SammichFM Distorted Audio From Out 1/2

[toneburst]

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?

a|x

[m00dawg]

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.

[toneburst]

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.

a|x

[toneburst]

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.

a|x

[m00dawg]

w00t! Awesome!

[bw]

For the record, I just had the exact same problem and resoldering the same two chips fixed it. Thanks!

[Wilba]

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... :wink: