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Problem with new Art Pro Channel II

W

Whoolie

Guest
Nov 12, 2014
37
12
41
Denmark
#1
I just got my new pre/poweramp setup today, an ART Pro Channel II together with a used Crest Audio CA6.
I plugged everything in and powered it up.
The poweramp is working fine, no problems there, but the pro channel is a bit odd.
The first thing I noticed was that the VU meter didn't really move. I did have sound coming through, but the VU meter was barely moving a millimetre when the output was cranked to the max and the input was almost clipping. So, maybe that was by design when using the instrument input at the front, so I started dialing in the rest of the knobs...
After a while I got to the tube high voltage button. I pressed it and after about 4-5 seconds, the preamp tube character lit half way up on the LED meter below the VU meter, and the compressor below showed that it was ducking a few db. That's when I thought something must be wrong... There was no humming or other strange noise on the output.
So I started troubleshooting a bit, and I found out that problem would stop if I pressed the +20 db gain button. Now that was really weird!

I suspect a faulty unit, or at least a faulty tube. I will write to ART, but I wanted to hear if anyone here using the unit has experienced something like that?

Here is a video showing the problem:
 
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#2
Difficult to tell from the video what fault you're refering to, but on my older ProChannel, there are buttons that select what the VU meter is actually monitoring...are you sure it's configured right? Can't help you on the high tube voltage, mine only has a single tube voltage and it's not selectable.
 
#3
Yes, I tried the different settings for the VU meter, nothing worked as expected. The default setting (no buttons in) is to monitor the output.
I really suspect a faulty tube, but then again, it doesn't make any sense to me, that the +20db gain button affects the tube character LED meter, even if the tube i faulty.

I'm awaiting a reply from ART. I really hope I don't have to get a replacement....
 
#4
Where did you get it from? On the rare occasions that I've had to return stuff, dealers have been very cooperative and I've had the replacement in my hands within a few days. Thomann take the longest. They exchange stuff without quibling about it but, not unreasonably, they don't ship the new until they receive the original one back and check it; so the transport delays of getting stuff shipped back from the UK to Germany then back the other way makes it about 7-10 days.
 
#6
Are you passing any signal through the front end? Or just clicking things on and off? It is hard to tell what is going on, as you are not changing anything meaningful on the unit.

You should be using the voltage on high, and should not be using the mic input controls at all. The Vu meter is only going to move a lot if you have the one of the two selector buttons pushed in.

I am not seeing any inherent problem with your pre.
 
#7
I'll try to clarify. I wasn't putting any signal through in the video. The same phenomenon happens with no input connected at all, and the gain and preamp output all the way down.
As far as I can tell, the LED meters should not be lit up no matter what you do, when there is no input and the gain and preamp is all the way down.
I have to adjust the input gain and preamp output controls to the output of my bass, the only controls that don't affect the instrument input is the variable impedance and 48v phantom.

Do you have the Pro Channel II? If so, does the tube character LEDs light up like in the video when you engage the high voltage?
Also, the compressor shows that it's compressing the signal. It's like there's a DC voltage somewhere when I use the high voltage button, that tells the compressor to do something and lights up the tube character LEDs.
 
#9
I did play it through a poweramp and cab, and there was no weird sounds or noise, but I could hear that the compressor was doing something unwanted to the signal when it showed the "fake" compression with the high voltage button in.
I'm 90% sure it's a malfunction and the more I think about it, the more I believe it's a faulty DC voltage that tells the compressor circuit to compress the signal. The strange thing is that the +20db button removes the problem.
It is definately not doing what it's supposed to do.
No other way than to get a replacement... Maybe I'll try replacing the tube before I send it back.
 
#11
Whoolie said:
I just got my new pre/poweramp setup today, an ART Pro Channel II together with a used Crest Audio CA6.
I plugged everything in and powered it up.
The poweramp is working fine, no problems there, but the pro channel is a bit odd.
The first thing I noticed was that the VU meter didn't really move. I did have sound coming through, but the VU meter was barely moving a millimetre when the output was cranked to the max and the input was almost clipping. So, maybe that was by design when using the instrument input at the front, so I started dialing in the rest of the knobs...
After a while I got to the tube high voltage button. I pressed it and after about 4-5 seconds, the preamp tube character lit half way up on the LED meter below the VU meter, and the compressor below showed that it was ducking a few db. That's when I thought something must be wrong... There was no humming or other strange noise on the output.
So I started troubleshooting a bit, and I found out that problem would stop if I pressed the +20 db gain button. Now that was really weird!
Click to expand...

Hello,

Sorry to breath new life in an old thread. But I bought a Art Pro Channel II and have exactly the problem you're describing here. Did you after all got a solution?
 
#14
HAHA, Got it working. It's a case of getting grips of the gain structure. You have to drive the unit quite loud and the first point where the VU meter is tapped of is from behind the EQ. So mainly cutting frequencies (which is what I do more than boosting) is n't helping either. And both preamp and compressor have a output level compensastion knob to compensate for losses in input driving or compression. Got it sorted now. And got a big fat nice sound from the Art. Amazing piece of gear.
 
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