Phono Preamplifier for moving magnet cartridges

Reference Series - Phono Preamplifier
Reference Quality RIAA Moving Magnet Cartridge Amplifier

Introducing the Reference Series Phono Preamplifier...

The phono preamplifier has been designed to offer a true reference quality sound experience, by this we mean a sound that is not only very enjoyable to listen to, but also technically accurate with an absolute minimum deviation from the recommended RIAA curve, together with very low distortion & noise ensures the best performance from any moving magnet or high output moving coil cartridge.

We have also included many useful features such as three position gain to ensure a perfect match, a six position front mounted capacitance loading switch for “on the fly” adjustments & a two position selectable resistance. We feel this is a worthy addition to our “Reference Series”.

Reference Quality Sound...

Sound quality is the single most important aspect & while products do vary in sound quality, some more than others, we believe a phono stage should never alter the sound by either adding or removing anything from the original signal. We have taken great care to ensure our phono preamplifier is as “transparent” as possible, the phono preamplifier essentially becomes invisible in your system with no inherent sound character of its own. The term "reference" in this case actually has meaning rather than being used just as a marketing term. This is something we regularly receive praise for from owners as it not only allows you to evaluate differences between cartridges, but lets you hear how the cartridge manufacturer intended their cartridge to be heard without the phono preamplifier introducing any colouration to the cartridge or indeed to the mastering process involved with the record itself.

Phono preamp for all moving magnet cartridges

Suits all Moving Magnet & High Output Moving Coil Cartridges...

Due to the different requirements between moving magnet (MM) & moving coil (MC), rather than designing a combined phono preamplifier capable of accepting both MM & MC cartridges, this would have meant compromises having to be made since MM & MC require a difference design when it comes to the phono stage. Instead we designed the phono preamplifier with moving magnet in mind, since high output MC cartridges have very similar requirements these will also work just as well with the phono preamplifier. We also make a matching MC Transformer that allows owners to use any low output moving coil cartridge with the phono preamplifier.

Three stage adjustable gain...

We have also included for extra convenience a three position gain switch, this can be used so that the correct amount of gain is used for optimum signal to noise ratio & is just another refinement making the phono preamplifier more of a pleasure to use.

Adjustable resistance...

The phono preamplifier also has adjustable resistance, two settings are available from the standard 47K to a higher 100K setting, these can be selected via the two position switch on the rear panel (all builds from March 2022). The higher setting is of benefit to many moving magnet cartridges & often allows for greater high frequency extension. This feature also has a benefit when used with our matching MC Transformer for low output moving coil cartridges allowing for an even greater choice of cartridge loading options rather than having a fixed 47K.

Six position capacitance cartridge loading...

The phono preamplifier is designed to give you complete control, therefore we have designed it with user selectable capacitance. This switch is conveniently placed on the front panel so you can adjust the cartridge loading live while playing music, this will ensure a correctly set up system in order to obtain optimum sound quality, six positions are available from 22pF to 330pF.

Soft start feature...

The phono preamplifier also includes soft start circuitry, this ensures that any turn on/off transients are completely eliminated, so when you switch on you will not hear any nasty pops or thumps, this is just one of many refinements we have included in the design of the phono preamplifier.

High overload margin preserves musical transients & prevents clipping...

During the design stage we also paid particular attention to the maximum input level capability of the phono preamplifier. Several popular cartridges were tested for output level & while the nominal output of most moving magnet cartridges vary between 3.5mV to 5.5mV (1kHz 5cm/sec), in reality music content contains peaks & transients which were measured at well over 50mV & in some cases 90mV.

If the amplification circuitry is not designed to handle such peaks then these transients will essentially become clipped, along with the occasional vinyl pop or click which can present even more of a problem. Despite these lasting no more than a fraction of a second, if the amplifier can not handle such levels then it will cause clipping of the signal which in turn causes unpleasant amplifier distortion. How much of an audible difference this makes would then all depend on how well the amplifier handles momentary clipping. At the very least this situation is not correct & is a condition that should never be allowed.

We have taken great care in the design of the amplification circuitry in order to avoid these potential issues. Many phono stages will quite often provide a maximum input of only 30-40mV, while a few may manage to cope with a little higher. However, with the phono preamplifier we have been able to provide an extremely high input level capability of 330mV (low gain), 194mV (medium gain) whilst still achieving a highly respectable 93mV (high gain). This ensures whichever cartridge you decide to use, whether it be a modest 3mV, a high output 5.5mV, or even a cartridge that is known for being very problematic when it comes to overloading a phono stage. You can be assured that the phono preamplifier will faithfully reproduce all music content accurately with clarity & detail, with no possibility of clipping or distorting the signal.

Quality components for performance & long term reliability...

Inside each reference phono preamplifier you will find some of the highest quality components, such as 1% polystyrene capacitors*, precision Vishay Dale resistors & Elna Silmic II capacitors, each are chosen for performance & long term reliability.

