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Post by peterhess on Apr 7, 2018 10:04:21 GMT -6
Hoping for some advice here: when calibrating this guy, was adjusting the bias trimmer, and smoked adjacent R51 (10R). Any ideas what I may have done wrong? It’s beyond my understanding. Also, going to order some replacements from Mouser: the range of resistor options is so great; exactly what should the description be of the new resistor: metal film?
Build was clean, and by no means my first, I’ve built Skulptor 573s, Hairball 1176 rack (and successfully calibrated), and all the DIYRE business. Thanks a million for your help, fellas...
P
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Post by matt@IAA on Apr 7, 2018 11:12:01 GMT -6
Xicon 271-10-RC or 273-10-RC will be fine. The only difference between 271 and 273 is the power rating - just match what was there (1/2 or 1/4 watt).
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Post by mdmitch2 on Apr 7, 2018 17:54:54 GMT -6
Those transformers are easy to reverse -- I would check that first, and then diode orientation. I haven't built the 1081, but usually Colin lays things out so that all the diodes are facing the same direction, and caps and transistors as well.
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Post by peterhess on Apr 8, 2018 8:34:59 GMT -6
Thanks both of you for your replies!
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Post by Bender on Apr 9, 2018 10:29:50 GMT -6
Nothing like the onset of fear when firing up a build and smoke escapes!
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Post by kilroyrock on Apr 9, 2018 12:13:27 GMT -6
if you open it up too wide it sends too much power - make sure your audio signal is the correct decibel. if you're trying to get it it up louder, you may not realize you've got your signal too low. Start completely down and start over after you replace the resistor. It's a good thing that resistor is there (usually on purpose, from my experience with de-mojo-ing some opamps).
I almost burnt up the resistor on the 73 build, i realized last minute it was getting a little TOO hot. I then also tried to send so much signal to the second of the pair, that the plastic on the transformer started acting like a speaker..
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Post by peterhess on Apr 11, 2018 15:27:59 GMT -6
So you’re saying that resistor blew up from my going to far on the trimmer? I’d love if that were the case! I was seeing little or no voltage change on my mm, and kept going on the trimmer. Is the range that wide on those trimmers? My inexperience is showing... thanks for the advice!
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