Audio T Verdict
There are records we own because they're pristine, and records we own because they're irreplaceable. The Vinyl NRS Box S3 is designed very much with the second group in mind.
Placed after your phono stage, it uses real-time digital processing to tackle two different problems independently. De-Crackle detects short clicks and crackles and reduces their impact, while Pro-Ject's Vinyl Noise Reduction System targets the more continuous surface noise and turntable rumble that can make a well-loved pressing tiring to listen to.
Crucially, it doesn't force you into an all-or-nothing approach. De-Crackle sensitivity is adjustable, two processing intensities are provided, VNRS can be switched independently and both systems can be used together. And if the record simply doesn't need any help, switch the NRS Box off and its electronics disappear from the signal path completely through a galvanic bypass.
We wouldn't use it as an excuse to neglect proper record cleaning or turntable setup, and no electronic processor can physically repair a damaged groove. But for treasured records where clicks, surface noise or rumble are getting in the way of the music, the Vinyl NRS Box S3 is a genuinely unusual and useful piece of Hi-Fi equipment.
Pro-Ject Vinyl NRS Box S3
The Vinyl NRS Box S3 is a real-time vinyl noise-reduction processor designed to make worn, noisy and difficult records more enjoyable to listen to.
It combines two independent processing systems:
- De-Crackle for reducing transient clicks and crackles
- VNRS for reducing continuous vinyl surface noise and low-level turntable drive noise
The two functions can be used independently or together, allowing the amount of processing to be matched to the condition of the individual record.
Where Does the Vinyl NRS Box S3 Go?
The Vinyl NRS Box S3 operates at line level.
The correct signal path is:
- Turntable
- Phono preamplifier
- Vinyl NRS Box S3
- Integrated amplifier or preamplifier
- Power amplifier and loudspeakers where applicable
It Does Not Replace Your Phono Stage
The Vinyl NRS Box S3 must receive a line-level signal. A conventional turntable cartridge should therefore connect to a suitable phono preamplifier first. Do not place the NRS Box between a cartridge and an MM or MC phono stage.
Using a Turntable With a Built-In Phono Stage
A turntable with its own switchable or permanently active phono preamplifier can also be used, provided its output is set to line level.
That line-level output then connects to the Vinyl NRS Box S3 before continuing to a conventional amplifier line input.
24-Bit/96kHz Digital Signal Processing
Although the NRS Box has analogue RCA inputs and outputs, its noise-reduction functions operate in the digital domain.
When the processor is switched on:
- The incoming analogue line-level signal is converted to digital.
- Internal sampling operates at 24-bit/96kHz.
- The noise-reduction algorithms analyse and process the music.
- The processed signal is converted back to analogue.
- The analogue line-level signal leaves through the RCA outputs.
56-Bit Double-Precision Internal Processing
Pro-Ject specifies a 56-bit accumulator with double-precision processing for the internal DSP calculations.
This greater internal calculation depth is used while the algorithms manipulate the 24-bit/96kHz audio data.
Does the NRS Box Digitise My Vinyl?
Yes, but only while its electronic processing is active. This is how the De-Crackle and VNRS algorithms operate. Switch the unit off and the DSP is removed from the signal path completely through the galvanic bypass.
De-Crackle
The De-Crackle system is intended to reduce the audible impact of short clicks and crackling caused by a worn, damaged or contaminated record surface.
The algorithm analyses high-frequency components in the signal to identify the short transient peaks associated with crackles.
When a crackle is detected, the processor reduces its level rather than simply applying a continuous high-frequency filter to the entire recording.
Adjustable De-Crackle Sensitivity
The large rotary control on the front panel adjusts how sensitive the De-Crackle detection algorithm is.
Pro-Ject recommends beginning around the centre position and adjusting gradually until crackles are being reduced without producing an unwanted audible effect on the music.
The optimum setting can depend on:
- The condition of the record
- The music being played
- The cartridge
- The phono preamplifier
- The relative level of the clicks and musical signal
Crackle Detection LED
A red LED beside the De-Crackle control provides immediate feedback when the algorithm identifies and reduces a click or crackle.
This makes it easier to see when the processor is working while you fine-tune the sensitivity by ear.
Turn De-Crackle Fully Off
Turning the De-Crackle control fully anticlockwise switches the De-Crackle algorithm off.
This is useful if you have a record with little or no obvious clicking but still want to use the separate VNRS noise-reduction system.
