "Awwww..."
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Especially the label.
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Nov 25, 2008 at 6:10 PM Post #13 of 122

Orcin

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Wow, what a beautiful amp!
 
Nov 25, 2008 at 6:14 PM Post #15 of 122

Voltron

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Glad the beauties arrived safe and sounding great! Amphead and AMB and all the rest did a fantastic job on it and I hope you enjoy it for years to come.

Cheers!
 

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