I bought my 2 Pi speaker kit 16 years ago. No problems hooking them up to any amps over the years. Recently I have had trouble with them on SMSL amps only.
They put out what I'd call "digital static". Like what it sounds like when you feed digital coax cable into an RCA audio input. It happens to both speakers, and both speakers work fine with other amps. I have replaced the SMSL amps with other SMSL amps and the problem remains. The SMSL amps work fine with other speakers.
The static does not increase or decrease with the volume knob, and I can barely hear the source playing. It happens on all inputs regardless of whether there is a source playing.
Does anyone know what sort of problem would cause this problem between a specific amp type and a specific speaker type?
Pi Speakers are high-efficiency designs. Sometimes speakers like these will expose amplifier noise that isn't noticeable when using other speakers. This is more commonly expressed by tube amp owners than solid state, because some tube amps generate a little more low-level noise, usually power-supply hum. But some solid state amps do it too, and also some sources - regardless of amplification - and in those cases, it's usually hiss.
gofar99 Messages: 1857 Registered: May 2010 Location: Southern Arizona
Illuminati (5th Degree)
Hi, Most curious. SMSL is a good company. I use one of their DAC and it it great. I find it hard to imagine that they would have amps that put out noise like you indicate. I would contact SMSL and ask them about it. I imagine that the amps are digital switch mode ones, but normally the frequency is way above audio and well filtered. Is it possible that something else in the system is also digital and it is resulting in a mix/beat issue and creating a sum and difference signal that is being amplified. Possibly something as simple as a nearby light dimmer or perhaps a power filter or PC attached to the system. I mention these possibilities as I once had a small digital amp attached to a video monitor and it was getting the feed from the CATV. The cable company came to the house and said that something inside was causing wideband interference on some non TV channels. They hunted it down to the amp. Removed and the interference went away. Keep us posted on what you find so we can help others if it comes up again.