The CD player manual (online PDF?) might give you the output level. The typical/standard value might be 2Vrms but not all are like that.
You could look at the gain of the preamp and the gain of the MX50SE (written on the bottom of the PCB in silkscreen) and see if you have excessive gain. With the CD player I don't think the MX50SE will need the gain of a preamp. But it sounds like you would like the tone control adjustments?
If someone has a schematic for the XH-M164 preamp it might be fairly easy to look around the op-amps and figure out the gain from the resistor values. (And thus suggest an adjustment.) I don't have the schematic. Perhaps someone else has the schematic?
You could look at the gain of the preamp and the gain of the MX50SE (written on the bottom of the PCB in silkscreen) and see if you have excessive gain. With the CD player I don't think the MX50SE will need the gain of a preamp. But it sounds like you would like the tone control adjustments?
If someone has a schematic for the XH-M164 preamp it might be fairly easy to look around the op-amps and figure out the gain from the resistor values. (And thus suggest an adjustment.) I don't have the schematic. Perhaps someone else has the schematic?
Input the level for this Audio amplifier MX50-SE is 1.5V!
For CD-PLAYER output level is the tpical 1.8V, and FM-TUNER output level is 2V,
What is the ouput level of this ton control XH-M164?
Thanks
For CD-PLAYER output level is the tpical 1.8V, and FM-TUNER output level is 2V,
What is the ouput level of this ton control XH-M164?
Thanks
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That depends on the gain and the input level.
Do you know the gain of the preamp? If not perhaps you could measure it with REW software and a computer/laptop/soundcard?
Or can you make your CD player or PC or something else output a 1kHz sine wave and use an AC volt meter to measure the input and output amplitudes to measure the gain?
Ok!
R9,R22=100k and R6,R20=2k
Au1=20log(R9/R6)+1=20log(100/2)+1=20log50+1
34,98dB Gain for XH-M164
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If those are the resistor values I guess Av=50 and we have 34 dB. Wow, is it really that high? I assume you double checked R9 & R22 color code/value? That is a lot to put between a CD player and an LJM power amplifier. I would think the CD output would be pretty close to enough for the LJM.
So with that information perhaps you can look at Post 12 along with the gain equation/resistor values and you can then adjust the gain to the value you desire?
Did you find the gain information in silk screen on the bottom of the LJM MX50SE PCB?
So with that information perhaps you can look at Post 12 along with the gain equation/resistor values and you can then adjust the gain to the value you desire?
Did you find the gain information in silk screen on the bottom of the LJM MX50SE PCB?
