BOM discrepancies March 2012

[johndykstra]

Hey guys.

just a heads up for others building these kits (C84)

This is my forth model of 7thO, and to this point, the BOM has been spot on with the resistors. I sure am glad this was not my first kit, because up until I started my A12, I had never touched a multimeter. In fact, I used it to verify my work at the end of those builds (A12, N72s, B15) but I never checked the readings as I built as they suggest you do.

Initially, I had planned to list specific differences, but they piled up a bit (I want to say 4-5 instances when the BOM called for an IRC type resistor but I was provided with a Yageo... or different color denotations within Yageo types). Keeping my cool, I decided to pull out the multimeter and figure out what I needed, and what was given to me. Turns out the parts spec'ed for the application. In the instances in which an IRC were specified, but I was provided with Yageo, the readings kept with the stricter tolerance provided by the IRC type resistors.

Now that I am testing each resistor before installation, I am noticing the variance in the Yageo brand's readings. Having done a bit of homework, I know that this is to be expected. I purchased a stereo pair of C84's for overhead duty, and am assembling them together. Instances when there are 4-5 resistors of the same value for a single kit, I am measuring the actual value of all resistors and "matching" the pair of preamps as best I can... putting similar variances in the same R location. Will this make my pres more of a "matched" pair? Dunno. I do wish I knew enough about the circuit path to be able to know where the variance up or down my be more detrimental or beneficial in on location vs. another, but such is life. I will have to take comfort in knowing that at the very least, I did my best to match them. Better or worse.

Given the hiccup of having to actually do some amount of brain activity while stuffing resistors; while making the process a bit longer, has most certainly made it a more fun build. I feel as though I have learned something. I like that.

Ok. Enough jibber jabber. The resistors are stuffed... time to lock 'em down.

Thanks goes to 7thO for making some incredible products!

John