beta22 Build

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I figured this needed an update--I recently took a canvas of what parts I needed for all my projects to get (closer to begin) done and ordered a crap load from Digikey! I'm still waiting on some backordered parts, which I counted on for some of the nicer bits (thank goodness for the free shipping deal they have on right now!!) and I won't put on the transistors until last because of the frequency that I'm handling the board right at the moment.

~

Unboxing
IMGP0007_sm.jpg


~

All thrown down (phew!)
IMGP0013_sm.jpg




~

Glam shots
IMGP0022_sm.jpg




~

That's it for this update!
Stay tuned!




I love my camera :D
 
Looks awesome so far, Why are your high wattage resistors so high off the PCB board?

When are you going to test them?

Ps. If you just so happen to accidentally blowup any traces on the PC boards, I've got one (Or two).

Thanks!

With regards to the resistors, it's just something I do. I like high-power things to have a lot of air around them in order to keep them properly cooled.

I'll probably be testing sometime next week, is I can find insulating bushings or plastic screws for the power transistors by then. Heading up to a farm to clear some trees and start work on a barn this weekend.

And thank you for the offer! I'll keep you in mind if things go wrong :)
 
Small signal transistors; tested, bent, and soldered! :D

121ohm resistors and 470uF caps came this past week! I was out of 1N4148 diodes, but luckily I had pulled the guys of a Viewsonic CRT monitor earlier in the spring and harvested many good-testing diodes from that :)

Also, I got annoyed while tapping the heatsinks--while I don't mind tapping small holes, tapping a hole with a quarter of the material missing is annoying to no end. In the time it took me to hand-tap six holes, I was able to power-tap the rest of the set. Apply cutting fluid frequently.


beta22
IMGP00162_sm.jpg




sigma22
IMGP00132_sm.jpg




The team!
IMGP00192_sm.jpg




Powertapping!
IMGP00102_sm.jpg



 
Last edited:
SCHOOOOOL'S OUT FOR SUMMER!! I've been busy and I'm ready to run a test.

Got all the power transistors insulated with some mil-spec silpads.

Quick Q: what fuse rating should I use for a three-board setup running at 30V? Fuse will go at the primary of the power traffo.


*edit* found it! 2A slo-blow
 
This has been a slow going project... I put the resistors down-close to the board, still leaving a bit of a gap (~1/8") underneath.

Working on the chassis now; I got some aluminum plate and have everything roughly located. Tested a board and biased it up with no explosions.

The beta22 lot I bought came with a 50k ALPS Blue, but I've been thinking about going balls-to-the-wall and building-up a binary, 6 relay attenuator (64 steps) + 1 for mute (maybe). Bought in on Ed's Omron G6H-2 group-buy so I've got a few of those kicking around, in addition to a bunch of USSR military surplus signal relays.

Question: 50k or 10k for the three board configuration? I've been looking at this thread for inspiration.
 
since you started with b22, why not go for the lcduino and delta1?

ob disc: I worked on that design along with amb ;)

I'm glad you moved the .47's down to the board. they don't get that hot and they benefit from shorter leads and being closer to the ground plane.

also, use lower resistance on the attenuator. the 25k or 50k is too high. shoot for 10k or so. it will be lower noise.
 
you need some code to twiddle the latching relays. but you don't need an lcd *installed*, per se. you could use one to setup the config you want, then remove the lcd and use only IR or a pot or even rotary for vol control.

there's a huge amount of value in the display, though; and its fully dimmable so you can get it out of the way if you don't want to see things ;)

the stock firmware takes the full 32k, so a 328 style arduino is what is recommended. that's the current non-mega variety, btw.

if you edit it down and remove all lcd stuff, you could trim it down and fit on the older arduino chip; but then you'd have to support the code and there's no good reason to break working code. just ignore the lcd once you set it up and use a 328 atmega chip. they're $4 or so at mouser. the older chips are not much cheaper so there's no reason to use them anymore.
 
Last edited:
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.