Sunfire Audio Players & Recorders - Recent Questions, Troubleshooting & Support

The HRS-10, HRS-8 and HRS-12 amplifiers are practically identical, and they share six small, weak electrolytic capacitors in the power supply board. They are located in pairs. The cheap, original capacitors dry out after several years, and cause the hum. Upgrading them to high quality (e.g., Panasonic) low-ESR capacitors will typically solve the hum, and will last longer than the originals used by Sunfire.

Sunfire Hrs10... | Answered on Jun 09, 2019

I think it will be most likely a semi-conductor device that is overheating. Probably the main amp device. Subs are basically mono amplifiers.

Sunfire True Sub... | Answered on Feb 15, 2018


Sunfire Mk2 hum repair tips

Take a look at my video to get an idea of how to open the Sunfire MK2 properly and also get an idea what sort of dangers live inside the box. There are several fixes that have worked for me in the past and one that is not working now.

on Feb 03, 2018 | Sunfire True Sub MK II Subwoofer

Your sub may have gone into protective shutdown to prevent failure as a result of "thurderous (sic) performance".

Sunfire True Sub... | Answered on Mar 18, 2017

The unit could have been getting bad power. A surge protector / power conditioner might help prevent another problem.

Sunfire SDS10... | Answered on Aug 12, 2016

Start with the volume way down on the sub.

Connect the line out of a source you know is working with cables you know work to the inputs of the sub. Try left and right.

This will let you know if the problem is in the sub or the output you're trying to use.

Sunfire True Sub... | Answered on Oct 05, 2015

If you remove the volume knob, and tighten the nut below, it should take care of the popping noise, as well as any input noise issues. Based on my experiences with my MKII

Sunfire True Sub... | Answered on Sep 15, 2015

It sounds like you are describing an earth loop problem. I won't go into detail in this post, but try an isolation test first. disconnect everything from the reciever except the sub and try connecting say a BATTERY powered mp3 player or cd player to minimise connections to the electrical mains earth. you could also isolate things by taking your sub to a friend's house and trying it on their system.
If it is an earth loop use a process of elimination to find out which two pieces of equipment causes the earth loop. then apply filtering.
you can buy earth loop isolation transformers for about AU$26 and I've used one on my sub myself. Theyhave RCA (phono)plugs on each end and they connect inline with the signal cable to the sub amp.

as for the thumping sound it might be the speaker protection circuitry cutting off the amp to protect the subwoofer speaker from damaged. This might be triggered if the earth loop sound is causing the sub amp to overload and clip.

Failing this there might be a dried out overheated electro capacitor in the amp circuit causing the hum. Hav a chat to your local electronics person, who should be able to spot it!
Hope this puts you on the right track
Happy Hunting!

Sunfire Audio... | Answered on Aug 19, 2015

I had the same problem as this, the fix was quite simple and the hum never came back.

If you pull straight out on the sub amp's volume knob it will slide off, then to fix the hum, tighten the nut that is behind the knob on the potentiometer and your hum should go away. My hum went away and never came back after this fix. Hope this helps you.

Sunfire True Sub... | Answered on Oct 14, 2014

Easy. Your home theatre amp will have a sub or LFE output ( RCA plug ). You simply connect this output to the input ( usually the left side, or use a Y splitter and use left and right inputs, or the LFE input if your sub has it ). Then, you must turn the sub on in your recievers setup menu, and your sub should work.

Sunfire True Sub... | Answered on Sep 23, 2014

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