Taperssection.com
Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: jerryfreak on July 05, 2015, 03:33:24 PM
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from last night, nbobs>tinybox (high gain)>ad2k at +24 db input level>digi in>pmd661 . was peaking at 12 db, i though i was ok but it appears im brickwalling/limiiting somewhere
(http://i.imgur.com/H3fq47V.png)
close up
(http://i.imgur.com/OEr5JdF.png)
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ah that makes sense. was in my bag and wasnt even watching. are all TB's the same max input level? i have 2
the one i bought from you in sept 2013, where i requested both LNA + headphone amp and you had some design compromises with that combo so i ended up with:
"I built your box with standard gain (4/16/30) as the headphone amplifier was unstable at 40dB gain with maximum load and volume using the Nbox input. "
and:
"I used a new intermediate amp in this unit as it was more stable than the low noise amp. Noise performance is in between; -122dBV (unweighted) EIN vs. -125dBV for the low-noise amp and -115dBV for the standard amp. Its noise floor will be lower than the CMR or Nbox microphones. It also uses 1/3 the current of the low-noise amp and only twice that of the standard amp, so runtimes will be longer than with the low-noise amp. "
I also own ghomenghasts which was built more recently:
http://taperssection.com/index.php?topic=172272
i dont have specs on this new one but i assume its an off-the shelf unit? it has a 3 way toggle for power (high (up)/off(center)/low(down)). my old TB only has off and on in that switch. whats the difference? my pinout on my old unit is:
"6-pin input pinout: 1 +8V 2 R+ (CMR) 3 L+ (CMR) 4 +54V 5 R-&16V (Nbox) 6 L-&16V (Nbox) chassis gnd"
wanna make sure i dont cook my CMRs by accidentally sending high voltage to them, though i think cabling takes care of that. I have no idea of how ghormenghast's pinout is, only that it works with nbobs as is
thanks
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ok so if you say the TB clips at +13dBu, i should be running the ad2k input level at +14dBu to match the levels, so 0dB on the ad2k is within a dB or so of the tinybox's clip point
and 'mid' gain (+18dB) would be best in this case
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I've only used the high gain setting on mine once for a quiet show at a bar. I have nowhere to post the recording since they're not on LMA.