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Roll Call: Who's building, built, or thinking of building a beta22? - Page 7

post #91 of 2875
7/11/07 at 3:38pm
Cases are nice and all, but how's it sound?
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post #92 of 2875
7/11/07 at 4:19pm
guys, for hooking up a power entry module to the transformer, i know its recommended to use something like fastON connectors etc, but is this just for ease, or for safety etc as well? would it not be suitable to just do a careful job with well insulated 16 AWG wire and heatshrink the connections nicely?
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post #93 of 2875
7/11/07 at 4:33pm
If I'm understanding you correctly you're asking about using faston connectors to wire your trafo to the power inlet module. If that's the case, yes it would be suitable to do as you describe and just direct solder the wires to the module and insulate them with shrink. The only issue you could face is if you ever need to remove the trafo it's a much more arduous task dealing with the soldered connections.
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post #94 of 2875
7/11/07 at 5:59pm
Quote:
Originally Posted by The Burn Pt.2 View Post
nm
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post #95 of 2875
7/15/07 at 5:32pm
i'm getting a dc offset on one of my boards of 58mV. The Jfets were matched by jeff(ordered a kit from him), so I don't think thats the problem. Should i just get a lower value resistor for R13 and extend the trimpot range?
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post #96 of 2875
7/15/07 at 6:41pm
well, i swapped q3 and q4, got the dc offset down, but now something weird happened...

measuring across r34, wasn't getting a reading, so i fiddled with VR2, and got the number up some, but it was fluctuating quite a bit, up and down, up and down. Went back, fixed vr1 so was reading 4.5 V across R9, then when i went to mess with VR2 again, no reading....(in mV, of course)

did I fry my jfets desoldering them?(I hope not)


EDIT:
Another interesting note, i hooked up a source and some crappy earbuds, and i get music with little hum (odd...)
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post #97 of 2875
7/15/07 at 8:08pm
1. I wouldn't trust crappy earphones when testing for hum. I've had little buds that hummed regardless of how quiet an amp was with my ER4Ps. Some headphones/earbuds really do just suck. If you amp tests fine with regards to DC offset you don't have all that much to worry about.

2. You may or may not have fried the fets in the solder/desolder cycle. However, given the intermittent characteristic it would make a lot of sense to reflow all of the joints from the swap since you might have a cold joint.
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post #98 of 2875
7/18/07 at 2:52pm
well. just an update..got my s22 finished and mounted along with the trafo in my par-metal case (black anodized, 16"x16"x4"), ya its a beast. lol. everythings goin smoothly so far, rest of my b22 boards probably populated later this week. man, although im relatively new to the circuitry stuff and thats DEFINITELY my weakness (as uve all noticed by now ), im GLAD that casework and carpentry type work was my strong suit coming into this project, because i would NOT want to do this casing without experience! man, i can not speak enough for how handy the drill press in the basement has been! quickie question, i dont (yet?) have a nice big stepped drill bit, so for getting the really large holes, ie for the power entry module etc, any tricks? would drilling out a series of smaller holes and then dremmelling or something probably be my best bet?
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post #99 of 2875
7/18/07 at 3:19pm
Quote:
Originally Posted by el_matt0 View Post
would drilling out a series of smaller holes and then dremmelling
That's the approach I used. Measure carefully and it's okay to be a little on the smaller side since you can always file to fit.
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post #100 of 2875
7/18/07 at 5:13pm
yep exactly what im ABOUT to do. smaller is always better. i imagine TOO big would be no good . it would definitely suck to hafta shop around to find a power entry module to fit a botched hole lol!
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post #101 of 2875
7/18/07 at 5:30pm
I'm planning on starting to build my Beta22 (for the second time, I buggered it the first time) tonight after work. I'm hoping to have enough time to finish one board completely.
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post #102 of 2875
7/19/07 at 12:35am
So far I've got all the diodes, all the resistors, and all the CRDs installed. I've also got all the JFETs, and have the BJTs installed. I've been going at this for about 4 hours so far, and I'm starting to go a bit stir crazy.
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post #103 of 2875
7/19/07 at 1:15am
I like doing all the same component on all the boards at the same time. That way as long as your doing it right all the boards should get built the same. Well except for the ground board but that is only a couple components different. Plus I think it saves time in the long run because you only have to reference and pull out the parts one time.
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post #104 of 2875
7/19/07 at 1:38am
Woot. Well, I finished getting all the BJTs installed. All I have left are the POTs, the capacitors and the mosfets. If I can get another 4-6 hour chunk of time free, I should be able to finish get all the soldering done and get the set up and biasing done.
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post #105 of 2875
7/19/07 at 4:30am
Quote:
Originally Posted by gates_2 View Post
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
be careful though. I have ask Russ White about the joshua tree attentuator and it seems to be similar to a shunt attenuator not series/ladder.
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