CECAA850 Posted February 19, 2014 Share Posted February 19, 2014 I was trying to find out what voltage the amp needs to drive it to full output. Does .775v sound about right? Thanks, Carl Quote Link to comment Share on other sites More sharing options...
Quiet_Hollow Posted February 19, 2014 Share Posted February 19, 2014 That checks, according to the Crown literature. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 19, 2014 Author Share Posted February 19, 2014 Thanks. My pre-amp only puts out 1.0v and I really have to crank the knob to get things going. Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted February 19, 2014 Share Posted February 19, 2014 isn't 1.0 > .775? why wouldn't it be able to drive full output? Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 19, 2014 Author Share Posted February 19, 2014 isn't 1.0 > .775? why wouldn't it be able to drive full output? Yes it is. Like I said, I really have to crank the knob and wanted to verify that my preamp was capable of driving the Crown full out. I knew my preamp max voltage but wanted to verify the Crowns needs. Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted February 19, 2014 Share Posted February 19, 2014 gotcha. still trying to grasp input/output impedances, voltages, dB's and how they affect one another. If you connected a preamp closer to 2v, then you would only need to crank maybe 50% to reach full output on the amp? Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 19, 2014 Author Share Posted February 19, 2014 Pretty much, assuming the voltage output was linear. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 19, 2014 Author Share Posted February 19, 2014 Pretty much, assuming the voltage output was linear. Just checked, mine's definitely not linear. You'd have to measure the voltage to tell for sure where you'r amps required voltage is in relation to the dial. Something else occurred to me. My amp has been modded. It may (or may not) have changed the voltage needed to drive it. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 19, 2014 Author Share Posted February 19, 2014 I also have balanced to unbalanced adapters on my amp so that it will accept RCA's. That may be screwing with the voltage as well. It's a PITA to get to the backside of the unit to measure things so I'll probably just continue to crank the knob. Quote Link to comment Share on other sites More sharing options...
babadono Posted February 19, 2014 Share Posted February 19, 2014 Yes, correct, not linear, from wikipedia: Audio control Low-power potentiometers, both linear and rotary, are used to control audio equipment, changing loudness, frequency attenuation and other characteristics of audio signals. The 'log pot' is used as the volume control in audio power amplifiers, where it is also called an "audio taper pot", because the amplitude response of the human ear is approximately logarithmic. It ensures that on a volume control marked 0 to 10, for example, a setting of 5 sounds subjectively half as loud as a setting of 10. There is also an anti-log pot or reverse audio taper which is simply the reverse of a logarithmic potentiometer. It is almost always used in a ganged configuration with a logarithmic potentiometer, for instance, in an audio balance control. Potentiometers used in combination with filter networks act as tone controls or equalizers. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 19, 2014 Author Share Posted February 19, 2014 Makes sense, thanks. Quote Link to comment Share on other sites More sharing options...
djk Posted February 20, 2014 Share Posted February 20, 2014 (edited) " It ensures that on a volume control marked 0 to 10, for example, a setting of 5 sounds subjectively half as loud as a setting of 10." This is incorrect. A log pot is -20dB at half rotation, that is about 1/4 as loud, not 1/2. Preamps like the Marantz 7, Yamaha C2, and the Lampton-Zukauckas have a semi-log taper that is -12dB at 1/2 rotation. Experience has shown me this works better than a log control. http://www.ssl.berkeley.edu/~mlampton/LamptonZukauckas.pdf Edited February 20, 2014 by djk Quote Link to comment Share on other sites More sharing options...
jacksonbart Posted February 20, 2014 Share Posted February 20, 2014 actually its a crystal glass and 2 ice cubes 1 Quote Link to comment Share on other sites More sharing options...
Marvel Posted February 20, 2014 Share Posted February 20, 2014 Carl, Do you have one of the amps that Mark modified? Bruce Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted February 20, 2014 Share Posted February 20, 2014 (yes he does) Quote Link to comment Share on other sites More sharing options...
Quiet_Hollow Posted February 20, 2014 Share Posted February 20, 2014 still trying to grasp input/output impedances, voltages, dB's and how they affect one another. A great place IMO to start looking is at the decibel.That's the Rosetta stone. Aside from its formal definition, the decibel allows the math to jump from one unit value to another. If there was one term I'd spend the most time on trying to grasp, first off would be that. 1 Quote Link to comment Share on other sites More sharing options...
babadono Posted February 21, 2014 Share Posted February 21, 2014 " It ensures that on a volume control marked 0 to 10, for example, a setting of 5 sounds subjectively half as loud as a setting of 10." This is incorrect. A log pot is -20dB at half rotation, that is about 1/4 as loud, not 1/2. Preamps like the Marantz 7, Yamaha C2, and the Lampton-Zukauckas have a semi-log taper that is -12dB at 1/2 rotation. Experience has shown me this works better than a log control. http://www.ssl.berkeley.edu/~mlampton/LamptonZukauckas.pdf DJK, You sir are correct. Perhaps you should edit the wikipedia entry. Spent some time today re reminding myself how volume controls work. Thank you. Eric Quote Link to comment Share on other sites More sharing options...
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