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API A2D Calibration issue
Old 15th November 2009
  #1
Lives for gear
API A2D Calibration issue

I have an API A2D, and I usually track through the left preamp and converter. On a whim tonight I recorded through the right and discovered that the level in the digital section for the right side was significantly less.

Later I ran a 1kHz tone through a monitor and held up a 57 so that the preamp meter read "0". With the digital section's dial fully clockwise:

"A" read -18. "B" read -27. I repeated the test with the output of my mixer going to either A/D section with similar results (so it's not a preamp output problem). I used the same mixer output and same cable for both "A" and "B".

I've tracked using both preamps and both converters simultaneously many times before (usually acoustic guitar and vocal) and haven't noticed the low level on A/D "B" before (which isn't to say it wasn't the case) but I can't think of anything that would have caused the change.

Any illumination? And any way to get this fixed without losing my A2D for 4-6 weeks?
Old 15th November 2009
  #2
Lives for gear
 

-6db is a cable unbalancing, which leads me to suspect you have half-dislodged a cable at the patchbay or lost balancing in one of those cables.

Switch the cables into the converters ("A to D in" on the A2D itself) and see what happens. Maybe see if the connection isn't balanced in the jack there.
Old 15th November 2009
  #3
Lives for gear
Interesting...

Within the A2D, the output of the preamp is half-normalled to the A/D of course, and the level drop occurs without anything patched...

But if I have patched in to the A/D section of "B", and I pull out the cable slightly, the level jumps about 6 dB (very close, but just below the level of A/D "A"). If I pull out the cable of "A" slightly the signal just goes dead.

It seems to me the problem is definitely within the digital section "B" of the A2D. I've tried 2 cables, but in any case "A" has expected results. And it's not (simply) the connector for "B", as it happens in the normal situation with no cables at all.
Old 15th November 2009
  #4
Lives for gear
stupid question- you havent engaged the pad switch on one side have you?
Old 15th November 2009
  #5
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Quote:
Originally Posted by nigel saunders View Post
stupid question- you havent engaged the pad switch on one side have you?
or turned the attenuator knob?
Old 15th November 2009
  #6
Lives for gear
I wish! The digital section doesn't have a pad (no pads were pressed on the preamps in any case). The digital section's "digital input level controls" are fully clockwise.
Old 15th November 2009
  #7
Lives for gear
 

Probably can find a competent tech to look while-you-wait if you're near a major music city.
Old 4th November 2010
  #8
Lives for gear
 
Lando Calrissian's Avatar
I'm having this same calibration issue! The level on my right channel is 1-2 db less than the left. Both channels and digital section are set equally on the front. Any ideas?
Old 17th November 2010
  #9
Gear Head
 
streetvibes's Avatar
 

Unscrew the cover and look for trim-pots to turn, then look at your meter while doing so. Great partytrick.
Old 18th November 2010
  #10
Gear Head
 

Hmmm....i've got the same problem here with my A2D. Lower level on the right hand side BUT it corrects itself if i press firmly between the channel A digital gain pot and the channel B line in....!!

Is the problem apparent when you first power on ?

This is the second A2D i've had. I had problems with the first one and had to send it back. I'm also on my second 2500 - the first one was brand new yet wouldn't power up at all. My current (second) one is starting to act up too.

Is there a correlation between price and reliability - the more you spend the less reliable the gear becomes....?!?
Old 18th November 2010
  #11
Lives for gear
 
Melgueil's Avatar
 

Man these stories are depressing - I mean really.

I was considering an A2D - now what ? I know API has the reputation and such but wow. I own a Great River. I could run it over with a freight rain - or maybe tie my dog to it. 3 years. No hiccup, whatsoever.

I hate hearing this stuff - the A2D looks like a cool box and a nice addtion to my rack ....damn
cdlt
Old 18th November 2010
  #12
Gear Head
 

Yeah it is depressing. The A2D sounds fantastic, but the issue with channel B playing up has effectively made it useless until i can get it properly serviced.

