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Smart C" stereo-imbalance? Effects Pedals, Units & Accessories
Old 15th December 2008
  #1
Gear Maniac
 
LSD-Studio's Avatar
 

Smart C2 stereo-imbalance?

Hey there...

I've just sent several testones through my C2 (DAW-->RME ADI8-->C2-->Apogee-->DAW)

when the C2 is bypassed the levels on the left and right channels are absolutely the same (so it's not the converter).

but when I put the C2 in the change (w/o any compression as well as with the C2 compressing in stereo-mode) the right channel is 0.06dB louder.


is there a way to tweak some internal pots of the C2 (if so, which), or would it be better to just make up for the 0.06 dB on the way back in (the levels on the apogee can be set independently)?
Old 16th December 2008
  #2
Lives for gear
 

I found this on my unit many years ago. Never got any answer from anyone about what to do about it. Since I always use it on 2 buss I calibrated the input of my 2192 to deal with it. Not ideal but I love the unit on mixdown.
Old 16th December 2008
  #3
Gear Addict
 
leebridges's Avatar
 

i could definitely be wrong, but i think the make-up gain controls on the individual channels still work independent of each other (even in stereo-link). what is stereo-linked is the amount of compression applied to each channel.

anyone else with a definitive answer?
Old 16th December 2008
  #4
interesting, mine has that too! as it's in Brasil i've decided to just live with it, i make up the difference elsewhere.
Old 16th December 2008
  #5
Gear Maniac
 
LSD-Studio's Avatar
 

the gain-pots are linked as well in stereo-mode...plus, I think the increments are bigger than the 0.06dB.

so it looks like I gotta make up for it after the comp in the apogee.
would still prefer to tweak an internal trimpot to fix this
Old 16th December 2008
  #6
Lives for gear
 
stevetgn's Avatar
Not sure where you are based but Alan would certainly help you out here in the UK if you give him a shout.
Old 16th December 2008
  #7
Smart Research
 

C2 Calibration

Sorry not to pick up this thread till now....(thanks for the link Lasse)

As you found, yes, all the controls are from the left channel when in Stereo mode, and the makeup increments are 0.5dB.

We have a method of trimming any standing gain offset internally, which I'd be happy to provide to anyone who wished to send their C2's back for a few days ?. Hopefully a fix could also be found if you are outside the UK, and it could be done locally if you have a tech happy with handling 1206 size surface mount components. Best thing is to email via Smart Research website for support/help......

Alan Smart
Old 17th December 2008
  #8
Lives for gear
 

I'm having this problem with my unit as well. I'll send an email thanks Alan.
Old 17th December 2008
  #9
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paterno's Avatar
 

I run into this every once in a while, and all I've had to do is re-seat the three single-line socketed IC's on the left and the right. It is almost always the right side that dips in level for me. I usually spray out the sockets while I'm at it. I have a very early C2, so I'm not sure how much the design has changed in the subsequent years.

good luck,
John
Old 17th December 2008
  #10
Smart Research
 

John, if R level changes occassionally, it may be connected with movement around those VCA's you described. In early units, some 22ohm resistors in positions R119 and R120 next to the VCA's could go intermittant, so spraying/handling the VCA's might also fix this.

Also, next time it might be worth checking underneath the PCB that all the IC socket pins are correctly soldered, and no VCA pins are bent over ?.

Give us a shout or Sunset Sound if you'd like a hand ?...Al
Old 17th December 2008
  #11
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paterno's Avatar
 

Quote:
Originally Posted by Dailydb View Post
John, if R level changes occassionally, it may be connected with movement around those VCA's you described. In early units, some 22ohm resistors in positions R119 and R120 next to the VCA's could go intermittant, so spraying/handling the VCA's might also fix this.

Also, next time it might be worth checking underneath the PCB that all the IC socket pins are correctly soldered, and no VCA pins are bent over ?.

Give us a shout or Sunset Sound if you'd like a hand ?...Al
Hey Al --

Is it worth just changing out those resistors? Are they labeled on the circuit board as R119 and R120? And is it one resistor per side, or are there a pair on the Left side for me to consider as well?

thanks!

John
Old 17th December 2008
  #12
Smart Research
 

Quote:
Originally Posted by paterno View Post
Hey Al --

Is it worth just changing out those resistors? Are they labeled on the circuit board as R119 and R120? And is it one resistor per side, or are there a pair on the Left side for me to consider as well?

thanks!

John
Yes, though if they fail these would usually cause a big change, it may be worth it as a precaution. Two on each side: 1% size 1206 resistors, L is marked R72 and R62 on the PCB (slightly different places to Right)....good luck !

Al
Old 18th December 2008
  #13
Gear Maniac
 
LSD-Studio's Avatar
 

well, I'm living outside the UK (Germany) and am constantly using the C2.
I AM pretty handy with the soldering iron though, so if there's a fix, could you PM me how to perform it?
Old 18th December 2008
  #14
Smart Research
 

Quote:
Originally Posted by LSD-Studio View Post
well, I'm living outside the UK (Germany) and am constantly using the C2.
I AM pretty handy with the soldering iron though, so if there's a fix, could you PM me how to perform it?
No problems....bear with me for a few days as I need to document this properly, eat some mince pies, then I'll email.

I can eat pies fast though !

Al
Old 19th December 2008
  #15
Lives for gear
 
heathen's Avatar
 

Hey Al that would be great to post a fix as yes mine is about 0.1 db out on the left, though I've lived with this for so many years I think I've made my own extra switch position by constantly having the pot in between.
Old 20th February 2009
  #16
Smart Research
 

Ate too many mince pies.....

I've now updated the 'C2 Alignment&Service notes' to include the method to trim the 'idle gain' imbalance internally.....(though a little later than I'd hoped..sorry !)

Please email via smartresearch for a copy, or it will go up on the website shortly.

Al.
Old 21st February 2009
  #17
Lives for gear
 
Aisle 6's Avatar
Thanks Al.
I'll keep an eye on the website.
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