Just received my SCA pre-kit!!

[KingDaddyO]

UPS just dropped my Seventh Circle Audio rack kit off! I'm building the N72 & J99 modules to begin with. Now to get those 990C's on order...

JUST KNOCK LOUD... I'll be busy this holiday season.

[dkatz42]

Originally Posted by ArtGarceau

The only parts of the build that kinda pissed me off was building the power harness and getting the smaller transformer on the board.

I picked up MTA connectors (Mass Termination Assembly--sounds like Jonestown...) and the appropriate tool from Digikey; it made the whole process much cleaner and more reliable and faster (since I built 16 channels worth.) The SCA forum has a posting with the part number info for this stuff.

The transformers on the N72 are a pain, but the sonics are worth it. I used clipped resistor leads to connect most of the pins (the ones unlikely to short), which make it easier because they're stiff enough. Just guide them into place as you mount the transformer. Oh, and look at the screening for the pin numbers carefully; they're a little confusing and a number of folks have gotten it wrong.

Originally Posted by ArtGarceau

Also...metering every last resistor for the value is what took the most time. After that I flew through the build.

I spread the pain out by doing it as I went. Basically, I'd grab a resistor out of the pile, read the color code, go back to the BOM to see how many there were supposed to be of the same value, grabbed them all, measured them all (a clip lead on one end of the ohmmeter lets you grab them all at once and sequence through the other ends quickly with the free probe), and put 'em on the board. Many hundreds of resistors later I managed to never goof one (whew!)

[KingDaddyO]

Originally Posted by ArtGarceau

I had built some N72 kits a while back and they are awesome. The only parts of the build that kinda pissed me off was building the power harness and getting the smaller transformer on the board. Not difficult...just a pain in the nuts.

Also...metering every last resistor for the value is what took the most time. After that I flew through the build.

I have heard a few comments similar to yours, regarding the harness. I'll be doing a lot of catch-up reading on the boards later tonite.

Let me ask you - did you need to meter the resistors because of precision tolerances or something else? I ask because the color codes should accurately indicate the values.

Thanks for your comments.

[KingDaddyO]

Originally Posted by dkatz42

I picked up MTA connectors (Mass Termination Assembly--sounds like Jonestown...) and the appropriate tool from Digikey; it made the whole process much cleaner and more reliable and faster (since I built 16 channels worth.) The SCA forum has a posting with the part number info for this stuff.

The transformers on the N72 are a pain, but the sonics are worth it. I used clipped resistor leads to connect most of the pins (the ones unlikely to short), which make it easier because they're stiff enough. Just guide them into place as you mount the transformer. Oh, and look at the screening for the pin numbers carefully; they're a little confusing and a number of folks have gotten it wrong.

I spread the pain out by doing it as I went. Basically, I'd grab a resistor out of the pile, read the color code, go back to the BOM to see how many there were supposed to be of the same value, grabbed them all, measured them all (a clip lead on one end of the ohmmeter lets you grab them all at once and sequence through the other ends quickly with the free probe), and put 'em on the board. Many hundreds of resistors later I managed to never goof one (whew!)

Good info - thanks mate!

[bluesman714]

You need to meter each resistor just to be sure that you haven't made a mistake reading the color code, these are 1/4 watt resistors & the color code bands are very tiny. I used a loupe to help identify & a DVM to confirm.

[dkatz42]

Originally Posted by KingDaddyO

did you need to meter the resistors because of precision tolerances or something else? I ask because the color codes should accurately indicate the values.

It's a good way to double-check. Further, with 1% resistors you can get color codes that are valid in either direction (since the tolerance stripe is brown.) Also, some of the colors are hard to differentiate on some of the resistors.