SA-9500II noise

The Rebel

The Rebel

Active Member
Hi all Pioneer techs. I have an 9500II amp that has been giving me problems with popping through the speakers, and pulsing the woofers when turning the volume knob. Each click of the volume results in a pulsing woofer on my test speakers. When I first got this amp 13 years ago it had a bit of a hum to it, but I never noticed the speakers moving like I do now. What I've done so far is to remove the volume pot and spray NuTrol into all three sections of it, working it in by turning the knob back and forth. I've done the best I can cleaning all switches and controls. The pulsing and hum is worse when in the phono stages. It will also do it in the AUX stage, somewhat different, but still pulsates the woofers with a popping noise when turning the volume pot. Flipping most of the switches makes a pop through the speakers and causes the woofers to pulse in and out. Changing the input selector switch does it too. It also does this through the headphone jack. The low pass filter makes the thumps and speaker move less. Can someone point me to a thread on repairing this, or give me an idea where to start testing. I have a schematic, but haven't found a service manual yet. Thanks for any help.
 
The Rebel said:
Care to share a link for the 9500II manual? I've looked there several times with no success, all I find is the SA-9500 manual.
Click to expand...

I see satellite65 has posted another alternate source but it is also on hifiengine under the SA-9500. If you scroll down it will allow you to click on the MK II button and you will find both manuals.
 
Cuppy said:
I see satellite65 has posted another alternate source but it is also on hifiengine under the SA-9500. If you scroll down it will allow you to click on the MK II button and you will find both manuals.
Click to expand...
Thanks Cuppy. I did that the first time I looked there, and had forgotten about it. Turns out I already had it in my downloads. :rolleyes:

Ok, now to any suggestions on where to start?
 
Don't know if this video will help. This is most likely fairly common on these units. I haven't taken any of the switches or pots apart to clean them, this problem seems like something a little deeper than that to me.

 
The Rebel said:
Don't know if this video will help. This is most likely fairly common on these units. I haven't taken any of the switches or pots apart to clean them, this problem seems like something a little deeper than that to me.

Click to expand...

That does seem like similar symptoms to what you are describing. Unfortunately, I am not experienced enough to give advice as to where to begin. Hopefully, someone with more experience will chime in.
 
Cuppy said:
That does seem like similar symptoms to what you are describing. Unfortunately, I am not experienced enough to give advice as to where to begin. Hopefully, someone with more experience will chime in.
Click to expand...

That is my video. I want it to be clear enough to anyone, if my wording was cornfusing.... :)-
 
My first thought was for you to check the bias and the DC offset. Potential pulses of DC would have a similar effect.
 
i had simiar issues with the volume control and various switches on a SA-9900 (different but not too much). Recap of the Control Amp, AWG-045 in your case, made a significant differnce.
 
I've gotten to look at this amp again recently and have found that it is in the pre amp section. I get all the same clicks and pops when I use it as a pre amp. Can anyone point me in the right direction on this? I apologize for stringing this out, but life happens a lot around here, and I have way more amps and receivers that I listen to, and work on. This is a nice amp and well worth my effort to get him back in good shape. Thanks for any tips on where to start looking.
P.S. You can go to the video above and see exactly what it's doing, that's my amp in the video.
 
Mark, that is covered in my first post. Everything still makes the exact same clicks and sounds as before I did it.
 
Can you run the pre-amp output to another amp and confirm the popping stays with the pre-amp? If it is in the pre-amp, i would sugest re-cap the Switch and Control amp cards.
 
Jerry's TV said:
Can you run the pre-amp output to another amp and confirm the popping stays with the pre-amp? If it is in the pre-amp, i would sugest re-cap the Switch and Control amp cards.
Click to expand...
The Rebel said:
I've gotten to look at this amp again recently and have found that it is in the pre amp section. I get all the same clicks and pops when I use it as a pre amp.
Click to expand...

Yessir, that is precisely what the above post is contributing to this discussion. After unplugging the pre-out jumpers and connecting another stereo amplifier to the pre-out jacks, all of the same clicks and pops are still there, leading me to this conclusion.
Thanks for the suggestion on the switch and control amp boards. I'm still hoping someone that has had this exact same issue will chime in before I dive head first into something that can bite back. Thanks Jerry's TV.
 
It's been a few years, but the OP PM'ed me that he is still looking for a solution to the problem.
I'll reply here so that others can jump in...

I agree after watching the video that this is something other than dirty controls.
It appears to me that there is probably DC leakage into the signal path.
I would start by replacing cap's in the signal path on the AWG-045 Control Amp, particularly C15,16,25,26,33,34,41,42,49,50.
 
satellite65 said:
It's been a few years, but the OP PM'ed me that he is still looking for a solution to the problem.
I'll reply here so that others can jump in...

I agree after watching the video that this is something other than dirty controls.
It appears to me that there is probably DC leakage into the signal path.
I would start by replacing cap's in the signal path on the AWG-045 Control Amp, particularly C15,16,25,26,33,34,41,42,49,50.
Click to expand...
:)
 
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