When running my ART MPA II pre-amp into my PreSonus AudioBox1818VSL using the SPDIF connection, there is a seemingly random generated click/pop. It' s in both channels at the same time, and it's not in the analog outputs. Is this a clock issue? Am I supposed to be giving a certain clock control? They are both running 44.1K/24bit. I am using the analog outs now, but I will want those digital channels back sometime. I use the SPDIF when tracking drum overheads.--thanks for any help.

 

Have you tried connecting the wordclock out from MPA to wordclock in on the AudioBox? That would make the AudioBox a digital clock slave which is preferable since it converts A to D. Or try the other way round but make sure the WC is connected, too. Connecting wordclock as well as SPDIF usually takes care of "things".

I can see you dont have WC in on the AudioBox. So connect the WC out from AudioBox to MPA WC in then. Making MPA a digital clock slave.

edit: or try a higher quality and/or shorter SPDIF cable. You could also try connecting both SPDIF I/Os so MPA would be able to receive the clock from AudioBox. But I prefer WC and it never fails. Only if the thing is somehow broken.

 

Last edited: Feb 5, 2016

Thank you. I am getting ready to track some vocals today, so I'll try your suggestions and run both the analog and SPDIF outs/ins and see what happens. Or listen to what happens, I mean.

 

Good luck! I think it'll work. Optical connections can often be troublesome, but coax SPDIF can be troublesome, too, in rare cases [bad cable, bad chip].

Have you noticed that we have the same number of "likes"? Interesting!

 

According to this, an external clock can improve the sound of your converter. https://www.sweetwater.com/forums/showthread.php?49165-What-is-Word-Clock

 

When you have multiple digital devices it could be nice to invest into some standalone master wordclock, but in case of just a couple of digital devices I don't think it's necessary to worry about it.

But buying it to improve the sound of your converters... sorry but I think [and read] that's mumbo-jumbo territory.

It's main use is to avoid clicks, "chirping", and jitter, not improve audio in any other way. These things are quite imperceptible with your ears only.

 

The article says that the little "jitters" cause phase distortion in the upper frequencies? Usually I am fine with 8 analog channels on the interface (so just one A/D converter), but I do like the ART for adding some tube and adjusting impedance on vocal mic, and the 2 extra digital channels come in handy when tracking drums.

 

Yes! This effectively puts AudioBox into a digital slave mode and receiving the digital clock over SPDIF. That could work.

Let us know if it worked rhythmatist.

..and don't forget to bring up the cowbell! I love your avatar!

 

Thanks, SineWave and MYCbeats. Switching the AudioBox clock setting to SPDIF took care of the issue, and I learned something about word clock.

 

Cheers for the Voice Channel - I've got one as well. Love this freaking thing. Hard to believe it's only a ~$400 box.

 

I have had very good luck with ART products. My ART MPA II makes all my mics sound better than using just interface inputs, though I am very happy with PreSonus stuff, too. I also have an ART phono pre-amp for my turntable. I got my MPA II as an "open box" discount-full warranty. I have gotten some good deals on some products that way. (my Blue Reactor was "open box" too.) ART tubes do a decent job for the price. Would like to have an Avalon or LA, though.....$$$$$$$$$$$$$$--Thanks again.

 

I'm just encouraged by hearing (reading) you say the ART pre makes all your mics sound better. I'm at a point in my audiophile-life where I know there are people with better ears and more experience who might hear things I dont, and I just say F it. But seeing as you're one of those people, it reaffirms what I believe about my preamp

Cheers

 

I love their stuff, they just work.

The pre on my Voice Channel has really low noise, the variable Independence knob is a blessing if you're a one mic pony. The compressor isn't that good for vocals, but it works well as a contingency. Eq is great (though I wish it had a finer range than +/- 12dB), Gate is smooth and click free, De-esser is a bit too gentle, but atleast it helps lighten the load on the converters. The two tube settings are great.

I'm glad you got your digital output to work. If I had a need for 8 channels over ADAT I'd use spdif too but I've heard that ADAT clock is a bit more stable than SPDIF in general.

Also one funky thing that I've noticed is that my Voice Channel's output comes out of ADAT 9 and 10, 9 is distorted, but 10 is clean.
See if thats the same for SPDIF.

 

That depends on the clocking chips/circuit and cables. Coaxial cables are more reliable than optical cables, but if the chips and the clock circuit is quality made any working cable should work and you'd get a stable, non-clicky, non-jittery clock. That is from my experience. One of my clients have a huge rack of preamps that he uses for live recordings, and I can tell you it was really fussy to make all the 48 digital channels work in sync perfectly. He would be completely lost without me.

 

The biggest thing seems to be the ability to adjust the impedance. Changes just about all mics by dialing that around. Changes the sound of the instruments when you use it as a pre for that, too. And sometimes, you just want to push the tubes a little past saturation for shits and giggles.

 

No problems. really hard to tell any/much difference between the analog and and the SPDIF tracks. Recorded both at the same time and A/B 'ed, at least in my cans....no trouble with either channel.