Silence of the Amps

I take an old class AB Amplifier with a 15 Gigawatt cooling fan and replace it with some quieter fans.

[@poldelepel]

Hey dak, Putting 2 same fans in series gives you more pressure, not more airflow. (Putting them in parallel would make it vice versa: more flow, same pressure). So 1 fan would have been probably enough. Putting only 1 fan in stead of 2 at the rear would also have lowered the noise with another 3dB. I would've only put 1 fan, because you don't really need the extra pressure... PS for next time: And for even more noise reduction you could have used even more quieter fans like noctua, be quiet, noiseblocker,...

[@K-Effect]

Has the amplifiers heat sink deformed any part of the plastic fan or zip ties when using the amplifier during a high powered session?

[@jameslewis974]

But the main reason im contacting you well trying to anyways is i have a kicker zx350.2 that has no output lights up fine doesn't pop fuses doesnt go into protect just nothing coming out of speaker outputs i took the board out no amokey smell no heat damage no visible signs of a resistor or diode frying or discolor on any of the transistors from over heating can you give eme some suggestions i dont have a oscilloscope but i have nice Dmm's and is it worth buying one of those small oscilloscopes the size of a Dmm for like 50= 100 bucks. Is it something you would be willing to take a look at? Please get back to me

[@Dakoustics]

I'm personally not an expert in amp repair, but here are some suggestions: 1. make sure the amp is getting signal, might sound dumb/obvious, but a clean break in the cable could mean no signal at certain angles. 2. Check for cold solder joints. Less likely for high current paths, though hairline cracks in certain areas could result in no output. Probe around with a continuity tester, see if anything is open circuit, or reflow suspicious joints. 3. carefully probe across the big capacitors in the amp, they should read a voltage of something like 40v DC when switched on. If there's nothing there, likely switching FETs or control IC for the fets. If there IS voltage there, the fault is somewhere in the signal path. This is tricky to diagnose without an Oscope. Could be input filters, step-up drivers, output transistors. Not really much I can offer you there. I'm in the process of improving my amp repair skills, hopefully some of this advice might help, good luck

[@jameslewis974]

@@Dakoustics thanks for the reply and suggestions. I know it had a good signal going into the amp because i hooked up my Infinity Kappa 202a and had zero issues or probs my first guess was ouput transistors. I was trying to get some feedback about if those lil Dmm sized o scopes are worth it they start off around 40 and go from there ive been looking for a good priced bench oscilloscopes with the full screen. But they either want twice what its worth or dont want to sell

[@jameslewis974]

@@Dakoustics i was checking all tHe legs on the transistors on both sides of the board and i found on 1 maybe 2. Transistors on the solder side that Instead of each of the 3. Legs bei g soldered to board in individjual solder beads that 1 all 3 legs ths solder pooled together so all 3 legs of that transistor are soldered together.and. i think 1 on opp side has that with 2 of the 3 legs.