first time kit builder with a resistance problem

T Scott · 13281

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Offline T Scott

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on: January 30, 2010, 11:14:52 AM
Finished the SEX and went to measuring resistances. Everything fine until I got to the terminal strip with all the diodes attached. C1, C2, and C5 are all at 0 ohms but C4 was around 500 ohms. I examined all the diode directions and connections in general and could not find a flaw. so I re-soldered the connections around C4 and C5 and the power transformer (hoping to rectify a cold solder joint). Interestingly the resistance seemed to go down (measured around 200 ohms) but now it seems to be back at the original. Any thoughts, suggestions on tracking this down further would be appreciated.



Offline JC

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Reply #1 on: January 30, 2010, 12:48:27 PM
IIRC, there is a little jumper of hook-up wire between C1 and C4; with that in place, the readings on those two terminals should be exactly the same.

Is there any possibility that this wire broke inside the insulation somehow?

Jim C.


Offline T Scott

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Reply #2 on: January 31, 2010, 11:59:04 AM
OK Jim, I really owe you one. It turned out that there was no jumper there. Apparently when you originally place it on C1-C4, the soldering comes later. Somehow I had not mechanically secured it so at some point it had loosened sufficiently to drop off. So I quickly found and soldered it in place - everything perfect in terms of measurements and I am listening to sweet music as we speak.

Thanks ever so much. You saved me hours of going back over my connections!!

But, since I have your attention, tell me what to use for the "10 ohm resistors" across the output terminals if you are instead using headphones? Not sure what Doc B has in mind there.

Thanks again.



Offline Doc B.

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Reply #3 on: January 31, 2010, 12:39:29 PM
The 10 ohm resistor is not needed.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline JC

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Reply #4 on: January 31, 2010, 12:52:02 PM
Good deal!  And, I see Doc has already answered your other question. 

I think you are exactly right, the jumper went in place first, then other parts were added to those terminals before soldering.  I expect yours got dislodged as the other parts were installed.

Enjoy!  And, well done!  Having something come loose before soldering is an altogether common occurrence, and you evidently only had it happen once!

Jim C.


Offline T Scott

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Reply #5 on: January 31, 2010, 02:01:22 PM
Jim,

You are very gracious...it was a dumb mistake. Regardless, it is solved and I am in business.

Since I am away from my home base I had only my iPod as a source. But regardless, listening to first Lyle Lovett, then Estrella Morente and then Lizz Wright was truly a religious experience. The SEX was so open and flowing in sound. Just got goosebumps.

Yes, Doc answered the other question so I won't worry about the output terminals. Once I get back to Maine I have a pair of Klipschorns that I procured back in the dark ages when I went to Hope AK to meet Paul and Bob in the dumpy little warehouse that was Klipsch. Be interesting to see how they will sound.

Thanks again.