Phono Preamp FAQ!

What's a phono preamp and do I need one?

If you've ever listened to an analog LP, you've listened to it through some type of phonograph preamplifier! A phono preamp provides the necessary amplification for the tiny signals emanating from your phono cartridge so they’re at the same approximate level as other sources such as CD. It also implements a very special equalization curve developed by the Recording Industry Association of America (RIAA) so that all records play back correctly with universal compatibility on all turntables. If you take an ordinary turntable and try to plug it directly into a line or auxiliary input or sound card, you'll barely hear anything but a faint, scratchy whisper.

Don't most receivers have phono preamps built-in?

It depends; older models, yes. Newer A/V receivers sometimes don't and require an external phono preamp, which you then connect to an auxiliary line input. Even if your receiver has a built-in phono preamp, an external preamp will likely offer a significant improvement in sound.

Why vacuum tubes? Aren’t they costly and difficult to get?

A tube preamp will always be significantly more expensive and difficult to make than any solid-state preamp using transistors or IC op-amps, but many folks simply prefer their sound. Moreover, many listeners feel that low-level stages such as phono and microphone preamplifiers benefit the most from the uniquely clear, open, three-dimensional sound of a great tube-based design.

How much preamplifier gain do I need for my system? Is 34 dB enough?

The required phono gain of any audio system depends on many factors, chiefly among them the output of your cartridge and the sensitivity of your receiver or line stage and power amplifiers. For most moving-magnet (MM) and high-output moving coil (HOMC) cartridges with outputs greater than 2 mV, either of my preamps will work fine; but again, this also depends on line stage and power amp gain and how important it is to have identical volume control settings between sources such as phono and DAC. Personally, I like the Ortofon 2M Black cartridge with its high 5 mV output and this will drive my Model 1000 Mk. II (34 dB) or Model 2200 (40 dB) perfectly with only minor volume adjustments between sources. For lower outputs, such as the Sumiko Blue Point No. 3 high output moving coil cartridge at 2.5 mV output, the Model 2200 might suit many listeners’ systems better but the Model 1000 Mk. II would still work fine provided turning up the volume a little bit when switching to phono is acceptable. For low-output carts like the Ortofon MC Quintet Black S at 0.3 mV, an external stepup transformer such as the Ortofon ST-7 is mandatory with either preamp, as this gives equivalent preamplifier gains of 58 and 64 dB for the Model 1000 Mk. II and Model 2200, respectively.

Besides gain, would either of your preamplifiers be advantageous over the other for a given system?

Either preamplifier will drive any line input satisfactorily, but the Model 2200 has better output drive capability into loads as low as 5 kΩ owing to its use of Alan Kimmel’s amazing Hybrid Mu Stage gain blocks. Check the input impedance of your receiver, line stage, sound card, or ADC. The Model 1000 Mk. II will drive any load greater than 10 kΩ but is happiest above 25k.

I have one of those USB turntables that I connect straight to my computer. Do I need a phono preamp?

USB-type turntables have preamps and analog-to-digital converters built into them so you can just plug-and-play into a laptop or desktop computer. Some of them also have direct outputs from the cartridge and you will likely get better results with a high-quality outboard phono preamp.