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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: Weirdness on October 20, 2007, 01:53:02 PM
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Hopefully I'm putting this in the right place. I have had my ACM V3 since August and although I've recorded quite a few files with it, this is the first time I have noticed this issue. Sonically, the recordings sound fine but obviously something isn't right. Normally I just open the file with CD wave but it shows both channels together so this didn't show up. You will notice on the top of the left channel, it flatlines at around -12 and will not go over that mark. This is consistent on everything that I taped with my ACM V3. Before I had the ACM done, the unit was sent to Grace to have the polarity fix done and was given a clean bill of health. I compared to previous V2>AD500 recordings and this was definitely not happening before. Any ideas???
(http://i21.tinypic.com/4rq29w.jpg)
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I experienced similar symptoms with an old modSBM-1. Turns out it was a fried op amp. I'd call Doug, send him an email, and ask about a timetable for having the unit serviced. FWIW, in the interim the modSBM-1 sounded find if I didn't run levels above the threshold at which the top half of the waveform flattened.
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Sorry for putting this in the wrong spot. I have emailed a copy of the same screen shot to Doug, we'll see what he comes back with. If anyone can tell me how to fix this up in Soundforge or whatever other program I would appreciate it. It's been a long time since I had to alter a recording in any way, when I was running V2>AD500e everything had been running 100% perfect for some time. That's another category again though right... Anyways, I'll let you guys know how it turns out.
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I concur with Brian. I've seen the same thing in a preamp I built. The cause was a fried input chip (THAT1510).
You can't fix the results in an editor afaik. The signal has been clipped by the faulty chip.
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What a PITA... Anyways, I have just posted a question in comp recording help regarding trying to fix this up. It's 100% in the V3, I tested it out with entirely different everything and it's still doing the same thing even when I swap the mic cables so that's been confirmed at this point.
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I experienced similar symptoms with an old modSBM-1. Turns out it was a fried op amp. I'd call Doug, send him an email, and ask about a timetable for having the unit serviced. FWIW, in the interim the modSBM-1 sounded find if I didn't run levels above the threshold at which the top half of the waveform flattened.
This shows the perils of using hacked gear. While it may seem great to get "more quality" on the cheap, we should at least *test* gear after modding. (I'm saying Oade, not you.). I still remember finding faults in stock products, like the Edirol UA5, I found significant distortion (>1% THD) in the ADC near 0dB.
It seems, as with computers, you should not trust gear until it is fully checked out.
Richard
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I experienced similar symptoms with an old modSBM-1. Turns out it was a fried op amp. I'd call Doug, send him an email, and ask about a timetable for having the unit serviced. FWIW, in the interim the modSBM-1 sounded find if I didn't run levels above the threshold at which the top half of the waveform flattened.
This shows the perils of using hacked gear. While it may seem great to get "more quality" on the cheap, we should at least *test* gear after modding. (I'm saying Oade, not you.). I still remember finding faults in stock products, like the Edirol UA5, I found significant distortion (>1% THD) in the ADC near 0dB.
It seems, as with computers, you should not trust gear until it is fully checked out.
Richard
I guarantee you that unit went through hours of testing and burn-in on the bench before it left Oade. Whatever went wrong manifested after it left or was intermittent and not noticed during that period.
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Confirmed to be a bad chip in the V3. Kudos to Doug Oade, I overnighted it to him and he has fixed it for me in a day and is going to send it out tomorrow. Can't ask for much more than that. Unfortunately, I've had the unit for awhile but really haven't taken the time to listen hard to anything that I'd recorded. Everything looked fine in CD Wave so I figured that all was well. Anyways, that's the precice reason that I didn't sell my V2 off, it will come in handy at Ween tomorrow night...
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Props to Doug Oade, my unit arrived back at my doorstep safe and sound today. 1 week even to get to and fro, over the border and all. Can't ask for anything more than that...