Art Pro VLA ii - Strange behaviour

famous beagle

famous beagle

Well-known member
I just picked up one of these used off Amazon for $200. I fired it up tonight for the first time. Everything seems to be working, but I'm getting a strange level issue.

The signal seems to be much hotter on CH 2 than on CH 1. For example, if I play a guitar signal that's panned straight down the middle and send it into the unit, CH 2 is showing about 7 dB of GR when CH 1 will only be showing 1 or 2 with all of the settings exactly the same.

Likewise, I have to crank up the output knob a bit past +5 dB on CH 1 for the output to be equal to CH 2 with the output knob on 0 dB.

I've eliminated bad cables, and the source is fine. It's definitely something in the Art unit.

I was just wondering if anyone else had experienced any similar issues with this piece (or a comparable unit). Could a difference in tube be causing this by chance? Maybe one side has a 12ax7 and the other has a 12au7? I haven't checked the tubes yet.

Regarding the sound of the unit, it seems to be fine. In other words, when I adjust the threshold of CH 1 so that I'm getting equal GR on both sides, it sounds the same on both channels. However, I'm not able to get as much GR on CH 1 for sure. With the settings as extreme as possible, I'll get about -30 dB on CH 2 but only about -20 dB on CH 1.

Anyone have any clue?

Thanks
 
Check or swap out the tubes, and there are also adjustment pots in there if a recall....been awhile since I looked inside my two VLAs.
 
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Well dang. I swapped the tubes (CH 1 to 2 and 2 to 1) to see if the problem followed the tube, and it didn't help. I also noticed that when I turn up the output gain, there's a nasty noise that arises on CH 2, whereas CH 1 is totally clean. It's also exhibiting some other strange behavior. The meters will occasionally randomly jerk up and down sometimes on CH 2 even when no signal is present.

It looks as though I got a lemon. :( So I'm going to send it back while I still have the chance and cut my losses by eating the return shipping.
 
Just from left field, try flicking the -10 +4 button in and out a few times to see if there is a bad switch connection?

Alan.
 
I had the same sort of problem with my Pro VLA, and ALSO with my MPA, unequal levels with the same settings. I never sorted them out, just de-racked them and threw them in the closet.
 
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