"Typical" noise of Sprout 100 phono preamp

Hi listeners,
I am loving the sound out of my new Sprout 100. When the source is bluetooth, digital, or analog, and I crank the volume to the max, the speaker output is dead silent. Wow!

However, when “vinyl” is selected:

  • With no input connected, it emits a loud hiss. Clean white noise, but it is there nonetheless.
  • With my Technics SL1200mk2 connected and grounded, it emits a pulsing/stuttering/beating sound

Now, with my old Onkyo and cheap TCC TC-750 preamp, I get the same “noise”. But with a Pro-Ject Phono Box preamp, it is dead silent. Impressive.

The noise is likely caused by my wifi base station which is a couple feet away from the unit, and a couple feet away from the turntable. It is audible, albeit softly, when the Sprout’s volume is way down… and very loud when the volume is maxed.

I have read the “steps to troubleshoot noise” in the manual, and I get it.

My question is, how has your RF shielding of your Sprout 100 been? Does it emit loud white noise when on max volume with no input on Vinyl? Do you get any RF noise when the turntable is plugged in?

I was surprised that the Pro-Ject box is dead silent while the Sprout is not.

I know that a solution is to move/relocate stuff but I’m looking for a baseline of expectations here. I am new to PS Audio and the Sprout.

Thanks for any insight. (I will try to post a recording of what I am talking about.)

1 Like

Thanks for posting here. First off, Sprout’s phono input must be connected to a cartridge in order to stay at its lowest noise (that hiss you’re referring to). This is normal behavior and to be expected for an analog high-gain phono stage.

The Pro-ject box likely auto mutes or has a shorting arrangement on the input where if you don’t have an input plugged in it shorts it out to keep the noise low. We didn’t do that because it’s unnecessary.

If it is really bothersome to you one can purchase RCA shorting plugs and put them into Sprout’s phono inputs.

Let us know how we can help.

1 Like

Thanks @Paul , I’ve learned a ton from your videos and appreciate the thoughtful response here. The Pro-ject box is dead silent with the input plugged in. Surprising… I’ll investigate if it mutes, and I will double check with a record spinning on the inner groove.

All right a new test, with the Pro-Ject Phono Box sitting between my turntable and the analog input of the Sprout. The Pro-Ject emits the same amount of noise.
So, in my previous trial, the lack of noise I observed in the external Pro-Ject preamp was likely due to different proximity. In the end, the Sprout’s preamp quietness is about the same.

Just sharing this while I continue to enjoy the Sprout!

1 Like