[jdkJake]

Considering I am just starting down this road I don't even have a good iron yet. That is about $100 to add to the project.

Do you have a Fry's in the neighborhood? They always have a good price on the Hakko 936.

http://www.frys.com/product/454489?site=sr:SEARCH:MAIN_RSLT_PG

 

[deandake]

That is exactly the Iron I plan to purchase. $74 right now. I knew you guys would be informitive but didn't realize how supportive this group is. Thanks guys

 

[jdkJake]

Excellent iron. Especially at that price. You will not be disappointed.

 

[aloksatoor]

yep Also one thing i cannot live without it the cleaning gauze which frys sells (hakko brand) , looks like metallic wool but works wonders for cleaning solder much better than provided pad http://www.frys.com/product/1563515?site=sr:SEARCH:MAIN_RSLT_PG

 

[deandake]

That stuff looks awesome. Back when I did electronics repair they didn't have that.  My local Fry's doesn't have it. gonna try another one before ordering it.

 

[wquiles]

Once I tried using these metal sponges, I stopped using the pads altogether.  The metal sponge works AWESOME!

 

[bridge8989]

hey guys i ran into some problems with the ground plane board.  when i adjust vr1 to get the voltage across R9 to 4.5V im getting ~5.5V on R10/R12 and ~7.5V across R11. The heatsinks warms up pretty fast compared to the other 2 boards which are working properly.  anyone have any suggestions?

 

[ShinyFalcon]

Is your VR2 is all the way counterclockwise? Is your DC offset at zero? Can you measure the resistance between the two pins of VR2 (that are not connected)?

 

[bridge8989]

yea VR2 is fully CCW; all three of the pins are connected to the board, ~2 ohms between pin1/2 and ~470ohms  between pin2/3 on VR2.  is dc offset between output and ground? i tried adjusting it with VR3 but the pot maxes out @ .13V DC.

 

[deathg0d]

Quote:

yea VR2 is fully CCW; all three of the pins are connected to the board, ~2 ohms between pin1/2 and ~470ohms  between pin2/3 on VR2.  is dc offset between output and ground? i tried adjusting it with VR3 but the pot maxes out @ .13V DC.

Hi I encountered a almost similar problem like yours some time back, which was, no matter how i adjusted and checked and troubleshooted, the readings just cannot be achieved, i even replaced parts as suggested and suspected to be faulty and still the readings are not correct, everytime, i power up the board, the readings just went haywire and in a couple of minutes i see smoke coming out from one of the mosfet (i have replaced and checked countless of times on everything from soldering to components etc)
 
finally, i realised the cost of buying replacement parts and time i spent on troubleshooting came almost equivalent to getting a new single board kit set and populate it again, thus i choose the easy way out i guess and ordered a single board kit from gj and now i am a happy man with everything running great. i could be wrong but i personally guess there could be something wrong with the board itself since i have checked on everything else, so if you have checked and is pretty sure everything were done correctly, then try getting a new board or a new single board kit.
 

 

[chronomitch]

Well, I finally finishing stuffing the boards and wiring everything up, but now I have problems with the initial setup.
 
Without any of the Beta 22 boards connected, I get approximately 29 volts (positive and negative) from the Sigma 22. However, when I connect the first Beta 22 board (haven't tried the other two), the voltage is about 20 volts (positive and negative) and slowly climbs as time goes on (about 0.1 volts every few seconds). What's more, the heat sinks on the Beta 22 board get REALLY hot (too hot to touch).

 

[digger945]

Assuming that the heatsinks on the sigmas are cool with nothing connected, you should then double check the amp boards as per the Beta 22 website. It's hard to believe that the sigmas would drop that much voltage without a fuse blowing, or something being very wrong, like a part somewhere taking up smoking.

 

[jackmccabe]

Hi, I am planning on building a beta22 but I am currently trying to decide what gain I should get.
I am going to go balanced and I am wondering whether a gain of 5 (effectively 10) would be too high for either the grado rs1's or the ultrason hfi-780's.
Thanks

 

[ShinyFalcon]

2x gain is more than enough for those two. What attenuator do you plan on using?

 

[chronomitch]

Quote:

Assuming that the heatsinks on the sigmas are cool with nothing connected, you should then double check the amp boards as per the Beta 22 website. It's hard to believe that the sigmas would drop that much voltage without a fuse blowing, or something being very wrong, like a part somewhere taking up smoking.

The heatsinks on the Sigma 22 are cool with nothing connected.

I didn't notice any smoke for the first Beta 22 board, but I did notice a smell. Perhaps something was burning? I went ahead and tried hooking up another channel and I had the same problem: really hot heat sinks, low positive and negative rail voltages, and a strange smell. This time though, I also noticed a small amount of smoke. Unfortunately, though, I couldn't tell what part it was coming from.
 
How sensitive are Q1-Q4 to heat? When I was soldering the boards, I noticed I had put those parts in wrong at first, as per the Beta 22 instructions, and had to desolder them. I wonder if I gave them too much heat when I was trying to remove them.