Xtant X604 Repair

91h22a · 1st March 2011, 04:26 PM

So I have a x604 Amplifier here and It amplifies Left and Right Rear channels just fine. Left Front Channel and Right Front channels are a different story.

When I hook my function generator to Left front there is little amplification (gain set to min, DC 0.00v on all channels) out of the Left Front +- output terminals. But when I look at the Right Front +- output terminals-input still connected to Left Front- I have amplification of Left's input...It seems there is huge "crosstalk" (for lack of better word) between the channels. Is there anything common to this amp that might cause this? I appreciate any help/advice in advance.

Perry Babin · 1st March 2011, 10:44 PM

Are the jumpers set as shown in the attached photo?

91h22a · 1st March 2011, 11:32 PM

no. Balanced inputs defeated and gain is 0dB. I hope the attached image helps.

Also in the second image the LM311N (u22) circled, Its waveform on pin 2 and 3 do not match the 311 to the left(u21). they look to be garbage/noise. I looked at your tutorial's waveform of a x603 and u21 matches u22 does not. Thank you again for your help Mr. Babin.

Perry Babin · 1st March 2011, 11:38 PM

If you set them as shown in the photo I posted, does the audio section of the amp work properly?

91h22a · 1st March 2011, 11:42 PM

no it does not. When I have signal into Left Front input signal is amplified at max on right front and seems to be minimal on left.

Perry Babin · 1st March 2011, 11:50 PM

Compare the audio signals on the muting transistors (J108s?) at the input to the power amplifier circuit for each of those channels. Is the signal reaching the right front channel significantly greater than the signal reaching the left front channel?

91h22a · 2nd March 2011, 12:22 AM

Ok so I did not even make it as far as the muting circuit. In the first image below here is what all of the inputs look like without signal...it measures -1.04dc with no signal.

The second image, was verified before connection, perfectly good sine wave at the input.

So what do you make of this?

Perry Babin · 2nd March 2011, 02:24 AM

What frequency is this. It appears to be ~20kHz.

91h22a · 3rd March 2011, 12:43 AM

It was taken at 10 kHz. I was working with 1 kHz but must've hit the 10..
so the signal is very weak at the muting transistor for the left channel (the channel I was inputting to) and distorted. The right muting transistor had the signal,while having no direct input, and was also very distorted.

Perry Babin · 3rd March 2011, 12:46 AM

Try 100hz. Set the crossovers flat.

1st March 2011, 04:26 PM	#1
91h22a diyAudio Member Join Date: Sep 2007	Xtant X604 Repair So I have a x604 Amplifier here and It amplifies Left and Right Rear channels just fine. Left Front Channel and Right Front channels are a different story. When I hook my function generator to Left front there is little amplification (gain set to min, DC 0.00v on all channels) out of the Left Front +- output terminals. But when I look at the Right Front +- output terminals-input still connected to Left Front- I have amplification of Left's input...It seems there is huge "crosstalk" (for lack of better word) between the channels. Is there anything common to this amp that might cause this? I appreciate any help/advice in advance.

1st March 2011, 11:38 PM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	If you set them as shown in the photo I posted, does the audio section of the amp work properly? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

1st March 2011, 11:50 PM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Compare the audio signals on the muting transistors (J108s?) at the input to the power amplifier circuit for each of those channels. Is the signal reaching the right front channel significantly greater than the signal reaching the left front channel? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

2nd March 2011, 02:24 AM	#8
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	What frequency is this. It appears to be ~20kHz. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

3rd March 2011, 12:46 AM	#10
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Try 100hz. Set the crossovers flat. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links


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1st March 2011, 11:42 PM	#5
91h22a diyAudio Member Join Date: Sep 2007	no it does not. When I have signal into Left Front input signal is amplified at max on right front and seems to be minimal on left.

3rd March 2011, 12:43 AM	#9
91h22a diyAudio Member Join Date: Sep 2007	It was taken at 10 kHz. I was working with 1 kHz but must've hit the 10.. so the signal is very weak at the muting transistor for the left channel (the channel I was inputting to) and distorted. The right muting transistor had the signal,while having no direct input, and was also very distorted.

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