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Well, I thought my SammichFM was working perfectly, but I think I spoke a bit too soon. I seem to be getting a nasty distorted output from Audio Out 1/2. The output of out 2/3 sounds fine. Audio from 1/2 seems to be a distorted version of what's coming out of 1/2. Any tips on tracking down the problem?
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SammichFM Distorted Audio From Out 1/2
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#2
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Posted 19 July 2011 - 18:51
I'm taking a bit of a guess, but it sounds like one of the op-amps. I would check first to see if those are getting proper voltage. If the op-amp is getting too low of a voltage, it can sound crusty and otherwise distorted, though it may also sound quiet compared to the other outputs in that case. I would start there and work your way backwards. I can't claim to be an expert on the MBFM design though - just thought I'd share what I knew at least of op-amp behaviors I've experienced.
#3
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Posted 19 July 2011 - 19:00
m00dawg, on 19 July 2011 - 18:51, said:
I'm taking a bit of a guess, but it sounds like one of the op-amps. I would check first to see if those are getting proper voltage. If the op-amp is getting too low of a voltage, it can sound crusty and otherwise distorted, though it may also sound quiet compared to the other outputs in that case. I would start there and work your way backwards. I can't claim to be an expert on the MBFM design though - just thought I'd share what I knew at least of op-amp behaviors I've experienced.
Hiya, wow, rapid reply. I'll have a look into that.
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#4
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Posted 19 July 2011 - 21:45
OK, seems to be fixed now. I remelted some of the solder on IC51 and IC53, and all now seems well. Must just have been a bad joint on one of the two surface-mount chips.
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#5
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Posted 19 July 2011 - 22:45
w00t! Awesome!
#6
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Posted 07 October 2011 - 09:56
For the record, I just had the exact same problem and resoldering the same two chips fixed it. Thanks!
#7
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Posted 09 October 2011 - 01:47
It seems like 9 out of 10 problems with a sammich* are due to bad solder joints/shorts. Thus if it doesn't work, it's probably your bad soldering! just sayin... 
Buy Wilba a Beer Disclaimer: buying Wilba a beer gets you absolutely nothing in return likesuchas sammichSID kit order queue jumping, purchase of SIDs and MIDIbox troubleshooting assistance.
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