We all know that pops, clicks and crackles are all part of the vinyl experience. The sound of a worn record crackling softly as it revolves beneath the stylus can actually be quite pleasant, like the crackle of a fire on a cold summers evening. Noise can however detract from the listening experience, particularly if a record has significant wear or is to be digitised for archival purposes. Clicks, pops and crackles can mask detail and distract from the music, and there’s no doubting that a clean, quiet disc is always preferable to a noisy one. Removing vinyl noise in realtime is no easy task however, and to do so in a non destructive way has until now been nigh impossible. The SweetVinyl SugarCube aims to fill that gap.
The SugarCube isn’t the first device intended to de-crackle vinyl in realtime. Garrard’s MR101 Music Recovery Module was released in 1978 towards the end of the brand’s heyday in the consumer market. It was a magnetic phono preamplifier with a scratch reduction circuit designed to remove the noise associated with fairly significant scratches on LP records. It did so with some success, though it was a destructive process and is vastly inferior to even the most rudimentary digital solutions. The SAE 5000 Impulse Noise Reduction system was a digital device based around a 68K Motorola CPU and had an algorithm that analysed the signal for fast-attack, short-duration, out-of-phase signal elements. You can read a white paper on the system Here. Even Marantz later had a go in the mid 90s with the SX-72 scratch suppressor, though by then vinyl sales were reaching their all time low as the compact disc took over.
First impressions of the SC-1 are of a sleek, understated component with a minimalistic appearance, available in either a silver or black anodised chassis. A sparse front panel hosts buttons for Click Remove, Click Mon and Bypass, with a strength knob and status display. Around back are sturdy gold-plated RCA jacks for input and output, an RJ45 LAN connector and USB for the supplied wifi adapter. My only build quality gripe concerns the feet, the rubber protectors of which are o rings pressed into grooves in the foot. They can easily become dislodged and lost if the unit is relocated. I discovered quite by accident that 25 mm Sorbothane hemispheres are a perfect fit for the feet once the O rings are removed, providing a further level of isolation to the unit against external vibration.
The unit is powered externally by a 12V, 2A power brick for which there is an associated connection and power switch. There’s also a Pair button for pairing the SC-1 with the SugarCube app for iOS and Android. Pressing the Pair button displays a four digit pair code on screen which is entered into the app, a process that needs to be completed only once.
There’s a great deal more going on inside. The SC-1 incorporates 24-bit, 192kHz analogue to digital and digital to analogue converters. The SugarCube runs on the Debian 8 (Jessie) linux environment and runs a proprietary algorithm which, instead of identifying frequencies or bands of audio with problems as would a primitive noise reduction solution, looks for events in the time domain and removes them by interpolating the slope of the preceding audio.
Music has repeating patterns and musical sounds typically have an attack and decay while clicks and pops are isolated impulses that stand out in duration and strength. The SugarCube algorithm hunts for candidates to repair and applies a set of pre-defined rules to ensure no music is removed. Some sounds however, the click of a stick on a drum rim for example, can appear roughly symmetrical in attack and decay and thus be identified as a click or pop. The software rules are updated in such cases to avoid false detections. As with any noise reduction solution, the more complex the source material the greater the likelihood of the system detecting and falsely removing musical information. However the SugarCube algorithm operates similarly to how an engineer would manually remove noise from a recording, and thus achieves greater accuracy.
The SC-1 can be connected in various ways, and should be able to integrate into most systems. If you have an external phono stage, connect its output to the input of the SugarCube, and the output of the SugarCube to your amplifier. This method also applies to those using turntables with inbuilt RIAA preamplifiers. If your amplifier has a tape loop function, the SugarCube can be connected there. It should be noted that if this method is to be used, your amplifier’s tape loop function must be a true tape loop; that is to say, it must have the ability to play back its tape source while sending a second input to its recording jacks. Any amp or preamp with a ‘Tape Monitor’ switch or a ‘Record Out’ selector should satisfy this requirement, but not all amplifiers and preamplifiers with tape input and output pairs do. When in Bypass mode, the input to the SugarCube is shunted directly to the output via a relay. The bypass relay is in by default and will pass a signal even when the SugarCube is switched off.
