[compuryan]

Well I've sold many things in my setup and am going to order a kit from Glass Jar Audio soon for the balanced beta22 and sigma22. Glass Jar Audio looks great, has anyone used their kits before?

Also, will a single S22 board with 100VA transformer be sufficient to power the B22? I might upgrade later to two S22 boards but I'd like to stick to one now to keep the cost down, if possible.

Lastly, what potentiometer do you recommend for a low-cost balanced volume control solution?

Thanks everyone

 

[n_maher]

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. So unless you're comfortable with a pricetag north of $1000 and pretty skilled at casework I'd really recommend thinking twice about this undertaking.

That said your least expensive decent attenuation option is pretty much limited to the 4-ch Alps Blue pot and the only source I can remember off hand is Ebay. I think it'll run you ~$60 to $75 shipped from Germany.

But again, before buying anything I'd research the heck out of chassis choices and see if you can make that part of the equation work.

 

[FallenAngel]

1) There was just a thread about kits from GlassJarAudio, search please, this was only a few days ago and it went a few pages long.

2) Read amb's pages about Simga22, you'll know quite well it is capable of powering 4 Beat22 boards, driving any headphone off a single Sigma22. For speakers (and perhaps AKG K1000), 2 or more is better to split the load on the MOSFETs.

3) Lots of options, look at eBay.

ALPS RK27 Attenuator VolumeControl 100K Stereo/BALANCED - eBay (item 300277884870 end time Dec-04-08 19:25:56 PST)

Balance XLR 23 stepped attenuator volume control 10K - eBay (item 290274865267 end time Dec-12-08 12:47:37 PST)

50K 4 poles gangs Step attenuator Dale resistor Balance - eBay (item 360095154440 end time Dec-04-08 07:59:26 PST)

 

[chobint]

OOhh so does this mean we might have a balanced B22 at our next Ohio meet

My Bijou you listened to was a glass jar kit. I was pleased with it.

I snagged one of these for around $15 USD shipped on the bay.
ALPS RK27 Attenuator VolumeControl 100K Stereo/BALANCED - eBay (item 300277884870 end time Dec-04-08 19:25:56 PST)

And ya casing can catch you by suprise. But hey theres always the option to gut an old all metal chassis from the thrift store for 5-10 bucks till you figure somethin out

 

[MoodySteve]

If you want to keep costs down (though I do agree with n_maher about 'keeping costs down' and 'ß22' not going well together) it is worth considering putting everything in one enclosure. It will be VERY tight with 4 amplifier boards but I've already come up with a layout that neatly fits into a 17" x 12".

If you go this route, I'd suggest using a fully shielded and encapsulated transformer, which will reduce the 60Hz hum that the fields will induce into your wiring. I replaced my Avel-Lindberg tranny with a shielded one from SumR and there was certainly an audible improvement in the noise floor.

Good luck!

 

[compuryan]

Thanks for the advice everyone. I like the idea of going to a thrift store for a chassis. Luckily, there is a gigantic warehouse in downtown Dayton called "Mendelson's Liquidation Outlet". They have everything you could possibly imagine when it comes to electronics, machinery, computers, etc. I'm pretty sure I could find some chassis' there that would do the trick for very little money.

The balanced ALPS pot looks like a winner, I've never been a huge fan of stepped attenuators anyway. Aside from that I'll need 4 XLR jacks (in and out), IEC outlet for power, hookup wire, a volume knob, leds, a power switch, and solder. I'm not sure if I'm going to do a separate chassis for the power supply or not, I guess it depends on what I find. That will of course determine whether I need some sort of umbilical cord in the system or not.

So it doesn't seem like it'd cost me over $1000 at all, am I missing something?

 

[Uncle Erik]

Quote:

Originally Posted by compuryan /img/forum/go_quote.gif Thanks for the advice everyone. I like the idea of going to a thrift store for a chassis. Luckily, there is a gigantic warehouse in downtown Dayton called "Mendelson's Liquidation Outlet". They have everything you could possibly imagine when it comes to electronics, machinery, computers, etc. I'm pretty sure I could find some chassis' there that would do the trick for very little money.

That's exactly the kind of place you should go. Scout around for indicator lights, switches, feet, fuse holders, and that sort of thing. Those things really add up over a build.

I haven't built my Beta22 yet, but I was thinking of going dual chassis with a pair of these:

Metal Project Boxes

Only $18 each. Steel is a bit tougher to work with than aluminum, however, hole drilling isn't that bad with solid state amps.

Be sure to check out the rest of Nebraska Surplus - they have a great inventory and prices are fair.

 

[cotdt]

Quote:

Originally Posted by compuryan /img/forum/go_quote.gif So it doesn't seem like it'd cost me over $1000 at all, am I missing something?

It will cost over $1000 once you finish the amp to find out that it hums badly, and that the power supply needs a separate enclosure with special connectors and cabling. Then there's the ground loops. And I assume you are not including tooling costs? It's best to get it done right the first time, and have money in reserve just in case something goes wrong. And if you ever plan to sell the amp to fund a new project, you'd want a nice front panel (that is professionally labeled, i.e. 4 panels from Front Panel Express) and pleasing cosmetics.

 

[chobint]

Nice link Erik. Looks like a tempting opportunity to get my bijou properly enclosed once and for all. To bad for no shipping calc.

 

[holland]

shipping wasn't too bad, iirc. I bought 5 a while back, shipping was about $50. Total was $125. I have yet to use it though.

 

[TimmyMac]

My build has run $750-800 CAD so far, with 2 sigma22 boards and 150VA transformers for each. But, I'm building the chassis myself, and it's going to be a fair bit of work.

 

[FallenAngel]

That NABU case is a dream in terms of cost and durability. Unfortunately, it isn't easy to work with (fairly heavy gauge steel). Ventilation holes are highly recommended for a Beta22. Oh, it can look like this if you really screw up

http://i55.photobucket.com/albums/g1...08/sm08_17.jpg

 

[compuryan]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif That NABU case is a dream in terms of cost and durability. Unfortunately, it isn't easy to work with (fairly heavy gauge steel). Ventilation holes are highly recommended for a Beta22. Oh, it can look like this if you really screw up http://i55.photobucket.com/albums/g1...08/sm08_17.jpg

looks downright beautiful to me

 

[krmathis]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif That NABU case is a dream in terms of cost and durability. Unfortunately, it isn't easy to work with (fairly heavy gauge steel). Ventilation holes are highly recommended for a Beta22. Oh, it can look like this if you really screw up http://i55.photobucket.com/albums/g1...08/sm08_17.jpg

Ouch! Must be a pain handling that volume knob.

Nothing wrong cost wise though...

 

[compuryan]

Oh I see that now. I'm sure there is another knob out there that would do the trick, its just a matter of tracking it down.