I get a better indication when lineout specs are in voltage figures.
My preamp preouts are 75 ohms, a crossover I'm interested in has output preout power of 100 ohms.
What does this equate to in voltage at the outputs?
Since I'm using pa amps for my subs, my domestic preamp is starving the inputs of power. I have to max the gains on the amps to operate the subs. But its not enough for me.
Im leaving a bunch of spl's on the table this way.
So I thought defeating the onboard crossover and putting a dbx 223xs for a stand in would remedy two things.
But is a 25 ohm step up significant enough to light the subs up and push them properly?
Input requirements for the pa amp are selectable, either 1.4 Vrms and .775Vrms.
BTW I had set it on both to test. There is no difference between them in terms of main volume increases/decreases. Wich is baffling to me. The pa amp in question Crown xls 1002.
My main question about the 25 ohm increase with the dbx is the million dollar question. If it makes my subs work and actually push some air Ill pull the trigger.
The inline boosters I tried failed. This seems like one area where quality parts are not offered. Unless Im over looking something.
My preamp preouts are 75 ohms, a crossover I'm interested in has output preout power of 100 ohms.
What does this equate to in voltage at the outputs?
Since I'm using pa amps for my subs, my domestic preamp is starving the inputs of power. I have to max the gains on the amps to operate the subs. But its not enough for me.
Im leaving a bunch of spl's on the table this way.
So I thought defeating the onboard crossover and putting a dbx 223xs for a stand in would remedy two things.
But is a 25 ohm step up significant enough to light the subs up and push them properly?
Input requirements for the pa amp are selectable, either 1.4 Vrms and .775Vrms.
BTW I had set it on both to test. There is no difference between them in terms of main volume increases/decreases. Wich is baffling to me. The pa amp in question Crown xls 1002.
My main question about the 25 ohm increase with the dbx is the million dollar question. If it makes my subs work and actually push some air Ill pull the trigger.
The inline boosters I tried failed. This seems like one area where quality parts are not offered. Unless Im over looking something.
Sorry but absolutely NO relation between ohms and Volts.
Quite possible, typical Home Hi Fi levels are around 200-500mV while you stated your Power Amps can be set to 775mV (preferred) or 1.4V RMS which will be even harder to drive.
Your DBX crossover can probably take preamp level and rise it to Power amp needs.
Don´t blame high quality stuff you are using, rather to absolutely no clue on the part of the user.
Get a Tech savvy friend to help you, we can explain all day long but then somebody has to properly apply that to the situation.
It´s hard to follow your explanations, you are not using the proper terms. but I think your domestic preamp line/preamp out can´t properly drive your Pro PA power amps.
Quite possible, typical Home Hi Fi levels are around 200-500mV while you stated your Power Amps can be set to 775mV (preferred) or 1.4V RMS which will be even harder to drive.
Your DBX crossover can probably take preamp level and rise it to Power amp needs.
Don´t blame high quality stuff you are using, rather to absolutely no clue on the part of the user.
Get a Tech savvy friend to help you, we can explain all day long but then somebody has to properly apply that to the situation.
I agree this is a fairly complicated amp and a lot of DSP settings can be difficult to grasp if one is not acquainted with it.
A possibility is that the FILTER is set to HIGHPASS (or low cut if that makes more sense). Read the manual carefully. The service manual give you a more in-dept eplanation of how this amp functions. If needed you can revert to factory settings and try again from there. If all this seems over the top to understand, follow JMFahey's advice and let a friend help you.
Hugo
A possibility is that the FILTER is set to HIGHPASS (or low cut if that makes more sense). Read the manual carefully. The service manual give you a more in-dept eplanation of how this amp functions. If needed you can revert to factory settings and try again from there. If all this seems over the top to understand, follow JMFahey's advice and let a friend help you.
Hugo
...power of 100 ohms... Power is in Watts, impedance (resistance) is in Ohm's.
Considering an input impedance of the Crown in the order of 10kohm or more, so the difference in attenuation caused by this impedance difference will be:
10k / (10k + 75) =0.9925558 or 10k / (10k + 100) = 0.990099, a difference of 0.25%.
These are normal values for pro equipment, either unbalanced or balanced (twice the unbalanced value).
JMFahey is right in #3.
I have a commercial preamp, capable of 0.775Vrms unbalanced output. For the neccessary headroom, the supply rails in that pre are +/-30Vdc.
You connect an unbalanced signal to an unbalanced input... that's ok sofar.
You connect an unbalanced signal to a balanced input... that's only a half of what is needed. The result is the same then.
Does the DBX have balanced outputs? That will make a difference.
Interesting. Inline boosters.
I hope you do not mean 75ohm HF inline coax cable phantom powered signal boosters.
Can you post a picture of these?