When you switch the SugarCube on its display and bypass LED will light, and will remain static while it boots. The process of booting takes quite a while longer than expected. I connected to a wired LAN connection and was able to pair to the app with minimal effort, though the necessity for a pairing code is a minor inconvenience for those of us who can’t read the display owing to lacking or non-existent eyesight. Given that most apps can identify their respective hardware on a network automatically, so should the SugarCube be able to do the same. Automatic updates are applied when the SugarCube is left idle for a period of time, with an update status message displayed on screen. There doesn’t appear to be a way to manually trigger an update via the app or device itself, which would be a welcome addition.
The app is neatly presented and replicates the front panel controls of the unit. It is how most users will control the device, though it can also be controlled via a web browser once you’ve located the units IP address via the configuration page of your network router, or running the ping command in a windows command prompt or a unix terminal to ping the SugarCube hostname. I was pleased to note that on iOS at least, the app is fully compatible with Apple’s Voiceover assistive technology and was a pleasure to use.
The SugarCube is supplied with a calibration record. The 7” 33RPM disc contains a calibration test tone to set the units gain to prevent overloading the analogue to digital converters. Calibration is fully controlled via the app. I cleaned the calibration disc for best results, and ran it with my system to optimise the SugarCube as much as possible before testing.
I’ve been digitising records for many years and have tried a great many commercial software programs to clean up those recordings. Automated applications usually do a reasonable job on records with very light wear, but can’t handle heavily worn recordings. They also tend to remove unwanted musical information. The only software I have found to do a reasonable job, beyond prohibitively expensive professional solutions that are usually only semi-automated and not aimed toward the casual user, is Brian Davies’ ClickRepair. Manually removing clicks and pops can be a slow and laborious task, but it is by far the best way to achieve a professional transfer. At least, until now; so good is the SugarCube. In fact ‘good’ doesn’t do the SugarCube justice. This little device is simply remarkable.
I sadly don’t own any vinyl recordings that I can confirm are free from copyright. I would like to obtain something to use in future demonstrations; an obscure release perhaps, or something on an independent label who don’t mind me broadcasting their music for the purposes of demonstrating review products. For the time being however I can’t share samples of recorded music here. What I can do however is offer a couple of samples of the noise removed by the SugarCube, courtesy of the click monitor function. Click monitor allows you to hear just the noise removed by the SugarCube in real time, allowing you to adjust the strength knob to find the point at which maximum noise is removed without any music creeping into the signal. If you listen carefully you can hear the faintest trace of the music in the below recordings.
The first, a sample of Neil Sedaka’s ‘Laughter In The Rain’ from a thoroughly worn out compilation album of his entitled ‘Laughter and Tears (The Best of Neil Sedaka Today)’ Polydor 2383 399. This album lacked visible wear and had no groove distortion, but pops and crackles all the way through.
The second from a worn original pressing of Bat Out of Hell, covered in numerous scratches and marks. This one surprised me in that it didn’t crackle as much as I had expected, probably owing to a Microline stylus digging into untouched areas of the groove. Nevertheless, the two samples do demonstrate the SugarCube’s ability to effectively remove clicks and pops without affecting the music. In person both records sounded as if they were in mint condition, as did any record I played with the click remover engaged, even noisy modern LPs with pressing defects.
I tested the SugarCube with a wide range of genres from rock to classical, jazz to country and a few modern pop records too which are some of the noisiest, most dynamically compressed pressings I own. Only complex classical pieces presented any kind of challenge to the SugarCube algorithm, though a loss in dimensionality and texture, usually a minimal loss at that, was in most cases more than made up for by the lack of crackle. Despite its digital conversion, the SugarCube doesn’t make records sound ‘digital’. You need a very, very good system to hear any digital effects, and even then it takes an acute ear and a real desire to hear the difference. The only noticeable effect of the SugarCube in circuit is a slight delay between the needle talk coming from the record and the sound coming out of the speakers. The delay is half a second or so, and is only really noticeable when you lower the stylus onto the record as you don’t hear the usual ‘pop’ as the stylus catches the groove.
The SugarCube has a place in any mid to high end system, and makes playing back much loved but well worn vinyl a real joy. It also has a place in archival, where its algorithm can compete with the very best automated click repair solutions and produce professional quality digital transfers. There really are no downsides aside perhaps from premature wear of the playback stylus. As such having a second cartridge or stylus on hand to play heavily damaged discs is probably advisable. The SugarCube enhances the listening experience with vinyl old and new, and for that it earns a thoroughly deserved recommendation. Vinyl has never sounded so sweet.