APPJ mini 2013 RF issue


2010-01-13 3:09 am
Greetings to all. Absolute newb here, but IS able to desolder/solder as directed.

Problem: I intended to use the mini 2013 amp with a Denon TU-501 tuner as my MBR system. The first few minutes sound great, but when the amp warms up fully, stations above 99 become unlistenable. Below, all is fine. The kids over at AK, Tube forum, informed me that the power supply is to blame by virtue of its switching power supply generating RFI. I read a UK article that stated the RF enters the "mains" and will affect anything that shares the circuit. The Denon and the amp do just that (entire room is on one breaker, just two receptacles- hey, it's an old house!).

Question 1: can the internal switching power supply be modded to alleviate or reduce the RF?

Question 2: if modding is not feasible, can the internal power supply be bypassed and an external power supply be used?

Question 3: is there a device that "traps" RFI that could go between the outlet and either the amp OR tuner?

Question 4: Am I trying to turn a sows ear into a silk purse, metaphorically of course.

Thanks for looking and not laffing at me too hard!



2008-03-07 12:46 pm

Since the SMPS is inside the chassis, it is less likely for EMI at the power supply output being radiated into the air.

I would suspect insufficient filtering at the AC input. Which after looking at cheap ATX PSU from China is highly likely to happen. Got a power conditioner? And keep the power cord to it as short as possible.