Signals (as opposed to power) for audio are not spoken of in terms of power, but always in voltage (typically rms voltage, or a decibel version such as dBV or dBu).
Usually with audio signals outputs are low impedance, and inputs are high impedance, so very little voltage drop happens, making it simpler to just quote the voltage, since sent and received voltages are basically the same.
Radio frequency conventions are very different, BTW, as transmission lines are almost always required for signals (coax, UTP, STP, waveguide)
Audio power connections are typically talked of in power and impedance, ie 50 watts into 8 ohms.
Usually with audio signals outputs are low impedance, and inputs are high impedance, so very little voltage drop happens, making it simpler to just quote the voltage, since sent and received voltages are basically the same.
Radio frequency conventions are very different, BTW, as transmission lines are almost always required for signals (coax, UTP, STP, waveguide)
Audio power connections are typically talked of in power and impedance, ie 50 watts into 8 ohms.
I dont understand why they note preout line in omhs but ill gather that to link it given more time.
You pretty much summed up the entire situation. The crossover ino was/is the best possible link to marry pa equiptment with domestic and endure a happy union. Hence going back to my original question about that particular crossover making up for the volt shortcomings.
My add gets over stimulated sometimes and my explanations sometimes lack straight forward east to grab detail. Not sure if I am fully at fault for over complicating op but its not really important.
The amp is set up corectly, a 100hz cut off blends subs with mains, nor am I able to pinpoint direction. But Im left teased when I want to push bass without having the sats blazing full on.
I have the resistance set on the least resistance.
I think i was relatively clear not blaming quality parts on this that or the other thing.
I was blaming a poj part I found to boost my low lines. Not suggesting the dbx is junk, i have multiple parts from dbx parent company.
The junk in question, that took on an ugly very noticable hum through subs, not the xover. I can see that (dbx) staying unless I switch it out for a Bryston 10B. But still staying. It wasnt a purchase I had in mind until going over sub dillema atm.
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An outputs output impedance is specified so that when choosing the unit to be connected to that output, a suitable input impedance can be secured. The "rule" is to see to that the output impedance is distinctly lower than what is being driven. Say 10 (or 100) ohms out driving a 10k load. This is why output impedance is specified. Standards exists where out and input impedance are equal - in e.g. balanced 600 ohms systems.
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Thanks for your post. All are appreciated.
The reason is fine and serves a purpose.
I was hoping for something that doesnt apply then.
I simply seen it with other preout specs and assumed that it did apply with a different measurement.
Why they don't note output voltages in plain easy to read print as others do still escapes me however.
Attachments
Crown was absorbed by Harmon too, I wasn't even counting them but that makes five.
Harmon bought Madrigal then they picked up Crown and dbx as it turns out.
When I selected the volts I flipped back and forth while sitting at the stereo.
I should of set it than walked around the room. .775 is more weighty, marginally. Better but I think Ill grab the seperate xover. I'd like the lows to have more flexibility, and come in sooner down through lower volumes.
Harmon bought Madrigal then they picked up Crown and dbx as it turns out.
When I selected the volts I flipped back and forth while sitting at the stereo.
I should of set it than walked around the room. .775 is more weighty, marginally. Better but I think Ill grab the seperate xover. I'd like the lows to have more flexibility, and come in sooner down through lower volumes.
Something is not correct here.
There could be an issue regarding balanced & unbalanced input connection wiring.
The .775Vrms selection should give you significantly more output level.
But they DO, clearly.
The most mentioned value is 500mV
* first mentioned in S/N ratio
They also mention higher (2V) and lower (100mV) as reference, before somebody asks: "but what if ..... ?"
* they also mention maximum output signal: 8V RMS
Notice all these values "dance around" 500mV ... a few dB higher or lower.
* sensitivity spec is referred to 500mV output.
You cropped out part of that spec screen, not surprised if 500mV is also mentioned related to some other spec.
So the answer to your question is: that Preamp is optimized for a 500mV output.
That said, it´s also silent enough to be used with down to 100mV signals, and powerful enough to put out some 2000mV output with negligible distortion.
They also warn you (indirectly) that it will clip if you surpass 8000mV output signal ... which is the Real World spec for normal OpAmps fed +/-15V rails, what I expect to find there (as in it being "Industry Sandard")
In a nutshell, I see that preamp spec set as properly written, following Industry Standards.
Nothing cheating or misleading.
Here comes the dentist to pull some teeth..
Sub, how about you tell us What the actual units are, How you have it wired, And what you hope to achieve.
That way, instead of wild guesses and speculation, we can look at real info based on what you have, so people can offer proper advice.
Sub, how about you tell us What the actual units are, How you have it wired, And what you hope to achieve.
That way, instead of wild guesses and speculation, we can look at real info based on what you have, so people can offer proper advice.