I'm running a PDX-M12 and PDX-F6 in my truck, for about 12 years now and these are FANTASTIC amplifiers. Expensive, but such a good line of amps. And it's not some off the shelf Korean amp. These things are serious. Plus you can stack them which is an awesome option for mounting.
I have the same problem, I did it like you, only there is no Oscilloscope, I inserted a multimeter probe at the output of 43 volts and started to heat it with a hairdryer and it became 0 volts .which transistors did I install and replace in the end? how about marking 1D, 3D and KJD? Analog KJD did not understand it looks like BAW56? thanks
Alpine PDX amplifiers are a copy of UCD or Ncore self oscillator amplifiers, the sneaky thing is that discrete transistor circuit is the comparator stage, we analysed this circuit many years ago on diyaudio.
Just to throw you for a loop even more. So Some of the earlier Alpine Class D amps.. I think the four channel PDX amplifiers were designed in help from Ice Power. There were actually chips on the PCB that said Ice Power at one point. I dont know if they still help design the X series and newer amps (or the mono PDX amps like this), and just took their name off of the PCB and chips, or if Alpine does it themselves... but there was a connection at one point between Ice Power and Alpine. Either way. ice power, and hypex are both well respected class D amplifier designers and manufacturers. For being in the car audio space... these Alpine amps are really some of the nicest class D car amplifiers you can get your hands on. Some other ones I really like are the Audiotec Fischer class D amplifier/DSP combos (Helix V8, V12, Psix, etc) they are made with Texas Instruments class D chips and perform exceptionally. Rockford Fosgate and Kicker are also some notable names as well for good class D amps.... Nothing wrong with the cheap Korean/Chinese class D amps, especially for subwoofer duty... but I do personally prefer Alpine, or Helix amplifiers for car audio if I am going to use Class D.
@@CL-yp1bs I was looking at the Helix M4 and M6 dsp amps but was wondering about their sound quality. Its Helix, so I figure it must be pretty good SQ wise. Do you have any opinion on their design or sound quality?
@@davidfuller581 No, I won't say its an "exact Ncore/UcD or Clone for that matter" but it's very close! they did some work in the feedback loop in the modulator to stay clear from patent infringement,just so you know UcD patent (PHILIPS) expired 2023-05-08 see (US7113038B2) and Ncore (Hypex Electronics BV) still runs until 2030-02-17 see (US7113038B2).
Hello, I see that you have experience with alpine powers. I have a pdx v9 that a channel fails and goes into protection just by touching the channel one input with your hand have you had this problem can you guide me I'm from Argentina we don't have much information thank you very much in advance
@@sergiomazzini1322 hello, this isn't a common fault or issue that I could easily tell you to do this do that and it would be fixed. The amplifier will need to be inspected and diagnosed professionally with an oscilloscope etc.
Sometimes dodgy transistors react for heating, sometimes for cooling by liquid gas out of an upside down air duster can. So besides the hot air, you should keep such duster can or dedicated cooling spray at hand when troubleshooting or trying to pinpoint the faulty one.
@@barevids WHAAAAAAAAT? that blows my mind!!! Well, thank you so much for having done them, i personally really enjoyed the series and loved the way you broke it all down to science. Enjoy your weekend!!
Glad to see a video on the PDX line. Would this failure create DC voltage output on the speaker terminals? This model was known to smoke subs by injecting DC voltage. The only other known failure was a damaged ribbon cable. My reason for concern is that I have several F4s, M12 and M6 versions and would like to keep them running for as long as possible 😅
He didn't come out and say it, but does say that it's a full-bridge amp and that only half the output is working while the other half isn't outputting anything...so it's got the 43 V DC output failure. This is the only repair video anywhere addressing what the most likely root cause is and why it occurs.
