Phono Stages Matter
Analog playback is critically impacted by your choice of phono stage, and a good design will give you the most from your cartridge and analog rig.
Gain, headroom, loading, noise and stereo/mono playback are all considerations for optimal analog playback. Consider the fact that a signal is being created by a stylus travelling the micro grooves of a vinyl LP, purely by mechanical energy and magnetics.
The signal from the cartridge is VERY small! While digital products typically output ~ 2Vrms to the preamp, a phono cartridge outputs a signal as high as .005Vrms to as small as .0002Vrms! This is a factor of 1/1000! So yeah, we need gain!
The first gain stage is the most important for any phono stage! It must produce A LOT of gain, AND adequate headroom to not limit dynamics. This is often done with either transformers or active circuitry. The PH 9.0 phono stage uses both. The MC input is transformer-coupled to a very high gain tube-jfet hybrid amplification stage. The MM input simply bypasses the step-up transformer with fixed 47K loading.
This first stage is the most critical in terms of noise. Remember that any noise present at this stage, is also amplified. Signal path length, grounding and every other induced or field generated noise must be minimized at this stage. This is what can make or break a great phono stage. We take great care in our phono designs because every detail counts
Following the first stage, there is 20dB of gain lost to the RIAA filter. In ModWright phono stages, this is done passively because we don’t believe in global negative feedback and this also preserves the delicacy of the signal. At this point, the PH 9.0/X/T and PH 150 use a 6922/6DJ8/7308 based high gain tube stage. The PH 150 handles this with inductive loading while the PH 9.0/X/T designs use SS plate loads.
The final stage in most phono preamps is a low impedance or buffered output stage. The PH 9.0/X/T and PH 150 designs use inductive coupling here. This design choice translates to low noise, great sonics and the balanced bass response that our analog products are known for.
This covers gain, headroom and noise. The other details that make a flexible phono stage include mono/stereo switching, loading and gain adjustment or attenuation.
The PH 9.0/X/T and PH 150 all have Stereo/Mono toggle switching, adjustable loading and gain adjustment (0, -6dB, -12dB), on-the-fly. This means that you can adjust any or all of these features while the music is playing.
Analog playback is special and will always be with us. By the very nature of how music is retrieved from the grooves of vinyl records, it’s clear that a very good phono stage is key to excellent sound. The ModWright PH 9.0/X/T and PH 150 tube phono stages navigate gain, headroom and noise gracefully, while providing on-the-fly mono/stereo switching, loading and gain adjustment. At ModWright, we take vinyl very seriously and know the value of good phono stage design.