Two De-Crackle Processing Intensities
The Vinyl NRS Box S3 provides two levels of De-Crackle processing.
Basic
The normal mode applies lighter processing and should be the first setting to try.
- Designed for lighter or occasional crackling
- Less intervention in the musical signal
- Published reduction up to 8dB
- Operating region specified from approximately 3kHz to 20kHz
Advanced / Intensity
Pressing the Intensity button engages the stronger algorithm.
- More aggressive crackle reduction
- Useful for more heavily worn records
- Published reduction up to 12dB
- Operating region specified from approximately 2kHz to 20kHz
Start With Basic Processing
More processing is not automatically better.
Pro-Ject recommends beginning with the basic De-Crackle mode and adjusting the sensitivity before engaging the stronger Intensity setting.
The advanced algorithm can be more effective on badly worn records, but because it processes the signal more heavily, the best setting should ultimately be chosen by listening.
Use Only as Much Processing as the Record Needs
A lightly marked LP may only need a modest De-Crackle setting, while a heavily worn second-hand pressing may benefit from the stronger Intensity mode. Adjust it record by record rather than leaving every control permanently at maximum.
Vinyl Noise Reduction System
VNRS stands for Vinyl Noise Reduction System.
While De-Crackle concentrates on short transient clicks, VNRS is designed to reduce the more continuous noise floor associated with vinyl playback.
This can include:
- Surface noise
- Background hiss
- Low-level turntable drive noise
- Rumble
How VNRS Works
For VNRS processing, Pro-Ject separates the signal into two frequency bands and feeds them into two expander stages.
The intention is to improve the effective signal-to-noise ratio while avoiding the obvious pumping or modulation effects associated with simpler noise-gate techniques.
Up to 8dB Noise Reduction
Pro-Ject specifies VNRS noise and rumble reduction of up to 8dB across 20Hz to 20kHz.
The amount of audible improvement will naturally depend on the record, turntable and level of the unwanted noise in the first place.
VNRS Is a Separate Function
VNRS is activated with its own front-panel button.
You can therefore use:
- De-Crackle by itself
- VNRS by itself
- De-Crackle and VNRS together
- Neither, using full galvanic bypass
VNRS Has One Processing Setting
Unlike De-Crackle, the VNRS algorithm does not have a continuously adjustable sensitivity control or separate basic and advanced modes.
It is simply switched on or off.
De-Crackle Versus VNRS
De-Crackle
- Targets clicks and crackles
- Transient processing
- Adjustable sensitivity
- Basic and advanced intensity
- Can be completely disabled with the rotary control
VNRS
- Targets continuous noise
- Surface-noise reduction
- Turntable-drive-noise reduction
- Two-band expander processing
- Single on/off processing preset
It Doesn't Physically Repair the Record
The Vinyl NRS Box S3 processes the audio produced while the record is playing.
It does not repair scratches, restore worn groove walls or recreate musical information which is no longer present on the record.
Its purpose is to reduce the distraction created by audible noise and transient damage so that the remaining musical information is easier to enjoy.
Record Cleaning Still Matters
A good record-cleaning routine should remain the first line of defence against clicks and surface noise.
Dust, debris and contamination that can be physically removed from a record are better dealt with at source rather than electronically processed afterwards.
The NRS Box becomes particularly useful when the noise remains even after the record and stylus are properly clean.
Input Level and Clipping
Because the Vinyl NRS Box S3 receives the output from a phono stage, different phono preamplifiers and cartridges can produce significantly different line-level signals.
Pro-Ject specifies a typical input level of approximately 300 to 500mVrms, with a maximum clipping level of approximately 1.55Vrms / 4.4Vpp.
Clip Warning LED
If the incoming signal approaches overload, a red clipping indicator warns you before actual clipping occurs.
The indicator operates approximately 0.6dB below real clipping.
What Should You Do if the Clip LED Flashes?
If your phono preamplifier has adjustable gain, Pro-Ject recommends reducing its output gain first.
If the phono stage cannot be adjusted, the NRS Box provides its own -6dB input attenuation.
-6dB Input Attenuation
Pressing the -6dB button reduces the signal level entering the processing electronics by 6dB.
This gives additional headroom for particularly high-output phono-stage and cartridge combinations.
