Roll Call: Who's building, built, or thinking of building a beta22?
Jun 15, 2007 at 7:45 AM Thread Starter Post #1 of 3,218

Nebby

Headphoneus Supremus
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I've seen more than a few posts about the beta22 pop up recently, so I figure I'm not the only one getting ready to build one
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Post here if you're thinking of building one, currently building one, or already built one! If you already built one, pics and specs would be handy!

I'm planning on building one, but it seems my laundry list of wanted features will have to be pruned down a bit for practicality's sake. On a more positive note, I think I've figured out how to mount the six beta22 boards I have planned in a nice and efficient manner with bigger heatsinks
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Jun 15, 2007 at 8:22 AM Post #2 of 3,218
I've got a box of boards and parts, but haven't gotten around to it yet. I've got what I need to build a fully-balanced one, with four amp boards and two power supplies. I will get to it, but there's a tube amp I'm dying to build. And work has been keeping me late, as well. But I will build it, sooner or later.
 
Jun 15, 2007 at 2:26 PM Post #3 of 3,218
I will build one late this summer/early fall, but I have a couple of other amps to build first, both for education and experience. I find that the more experience I get, the better job I do, and I want the B22 to be done right. Also, I'd like to have some understanding of it while I build it.
 
Jun 15, 2007 at 2:28 PM Post #4 of 3,218
I'm currently in the ordering stages of building a B22 for my friend... Gonna try that jason tree relay-based attenuator- should be fun
 
Jun 15, 2007 at 2:45 PM Post #5 of 3,218
I've built two of them, both active ground using AMB's backplane. They sound awesome!

Pictures of my build are on AMB's gallery (which I can't link to for some reason). Here's an alternate link:
http://kklee.smugmug.com/gallery/2538766#142082532

I highly recommend reading through the build threads on Headwize. Even though the build is straight forward, the sheer number of parts involved makes it easy to make mistakes (and hard to troubleshoot).
 
Jun 15, 2007 at 2:52 PM Post #6 of 3,218
Still trying to finish my build- I'm about 90% finished.

I've taken the harder route...separate power supplies and transformers for each of the channels . Each amp and power supply is mounted directly on large off-board Conrad heatsinks.

I'm planning on using this amp for headphone and speaker use.
 
Jun 15, 2007 at 4:19 PM Post #7 of 3,218
I've started collecting parts, but I doubt I'll actually heat up a soldering iron for it within the next four months. There are a few other projects I need to finish first before tackling the β22. I spent a few hours last night reading through the AMB guide on it. It's definitely something I want to build.
 
Jun 15, 2007 at 4:20 PM Post #8 of 3,218
Quote:

Originally Posted by gmckay /img/forum/go_quote.gif
Still trying to finish my build- I'm about 90% finished.

I've taken the harder route...separate power supplies and transformers for each of the channels . Each amp and power supply is mounted directly on large off-board Conrad heatsinks.

I'm planning on using this amp for headphone and speaker use.



This is pretty much what I'm planning on doing, so I apologize in advance for asking so many questions. Are you using 4 channels? How did you mount the Conrad heatsinks, and which Conrad heatsink did you use? Also, which transformers did you use? Do you have any pictures of your current setup?

Thanks in advance for any questions you can answer
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Quote:

Originally Posted by gates_2 /img/forum/go_quote.gif
I'm currently in the ordering stages of building a B22 for my friend... Gonna try that jason tree relay-based attenuator- should be fun


are you talking about the Joshua Tree attenuator? I think I will be using that for my balanced pot, and standard pots for my SE outputs.
 
Jun 15, 2007 at 6:20 PM Post #10 of 3,218
My β22 amplifier is built as 3-channel active-ground configuration and is housed in an ATI-737U enclosure.
The β22 boards are mounted on a ε22 backplane board to reduce wirings and keep the internal of the amp tidy.
All electrolytic capacitors used on the amplifier boards are Black Gate Std. and the small values capacitors are MKT, MKP and polystyrene. Manganin 1% resistors (type PBH) are used at the output while Vishay-Dale RN55D resistors are used on the remaining part of the amp. All BJT’s are matched within 5%. The gain is set to 5. The volume control is an Alps RK40 "Black Beauty" and the 50mm knop from DACT.

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Jun 15, 2007 at 9:14 PM Post #13 of 3,218
I finished my balanced one earlier today (had to change the gain). Well, it's mostly done...I still don't have any knobs, lol. That's it, though. It's fully functional.

-edit- didn't see the joshua tree attenuator until after i built my pair of stepped attenuators. wish i had, though...it looks pretty cool (and would have helped with wiring a bit (no backplane board).
 
Jun 15, 2007 at 10:09 PM Post #14 of 3,218
I'm planning to build both the β22 and Millett Max, but have much on my plate to finish first though. My Dynalo is running and two Dynahi's are just about populated but have not been fired up yet. All three cases are just about done and are awaiting paint. I'm also in the process of looking for a house and selling mine, so DIY projects are on hold until the move is over.

However, I have ordered the Millett Max pcb and β22 backplane pcb, but not the other parts. Looking forward to hearing all 4 amps for a side-by-side comparison (hopefully near the end of the year)!

Dave...
 
Jun 15, 2007 at 10:22 PM Post #15 of 3,218
Quote:

Originally Posted by bryerd /img/forum/go_quote.gif
I'm planning to build both the ?22 and Millett Max, but have much on my plate to finish first though. My Dynalo is running and two Dynahi's are just about populated but have not been fired up yet. All three cases are just about done and are awaiting paint. I'm also in the process of looking for a house and selling mine, so DIY projects are on hold until the move is over.

However, I have ordered the Millett Max pcb and ?22 backplane pcb, but not the other parts. Looking forward to hearing all 4 amps for a side-by-side comparison (hopefully near the end of the year)!

Dave...



Yep, can you see the eyes?....he's got it, the sickness. With only 11 posts too, man you're hooked bad
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