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Roll Call: Who's building, built, or thinking of building a beta22? - Page 132

post #1966 of 2890
11/11/09 at 3:31pm
Well mine is done and working great FWIW.
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post #1967 of 2890
11/12/09 at 12:06am
That looks great cfcubed- I love the price point you were able to hit with that build!

On that note my 3-ch is nearly complete as well. I'm listening to it for the first time right now! Sounds amazing...
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post #1968 of 2890
11/12/09 at 1:05am
Quote:
Originally Posted by cfcubed View Post
Well mine is done and working great FWIW.
any working B22 is a beautiful amp. i also prefer the minimalist aesthetic. excellent job on squeezing the components into a small package too. i guess considering your work on the CTH, compactness is your specialty .
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post #1969 of 2890
11/12/09 at 2:02am
Thanks guys. Yes, guess I wanted/enjoyed the challenge of building it on a low budget. Looking forward to comparing this to a "proper" 3-ch b22 this weekend.

@Anonanimal - It is a special time when you pwr up a new build & get to hear for the 1st time

@fishski13 - re:considering your work on the CTH, compactness is your specialty Guess I like that challenge too... Right up to the point of final assembly Then I start wondering why I keep doing these compact builds
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post #1970 of 2890
11/12/09 at 11:26am
Quote:
Originally Posted by cfcubed View Post
Well mine is done and working great FWIW.
Nice job! If I could make a suggestion it would be to add additional ventilation to both the top and bottom panels. As crowded as that is on the inside I think you'll want more airflow to keep things working happily in the long term.
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post #1971 of 2890
11/12/09 at 12:22pm
Quote:
Originally Posted by n_maher View Post
Nice job! If I could make a suggestion it would be to add additional ventilation to both the top and bottom panels. As crowded as that is on the inside I think you'll want more airflow to keep things working happily in the long term.
Thank you very much for this Nate.... I plan to let 'er heat up for an hour or two tonight w/a temp probe inserted into one of the rear panel 1/4" holes. Using a hand on the (thin) top it's seeming to only get warm after a couple hrs.

I'm loath to trying to match/expand the small hole pattern in the top, esp w/its extreme thinness. That's why I lined the bottom & back plates w/holes.

Perhaps you can give her a listen Saturday (& maybe CTH too), I'd appreciate your thoughts on them.



Notes:
  • Not a spec of hum detectable w/my most sensitive cans (D2000s). Update: Some hiss tho from 12 -> 4 pot volume (but not @ full volume) w/source muted, well above my listening levels.
  • W/R34 set to 55mV (~120ma) after 1 hr, drawing a bit less than 500ma from each wallwart. Of course they are in series w/center-tap = tip<->sleeve giving 26-0-26 (52VAC) under load.
  • Can see shielded cable where it matters (all input wiring, DPDT A/C switch wiring). 1st PS caps & heatsink positioning to further block A/C.
  • If I keep this PS arrangement will get cable wrap for 2 WW wires & install good 3-cond pwr jack + plug. Those jacks are the weakest physical link ATM.
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post #1972 of 2890
11/12/09 at 11:27pm
Finished 3-ch sitting on my desk making some sweet, sweet sounds.

It's dead silent (input muted) through a full volume sweep when stacked with the power supply, using shielded StarQuad on the input wiring. I used the standard output gain of 8.

I want to give a huge thanks to Amb and the rest of the community for all of the great projects and I look forward to what the future may bring!

Edit: Sorry the pictures are lame but my camera is old and I don't have a tripod...



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post #1973 of 2890
11/12/09 at 11:41pm
By golly, that’s a thing of beauty...
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post #1974 of 2890
11/12/09 at 11:46pm
Very excellent =]
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post #1975 of 2890
11/13/09 at 12:09am
@ Anonanimal very nice & neat build. Great that it sounds as good as it looks.
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post #1976 of 2890
11/13/09 at 1:43am
Thanks for the kind words! I know it's not very visually exciting but I was trying to keep it as subdued as I could- and I'm very partial to black vs silver. There's no external LEDs or anything like that- just a faint red glow from inside when it's powered on. I'll try to get a night shot of it when I have a bit more time.
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post #1977 of 2890
11/13/09 at 1:17pm
Quote:
Originally Posted by Anonanimal View Post
Finished 3-ch sitting on my desk making some sweet, sweet sounds.
Nice, clean build. Well done!
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post #1978 of 2890
11/14/09 at 5:21am
Very good job, of putting an excellent sounding amplifier together!
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post #1979 of 2890
11/17/09 at 2:12pm
Quick question about power switches. I am looking at this one: Switch The first question is about the current limit, which is 3A. I am not really sure how much a 3 ch. beta will draw driving only headphones. Also, in terms of the design, I am just making sure that latching means that I will press the button and the switch will maintain contact.

One more question: are there any decent potentiometers in the $40-60 range that are better than the Alps blue velvet? I have one on my CK2III and I would like something beter for the beta.
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post #1980 of 2890
11/17/09 at 2:32pm
Quote:
Originally Posted by tintin47 View Post
Quick question about power switches. I am looking at this one: Switch The first question is about the current limit, which is 3A. I am not really sure how much a 3 ch. beta will draw driving only headphones. Also, in terms of the design, I am just making sure that latching means that I will press the button and the switch will maintain contact.

One more question: are there any decent potentiometers in the $40-60 range that are better than the Alps blue velvet? I have one on my CK2III and I would like something beter for the beta.
The link for the switch doesn't work for me, but I assume it's one of the Bulgin vandal-resistant latching switches. Yes, 'latching' means that if you press it, it stays 'on' until you press it once more. 3A is more than enough for normal operation; where you may get into trouble is transformer inrush, where the transformer (briefly) pulls a relatively large amount of current when it's first energized. This can be minimized by using a thermistor or even a power resistor in line with the primary.

Regarding replacements for the RK27, there's the Noble AP25 (available on eBay), the TKD 2CP-2511 and the Audio Note Noble equivalent (both available at Parts Connexion). Allen-Bradley probably has some usable ones, though you'd have to look in industrial catalogs (they don't target audio).
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