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About juanquielectronico

  1. Hi, I have a dead crown I-tech 4000, and I need the schematics in order to repair the amplifier. Please, can anyone send me the amplifier schematics? Thanks.
  2. Hi, my amplifiers aren't in guarantee because wasn't purchased in Spain. I have problems with two XTI 4000 units. I tried ribbon problem fixation, resoldering pots, and my problem in a unit, persists. Recently, I have decided trying fixed resistor network in the gain amplifier in order to eliminate ribbon and pots from the equation. I have a question referent to XTI gain. In System Architect, the input level meter, is the level in the diferential input amplifier? In my units, I have advised that I cannot adjust this gain with pots, and I don't know if this is a pot problem, or because this level is measured in the previous stage. Thank for your help and regards. Juan Carlos.
  3. Hi, I have problems with my XTI units. I have the cut off problems, and some problems with pots. It is possible to obtain the XTI4000 Schematics? Thank you very much and regards.
  4. How much it is possible to reduce this digital gain in order to rise the analog input signal? Is not possible saturate the analog input , or to reach the limit reference of the A/D? This would produce a hard clipping situation without reaching the maximun power limits of the amplifier. If this gain adjustment is good in order to supress this noise, If this noise ocasionated in the ADC? I was wrong with the class of this amplifiers, not Class D+AB Thank you very much for your answers.
  5. Hi, I solved the cutoff channel too long time ago with resoldering pots. The ribbon was not the problem (I checked). I suppose that you are relating to the gain problem with one channel. This problem appeared in the other unit, I haven't opened, but it is possible that this gain problem could be caused by the ribbon. I will check this as soon as possible. And, this is important: I would like to know, if the hiss noise in the XTI units can be removed with a input low pass filter around 30KHz (2nd order or higher). I explained in the other post. Can anyone check this?. Thank you very much
  6. Is possible eliminate this hiss with a input low pass (second order or higher) filter arouund 30KHZ in order to eliminate high frecuency noise pickup? I have observed the same problem in Class D amplifiers. I have two units of the XTI4000 conected from driverack(DBX) with balanced lines, and ground isolated via audio transformers, but I can not eliminate this hiss. I'm designing a class D amplifier, and, in my design, I have encountered the same problem. The obvious manner to eliminate this noise, is low pass filtering the input, because the high frequency harmonics received at the input, are producing a variation in the high frequency PWM of the power stage, this error in the PWM, is modulating noise in the audio band (the undesired hiss). I would like to ask if it is possible that this was causing in a similar way the hiss noise in the XTI units. ¿Is the class D power stage of this class I amplifier self oscillating, or a clocked design? ¿How can we eliminate finally this terrible noise? To Don Richard: I have the same problem of cutted channel with a XTI, I have checked all the fixings (ribbon, resoldering conectors), and finally, the last try to fix, was resoldering pots. I have not anymore problems with this unit. The pots of this units aren't very good (in my opinion), I have mesured, and the result was a non lineal variation of the resistor value. I have a unit that is functioning in a gain erratic mode in one channel. Is imposible to adjust the stereo balance. I have non gain variation at this pot when adjust (this is not the unit that i have resoldered) . Sorry for my bad english, and thanks and regards.