The β22 is done! Pictures on page 5
Dec 3, 2008 at 8:34 PM Post #16 of 101
compuryan,
stuffing boards is the easy part. chassis work requires careful patience and component layout is critical. plan, plan, and plan some more again. i would read the B22 thread at Headwize more than once.

good luck. i hope you enjoy what should be a very rewarding project.
 
Dec 8, 2008 at 9:23 PM Post #17 of 101
Dec 8, 2008 at 9:51 PM Post #18 of 101
Quote:

Originally Posted by compuryan /img/forum/go_quote.gif
After doing some research, I don't think ALPS makes a balanced version of the RK27, which means the ones on ebay are fakes.


I'm quite sure they make one.
http://avpg2.homepage.t-online.de/PDF/RK27114_5KDX4.PDF
Which means you're wrong.
smily_headphones1.gif
 
Dec 8, 2008 at 10:11 PM Post #19 of 101
crap I hate when I'm wrong. but thank you for clarifying. I just found another option which I think is even better. Michael Percy Audio still sells balanced versions of the Alps Black Beauty for $39. This discontinued Alps model is superior to the blue velvet and only costs a little bit more. I'm going for it.
 
Dec 8, 2008 at 10:11 PM Post #20 of 101
alps rk27 datasheet from mouser, top of the third page. I did a little research before I bought mine. Mine from ebay appear legit, solid build. I've yet to test more than one channel per pot tho. edit: but n_maher beat me to it, o well
 
Dec 8, 2008 at 10:20 PM Post #21 of 101
Quote:

Originally Posted by compuryan /img/forum/go_quote.gif
crap I hate when I'm wrong. but thank you for clarifying. I just found another option which I think is even better. Michael Percy Audio still sells balanced versions of the Alps Black Beauty for $39. This discontinued Alps model is superior to the blue velvet and only costs a little bit more. I'm going for it.


If this (50K/100K/250K balance controls… $39.00) is what you are referring to in Percy's catalog, that isn't a 4 deck (balanced) pot. It is a balance control (L-R channel balance).
 
Dec 9, 2008 at 3:16 AM Post #22 of 101
Quote:

Originally Posted by Pars /img/forum/go_quote.gif
If this (50K/100K/250K balance controls… $39.00) is what you are referring to in Percy's catalog, that isn't a 4 deck (balanced) pot. It is a balance control (L-R channel balance).


I emailed him and he replied telling me just that. Well, I guess I'm going for the balanced RK27 from ebay.
 
Dec 9, 2008 at 3:58 AM Post #23 of 101
Quote:

Originally Posted by compuryan /img/forum/go_quote.gif
crap I hate when I'm wrong. but thank you for clarifying. I just found another option which I think is even better. Michael Percy Audio still sells balanced versions of the Alps Black Beauty for $39. This discontinued Alps model is superior to the blue velvet and only costs a little bit more. I'm going for it.


You're back to hating it again. There's never been a balanced/4-gang RK40, at least not from the factory. I have seen one, but it was a complete custom job and required 2 RK 40s.
 
Dec 12, 2008 at 5:09 AM Post #24 of 101
I came up with an idea today for what to use as an umbilical cord to connect the separate power and amp boxes. I have lots of good condition computer power cords (IEC on one end and AC plug on the other) at my house. There need to be four separate wires going from chassis to chassis so if I used two cords (not using the ground pin on the cords) it would be perfect. I would install IEC outlets on the sig22 chassis and a simple AC-style outlet on the b22 chassis, and the DC current would flow through the wires in the computer cords from power supply to amp.

It would make things simple, and it'd be really cheap. I think it'd be just fine, am I right?
 
Dec 12, 2008 at 6:06 AM Post #25 of 101
I have no doubt it will work, but I would never do it. If you ever mess up and route AC from your wall backwards thru your sigma, you're going to #%$@ a brick.

One way to save on DC connectors is to make the umbilical from the sigma permanent, i.e. soldered in, and then you only need one 4pin connector for your B22. I remember someone else having a thread up asking about viable 4 pin connectors a few months ago.
 
Dec 12, 2008 at 6:27 AM Post #26 of 101
It's a very bad idea to (mis)use connectors/plugs which are customary for other purposes. In this case, you're talking about AC mains voltages, and someone is going to make a mistake and plug it in the wall outlet. Ouch.

I like the Amphenol circular connectors that I used on my build. It's very rugged, has a locking collar so it can't be pulled out by accident, has a high current rating, and could never be accidentally connected to anything wrong. They are fairly expensive, but we're talking about a β22 and σ22 here, so the connectors are a small percentage of the total cost. To save a few dollars on this seems to be silly.

P.S. You'd also be amused how these Amphenol connectors would impress people, too. I've brought my β22 and dynahi amps to many meets and I always get asked about those connectors.
 
Dec 12, 2008 at 8:38 AM Post #27 of 101
Quote:

Originally Posted by n_maher /img/forum/go_quote.gif
The words "keep costs down" and "balanced beta22" really don't belong in the same conversation. As you will undoubtedly discover (and may have already) populating the pcbs may account for as little as 50% of the total project cost and with this build most certainly less than half the time investment.


truer words were never spoken. If you're on a budget (anything less than a grand) the B22 is probably a bad choice.
 
Dec 12, 2008 at 9:37 PM Post #28 of 101
I guess better safe than sorry when it comes to connectors. It would really suck if someone tried to plug it into the wall. Wiring it to the power supply sounds like a good idea. It'll be less connectors to deal with.
 
Dec 31, 2008 at 11:14 PM Post #29 of 101
Aright guys, things are going really really well. I am almost finished filling the boards and have already started getting the chassis stuff together.

One question though: Does the polarity of the LEDs matter (I think it does) because I can't seem to figure out which way they go in, there is no clear indicator on the boards of which is + and - for any of the LEDs. Maybe I am missing something obvious. Thanks!
 
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