Topic: ua-5 question

[Brian Skalinder]

If the overall gain is from zero to 50dB, then each "clock hour" division should give about 5dB gain.

Assuming it's linear, that makes sense...but I don't believe it is given how sensitive the gain knobs get at high gain.

[el gato]

Richard

I almost always have to set my gains right at 3 o'clock.  It has been my experience that once you move past 3, it takes a much smaller turn to get a larger boost (hope that makes sense)

[poorlyconditioned]

Richard

I almost always have to set my gains right at 3 o'clock.  It has been my experience that once you move past 3, it takes a much smaller turn to get a larger boost (hope that makes sense)

OK, thanks for the help.  AS Brian said, maybe things are nonlinear -- gain changes getting more extreme as you move to the right.  I'll run some tests and report back.

  Richard

[leegeddy]

Richard

I almost always have to set my gains right at 3 o'clock.  It has been my experience that once you move past 3, it takes a much smaller turn to get a larger boost (hope that makes sense)

OK, thanks for the help.  AS Brian said, maybe things are nonlinear -- gain changes getting more extreme as you move to the right.  I'll run some tests and report back.

  Richard

i highly doubt that the gain pot on the ua5 is nonlinear.

marc

[Brian Skalinder]

i highly doubt that the gain pot on the ua5 is nonlinear.

Perhaps I'm using the wrong terminology.  Let me explain it this way:  the gain knobs seem more sensitive as I turn them up.  For example, turning the knob one clock-hour, from 09:00 to 10:00 seems to increase the gain less than turning the knob one clock-hour from 04:00 to 05:00.  I've not measured this, but that's the best way I can think of explaining the increased sensitivity I sense at higher gain.

[§†∑∫åµÞ≥¥]

i highly doubt that the gain pot on the ua5 is nonlinear.

Perhaps I'm using the wrong terminology.  Let me explain it this way:  the gain knobs seem more sensitive as I turn them up.  For example, turning the knob one clock-hour, from 09:00 to 10:00 seems to increase the gain less than turning the knob one clock-hour from 04:00 to 05:00.  I've not measured this, but that's the best way I can think of explaining the increased sensitivity I sense at higher gain.

Fwiw, I have noticed the same thing with my A-T933/853 > A-T8533x > UA-5.

[leegeddy]

i highly doubt that the gain pot on the ua5 is nonlinear.

Perhaps I'm using the wrong terminology.  Let me explain it this way:  the gain knobs seem more sensitive as I turn them up.  For example, turning the knob one clock-hour, from 09:00 to 10:00 seems to increase the gain less than turning the knob one clock-hour from 04:00 to 05:00.  I've not measured this, but that's the best way I can think of explaining the increased sensitivity I sense at higher gain.

brian;

i understand what you're saying and you're 100% correct. i'm quite sure that gain pots in the ua5 is linear; however, the actual resultant GAIN is not.
hopefully the following 2 graphs will help to explain.

(this is based on Analog Devices SSM2017/2019 Gain equation).

i plotted 100 resistor points representing an infinite gain pot (10000 ohm > 100 ohm). this is column A.
column B is the gain based on the gain resistor (Rg): G=1+(10000/Rg)
column C is the gain in dB: A=20*log(G)

x axis (linear) is Rg, y axis (linear) is dB:


you can see that as you turn the gain pot linearly, gain in dB goes up non-linearly (logorithmically, in fact).

if you change the x axis to log scale, then it staightens out.


marc

[Ray76]

my brain is bleeding.

[Brian Skalinder]

i understand what you're saying and you're 100% correct. i'm quite sure that gain pots in the ua5 is linear; however, the actual resultant GAIN is not.
hopefully the following 2 graphs will help to explain.

Yup, explains perfectly.  Big thanks, Marc!

[dklein]

Log(arithmic) taper pots are sometimes called audio pots.  But then even those are typically not true log pots...so almost every pot ends up being more 'powerful' at the end of it's range when we're talking about audio.  A log pot is a better approximation of how we perceive loudness.
(and no, taper isn't a reference to us.  It describes how the change 'tapers' - linear or log)

[jeromejello]

Richard

I almost always have to set my gains right at 3 o'clock.  It has been my experience that once you move past 3, it takes a much smaller turn to get a larger boost (hope that makes sense)

thanks for the 411... i was trying to get a base line for the gain and i taped the opening act at about 11 o'clock and thought it wasnt to the fullest performance... the guys next to me had thier gain all the way to 5 o'clock... i thought i should tap it out... i went around 2-3 o'clock and adjusted the main a tad (about 11 o'clock).  i was definately under my meters... once i get a svu1 (and some more logged time) i will get a better hold on these knobs.

[poorlyconditioned]

Richard

I almost always have to set my gains right at 3 o'clock.  It has been my experience that once you move past 3, it takes a much smaller turn to get a larger boost (hope that makes sense)

OK, thanks for the help.  AS Brian said, maybe things are nonlinear -- gain changes getting more extreme as you move to the right.  I'll run some tests and report back.

  Richard

I'm going to quote myself!  I did some hack experiments.  I just put a 1kHz sinewave out of my headphone jack into the UA5 Neutrix inputs.  I took the output from analog line out.  Does headphone output affect line out level?  I dunno, but I set it to max anyway.

I measured the input level with a voltmeter and got something like 130mV.  At the minimum sens the output was almost the same, 140mV.  At 9 o'clock it went up by *very* little.  At 12 o'clock it was up about 8dB. (dB power, 20*log10(Vout/Vin)).  At 3:00 it was up about 20dB. That is, at 3:00 the signal is amplified by ten times in voltage, one hundred times in power.  I didn't measure it, but between 3:00 and 5:00 there must be a *huge* change gain, going from 20 to 50dB!

So, here is my suggestion: For AT853 (sens -45dB) , start around 3:00 to give 20dB gain.  For hotter mics (eg, sens -35dB) maybe start at 12:00 for 8-10dB gain.

Damn, I just wish that control were linear in dB.  Oh well.

  Richard

[Myco]

Also, you do not necessarily need to record at 44.1, I record at 48 and then resample it to 44.1. Just set your sample rate on the UA-5 to 48 and it will record at that sample rate.

[admkrk]

unless i missunderstand the original ?, i think ya'll are looking too deep. ime, the gain level on a ua-5 depends on the mics. w/ the naks(and batts), i have the gain all but pinned(5:00?). i just tryed it w/ rode nt5s(pp) and had the gain at around midway(12:00). the only difference in the setup(exept for venue) was the mics.

so..........  afaict, were you set the gain on the ua-5 is dependent on the source you're feeding it.


.............throw your stones now.

     kirk

[poorlyconditioned]

unless i missunderstand the original ?, i think ya'll are looking too deep. ime, the gain level on a ua-5 depends on the mics. w/ the naks(and batts), i have the gain all but pinned(5:00?). i just tryed it w/ rode nt5s(pp) and had the gain at around midway(12:00). the only difference in the setup(exept for venue) was the mics.

so..........  afaict, were you set the gain on the ua-5 is dependent on the source you're feeding it.


.............throw your stones now.

     kirk

Exactly!  That is what I predicted in my last post...  Good to hear a confirmation for my undeducated guess about the right level for C4's though.

 Richard