Hello everyone,
I am new to this forum and this is my first post. I did use the search function for my topic but had no luck, thus I decided to actively ask you guys for some advice.
As title says, I have a turn on/off pop using an Alpine PDX-M12 for my sub.
Some background: I am currently in the process of upgrading my car stereo. As part of this upgrade I have doubled my sub. So instead of using a single 10" Wavecor sub I am now using 2 of them in a CB, wired in parallel (they are 4 Ohms drivers). My previously used Alpine MRV-T757 (used to run in bridged mode to fire one Wavecor sub) was no longer sufficient to power 2 of them so I was looking for a more powerful amp. I ended up buying a PDX-M12 used.
After installing the M12 and connecting it to the newly built double sub I noticed a slight turn on/off pop which was not present in the previous setup. It is not very loud but audible and I would like to get rid of it, if possible.
I searched the net and came across some threads in other forums where people were reporting same symptons but no real solution or clear root cause. Others were reporting no issues whatsoever with these amps. Seems almost like a hit or miss situation with these amps.
So I am really wondering if something is broken in my amp that can be repaired or if this is maybe a design flaw of the PDX series which surfaces only in very particular setups or equipment combinations.
Thanks a lot for your support!
Holger
I am new to this forum and this is my first post. I did use the search function for my topic but had no luck, thus I decided to actively ask you guys for some advice.
As title says, I have a turn on/off pop using an Alpine PDX-M12 for my sub.
Some background: I am currently in the process of upgrading my car stereo. As part of this upgrade I have doubled my sub. So instead of using a single 10" Wavecor sub I am now using 2 of them in a CB, wired in parallel (they are 4 Ohms drivers). My previously used Alpine MRV-T757 (used to run in bridged mode to fire one Wavecor sub) was no longer sufficient to power 2 of them so I was looking for a more powerful amp. I ended up buying a PDX-M12 used.
After installing the M12 and connecting it to the newly built double sub I noticed a slight turn on/off pop which was not present in the previous setup. It is not very loud but audible and I would like to get rid of it, if possible.
I searched the net and came across some threads in other forums where people were reporting same symptons but no real solution or clear root cause. Others were reporting no issues whatsoever with these amps. Seems almost like a hit or miss situation with these amps.
So I am really wondering if something is broken in my amp that can be repaired or if this is maybe a design flaw of the PDX series which surfaces only in very particular setups or equipment combinations.
Thanks a lot for your support!
Holger
Does it pop with no RCAs plugged in?
What's the DC voltage across the speaker terminals with the amp on?
What's the DC voltage across the speaker terminals with the amp on?
Pop is also present with no RCA connected (but appears to be more pronounced with RCAs connected).
I measured the voltage across the speaker output. The amp is currently mounted in the trunk and that makes it diffucult to connect the probes directly to the output terminals (I don't reach them very well plus they are recessed in the chassis of the amp). Hence I measured at the end tips of the speaker connector which I had to unhook from the box. So the measurement was with amp on but no speaker connected. Hope this is not a problem...
The reading I got was 160mV DC.
I measured the voltage across the speaker output. The amp is currently mounted in the trunk and that makes it diffucult to connect the probes directly to the output terminals (I don't reach them very well plus they are recessed in the chassis of the amp). Hence I measured at the end tips of the speaker connector which I had to unhook from the box. So the measurement was with amp on but no speaker connected. Hope this is not a problem...
The reading I got was 160mV DC.
160mv is a bit high but I don't think it's worth risking going into the amplifier to try to 'repair' it. I don't know the M12 but a similar amp had no adjustments for DC offset. the offset was left to the random chance of the input offset voltage of the op-amps that were installed.