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I like my GML 8200 - BUT...
Old 25th January 2013
  #61
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Alécio Costa's Avatar
 

Verified Member
Calibration

My Pendulum OCL2 is a breathe to match. The IBis EQ has a slight minor diference between L and R.

The STC8 requires a bit more attention of L R output gain to match.

Soon I will post my impression about an Avalon 2055 EQ.

BTW, None of my units are stepped or modded "ME" versions.
Old 30th January 2015
  #62
Gear Nut
 
BOMI's Avatar
Hello to all, suddenly the power of my GML 8200 he began to make a noise of electric type. I measured, therefore, the background noise of the equalizer ......
The result with all the knobs set to zero has been:
- Left Channel - 85 dbfs
- Right Channel - 91 dbfs
in the left channel there is a noise that affects low frequencies and in the right channel you hear a noise that goes on mid-high frequencies (I did not use any analyzer, just maybe if I do this you need to do to see the result).
According to you can depend dall'alimantatore this noise difference?
Or maybe is it normal?
Thank you all and I hope to get answers.
Old 30th January 2015
  #63
Quote:
Originally Posted by Gomez View Post
Ok, I got a very informative reply from GML. However, I did get the obvious answer "buy the mastering version" the only problem with that is that it costs twice as much .

Here's the reply from Jeff Warren:

"Hello,
Thanks for contacting me. And, congratulations on your recent purchase, although I'm sorry to hear the unit is not operating exactly how you want it to.

We strongly encourage mastering clients and others requiring high precision to consider the Model 9500 rather than the Model 8200. The 9500 employs switches and discrete resistors for all controls and thus provides not only L/R matching but also consistency across the entire production history of the unit and vanishingly low distortion performance. Because the 8200 employs potentiometers, the front panel markings can only ever be approximate.

L/R matching depends on various components, each with its own tolerance (5 or 10% in capacitors, 1% resistors). The controls themselves have the widest tolerance (10%); however, this only specifies end-to-end (total resistance) tolerance: anything is possible between the full-ccw and full-cw positions, especially for a non-linear taper. Also, keep in mind when looking at L/R matching that all three controls (level, frequency and bandwidth/shape) matter -- including, naturally, their tolerances.

While the only solid guarantee for L/R matching is to use switches with discrete resistors, GML production attempts to provide L/R matching so far as is practical by selecting controls in matched pairs to be inserted in the same position of each channel. The effectiveness of this measure, however, is limited by the reality of non-idealized potentiometers.

Noting this, conducting a post-manufacture hand-matching procedure to establish marginally improved L/R matching is certainly possible -- but is likely to be judged cost-prohibitive.

Best regards,
Jeff
=====
Jeffrey Warren
GML, LLC.
Nashville, TN USA
www.massenburg."


Although I really appreciate Jeff's informative email, I guess it sums it all up. Not the reply I was hoping to get form the creators of the "Parametric Equalizer offers astonishing precision and sonic accuracy when sculpting the response of any source." a it says in the manual. Interesting, as I said, my Mass Pass and IBIS are not that off...

I think I may pass...
I use a non mastering 8200 for mastering and as you say the chances of level matching visually are nil. 40 hz will not be 40hz and 40hz on the left (which isn't 40hz anyway) will probably be a different not 40Hz on the right....BUT the mastering version is double the cost and the unit DOES sound great so what to do? I developed this workflow. Neutralise the unit. Use a digital EQ like the MDW EQ to find an area of interest say 63Hz and a good q value, set up a plug in scope and level system like the Flux metering essentials. Send a test tone at 63Hz boost the left and sweep till you get a straight line leaning left in your scope. Now boots right and sweep till the oval becomes a straight line (you are frequency matched) Then adjust boost/cut till that perfect line is smack in the middle. Repeat process. I would not be surprised if that didn't get you better matching than the mastering version and it sounds amazing when properly lined up. Of course recalls are a bitch and it takes longer. So long run does the time = enough money to = just buy the mastering version (which also has a lower noise floor) that depends but for now I get THAT sound and it is amazing for half the price. You can get em second hand now for around £2500 UK and thats great.
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