Tascam us-2x2 blown inputs (noise on signal) help
Good day folks. I thought I'd ask for some advice from any potential audio gurus out there on this external sound card, mixer thingy, though this is going to be more of a general discussion about faults that can occur on audio equipment of this kind, since it's otherwise a very specific issue on a very specific piece of hardware, so it's unlikely we'll track it down easily.
The problem is as follows: the chap who brought it in said he damaged it by plugging in the speaker outputs (amplified signal that is) of some tape deck or something to the inputs on the front which normally take a mic or line input. The sound card didn't quite like this apparently since the signal shot into it somehow and damaged something in such way that now I'm getting poor audio quality on both inputs (sounds like sh!t to put it simply) and it gets worse the higher you turn the gain on that channel, plus it peaks out really easily....yeah, good luck figuring out what happened there :|
When used as an USB sound output it works fine, so the issue is not with the output, but the inputs.
This is where general discussions may commence: is there a typical "topology" so to say that mixers/consoles/sound devices with line inputs like these typically follow that would allow us to get even close to the area that got busted ? What would be the first thing to check in this case ? Signal DOES come through, but again sounds very distorted. I took it apart, but of course it's all SMD and doesn't show any signs of physical damage. I can post pictures if need be, but to put it very simply, what I noticed was both channels seem to eventually terminate in an op-amp, which I ASSUME operates as an amplifier and then gets sent off to the main IC or whatever. Other than that, there's some TO19 trannies in there and some electrolytics.... The whole circuit looks symmetrical, so it's got a perfectly even number of components and they're all "mirrored", so say two trannies for one channel, another 2 for the other. 2 caps for the first channel, another 2 for the other....you get the idea...should I dive right in and try replacing that op-amp ? What would excessive input drive damage first in an audio device of this kind ? :| Cheers and thanks...I shall return with pics to at least get an idea of what's in there.
The problem is as follows: the chap who brought it in said he damaged it by plugging in the speaker outputs (amplified signal that is) of some tape deck or something to the inputs on the front which normally take a mic or line input. The sound card didn't quite like this apparently since the signal shot into it somehow and damaged something in such way that now I'm getting poor audio quality on both inputs (sounds like sh!t to put it simply) and it gets worse the higher you turn the gain on that channel, plus it peaks out really easily....yeah, good luck figuring out what happened there :|
When used as an USB sound output it works fine, so the issue is not with the output, but the inputs.
This is where general discussions may commence: is there a typical "topology" so to say that mixers/consoles/sound devices with line inputs like these typically follow that would allow us to get even close to the area that got busted ? What would be the first thing to check in this case ? Signal DOES come through, but again sounds very distorted. I took it apart, but of course it's all SMD and doesn't show any signs of physical damage. I can post pictures if need be, but to put it very simply, what I noticed was both channels seem to eventually terminate in an op-amp, which I ASSUME operates as an amplifier and then gets sent off to the main IC or whatever. Other than that, there's some TO19 trannies in there and some electrolytics.... The whole circuit looks symmetrical, so it's got a perfectly even number of components and they're all "mirrored", so say two trannies for one channel, another 2 for the other. 2 caps for the first channel, another 2 for the other....you get the idea...should I dive right in and try replacing that op-amp ? What would excessive input drive damage first in an audio device of this kind ? :| Cheers and thanks...I shall return with pics to at least get an idea of what's in there.
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