-6dB Does Not Affect the Bypass Path
The -6dB attenuation operates only while the Vinyl NRS Box S3 electronics are active. If you engage -6dB and then switch the unit into galvanic bypass, the bypass signal will therefore be 6dB louder than the processed signal.
Pure Galvanic Bypass
One of the most useful features of the NRS Box is what happens when you switch it off.
The internal processing electronics are removed from the signal path and the RCA Line In is connected directly to the RCA Line Out.
Pro-Ject specifies the resistance of this galvanic link at less than 0.3 ohms.
Bypass Means No DSP
With the unit switched off:
- No analogue-to-digital conversion is taking place
- No digital processing is taking place
- No De-Crackle algorithm is active
- No VNRS processing is active
- No -6dB attenuation is active
- Input and output are directly linked
This makes it very easy to compare the processed and unprocessed record.
Approximately Three Seconds to Activate
When switching from bypass back into active processing, the electronics require approximately three seconds before the unit reaches normal operating mode.
One RCA Line Input
The rear panel provides one stereo pair of RCA Line In sockets.
Connect these to the line-level output of your phono preamplifier.
One RCA Line Output
A second stereo RCA pair carries the processed or bypassed signal to your amplifier or preamplifier.
Connect it to a normal line-level input such as:
Do Not Connect the Output to Another Phono Input
The Vinyl NRS Box S3 operates after the phono preamplifier. Its output is therefore line level and should feed a normal amplifier line input rather than a second MM or MC phono stage.
No Digital Output
The internal 24-bit/96kHz conversion is used solely for the NRS Box's processing.
The product does not provide a USB, optical, coaxial or other user-accessible digital audio output for recording or connection to a DAC.
The output presented to your Hi-Fi system remains analogue RCA.
Not a Vinyl-Ripping Device
The Vinyl NRS Box S3 does not record, store or create computer audio files from your records.
It processes playback in real time.
Frequency Response
Pro-Ject's current specification gives:
- 20Hz to 20kHz: -0.6dB / +0.1dB
- 30Hz to 20kHz: -0.2dB / +0.1dB
Low Processing Distortion
The current dedicated specification publishes total harmonic distortion below 0.009% at a 500mVrms input level.
The aim is for the processing to reduce the distracting noise without introducing obvious additional coloration into the remaining programme material.
When Should You Use the NRS Box?
It is most useful with records where the musical performance is still valuable but the condition of the pressing has become distracting.
Examples might include:
- Rare records which cannot easily be replaced
- Second-hand records with persistent surface noise
- Older favourite pressings with repeated clicks
- Records with light groove wear
- Pressings with significant background noise
- Turntable systems where low-level drive noise is troublesome
When Might You Leave It in Bypass?
For a clean, quiet pressing where there is little meaningful noise to reduce, simply switch the Vinyl NRS Box S3 off.
The galvanic bypass means the unit can remain permanently wired into the system without forcing every record through its DSP.
Useful for Large Second-Hand Collections
If a significant part of your record collection comes from second-hand shops, record fairs or inherited collections, record condition can vary enormously.
The ability to vary De-Crackle sensitivity from one LP to another is particularly useful in that situation because the amount of processing does not have to remain fixed.
Full Aluminium Housing
The circuitry is housed inside Pro-Ject's compact metal S-Line enclosure.
The full aluminium case provides mechanical protection and useful shielding around the sensitive analogue and digital electronics.
Compact 103mm Width
Despite its processing capability, the NRS Box occupies very little shelf space.
Current Pro-Ject dimensions are:
- Width: 103mm
- Height: 37mm
- Depth: 104mm
- Depth including sockets: 119mm
340g Without the Power Supply
The main unit weighs approximately 340g excluding its external power adaptor.
External 18V Power Supply
Power is supplied by an external 18V / 500mA DC adaptor.
Pro-Ject specifies approximately 2.2W consumption while operating, excluding losses within the external power supply.
With the unit switched off into galvanic bypass, the electronics themselves consume 0W.
Black or Silver
The Vinyl NRS Box S3 is available in:
How to Set It Up
- Connect your turntable to its normal phono preamplifier.
- Connect the phono preamplifier's line output to the NRS Box Line In.
- Connect the NRS Box Line Out to a normal amplifier line input.
- Play a record and switch the NRS Box on.
- Check that the clipping LED remains off.
- If it clips, reduce phono-stage gain or engage -6dB attenuation.
- Begin with De-Crackle in basic mode around the centre sensitivity position.
