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loop_

Beta22 (short review + pics)

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OK have found one free evening to post about this. pics first!

 

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Beta 22

Full info: http://www.amb.org/audio/beta22/

My build: PSU case is a hammond, Amp case from ati enclosures, Recommended parts were used (Panasonic FC capacitors throughout). Most 'boutique' component is the CT2 stepped attenuator, following which UPOCC copper wire from ahfartaudio was used throughout the amp, and the RCA sockets are neutrick

 

DIY info

 

ease of build

Pros: 1) uses PCBs 2) parts are easy to find 3) once assembled and powering fine, the adjustments which need to be made are relatively straightforward. 4) Most importantly, documentation is thorough and Amb has a thread where he'll answer all your questions

Cons: 1) all discrete design = high parts count. 2) 3 values need to be adjusted for each board. 3) This amp is very sensitive to temperature: quiescent current goes down when ambient temperature goes up. I tried to keep my amp as ventilated as much as possible and spent a day drilling holes. However, the temperature was still too hot for my liking so I just listen to the amp without the top cover now...4) have to be very careful when taking measurements: I shorted some parts while doing so and burnt them.

 

Case work

Pros: with the backplane, you don't need to drill that many holes for the base, and wiring is easy

Cons: 2 box solution recommended. Ventilation is necessary (this amp and psu runs hot!) so hole drilling is needed if your box is not punctured enough!

 

Sound

 

Setup used: Cambridge Audio Azur 540Cv2 - beta22 - HD600/HF-1

 

This amp needs about a good 10 minutes warm up before it starts sounding good, but as mentioned, once it gets too warm and the current starts to drop it sounds worse, so you have to be careful. Nevertheless, once you get the temperature right you get a nice sound.

 

Caveat: All diy amps sound a little different from each other, since they use different parts etc etc. So my description might not be true of the professionally made b22.

 

Basically, this is a quality amp, so in terms of detail, soundstage, it's all there. In terms of its character, I would describe the sound as warm, smooth, and laid back. It's not laid back in the sense that it sounds weak though: one thing about this amp is that you feel like there's alot of power driving the music. There is this sense of weight throughout the frequency range - bass is plentiful even for the HD600, and the mids and highs are very meaty. One might however feel that the highs don't extend enough because of its warm signature, and in terms of dynamics it won't please someone who likes a fast, light, zippy listen. This amp is about power, not speed. imho, having owned SS amps and tube amps, I think if someone is looking for the warmth of tube amps with the details of SS, this is one amp which must be considered.

 

I've tried to be as neutral as possible, and I think in terms of general character this is a good description, and the rest is really about component matching. To this extent I'd say that this amp should be paired with silver cables, and frankly, I don't think the HD600 is the best match. Too warm sometimes; I think low impedence phones like my hf1 sound better out of it, as they benefit especially from the high current this amp provides. I particularly liked it with my W1000 when I listened to it back home. I think that's a match made in heaven! Anyway I didn't bring it to my hostel because I fear wood cups getting scratched. Have a K701 on its way so we'll see how that works out!

 

**EDIT: After about 200++hours burn in, something just 'clicked' and this has become a real kickass amp. Previously I was not very happy with the overly warmish character, the slow speed, and the fact that everything seemed to come from just one distant point i.e. great soundstage, but separation was slightly lacking. Now, the soundstage is still very wide but the layers are becoming very apparent. I let my friend listen to it and before burn in, she had loved my other diy amp alot more than this one but when she heard it again a month later she noticed that the b22 is much better now because "you can tell the drums are further away from the vocalist". It has also become relatively brighter with burn in, and definitely faster, especially with the bass tightening up. It's now a really good match with my setup

 

I'd thought that as it didn't have capacitors in the signal path, and that I didn't use any boutique caps which have notoriously long burn-in, that burn-in wouldn't make any difference. I'm so wrong!

Edited by loop_

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Well done, man. The case work is so sweet too. Wow, I am speechless with the beauty of the build. It should sound good, it is supposed to be the "king" of the diy amps.

Edited by heady

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That wld be my next diy amp, in the future, hopefully. Haha. Working on my Ckk3 now.. It sure looks awesome man! :) Is it a S22 PSU inside the hammond?

 

Anyway, I wonder how much did you spent on the amp and psu in total, including cases?

Edited by ezzo

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It just makes me drool.....

 

I want one of these someday but somehow my room doesnt have space for such an amp.

 

One day.. one day.. drool.. drool...

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thanks for the compliments; it's really not hard to make this one look nice, with the backplane board sorting all the wiring for you...

 

This is the case I got: http://www.atiresearch-anodized.com/ATI-737U.html. it wasn't cheap can't remember but shipping alone was like 30usd, which was like 50% packaging go figure...Very nice case though

 

The psu is in the hammond as mentioned. Can get from farnell

 

 

Cost wise, I don't know because this thing was dragging on for like 4 months plus and I didn't take my accounts. But I would say at least 1000sg, probably cos of that silly DACT volume pot i'm using (250). Well, it's sounding nice though!

 

 

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But I would say at least 1000sg, probably cos of that silly DACT volume pot i'm using (250). Well, it's sounding nice though!

Ok, I knew the b22 was ex but I just got cured of my "lust" for it. :rclxub: Thanks loop_ for your help in curing me. :lol:

 

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heady, i teach you.

 

first just buy the pcbs and the parts you need from amb. that will be like 100plus US? then next month buy the casing, then after that other parts....won't feel it at all!

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heady, i teach you.

 

first just buy the pcbs and the parts you need from amb. that will be like 100plus US? then next month buy the casing, then after that other parts....won't feel it at all!

 

Sounds like credit card instalments. lol

 

:lol:

 

 

 

 

Edited by heady

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i just completed my b22 too.

i have recabled my hd600 with upocc cryo silver wires.

i also have the stock hd600 cables.

i agree with most of your points.

the speed of ss with the warmth of tube and also the temperature dependant part.

 

the thing i disagree is that the b22 dont extend high enough. i found that the warm signature is just nice. the sound it produces is also very emotional and musical.

 

btw my setup is iMod > b22 > hd600

it could be the source that's causing the difference.

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