S300 amp hiss/white noise from tweeter normal?


I’m new to the speaker world and my S300 is connected to a pair of Paradigm Persona B speakers (they’re rated 92db in sensitivity), and I can hear a very audible white noise coming from the S300 amp regardless of the volume of the Gain Cell Dac I’m using. I’m wondering

  1. Is this normal
  2. Would it do any long term damage to the tweeter if I leave the S300 amp on?

I also noticed that the SONOS amp would not produce any hiss/white noise.

I owned the S300 for several years. I’m not sure what volume level of hiss you are referring, but I had a constant RF type hiss to which I devoted a lot of time trying to eliminate without success. I could hear the hiss when music was not playing, and somewhat during quiet passages, but it was not noticeable when music was playing at volume.

I now have a Hegel H90 with the same speakers and cables. All is dead quiet. The hiss that was endemic to the S300 is gone. But I never found the S300 hiss to be so loud that I had concern for the health of my speakers. It was nothing like that. If you’re experiencing loud hiss, give PS Audio a call. They are super helpful.

That noise is mostly coming from either high frequency oscilation or switching diodes in the power supply. It is the exact reason I build my own power amps, in which I supplied VERY regulated power to the pre stages and only “power” power to the last stage. The reason you are able to hear it is that your tweeters are able to reproduce it, because they are simply just good enough. So… Been there, done that, solved it…

my S300 is dead quiet - maybe contact PSA about your unit

What is feeding the S300s?

Not normal at all. I’ve heard the S300 hooked up to a number of different speakers with efficiencies all across the board. If your ear is almost touching the tweeter, sure, you might hear some noise. But if you’re seated a few feet from the speakers you shouldn’t hear any noise. Does it get louder if you turn up the GDAC?

Just to be clear, I have to put my ear fairly close to the speaker tweeter to hear the hiss/white noise. But when I do, it’s really clear.

@Paul it’s connected with the Gain Cell Dac, and when the Gain Cell Dac is completely disconnected from the S300 (input XLR cables disconnected), the hiss is still there. When I turn up the volume of the Gain Cell Dac all the way up, the hiss will increase volume very slightly.

It’s within reason. Dead silence with your ear close to the tweeter is hard to achieve. No harm will be done to the tweeter. It getting a little louder with the GDAC turned up max is expected. You’re adding gain to any RF that is around the system and in the room.

That’s absolutely normal to have that level of hiss. Same with my system.

As mentioned, having owned the S300 with afore mentioned hiss, my current Hegel is dead silent in comparison. While it may be normal for the S300 to have the hiss, my experience with Hegel leads me to believe the hiss is a minor deficiency in the S300’s design.

Simple answer to your question. Hiss or noise coming from a 3.2 k$ amp set designed to deliver clear and noise free audio is not normal.

I have active studio monitors connected to my GAIN Cell DAC and have no hiss or noise issues.

I can not imagine that expensive audio equipment transfers diode switching noise to speakers is a standard.

If the above would be the case, take the effort to read reviews with Measurment results before you buy and decide for a brand/type that measures clean and certainly does not cause audible hiss or noise.

Return any unit that causes audible hiss or noise. Unless you power off a crappy generator set and live in an heavily radiated area and do all kind of funny wiring with ground loops on which the manufacturer can blame that malfunction.

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And I would emphatically disagree with Rudolph. It depends on the gain of the amplifier and the sensitivity of the speakers.

All equipment has hiss. It’s the combination of the aforementioned, coupled with distance from the tweeter.

In the case of PS Audio amps we run higher gain than many amplifiers. Our gain is 30dB (30X) and the typical amplifier gain is between 25dB and 27dB.


If I understand you correctly you can get audible hiss (unwanted in my case irritating noise) when the speakers mismatch the amp or visa versa.

I do not argue that and admit that is is another factor that can contribute to noise / hiss.

However it does not change the fact that I would return that amplifier which seems not to be capable to drive “every” speaker without problems, audible hiss in this case.

The reason I spend thousands of dollars on Audio equipment is to have natural (no distortion) and noise free sound. Ie. the silence in or between music shall be silent and not hiss.

Or buy new speakers that match the amp, in case you are thinking about new speakers too.

Audible hiss is unacceptable.

I’d say one more reason for buying active speakers.


Respectfully… Read my input again or better: read about it on the web. Find out for instance that pairing transistors is in way too many cases just a commercial thing. It took me over 750 MOSFET’s to get 32 perfectly matched ones. And I mean “perfectly” all the same. No manufacturer does that cause it is fetish crazy. That’s the beginning of the slippery slope… You would be surprised how many very friggin’ expensive amps draw the power for the first two or three stages directly from the main power supply which is NOT regulated. It has ripple on it like crazy, that is amplified up to 30dB. I had a couple of Pass amps that had several volts on the speaker outputs. Monday morning models I presume. Easy to fix if you know what to do. I can go on for pages…

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Hi Guys,

Not try to start a real debate here. Just want to make sure this hiss is normal and expected, and it’s not a dysfunctional product : )

If you guys are curious what it sounds like, I recorded a video with the iPhone 11 pro’s microphone facing directly to the tweeter. https://streamable.com/gcarhw

The noise is not perceptible by either me or the microphone until you’re 5/6 inches away from it.

Hi Ronald I don’t doubt for a moment and am actually convinced that the best combination of semiconductors proved me the best sound.

Abacus has replaced the passive diode rectifiers of the power supplies of their top tier active speakers by active controlled fast switching FETs to improve SQ,

Sure that causes certain measurable noise and avoiding those peaks will result in les destroyed sound. However if that distortion causes audible hiss, something is wrong. And maybe it is a mismatch between amp and speakers.

It’s very annoying to find out when you just unboxed your new amp or speaker you have been looking forward to.

Would be interested to see your amp project.

What have you done with your pair of BHK 300? still in one of your systems?

It is normal. It obviously wont affect the quality of the music being played.

Audible hiss is per definition poor sound quality as it is not part of the recording, silence is supposed to be silent not hiss.

Even though you might not hear it when music is playing, it is not gone, it is distortion that is added to the sound.

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You are right but that is not what this was all about. Noise and hiss and other sounds that you hear when you keep your ear to the tweeter and have nothing to do with distortion. Distortion occurs when you are actually generating sounds (other than earlier mentioned noises) like music or rock & roll…

And then again: if you have a highly sensitive speaker you are in trouble…! Same as a highly sensitive… Nah never mind… LOL

Goed weekend…!