The Perfect Affordable Phono Preamp for Turntable Lovers
The Music Hall Mini Plus Phono Preamp is a phono preamplifier for MM and high-output MC cartridges. It is a perfect solution for attaching a turntable to today’s audio equipment, and it is extremely affordable. It's packed with features, too.
The Mini Plus is a low-noise, high quality phono pre-amp designed to work with moving-magnet and high-output moving-coil cartridges. The chassis helps ward off the effects of stray magnetic fields and provides a safe quiet environment for the sensitive electronics it houses thus providing you with the best sound possible from your turntable.
Other features include a built-in high-quality headphone stage and a switchable rumble filter.
"Unique and Serious Sound Features"
Music Hall spent hundreds of hours listening to and developing this phono stage, resulting in what the company calls "a couple of unique and serious sound features."
The first of these features is the addition of cartridge load capacitance, which is a typically overlooked component of playing MM cartridges. This adjustment allows you to fine tune the preamp to more closely match the characteristics of your chosen MM cartridge.
The second unique features is the trim-gain control. This allows you to boost or reduce the output of the pre-amp to get an ideal match in volume between the output of your cartridge, the volume level of the record you’re playing, and your system’s characteristics. It is an outrageously useful control and makes a magnificent improvement to the overall sound from your turntable and record collection.
See below for more detailed info on these two features.
RIAA EQ
The Music Hall Mini Plus is a phonograph preamplifier with RIAA EQ. RIAA equalization is a specification for the recording and playback of phonograph records, established by the Recording Industry Association of America (RIAA). The RIAA equalization curve was intended to operate as the global industry standard for records since 1954. However, it is almost impossible to say when the change actually took place.
RIAA equalization is a form of pre-emphasis on recording and de-emphasis on playback. A recording is made with the low frequencies reduced and the high frequencies boosted, and on playback the opposite occurs. The net result is a flat frequency response, but with attenuation of high frequency noise such as hiss and clicks that arise from the recording medium. Reducing the low frequencies also limits the excursions the cutter needs to make when cutting a groove. Groove width is thus reduced, allowing more grooves to fit into a given surface area, permitting longer recording times. This also reduces physical stresses on the stylus which might otherwise cause distortion or groove damage during playback.
A potential drawback of the system is that rumble from the playback turntable's drive mechanism is amplified by the low frequency boost that occurs on playback. Players must therefore be designed to limit rumble, more so than if RIAA equalization did not occur. Using a rumble filter to filter out the subsonic frequencies may help mitigate the noise from the turntable, and there is one onboard the Mini Plus.
Rumble Filter
The rumble filter, AKA "subsonic filter," cuts very low frequencies (below 20 Hz). The purpose of a filter like this is to get rid of annoying frequencies that disrupt the turntable's sound quality. A good rumble/subsonic filter should be inaudible, meaning you cannot hear when it is on or off in the program material you are listening to. What it will do is help with excessive very low frequency interruptions from the turntable to the preamp.
Cartridge Load Capacitance
The Mini Plus has three settings: 120 pF, 220 pF and 330 pF. Set the switch in the position you feel sounds best to you. The difference might be very slight, but it is there. Most cartridges come with a capacitance load recommendation in the spec sheet for the cartridge. For example the Ortofon 2M series asks for a loading of 150pF to 300pF. Most Audio Technica cartridges state 100pF to 200pF for loading.
The Mini Plus has been tested with multiple turntables and multiple cartridges. We have found it best to use your ears to set the loading. You can set the loading switch to any setting 120, 220 or 330 with any MM cartridge and no damage will be done to the mini plus or your cartridge. If you cannot hear a difference we would suggest that you do as the cartridge manufacturer suggests, and set the loading switch closest to their recommendation for the cartridge you are using.
Output Trim Gain
The trim gain control will attenuate the signal level up or down. It is not a volume control, meaning that signal will still be present even when the level is turned to the lowest point (in this case -10dB as labeled). If at half way up you are at 0 dB output level then all the way up you will have +4dB more gain, and all the way down you will be at -10dB down from a reference of the middle 0 dB. Most users will be best served to set the control at the middle or 0 setting to get the best out- come.
This is not always the case. In some situations you might need more gain, like when playing a quiet record or lower output moving-magnet cartridge. In the opposite situation you might need less gain from a hot or loud record, or if you have a high output cartridge. Newer cartridges tend to have a higher output level than older cartridges. For instance, the popular Ortofon 2M series of cartridges have 5 - 6mV of output. This is much higher than cartridges of old (3 - 5mV). When using a 6mV output cartridge, you might need to turn the trim gain control to just below the half or 0 setting. Many factors go into setting the proper level. We recommend to start at the middle, 0 setting, and adjust from that point to your personal preference.