- Adjust sensitivity while listening.
- Engage Intensity only if stronger crackle reduction is required.
- Engage VNRS separately if continuous background noise is still distracting.
- Switch the NRS Box off whenever you want a direct bypass comparison.
Don't Set It Once and Forget It
Record condition varies enormously. A sensible setting for one heavily worn LP may be unnecessary for the next pristine pressing. The front-panel controls are there so you can use the lightest processing that achieves the result you want.
Key Features
- Pro-Ject Vinyl NRS Box S3
- Real-time vinyl noise reduction
- Line-level operation
- Fits after phono preamplifier
- 24-bit internal sampling
- 96kHz sampling rate
- 56-bit double-precision accumulator
- Adjustable De-Crackle
- Crackle-detection LED
- Basic De-Crackle mode
- Advanced Intensity mode
- Up to 8dB basic crackle reduction
- Up to 12dB advanced crackle reduction
- Independent VNRS processing
- Surface-noise reduction
- Turntable-drive-noise reduction
- Rumble reduction
- Up to 8dB VNRS reduction
- De-Crackle and VNRS can operate together
- -6dB input attenuation
- Clipping warning LED
- Clip indication 0.6dB below clipping
- Pure galvanic bypass
- Less than 0.3Ohm bypass resistance
- One stereo RCA input
- One stereo RCA output
- No digital audio output
- No recording function
- 20Hz - 20kHz frequency response
- Less than 0.009% published THD at 500mVrms
- Full aluminium enclosure
- 103mm compact chassis
- 18V / 500mA external supply
- 2.2W operating consumption
- Black finish
- Silver finish
Frequently Asked Questions
Is the Pro-Ject Vinyl NRS Box S3 current?
Yes. It remains part of Pro-Ject's current S Line and Hi-Fi electronics range.
What does NRS stand for?
Noise Reduction System. Pro-Ject calls the continuous-noise processing function VNRS, or Vinyl Noise Reduction System.
What does the Vinyl NRS Box S3 do?
It processes a line-level vinyl signal in real time to reduce clicks, crackles, surface noise and unwanted low-level turntable noise.
Is it a phono stage?
No. A phono preamplifier must come before it in the signal chain.
Where does it go in my system?
Between the output of your phono preamplifier and a normal line-level input on your integrated amplifier or preamplifier.
Can I connect my turntable straight into it?
Only if the turntable already provides a suitable line-level output from its own built-in phono stage. A normal cartridge-level output must go through a phono preamplifier first.
Can I put it before my phono stage?
No. The NRS Box is a line-level processor.
Can its output connect to a phono input?
No. Connect the output to a conventional AUX, CD, Line, Tuner or similar input.
Is the processing analogue?
No. When active, the signal is converted to digital for DSP processing and converted back to analogue afterwards.
What resolution does it use?
24-bit/96kHz internal sampling.
What internal processing precision does it use?
Pro-Ject specifies a 56-bit accumulator with double-precision processing.
Does it have a digital output?
No. The internal digital conversion is for processing only. The external input and output are analogue RCA.
Can it record my records to a computer?
No. There is no USB recording or digital-file creation function.
What is De-Crackle?
It is Pro-Ject's real-time algorithm for identifying and reducing short clicks and crackles.
Can I adjust De-Crackle?
Yes. The large front control changes detection sensitivity.
Where should I start with the De-Crackle control?
Pro-Ject recommends beginning around the centre position and adjusting by ear.
Can De-Crackle be turned off independently?
Yes. Turn the control fully anticlockwise.
What does the red LED beside De-Crackle do?
It flashes when clicks or crackles are detected and reduced.
What does the Intensity button do?
It switches De-Crackle from the lighter basic algorithm to the stronger advanced processing mode.
Which Intensity mode should I use?
Start with basic processing. Use the stronger mode when a more heavily worn record needs greater crackle reduction.
How much crackle reduction does Pro-Ject specify?
The current specification gives 8dB for basic processing and 12dB for the stronger Intensity mode.
What is VNRS?
Vinyl Noise Reduction System. It targets continuous surface noise and turntable drive or rumble noise rather than isolated clicks.
How does VNRS work?
The signal is separated into two frequency bands and processed using two expander stages to improve the effective signal-to-noise ratio.
How much noise reduction does VNRS provide?
Pro-Ject specifies up to 8dB across 20Hz to 20kHz.
