Kniferide wrote: Tue Dec 07, 2021 11:16 am

cakes wrote: Tue Dec 07, 2021 10:43 am

Kniferide wrote: Mon Dec 06, 2021 1:33 pm

That's a bummer man. Both of mine are completely fine. Clipping that the resistors made the noise not a problem. I think this is why they are so cheap on the used market, seems like the QC was all over the place for the II units. I just compared one of mine to a standard channel on my A&H console and if I crank all of the gain and volume controls, the noise is about twice that of a console channel with the gain cranked all the way, which is acceptable for something that has several more gainstages and some tubes in there.

I like the idea of a control strip, but the Channel II does seem to have some quality control issues. dbx makes a couple of strips, one is the 286s. Much cheaper, looks a little better overall. (Just mentioning if someone here in the future was on the same path.) Maybe because it's solid state, it doesn't have as many potential issues? The Channel II usable, but limited, depending on what you want to do. I would probably not use it for vocals, which is the real bummer because that was why I got it. Anyway, I think I'm gonna save up for an MPA II in the long-run, and then see if a strip is needed after that and decide what to do. I might just split out the compressor in the meantime, I could always use one more as outboard gear.

Just checking, did you end up clipping those Resistors? I did some guitar tracking with mine last night and it was all good. I hate to have led you down a dead end path here.

cakes wrote: Tue Dec 07, 2021 11:40 am I did, once I checked that the hum/buzz did exist. Clipping them didn't make a huge difference, though. I think there's something inherently wrong with the unit. (I don't feel right asking for a refund from the seller, seeing as how I've modified the circuit board). It seems really strange to me that the EQ section gets fuzz without pushing it hard, even after switching out the 12at7. I haven't really read any reports on this happening to other people, seems unique here. I haven't had the time to break out the comp and EQ sections with the patchbay, but this is something on my list of things to look at. I might ask an electrical engineer friend to take a look at it on his bench.

tommy wrote: Tue Dec 07, 2021 11:54 am

cakes wrote: Tue Dec 07, 2021 11:40 am I did, once I checked that the hum/buzz did exist. Clipping them didn't make a huge difference, though. I think there's something inherently wrong with the unit. (I don't feel right asking for a refund from the seller, seeing as how I've modified the circuit board). It seems really strange to me that the EQ section gets fuzz without pushing it hard, even after switching out the 12at7. I haven't really read any reports on this happening to other people, seems unique here. I haven't had the time to break out the comp and EQ sections with the patchbay, but this is something on my list of things to look at. I might ask an electrical engineer friend to take a look at it on his bench.

Triple check the tube types for every socket position. For instance 12AX7 vs 12AT7 have pretty big differences in gain (and other specs).

brownreasontolive wrote: Tue Dec 07, 2021 12:17 pm My apologies if this was covered, but TLDR...
When you are experiencing this hum/buzz, what/how are you feeding signal to the ART?

I've skimmed over a lot of conversation here about tubes and modifications etc, but I'm not clear whether your feeding line level source from an interface, or just plugging in a bass guitar or something.

cakes wrote: Tue Dec 07, 2021 12:26 pm

brownreasontolive wrote: Tue Dec 07, 2021 12:17 pm My apologies if this was covered, but TLDR...
When you are experiencing this hum/buzz, what/how are you feeding signal to the ART?

I've skimmed over a lot of conversation here about tubes and modifications etc, but I'm not clear whether your feeding line level source from an interface, or just plugging in a bass guitar or something.

It's a good question.

I'm going from mic with an xlr on one end and a fixed 1/4 tsr on the other, into a patch bay, into a Tascam Model 12 console, into the DAW.

Totally possible that the channel in the patchbay has an issue. I have tested the cable by using it in other preamps and signal paths, that seems fine. I have switched between a dynamic mic and a large diaphram condensor, so it's not the mic. I've tried different channels in the console. I can try bypassing the patchbay and going strait into the board. I don't think I will find anything different, that's my hunch.

Another interesting tidbit is this: when the computer monitor is on, and there's a lot of white pixels, the hum and noise is more pronounced. And, if I am scrolling, it causes a lot more noise interference. This only happens when the Channel II is being used. So, it really sounds like something isn't shielded properly or whatever. I should also add that the Channel II is plugged into a power conditioner, so I was a little shocked by this discovery.

brownreasontolive wrote: Tue Dec 07, 2021 12:34 pm I would take the mixer out of the equation for a minute, first.
Try sending a line level source that you know to be noise free, from your DAW at -10 dBfs, to the ART, then back to your DAW.
Hit Play/Record and turn off any gear that shares the power source but doesn't needs to be on.
Examine the recorded audio and compare it to the source with just headphones and your DAW, if possible.

You likely can't trust the VU's for either the mixer or the ART (Tascam from age/caps and ART for quality).
As far as I can tell, we haven't really ruled out impedance issues either.

Kniferide wrote: Tue Dec 07, 2021 2:41 pm I think the Tascam is his IO to DAW. It would be worth plugging the ART directly into the Tascam on a Line input and seeing if the buzz is as bad. Definitely get away from the monitor for testing. I had an old Gateway monitor that I was using for a second mon for a while and was having a tom of issues with buzz/hum getting into everything. It was driving me nuts. one day when I was pluggin something in I unplugged the monitor and from under my desk heard the buzz go away and I got rid of it. It's way better now.