The original A2D that i had gave off this terrible burning smell the first time i switched it on. When i tried to take it out the rack the chassis was so hot i couldn't touch it. Worrying to say the least.
Old 18th November 2010
  #13
Gear Head
 

One additional customer story:

My A2D didn't output wordclock when I got it. The importer gave me permission to open the unit without voiding the warranty. The wordclock PCB was installed too far so that only one row of pins in the connector were connected. I removed the PCB and installed it correctly and it has worked since.
Old 20th November 2010
  #14
Here for the gear
 

Just thought I'd offer a contrasting experience -

I've owned and used an A2D almost daily for about 3 years now and never had any issues. Much of that use has been as part of a studio guitar rig which gets moved all over town by the cartage guys in a non-shockmount rack. It always works flawlessly and sounds great (knock on wood!).

Have you called API? They're great guys to deal with.
Old 26th March 2012
  #15
Here for the gear
 
Ricksterpt's Avatar
I had My A2D for 2yrs now channel B turn on and off weird.
Old 26th March 2012
  #16
Gear Addict
 
slackstallion's Avatar
 

I would bet 20 bucks, having never seen the pcb, that there is some kind of poorly designed ribbon cable assembly tethering sections together that is compromised. We see this all the time on amps, the varying db is a symptom. Probably side B routes through some ribbon cable or some terminal adapter with all sorts of leads shooting out from it. All this important sh%t running through some cheap cable being stressed at all sorts of angles.

Meaning there is probably a fractured solder joint (crowned from heat) or a wire that has lost contact at a terminal connector (think of a computer drive internal power cable). When that one guy pushed the faceplate and gets the instant fix, that is obviously related to a connection.

I will bet another 20 bucks that whatever design might have led to this was quietly fixed in a newer build version.

I could be way off, though. Pure speculation.
Old 26th March 2012
  #17
Gear Guru
 
u b k's Avatar
 

I also want to add that my a2d has kicked ass since the day I got it, 3 or 4 years now.

And API is great people top to bottom, but you should call your dealer and have them sort this out on your behalf, that's why you paid them their markup... it's their job.

BTW, have you confirmed via recording that the level difference actually exists, and that you're not having a metering issue? Each channel of the A2D meters is driven by two chips, one for the lower half of LED's and the other for the upper half. If one of those chips fails, your unit would still work fine but the meter on that channel would only display halfway up, making it look like the level is lower than it actually is.

Just a thought, good luck with it!


Gregory Scott - ubk
Old 26th March 2012
  #18
Lives for gear
Just as a follow up to my resurrected thread, I eventually sent the unit to API in Maryland and they fixed it. It was a damaged or otherwise non-functional op-amp that needed to be replaced.

It runs perfectly now.

Repair time was a little bit longer that I would have liked, though I wasn't in a huge rush. Parts were under warranty, but I had to pay a bit for labour.

Shipping back to Canada was pretty expensive (UPS I believe), and I've been told by someone who gets stuff shipped from the USA regularly that in hindsight I should have asked for a different means.
Old 26th March 2012
  #19
Gear Addict
 
slackstallion's Avatar
 

They charged you for labor? You should follow up with an email asking what typically causes opamp failure. At least you got it sorted out!
Old 27th March 2012
  #20
Lives for gear
Quote:
Originally Posted by slackstallion View Post
They charged you for labor? You should follow up with an email asking what typically causes opamp failure. At least you got it sorted out!
I believe the warranty is something like 1 year labour, 5 years parts, so it was beyond the labour warranty. I can't remember if it had failed before 1 year or not, but I did delay getting it serviced because I was using the good channel quite a bit and couldn't be without it.

Anyway, I love the product and I'm a satisfied customer. The shipping thing kind of sucked. I continue to dream of all the API products that I would like to own and consider myself lucky to have the one that I do.
Old 29th March 2012
  #21
Gear Guru
 
u b k's Avatar
 

Quote:
Originally Posted by M4-10 View Post
Shipping back to Canada was pretty expensive (UPS I believe), and I've been told by someone who gets stuff shipped from the USA regularly that in hindsight I should have asked for a different means.

The trick is for you to mark it as "return to domicile for repair" when you send it out, and for the repair facility to mark it as "repaired goods, return to owner". That eliminates most of the duties and fees in both directions.


Gregory Scott - ubk
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