Can VNRS be adjusted?
It has a single processing preset and is switched on or off rather than continuously adjusted.
Can I use VNRS without De-Crackle?
Yes. Turn the De-Crackle control fully off and engage VNRS.
Can I use De-Crackle without VNRS?
Yes.
Can both operate together?
Yes.
Does it remove every click?
No. Results depend on the record and chosen sensitivity. The system reduces the audible impact of suitable noise rather than physically repairing the groove.
Will it restore a badly damaged record?
It cannot replace groove information that has been physically destroyed. Its purpose is to make remaining clicks and noise less intrusive during playback.
Should I still clean my records?
Yes. Dirt and contamination that can be removed physically should still be dealt with through proper record and stylus care.
What does the -6dB button do?
It attenuates an excessively high line-level input by 6dB before processing to provide additional headroom.
How do I know if the signal is too high?
The red clipping LED warns when the input approaches overload.
When does the clip warning activate?
Pro-Ject specifies the warning approximately 0.6dB below actual clipping.
What is the normal input level?
Pro-Ject gives a typical input range of approximately 300 to 500mVrms.
What is the maximum input before clipping?
Approximately 1.55Vrms or 4.4V peak-to-peak under Pro-Ject's published specification.
Should I use -6dB if my phono stage has adjustable gain?
Pro-Ject recommends reducing phono-stage gain first where possible. Use the NRS Box -6dB control if the incoming level cannot otherwise be reduced sufficiently.
Does -6dB operate in bypass?
No. If -6dB is active while processing, switching to bypass makes the bypassed signal 6dB louder.
What happens when I switch the NRS Box off?
The processing electronics are removed from the signal path and the RCA input and output become galvanically connected.
Is the signal digitised in bypass?
No.
What is the bypass resistance?
Pro-Ject specifies less than 0.3 ohms for the galvanic link.
How quickly does processing start after switch-on?
Allow approximately three seconds for the electronics to become operational.
What is the frequency response?
Pro-Ject specifies -0.6dB / +0.1dB from 20Hz to 20kHz and -0.2dB / +0.1dB from 30Hz to 20kHz.
What is the published THD?
The current dedicated product specification gives less than 0.009% at a 500mVrms input level.
How many inputs does it have?
One stereo RCA line input.
How many outputs does it have?
One stereo RCA line output.
Does it have balanced XLR connections?
No. Input and output are conventional RCA.
Does it control volume?
No. It is not a preamplifier or volume controller.
Can I leave it permanently connected?
Yes. When no processing is required, switch it off and use its galvanic bypass.
Is it only useful for old records?
It is primarily intended for records where clicks, surface noise or drive noise are intrusive. Clean, quiet records can simply be played with the unit bypassed.
What is the case made from?
Pro-Ject specifies a full aluminium housing.
How large is it?
103mm wide, 37mm high and 104mm deep, extending to 119mm including the rear sockets.
How much does it weigh?
340g excluding the external power supply.
What power supply does it use?
An external 18V / 500mA DC supply.
What is the operating consumption?
Pro-Ject specifies approximately 2.2W while the electronics are active, excluding the external power supply.
What is the electronics consumption when switched off?
0W in the OFF / bypass state according to the current manufacturer specification.
What finishes are available?
Black and Silver.
Related Pro-Ject Products
Why Buy the Pro-Ject Vinyl NRS Box S3 From Audio T?
The Vinyl NRS Box S3 is unusual enough that hearing it in the right system is particularly worthwhile. The best De-Crackle setting varies with the record, cartridge and phono stage, while the input level also needs to be sensible if the processor is to operate without clipping.
Audio T can demonstrate how De-Crackle and VNRS work independently, help integrate the NRS Box at the correct point in your analogue system and show you how much processing is useful before it begins to become unnecessary.
- In-store demonstrations
- Correct signal-path setup
- Phono-stage compatibility guidance
- Input-level checks
- -6dB attenuation setup
- De-Crackle sensitivity demonstrations
- Basic versus advanced processing comparison
- VNRS demonstrations
- Galvanic bypass comparisons
- Turntable setup advice
- Record-cleaning guidance
- Cartridge and phono-stage matching
- RCA cable advice
- Ongoing after-sales support
Contact your local Audio T store to arrange a demonstration or discuss how the Pro-Ject Vinyl NRS Box S3 could fit into your existing vinyl system.