* For increased RIAA accuracy, multiple high quality polystyrene capacitors are used, while these are far more expensive than standard Polyester or Polypropylene often used, they ensure greater RIAA accuracy with no distortion in the signal path. While it may not be profitable for many manufactures to use such components, we have put so much work into not only the initial design of the phono preamplifier, but also with each & every one we build, therefore we see no point in using cheaper alternatives simply for the sake of saving a little extra on the cost of components.

More information can be found in our downloadable PDF

Technical Specifications...

Input Impedance: 47K & 100K (user selectable)
Input Capacitance: Six user selectable positions from 22pF to 330pF
Minimum Input Level*: 1.2mV (3.5mV to 5.0mV or higher recommended)

*Minimum input level quoted is to acheive 150mV output

Maximum Input Level: 330mV (low gain) / 194mV (med gain) / 93mV (high gain)

Maximum Output Level: (Input = 5mV) 150mV (low gain) / 300mV (med gain) / 620mV (high gain)

Frequency Response: 10Hz - 50kHz (-3dB @ 50kHz)
Total Harmonic Distortion: (BW=80kHz / unweighted) <0.002% (1kHz) / 0.002% (10kHz) / 0.003% (20kHz)
Stereo Crosstalk: (Corrected RIAA) -96dBu (1kHz) / -76dBu (10kHz) / -72dBu (20kHz)

RIAA Accuracy: 20Hz to 10kHz <0.05dB / 11kHz to 20kHz <0.1dB

Warranty: 3 Years from date of purchase
Dimensions/Weight: 210mm x 115mm x 70mm / 1.4Kg (inc transformer)

Items Supplied: Reference Phono Preamplifier, external mains transformer, instruction booklet, test results & receipt

* Test equipment professionally calibrated to meet national standards

Frequently Asked Questions...

Question: Does the phono preamp need any time from switch on to sound its best, like a running in time at all?

The design does not require any running in time, it will achieve measured performance a few seconds from switch on.

Question: I intend to buy a phono-amp mainly for listening but also for digitising a large collection of vinyl, I really don’t want any sonic signature being imprinted on every recording I do, would yours be suitable for this or if not then do you have any recommendations?

Absolutely, in fact over the years we have had owners use our phono preamplifier for this very task due to the way our preamplifier ensures your recordings are as "transparent" as possible, which as you rightly mentioned is important when digitising an entire collection. Some have also commented on the adjustable gain as being particularly useful for recording to avoid clipping their ADC. All of our products are designed to be as accurate & technically correct as we possible can (we always supply every product we build with individual test/performance graphs from professional test equipment which is also calibrated to meet national standards) so you can be confident the products will faithfully reproduce music without changing anything or introducing any problems. For example, our headphone amplifier allows you to hear headphones as they are intended to sound, after all if you pay good money for a headphone such as the Sennheiser HD800 with its widely known "spacial sound stage", I know most of our owners would certainly not want the headphone amplifier to change this in any way whatsoever & we agree.

It is exactly the same when it comes to the phono preamplifier, a cartridge manufacturer may produce a range of different cartridges, all with their own individual sound character as described by the manufacturer, but what would be the point to then have a phono stage stamp its sound character over every cartridge you use! Obviously any product can be made to sound different, especially phono stages since the RIAA filter is essentially an EQ which can be used in such a way in order to change the sound of a phono stage, while other coloration (distortion etc) can have an effect on the sound stage due to added harmonics that were simply not present on the cartridge or vinyl pressing to begin with, but this is mainly a by-product of valve amplifiers rather than modern day solid state. Of course it could even be intentional for a product to be made with any number of coloration’s in order to perhaps "stand out" in a group test or indeed a showroom demo. Our phono preamplifier has not been designed this way, none of our products are, the overall sound character, tonal quality, sound stage & so forth will all be determined by the choice of cartridge used & of course your speakers or headphones etc.. the preamplifier will not alter this in any way nor will it add or remove anything & is one of the reasons why people come to us since it avoids a lot of problems with matching.

Clearly that was the long reply!, the short answer would be yes, this will work perfectly for what you require :-)

Question: I keep reading about power supply upgrades with other makes, do you offer anything like this?

The linear power supply is located inside the main enclosure & has been designed to provide optimal performance, the external transformer is a high quality toroid made in this country, so the design as a whole does not require any aftermarket upgrades. We do not believe in supplying any of our products with inferior power supplies where you then have to purchase an "uprated" type in order for the product to perform as it should have done in the first place.

Pricing & Ordering Details...

Price: £549 + delivery

Delivery: £16.55 (Tracked/Insured)*

Build time: 12-14 days

Payment is by 10% deposit

Final payment upon completion.

Payments handled securely by "PayPal"

*Delivery is to UK Mainland only

To place an order please contact us at "sales@njc-audio.co.uk"

We will then be in touch with the secure payment link.