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When i use hardware stereo coder with 50 ohm mpx out impedance with rg58 in transmiter sound is wide and deep.
If use stereo coder in Breakaway, have stereo separation , but sound is thin, like missing some freq…Tried 2 soud card with 192khz , Terratec aureon space/sky 7.1 and realtek, same thing…
Thanks
Did you use the tilt & eq calibration in Breakaway, to correct for any (if any) non-linearity in each of those two cards?
what is the impedance of the transmitter’s exciter input, and what voltage does it want for 100% modulation? that’s what’s important in this case.
It`s logical to me that input inpedance is 50 omh , because is bnc mpx input in link, and its only input. Link is manufactured by db electronics…
[quote author=”JesseG”]what is the impedance of the transmitter’s exciter input, and what voltage does it want for 100% modulation? that’s what’s important in this case.[/quote]
So, impedance of Transmitter input and not Impedance of cable. i gues you used same cable for hardware coder and Soundcard output when you do your tests.
Better transmitters have Impedance switch, so you can choose fbetween, let’s say, 600ohm and 10Kohm, or 100ohm and 5Kohm
10k is good when you attach Juli@ soundcard, because output from that card is 10k (minimum).from hardware stereo coder mpx out impedance is 50 ohm, using rg58 and sound is ok…. Same cable using for soud card – transmitter connection
PS. Transmitter does not have impedance swithc
Which hardware box do you use iguman ?
the output of your stereo coder has an impedance it was rated to be loaded with. that’s what the output should be loaded with. it doesn’t actually have an impedance tho. you’re not sending signal TO your stereo coder’s MPX output, there-fore it is not considered a load, and doesn’t have impedance.
what’s happening is the soundcard is expecting much more impedance (load resistance) than what the transmitter’s exciter is providing as the load. so in other words, the soundcard is outputting only a small fraction of its intended current before you’re reaching 100% modulation.
that’s why i’m specifically asking what the impedance of the exciter’s input is.
the cable shouldn’t have any impedance on purpose, or you’re also adding capacitive inductance which reduces audio quality.
this is hardware
and have MPX output impedance?
what cable you suggest me for mpx signal from sound card?
lol i have two of this Coders.. i’m not use it anymore… put it on MpxTool and you’ll see why.
i found that CFD200 cable (used for WiFi Antennas) is very good for mpx cable. 50ohm and good capacitance.
You can find it everywhere and it’s chep.No matter what, the output provides voltage, and the input provides a load in the form of impedance.
If two devices are made for the same impedance & voltage, to have the proper current flowing to stay within the operational window, then great. If you put two devices together that are not made for working with each other in terms of impedance, the load…. then you’ll get situations where you have to limit the current a lot (i’m thinking in the case of your soundcard), or that you’ll have to provide more current than the device can give (not enough gain before distortion).
What the output of your stereo coder’s specs is saying… is that it’s expecting to be connected to an input with an impedance of less than 50 ohms.
The soundcard on the other hand is expecting something more around the 10,000 ohms area. So the output is way hotter (voltage) than what the input expects, in other words. So the soundcard has to be set to have a very very low output level compared to the maximum that it can do. Am I correct here? Throw us a bone iguman. 🙂
🙂 JesseG i try to rise level on transmitter with lower out on sound card. Also, to rise level on sound card but no success…
Perhaps i need some addapter or converter from larger (soundcard) to lower (transmitter) impedance. Do you have some elec. schem? 🙂
just add a resistor/s in serial on the cable. this will "pad" the output of the soundcard so that you can run the soundcard with more gain. not sure if that will fix the problem 100% tho.
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